Add libvorbis
16
LICENSE.md
|
@ -232,6 +232,22 @@ The [utf8proc](https://github.com/JuliaLang/utf8proc) library is released under
|
|||
>
|
||||
> Unicode and the Unicode logo are trademarks of Unicode, Inc., and may be registered in some jurisdictions. All other trademarks and registered trademarks mentioned herein are the property of their respective owners.
|
||||
|
||||
### `[vorbis]` libvorbis
|
||||
|
||||
libvorbis is released under the **3-clause BSD license**.
|
||||
|
||||
> Copyright (c) 2002-2018 Xiph.org Foundation
|
||||
>
|
||||
> Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
|
||||
>
|
||||
> - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
|
||||
>
|
||||
> - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
|
||||
>
|
||||
> - Neither the name of the Xiph.org Foundation nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
|
||||
>
|
||||
> THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
|
||||
### `[webrtc]` WebRTC
|
||||
|
||||
The [WebRTC](https://chromium.googlesource.com/external/webrtc) library is released under the **3-clause BSD License**.
|
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|
|
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@ -242,6 +242,36 @@ target_include_directories(ogg SYSTEM PUBLIC "lib/ogg-1.3.3/include")
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target_compile_options(ogg PRIVATE ${disableWarningsFlags})
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||||
set_target_properties(ogg PROPERTIES FOLDER lib)
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|
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# ... Vorbis
|
||||
add_library(vorbis
|
||||
lib/vorbis-1.3.6/include/vorbis/vorbisfile.h
|
||||
lib/vorbis-1.3.6/lib/bitrate.c
|
||||
lib/vorbis-1.3.6/lib/block.c
|
||||
lib/vorbis-1.3.6/lib/codebook.c
|
||||
lib/vorbis-1.3.6/lib/envelope.c
|
||||
lib/vorbis-1.3.6/lib/floor0.c
|
||||
lib/vorbis-1.3.6/lib/floor1.c
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||||
lib/vorbis-1.3.6/lib/info.c
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||||
lib/vorbis-1.3.6/lib/lpc.c
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||||
lib/vorbis-1.3.6/lib/lsp.c
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lib/vorbis-1.3.6/lib/mapping0.c
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lib/vorbis-1.3.6/lib/mdct.c
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lib/vorbis-1.3.6/lib/psy.c
|
||||
lib/vorbis-1.3.6/lib/registry.c
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lib/vorbis-1.3.6/lib/res0.c
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lib/vorbis-1.3.6/lib/sharedbook.c
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lib/vorbis-1.3.6/lib/smallft.c
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lib/vorbis-1.3.6/lib/synthesis.c
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lib/vorbis-1.3.6/lib/vorbisfile.c
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lib/vorbis-1.3.6/lib/window.c
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)
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target_include_directories(vorbis SYSTEM PUBLIC "lib/vorbis-1.3.6/include")
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target_link_libraries(vorbis
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ogg
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)
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target_compile_options(vorbis PRIVATE ${disableWarningsFlags})
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set_target_properties(vorbis PROPERTIES FOLDER lib)
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# Define Rhubarb libraries
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include_directories("src")
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@ -0,0 +1,40 @@
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*.o
|
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*.lo
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*.la
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||||
.libs
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||||
.deps
|
||||
aclocal.m4
|
||||
configure
|
||||
Makefile
|
||||
Makefile.in
|
||||
autom4te.cache
|
||||
compile
|
||||
config.guess
|
||||
config.h
|
||||
config.h.in
|
||||
config.h.in~
|
||||
config.log
|
||||
config.status
|
||||
config.sub
|
||||
depcomp
|
||||
install-sh
|
||||
libtool
|
||||
ltmain.sh
|
||||
missing
|
||||
stamp-h1
|
||||
m4/libtool.m4
|
||||
m4/ltoptions.m4
|
||||
m4/ltsugar.m4
|
||||
m4/ltversion.m4
|
||||
m4/lt~obsolete.m4
|
||||
libvorbis.spec
|
||||
vorbis-uninstalled.pc
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||||
vorbis.pc
|
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vorbisenc-uninstalled.pc
|
||||
vorbisenc.pc
|
||||
vorbisfile-uninstalled.pc
|
||||
vorbisfile.pc
|
||||
doc/Doxyfile
|
||||
doc/doxygen-build.stamp
|
||||
lib/test_sharedbook
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test/test
|
|
@ -0,0 +1,24 @@
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language: c
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compiler:
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- gcc
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- clang
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env:
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- BUILD_SYSTEM=AUTOTOOLS
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- BUILD_SYSTEM=CMAKE
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addons:
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apt:
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packages:
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- libogg-dev
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script:
|
||||
- if [[ "$BUILD_SYSTEM" == "AUTOTOOLS" ]] ; then ./autogen.sh ; fi
|
||||
- if [[ "$BUILD_SYSTEM" == "AUTOTOOLS" ]] ; then ./configure ; fi
|
||||
- if [[ "$BUILD_SYSTEM" == "AUTOTOOLS" ]] ; then make -j2 V=1 distcheck ; fi
|
||||
- if [[ "$BUILD_SYSTEM" == "CMAKE" ]] ; then mkdir build ; fi
|
||||
- if [[ "$BUILD_SYSTEM" == "CMAKE" ]] ; then pushd build ; fi
|
||||
- if [[ "$BUILD_SYSTEM" == "CMAKE" ]] ; then cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release .. ; fi
|
||||
- if [[ "$BUILD_SYSTEM" == "CMAKE" ]] ; then cmake --build . ; fi
|
||||
- if [[ "$BUILD_SYSTEM" == "CMAKE" ]] ; then popd ; fi
|
|
@ -0,0 +1,8 @@
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|||
def FlagsForFile(filename, **kwargs):
|
||||
return {
|
||||
'flags': [
|
||||
'-x', 'c',
|
||||
'-g', '-Wall', '-Wextra',
|
||||
'-D_REENTRANT', '-D__NO_MATH_INLINES', '-fsigned-char'
|
||||
],
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||||
}
|
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@ -0,0 +1,3 @@
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Monty <monty@xiph.org>
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and the rest of the Xiph.org Foundation.
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@ -0,0 +1,165 @@
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libvorbis 1.3.6 (2018-03-16) -- "Xiph.Org libVorbis I 20180316 (Now 100% fewer shells)"
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* Fix CVE-2018-5146 - out-of-bounds write on codebook decoding.
|
||||
* Fix CVE-2017-14632 - free() on unitialized data
|
||||
* Fix CVE-2017-14633 - out-of-bounds read
|
||||
* Fix bitrate metadata parsing.
|
||||
* Fix out-of-bounds read in codebook parsing.
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||||
* Fix residue vector size in Vorbis I spec.
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||||
* Appveyor support
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||||
* Travis CI support
|
||||
* Add secondary CMake build system.
|
||||
* Build system fixes
|
||||
|
||||
libvorbis 1.3.5 (2015-03-03) -- "Xiph.Org libVorbis I 20150105 (⛄⛄⛄⛄)"
|
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* Tolerate single-entry codebooks.
|
||||
* Fix decoder crash with invalid input.
|
||||
* Fix encoder crash with non-positive sample rates.
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||||
# Fix issues in vorbisfile's seek bisection code.
|
||||
* Spec errata.
|
||||
* Reject multiple headers of the same type.
|
||||
* Various build fixes and code cleanup.
|
||||
|
||||
libvorbis 1.3.4 (2014-01-22) -- "Xiph.Org libVorbis I 20140122 (Turpakäräjiin)"
|
||||
|
||||
* Reduce codebook footprint in library code.
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||||
* Various build and documentation fixes.
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||||
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||||
libvorbis 1.3.3 (2012-02-03) -- "Xiph.Org libVorbis I 20120203 (Omnipresent)"
|
||||
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||||
* vorbis: additional proofing against invalid/malicious
|
||||
streams in decode (see SVN for details).
|
||||
* vorbis: fix a memory leak in vorbis_commentheader_out().
|
||||
* updates, corrections and clarifications in the Vorbis I specification
|
||||
document
|
||||
* win32: fixed project configuration which referenced two CRT versions
|
||||
in output binaries.
|
||||
* build warning fixes
|
||||
|
||||
libvorbis 1.3.2 (2010-11-01) -- "Xiph.Org libVorbis I 20101101 (Schaufenugget)"
|
||||
|
||||
* vorbis: additional proofing against invalid/malicious
|
||||
streams in floor, residue, and bos/eos packet trimming
|
||||
code (see SVN for details).
|
||||
* vorbis: Added programming documentation tree for the
|
||||
low-level calls
|
||||
* vorbisfile: Correct handling of serial numbers array
|
||||
element [0] on non-seekable streams
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||||
* vorbisenc: Back out an [old] AoTuV HF weighting that was
|
||||
first enabled in 1.3.0; there are a few samples where I
|
||||
really don't like the effect it causes.
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||||
* vorbis: return correct timestamp for granule positions
|
||||
with high bit set.
|
||||
* vorbisfile: the [undocumented] half-rate decode api made no
|
||||
attempt to keep the pcm offset tracking consistent in seeks.
|
||||
Fix and add a testing mode to seeking_example.c to torture
|
||||
test seeking in halfrate mode. Also remove requirement that
|
||||
halfrate mode only work with seekable files.
|
||||
* vorbisfile: Fix a chaining bug in raw_seeks where seeking
|
||||
out of the current link would fail due to not
|
||||
reinitializing the decode machinery.
|
||||
* vorbisfile: improve seeking strategy. Reduces the
|
||||
necessary number of seek callbacks in an open or seek
|
||||
operation by well over 2/3.
|
||||
|
||||
libvorbis 1.3.1 (2010-02-26) -- "Xiph.Org libVorbis I 20100325 (Everywhere)"
|
||||
|
||||
* tweak + minor arithmetic fix in floor1 fit
|
||||
* revert noise norm to conservative 1.2.3 behavior pending
|
||||
more listening testing
|
||||
|
||||
libvorbis 1.3.0 (2010-02-25) -- unreleased staging snapshot
|
||||
|
||||
* Optimized surround support for 5.1 encoding at 44.1/48kHz
|
||||
* Added encoder control call to disable channel coupling
|
||||
* Correct an overflow bug in very low-bitrate encoding on 32 bit
|
||||
machines that caused inflated bitrates
|
||||
* Numerous API hardening, leak and build fixes
|
||||
* Correct bug in 22kHz compand setup that could cause a crash
|
||||
* Correct bug in 16kHz codebooks that could cause unstable pure
|
||||
tones at high bitrates
|
||||
|
||||
libvorbis 1.2.3 (2009-07-09) -- "Xiph.Org libVorbis I 20090709"
|
||||
|
||||
* correct a vorbisfile bug that prevented proper playback of
|
||||
Vorbis files where all audio in a logical stream is in a
|
||||
single page
|
||||
* Additional decode setup hardening against malicious streams
|
||||
* Add 'OV_EXCLUDE_STATIC_CALLBACKS' define for developers who
|
||||
wish to avoid unused symbol warnings from the static callbacks
|
||||
defined in vorbisfile.h
|
||||
|
||||
libvorbis 1.2.2 (2009-06-24) -- "Xiph.Org libVorbis I 20090624"
|
||||
|
||||
* define VENDOR and ENCODER strings
|
||||
* seek correctly in files bigger than 2 GB (Windows)
|
||||
* fix regression from CVE-2008-1420; 1.0b1 files work again
|
||||
* mark all tables as constant to reduce memory occupation
|
||||
* additional decoder hardening against malicious streams
|
||||
* substantially reduce amount of seeking performed by Vorbisfile
|
||||
* Multichannel decode bugfix
|
||||
* build system updates
|
||||
* minor specification clarifications/fixes
|
||||
|
||||
libvorbis 1.2.1 (unreleased) -- "Xiph.Org libVorbis I 20080501"
|
||||
|
||||
* Improved robustness with corrupt streams.
|
||||
* New ov_read_filter() vorbisfile call allows filtering decoded
|
||||
audio as floats before converting to integer samples.
|
||||
* Fix an encoder bug with multichannel streams.
|
||||
* Replaced RTP payload format draft with RFC 5215.
|
||||
* Bare bones self test under 'make check'.
|
||||
* Fix a problem encoding some streams between 14 and 28 kHz.
|
||||
* Fix a numerical instability in the edge extrapolation filter.
|
||||
* Build system improvements.
|
||||
* Specification correction.
|
||||
|
||||
libvorbis 1.2.0 (2007-07-25) -- "Xiph.Org libVorbis I 20070622"
|
||||
|
||||
* new ov_fopen() convenience call that avoids the common
|
||||
stdio conflicts with ov_open() and MSVC runtimes.
|
||||
* libvorbisfile now handles multiplexed streams
|
||||
* improve robustness to corrupt input streams
|
||||
* fix a minor encoder bug
|
||||
* updated RTP draft
|
||||
* build system updates
|
||||
* minor corrections to the specification
|
||||
|
||||
libvorbis 1.1.2 (2005-11-27) -- "Xiph.Org libVorbis I 20050304"
|
||||
|
||||
* fix a serious encoder bug with gcc 4 optimized builds
|
||||
* documentation and spec fixes
|
||||
* updated VS2003 and XCode builds
|
||||
* new draft RTP encapsulation spec
|
||||
|
||||
libvorbis 1.1.1 (2005-06-27) -- "Xiph.Org libVorbis I 20050304"
|
||||
|
||||
* bug fix to the bitrate management encoder interface
|
||||
* bug fix to properly set packetno field in the encoder
|
||||
* new draft RTP encapsulation spec
|
||||
* library API documentation improvements
|
||||
|
||||
libvorbis 1.1.0 (2004-09-22) -- "Xiph.Org libVorbis I 20040629"
|
||||
|
||||
* merges tuning improvements from Aoyumi's aoTuV with fixups
|
||||
* new managed bitrate (CBR) mode support
|
||||
* new vorbis_encoder_ctl() interface
|
||||
* extensive documentation updates
|
||||
* application/ogg mimetype is now official
|
||||
* autotools cleanup from Thomas Vander Stichele
|
||||
* SymbianOS build support from Colin Ward at CSIRO
|
||||
* various bugfixes
|
||||
* various packaging improvements
|
||||
|
||||
libvorbis 1.0.1 (2003-11-17) -- "Xiph.Org libVorbis I 20030909"
|
||||
|
||||
* numerous bug fixes
|
||||
* specification corrections
|
||||
* new crosslap and halfrate APIs for game use
|
||||
* packaging and build updates
|
||||
|
||||
libvorbis 1.0.0 (2002-07-19) -- "Xiph.Org libVorbis I 20020717"
|
||||
|
||||
* first stable release
|
||||
|
|
@ -0,0 +1,81 @@
|
|||
cmake_minimum_required(VERSION 2.8.7)
|
||||
project(vorbis)
|
||||
|
||||
# Required modules
|
||||
include(GNUInstallDirs)
|
||||
include(CheckIncludeFiles)
|
||||
|
||||
# Build options
|
||||
option(BUILD_SHARED_LIBS "Build shared library" OFF)
|
||||
if(APPLE)
|
||||
option(BUILD_FRAMEWORK "Build Framework bundle for OSX" OFF)
|
||||
endif()
|
||||
|
||||
if(BUILD_FRAMEWORK)
|
||||
set(BUILD_SHARED_LIBS TRUE)
|
||||
endif()
|
||||
|
||||
# Extract project version from configure.ac
|
||||
file(READ configure.ac CONFIGURE_AC_CONTENTS)
|
||||
string(REGEX MATCH "AC_INIT\\(\\[libvorbis\\],\\[([0-9]*).([0-9]*).([0-9]*)" DUMMY ${CONFIGURE_AC_CONTENTS})
|
||||
set(PROJECT_VERSION_MAJOR ${CMAKE_MATCH_1})
|
||||
set(PROJECT_VERSION_MINOR ${CMAKE_MATCH_2})
|
||||
set(PROJECT_VERSION_PATCH ${CMAKE_MATCH_3})
|
||||
set(PROJECT_VERSION ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}.${PROJECT_VERSION_PATCH})
|
||||
|
||||
# Helper function to get version-info
|
||||
function(get_version_info result current_var_name age_var_name revision_var_name)
|
||||
string(REGEX MATCH "${current_var_name}=([0-9]*)" DUMMY ${CONFIGURE_AC_CONTENTS})
|
||||
set(VERSION_INFO_CURRENT ${CMAKE_MATCH_1})
|
||||
|
||||
string(REGEX MATCH "${age_var_name}=([0-9]*)" DUMMY ${CONFIGURE_AC_CONTENTS})
|
||||
set(VERSION_INFO_AGE ${CMAKE_MATCH_1})
|
||||
|
||||
string(REGEX MATCH "${revision_var_name}=([0-9]*)" DUMMY ${CONFIGURE_AC_CONTENTS})
|
||||
set(VERSION_INFO_REVISION ${CMAKE_MATCH_1})
|
||||
|
||||
math(EXPR VERSION_INFO_CURRENT_MINUS_AGE "${VERSION_INFO_CURRENT} - ${VERSION_INFO_AGE}")
|
||||
|
||||
set(${result} "${VERSION_INFO_CURRENT_MINUS_AGE}.${VERSION_INFO_AGE}.${VERSION_INFO_REVISION}" PARENT_SCOPE)
|
||||
endfunction()
|
||||
|
||||
# Helper function to configure pkg-config files
|
||||
function(configure_pkg_config_file pkg_config_file_in)
|
||||
set(prefix ${CMAKE_INSTALL_PREFIX})
|
||||
set(exec_prefix ${CMAKE_INSTALL_FULL_BINDIR})
|
||||
set(libdir ${CMAKE_INSTALL_FULL_LIBDIR})
|
||||
set(includedir ${CMAKE_INSTALL_FULL_INCLUDEDIR})
|
||||
set(VERSION ${PROJECT_VERSION})
|
||||
string(REPLACE ".in" "" pkg_config_file ${pkg_config_file_in})
|
||||
configure_file(${pkg_config_file_in} ${pkg_config_file} @ONLY)
|
||||
endfunction()
|
||||
|
||||
message(STATUS "Configuring ${PROJECT_NAME} ${PROJECT_VERSION}")
|
||||
|
||||
# Find ogg dependency
|
||||
if(NOT OGG_ROOT)
|
||||
find_package(PkgConfig QUIET)
|
||||
pkg_check_modules(PC_OGG QUIET ogg)
|
||||
find_path(OGG_INCLUDE_DIRS NAMES ogg/ogg.h HINTS ${PC_OGG_INCLUDE_DIRS} PATH_SUFFIXES ogg)
|
||||
find_library(OGG_LIBRARIES NAMES ogg HINTS ${PC_OGG_LIBRARY_DIRS})
|
||||
else()
|
||||
find_path(OGG_INCLUDE_DIRS NAMES ogg/ogg.h HINTS ${OGG_ROOT}/include PATH_SUFFIXES ogg)
|
||||
find_library(OGG_LIBRARIES NAMES ogg HINTS ${OGG_ROOT}/lib ${OGG_ROOT}/lib64)
|
||||
endif()
|
||||
include(FindPackageHandleStandardArgs)
|
||||
find_package_handle_standard_args(OGG DEFAULT_MSG OGG_INCLUDE_DIRS OGG_LIBRARIES)
|
||||
|
||||
add_subdirectory(lib)
|
||||
|
||||
configure_pkg_config_file(vorbis.pc.in)
|
||||
configure_pkg_config_file(vorbisenc.pc.in)
|
||||
configure_pkg_config_file(vorbisfile.pc.in)
|
||||
|
||||
install(
|
||||
FILES
|
||||
${CMAKE_CURRENT_BINARY_DIR}/vorbis.pc
|
||||
${CMAKE_CURRENT_BINARY_DIR}/vorbisenc.pc
|
||||
${CMAKE_CURRENT_BINARY_DIR}/vorbisfile.pc
|
||||
DESTINATION
|
||||
${CMAKE_INSTALL_LIBDIR}/pkgconfig
|
||||
)
|
|
@ -0,0 +1,28 @@
|
|||
Copyright (c) 2002-2018 Xiph.org Foundation
|
||||
|
||||
Redistribution and use in source and binary forms, with or without
|
||||
modification, are permitted provided that the following conditions
|
||||
are met:
|
||||
|
||||
- Redistributions of source code must retain the above copyright
|
||||
notice, this list of conditions and the following disclaimer.
|
||||
|
||||
- Redistributions in binary form must reproduce the above copyright
|
||||
notice, this list of conditions and the following disclaimer in the
|
||||
documentation and/or other materials provided with the distribution.
|
||||
|
||||
- Neither the name of the Xiph.org Foundation nor the names of its
|
||||
contributors may be used to endorse or promote products derived from
|
||||
this software without specific prior written permission.
|
||||
|
||||
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||||
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION
|
||||
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||||
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
||||
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
@ -0,0 +1,47 @@
|
|||
## Process this file with automake to produce Makefile.in
|
||||
|
||||
AUTOMAKE_OPTIONS = foreign 1.11 dist-zip dist-xz
|
||||
|
||||
ACLOCAL_AMFLAGS = -I m4
|
||||
|
||||
SUBDIRS = m4 include vq lib test doc
|
||||
|
||||
if BUILD_EXAMPLES
|
||||
SUBDIRS += examples
|
||||
endif
|
||||
|
||||
m4datadir = $(datadir)/aclocal
|
||||
m4data_DATA = vorbis.m4
|
||||
|
||||
pkgconfigdir = $(libdir)/pkgconfig
|
||||
pkgconfig_DATA = vorbis.pc vorbisenc.pc vorbisfile.pc
|
||||
|
||||
EXTRA_DIST = \
|
||||
CHANGES COPYING \
|
||||
autogen.sh \
|
||||
libvorbis.spec libvorbis.spec.in \
|
||||
vorbis.m4 \
|
||||
vorbis.pc.in vorbisenc.pc.in vorbisfile.pc.in \
|
||||
vorbis-uninstalled.pc.in \
|
||||
vorbisenc-uninstalled.pc.in \
|
||||
vorbisfile-uninstalled.pc.in \
|
||||
symbian \
|
||||
macosx win32
|
||||
|
||||
|
||||
DISTCHECK_CONFIGURE_FLAGS = --enable-docs
|
||||
|
||||
dist-hook:
|
||||
for item in $(EXTRA_DIST); do \
|
||||
if test -d $$item; then \
|
||||
echo -n "cleaning $$item dir for distribution..."; \
|
||||
rm -rf `find $(distdir)/$$item -name .svn`; \
|
||||
echo "OK"; \
|
||||
fi; \
|
||||
done
|
||||
|
||||
debug:
|
||||
$(MAKE) all CFLAGS="@DEBUG@"
|
||||
|
||||
profile:
|
||||
$(MAKE) all CFLAGS="@PROFILE@"
|
|
@ -0,0 +1,149 @@
|
|||
# Vorbis
|
||||
|
||||
[![Travis Build Status](https://travis-ci.org/xiph/vorbis.svg?branch=master)](https://travis-ci.org/xiph/vorbis)
|
||||
[![Jenkins Build Status](https://mf4.xiph.org/jenkins/job/libvorbis/badge/icon)](https://mf4.xiph.org/jenkins/job/libvorbis/)
|
||||
[![AppVeyor Build status](https://ci.appveyor.com/api/projects/status/github/xiph/vorbis?branch=master&svg=true)](https://ci.appveyor.com/project/rillian/vorbis)
|
||||
|
||||
Vorbis is a general purpose audio and music encoding format
|
||||
contemporary to MPEG-4's AAC and TwinVQ, the next generation beyond
|
||||
MPEG audio layer 3. Unlike the MPEG sponsored formats (and other
|
||||
proprietary formats such as RealAudio G2 and Windows' flavor of the
|
||||
month), the Vorbis CODEC specification belongs to the public domain.
|
||||
All the technical details are published and documented, and any
|
||||
software entity may make full use of the format without license
|
||||
fee, royalty or patent concerns.
|
||||
|
||||
This package contains:
|
||||
|
||||
- libvorbis, a BSD-style license software implementation of
|
||||
the Vorbis specification by the Xiph.Org Foundation
|
||||
(https://www.xiph.org/)
|
||||
|
||||
- libvorbisfile, a BSD-style license convenience library
|
||||
built on Vorbis designed to simplify common uses
|
||||
|
||||
- libvorbisenc, a BSD-style license library that provides a simple,
|
||||
programmatic encoding setup interface
|
||||
|
||||
- example code making use of libogg, libvorbis, libvorbisfile and
|
||||
libvorbisenc
|
||||
|
||||
## What's here ##
|
||||
|
||||
This source distribution includes libvorbis and an example
|
||||
encoder/player to demonstrate use of libvorbis as well as
|
||||
documentation on the Ogg Vorbis audio coding format.
|
||||
|
||||
You'll need libogg (distributed separately) to compile this library.
|
||||
A more comprehensive set of utilities is available in the vorbis-tools
|
||||
package.
|
||||
|
||||
Directory:
|
||||
|
||||
- `lib` The source for the libraries, a BSD-license implementation of the public domain Ogg Vorbis audio encoding format.
|
||||
|
||||
- `include` Library API headers
|
||||
|
||||
- `debian` Rules/spec files for building Debian .deb packages
|
||||
|
||||
- `doc` Vorbis documentation
|
||||
|
||||
- `examples` Example code illustrating programmatic use of libvorbis, libvorbisfile and libvorbisenc
|
||||
|
||||
- `macosx` Project files for MacOS X.
|
||||
|
||||
- `win32` Win32 projects files and build automation
|
||||
|
||||
- `vq` Internal utilities for training/building new LSP/residue and auxiliary codebooks.
|
||||
|
||||
## Contact ##
|
||||
|
||||
The Ogg homepage is located at 'https://www.xiph.org/ogg/'.
|
||||
Vorbis's homepage is located at 'https://www.xiph.org/vorbis/'.
|
||||
Up to date technical documents, contact information, source code and
|
||||
pre-built utilities may be found there.
|
||||
|
||||
The user website for Ogg Vorbis software and audio is http://vorbis.com/
|
||||
|
||||
## Building ##
|
||||
|
||||
#### Building from master ####
|
||||
|
||||
Development source is under git revision control at
|
||||
https://git.xiph.org/vorbis.git. You will also need the
|
||||
newest versions of autoconf, automake, libtool and pkg-config in
|
||||
order to compile Vorbis from development source. A configure script
|
||||
is provided for you in the source tarball distributions.
|
||||
|
||||
./autogen.sh
|
||||
./configure
|
||||
make
|
||||
|
||||
and as root if desired:
|
||||
|
||||
make install
|
||||
|
||||
This will install the Vorbis libraries (static and shared) into
|
||||
/usr/local/lib, includes into /usr/local/include and API manpages
|
||||
(once we write some) into /usr/local/man.
|
||||
|
||||
Documentation building requires xsltproc and pdfxmltex.
|
||||
|
||||
#### Building from tarball distributions ####
|
||||
|
||||
./configure
|
||||
make
|
||||
|
||||
and optionally (as root):
|
||||
|
||||
make install
|
||||
|
||||
#### Building RPM packages ####
|
||||
|
||||
after normal configuring:
|
||||
|
||||
make dist
|
||||
rpm -ta libvorbis-<version>.tar.gz
|
||||
|
||||
## Building with CMake ##
|
||||
|
||||
Ogg supports building using [CMake](http://www.cmake.org/). CMake is a meta build system that generates native projects for each platform.
|
||||
To generate projects just run cmake replacing `YOUR-PROJECT-GENERATOR` with a proper generator from a list [here](http://www.cmake.org/cmake/help/v3.2/manual/cmake-generators.7.html):
|
||||
|
||||
cmake -G YOUR-PROJECT-GENERATOR .
|
||||
|
||||
Note that by default cmake generates projects that will build static libraries.
|
||||
To generate projects that will build dynamic library use `BUILD_SHARED_LIBS` option like this:
|
||||
|
||||
cmake -G YOUR-PROJECT-GENERATOR -DBUILD_SHARED_LIBS=1 .
|
||||
|
||||
After projects are generated use them as usual
|
||||
|
||||
#### Building on Windows ####
|
||||
|
||||
Use proper generator for your Visual Studio version like:
|
||||
|
||||
cmake -G "Visual Studio 12 2013" .
|
||||
|
||||
#### Building on Mac OS X ####
|
||||
|
||||
Use Xcode generator. To build framework run:
|
||||
|
||||
cmake -G Xcode -DBUILD_FRAMEWORK=1 .
|
||||
|
||||
#### Building on Linux ####
|
||||
|
||||
Use Makefile generator which is default one.
|
||||
|
||||
cmake .
|
||||
make
|
||||
|
||||
## License ##
|
||||
|
||||
THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.
|
||||
USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS
|
||||
GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE
|
||||
IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.
|
||||
|
||||
THE OggVorbis SOURCE CODE IS COPYRIGHT (C) 1994-2018
|
||||
by the Xiph.Org Foundation https://www.xiph.org/
|
|
@ -0,0 +1,32 @@
|
|||
image: Visual Studio 2015
|
||||
configuration:
|
||||
- Debug
|
||||
|
||||
platform:
|
||||
- Win32
|
||||
|
||||
environment:
|
||||
matrix:
|
||||
- BUILD_SYSTEM: MSVC
|
||||
- BUILD_SYSTEM: CMAKE
|
||||
|
||||
install:
|
||||
- git clone -q https://github.com/xiph/ogg.git %APPVEYOR_BUILD_FOLDER%\..\libogg
|
||||
- if "%BUILD_SYSTEM%"=="MSVC" msbuild "%APPVEYOR_BUILD_FOLDER%\..\libogg\win32\VS2015\libogg_static.sln" /m /v:minimal /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" /property:Configuration=%CONFIGURATION%;Platform=%PLATFORM%
|
||||
- if "%BUILD_SYSTEM%"=="CMAKE" mkdir "%APPVEYOR_BUILD_FOLDER%\..\libogg\build"
|
||||
- if "%BUILD_SYSTEM%"=="CMAKE" pushd "%APPVEYOR_BUILD_FOLDER%\..\libogg\build"
|
||||
- if "%BUILD_SYSTEM%"=="CMAKE" cmake -A "%PLATFORM%" -G "Visual Studio 14 2015" -DCMAKE_INSTALL_PREFIX="%APPVEYOR_BUILD_FOLDER%\..\libogg\install" ..
|
||||
- if "%BUILD_SYSTEM%"=="CMAKE" cmake --build . --config "%CONFIGURATION%" --target install -- /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
|
||||
- if "%BUILD_SYSTEM%"=="CMAKE" popd
|
||||
|
||||
before_build:
|
||||
- if "%BUILD_SYSTEM%" == "CMAKE" mkdir "%APPVEYOR_BUILD_FOLDER%\build"
|
||||
- if "%BUILD_SYSTEM%" == "CMAKE" pushd "%APPVEYOR_BUILD_FOLDER%\build"
|
||||
- if "%BUILD_SYSTEM%" == "CMAKE" cmake -A "%PLATFORM%" -G "Visual Studio 14 2015" -DOGG_ROOT=%APPVEYOR_BUILD_FOLDER%\..\libogg\install ..
|
||||
- if "%BUILD_SYSTEM%" == "CMAKE" popd
|
||||
|
||||
build_script:
|
||||
- if "%BUILD_SYSTEM%"=="MSVC" msbuild "%APPVEYOR_BUILD_FOLDER%\win32\VS2010\vorbis_dynamic.sln" /m /v:minimal /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" /property:Configuration=%CONFIGURATION%;Platform=%PLATFORM%
|
||||
- if "%BUILD_SYSTEM%" == "CMAKE" pushd "%APPVEYOR_BUILD_FOLDER%\build"
|
||||
- if "%BUILD_SYSTEM%" == "CMAKE" cmake --build . --config "%CONFIGURATION%" -- /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
|
||||
- if "%BUILD_SYSTEM%" == "CMAKE" popd
|
|
@ -0,0 +1,12 @@
|
|||
#!/bin/sh
|
||||
# Run this to set up the build system: configure, makefiles, etc.
|
||||
set -e
|
||||
|
||||
package="vorbis"
|
||||
|
||||
srcdir=`dirname $0`
|
||||
test -n "$srcdir" && cd "$srcdir"
|
||||
|
||||
echo "Updating build configuration files for $package, please wait...."
|
||||
|
||||
autoreconf -if
|
|
@ -0,0 +1,304 @@
|
|||
dnl Process this file with autoconf to produce a configure script
|
||||
|
||||
dnl ------------------------------------------------
|
||||
dnl Initialization and Versioning
|
||||
dnl ------------------------------------------------
|
||||
|
||||
|
||||
AC_INIT([libvorbis],[1.3.6],[vorbis-dev@xiph.org])
|
||||
|
||||
AC_CONFIG_MACRO_DIR([m4])
|
||||
|
||||
AC_CONFIG_SRCDIR([lib/mdct.c])
|
||||
|
||||
AC_CANONICAL_TARGET([])
|
||||
|
||||
AM_INIT_AUTOMAKE
|
||||
AM_MAINTAINER_MODE
|
||||
|
||||
dnl Add parameters for aclocal
|
||||
AC_SUBST(ACLOCAL_AMFLAGS, "-I m4")
|
||||
|
||||
dnl enable silent rules on automake 1.11 and later
|
||||
m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
|
||||
|
||||
dnl Library versioning
|
||||
dnl - library source changed -> increment REVISION
|
||||
dnl - interfaces added/removed/changed -> increment CURRENT, REVISION = 0
|
||||
dnl - interfaces added -> increment AGE
|
||||
dnl - interfaces removed -> AGE = 0
|
||||
|
||||
V_LIB_CURRENT=4
|
||||
V_LIB_REVISION=8
|
||||
V_LIB_AGE=4
|
||||
|
||||
VF_LIB_CURRENT=6
|
||||
VF_LIB_REVISION=7
|
||||
VF_LIB_AGE=3
|
||||
|
||||
VE_LIB_CURRENT=2
|
||||
VE_LIB_REVISION=11
|
||||
VE_LIB_AGE=0
|
||||
|
||||
AC_SUBST(V_LIB_CURRENT)
|
||||
AC_SUBST(V_LIB_REVISION)
|
||||
AC_SUBST(V_LIB_AGE)
|
||||
AC_SUBST(VF_LIB_CURRENT)
|
||||
AC_SUBST(VF_LIB_REVISION)
|
||||
AC_SUBST(VF_LIB_AGE)
|
||||
AC_SUBST(VE_LIB_CURRENT)
|
||||
AC_SUBST(VE_LIB_REVISION)
|
||||
AC_SUBST(VE_LIB_AGE)
|
||||
|
||||
dnl --------------------------------------------------
|
||||
dnl Check for programs
|
||||
dnl --------------------------------------------------
|
||||
|
||||
dnl save $CFLAGS since AC_PROG_CC likes to insert "-g -O2"
|
||||
dnl if $CFLAGS is blank
|
||||
cflags_save="$CFLAGS"
|
||||
AC_PROG_CC
|
||||
AC_PROG_CPP
|
||||
CFLAGS="$cflags_save"
|
||||
|
||||
AC_C_INLINE
|
||||
|
||||
AC_LIBTOOL_WIN32_DLL
|
||||
AC_PROG_LIBTOOL
|
||||
AM_PROG_CC_C_O
|
||||
|
||||
dnl Check for doxygen
|
||||
if test "x$enable_docs" = xyes; then
|
||||
AC_CHECK_PROG(HAVE_DOXYGEN, doxygen, true, false)
|
||||
if test $HAVE_DOXYGEN = "false"; then
|
||||
AC_MSG_WARN([*** doxygen not found, API documentation will not be built])
|
||||
fi
|
||||
else
|
||||
HAVE_DOXYGEN=false
|
||||
fi
|
||||
AM_CONDITIONAL(HAVE_DOXYGEN,$HAVE_DOXYGEN)
|
||||
|
||||
dnl latex tools for the specification document
|
||||
AC_ARG_ENABLE(docs,
|
||||
AC_HELP_STRING([--enable-docs], [build the documentation]))
|
||||
|
||||
if test "x$enable_docs" = xyes; then
|
||||
AC_CHECK_PROGS([PDFLATEX], pdflatex, [/bin/false])
|
||||
AC_CHECK_PROGS([HTLATEX], htlatex, [/bin/false])
|
||||
if test "x$PDFLATEX" = x/bin/false || test "x$HTLATEX" = x/bin/false; then
|
||||
enable_docs=no
|
||||
AC_MSG_WARN([Documentation will not be built!])
|
||||
fi
|
||||
fi
|
||||
|
||||
AM_CONDITIONAL(BUILD_DOCS, [test "x$enable_docs" = xyes])
|
||||
|
||||
AC_ARG_ENABLE(examples,
|
||||
AS_HELP_STRING([--enable-examples], [build the examples]))
|
||||
|
||||
AM_CONDITIONAL(BUILD_EXAMPLES, [test "x$enable_examples" = xyes])
|
||||
|
||||
dnl --------------------------------------------------
|
||||
dnl Set build flags based on environment
|
||||
dnl --------------------------------------------------
|
||||
|
||||
dnl Set some target options
|
||||
|
||||
cflags_save="$CFLAGS"
|
||||
if test -z "$GCC"; then
|
||||
case $host in
|
||||
*-*-irix*)
|
||||
dnl If we're on IRIX, we wanna use cc even if gcc
|
||||
dnl is there (unless the user has overriden us)...
|
||||
if test -z "$CC"; then
|
||||
CC=cc
|
||||
fi
|
||||
DEBUG="-g -signed"
|
||||
CFLAGS="-O2 -w -signed"
|
||||
PROFILE="-p -g3 -O2 -signed" ;;
|
||||
sparc-sun-solaris*)
|
||||
DEBUG="-v -g"
|
||||
CFLAGS="-xO4 -fast -w -fsimple -native -xcg92"
|
||||
PROFILE="-v -xpg -g -xO4 -fast -native -fsimple -xcg92 -Dsuncc" ;;
|
||||
*)
|
||||
DEBUG="-g"
|
||||
CFLAGS="-O"
|
||||
PROFILE="-g -p" ;;
|
||||
esac
|
||||
else
|
||||
|
||||
AC_MSG_CHECKING([GCC version])
|
||||
GCC_VERSION=`$CC -dumpversion`
|
||||
AC_MSG_RESULT([$GCC_VERSION])
|
||||
case $host in
|
||||
*86-*-linux*)
|
||||
DEBUG="-g -Wall -Wextra -D_REENTRANT -D__NO_MATH_INLINES -fsigned-char"
|
||||
CFLAGS="-O3 -Wall -Wextra -ffast-math -mno-ieee-fp -D_REENTRANT -fsigned-char"
|
||||
# PROFILE="-Wall -Wextra -pg -g -O3 -ffast-math -D_REENTRANT -fsigned-char -fno-inline -static"
|
||||
PROFILE="-Wall -Wextra -pg -g -O3 -ffast-math -mno-ieee-fp -D_REENTRANT -fsigned-char -fno-inline"
|
||||
|
||||
# glibc < 2.1.3 has a serious FP bug in the math inline header
|
||||
# that will cripple Vorbis. Look to see if the magic FP stack
|
||||
# clobber is missing in the mathinline header, thus indicating
|
||||
# the buggy version
|
||||
|
||||
AC_EGREP_CPP(log10.*fldlg2.*fxch,[
|
||||
#define __LIBC_INTERNAL_MATH_INLINES 1
|
||||
#define __OPTIMIZE__
|
||||
#include <math.h>
|
||||
],bad=maybe,bad=no)
|
||||
if test ${bad} = "maybe" ;then
|
||||
AC_EGREP_CPP(log10.*fldlg2.*fxch.*st\([[0123456789]]*\),
|
||||
[
|
||||
#define __LIBC_INTERNAL_MATH_INLINES 1
|
||||
#define __OPTIMIZE__
|
||||
#include <math.h>
|
||||
],bad=no,bad=yes)
|
||||
fi
|
||||
if test ${bad} = "yes" ;then
|
||||
AC_MSG_WARN([ ])
|
||||
AC_MSG_WARN([********************************************************])
|
||||
AC_MSG_WARN([* The glibc headers on this machine have a serious bug *])
|
||||
AC_MSG_WARN([* in /usr/include/bits/mathinline.h This bug affects *])
|
||||
AC_MSG_WARN([* all floating point code, not just Ogg, built on this *])
|
||||
AC_MSG_WARN([* machine. Upgrading to glibc 2.1.3 is strongly urged *])
|
||||
AC_MSG_WARN([* to correct the problem. Note that upgrading glibc *])
|
||||
AC_MSG_WARN([* will not fix any previously built programs; this is *])
|
||||
AC_MSG_WARN([* a compile-time bug. *])
|
||||
AC_MSG_WARN([* To work around the problem for this build of Ogg, *])
|
||||
AC_MSG_WARN([* autoconf is disabling all math inlining. This will *])
|
||||
AC_MSG_WARN([* hurt Ogg performace but is necessary for an Ogg that *])
|
||||
AC_MSG_WARN([* will actually work. Once glibc is upgraded, rerun *])
|
||||
AC_MSG_WARN([* configure and make to build with inlining. *])
|
||||
AC_MSG_WARN([********************************************************])
|
||||
AC_MSG_WARN([ ])
|
||||
|
||||
CFLAGS=${OPT}" -D__NO_MATH_INLINES"
|
||||
PROFILE=${PROFILE}" -D__NO_MATH_INLINES"
|
||||
fi;;
|
||||
powerpc-*-linux*spe)
|
||||
DEBUG="-g -Wall -Wextra -D_REENTRANT -D__NO_MATH_INLINES"
|
||||
CFLAGS="-O3 -Wall -Wextra -ffast-math -mfused-madd -D_REENTRANT"
|
||||
PROFILE="-pg -g -O3 -ffast-math -mfused-madd -D_REENTRANT";;
|
||||
powerpc-*-linux*)
|
||||
DEBUG="-g -Wall -Wextra -D_REENTRANT -D__NO_MATH_INLINES"
|
||||
CFLAGS="-O3 -Wall -Wextra -ffast-math -mfused-madd -mcpu=750 -D_REENTRANT"
|
||||
PROFILE="-pg -g -O3 -ffast-math -mfused-madd -mcpu=750 -D_REENTRANT";;
|
||||
*-*-linux*)
|
||||
DEBUG="-g -Wall -Wextra -D_REENTRANT -D__NO_MATH_INLINES -fsigned-char"
|
||||
CFLAGS="-O3 -Wall -Wextra -ffast-math -D_REENTRANT -fsigned-char"
|
||||
PROFILE="-pg -g -O3 -ffast-math -D_REENTRANT -fsigned-char";;
|
||||
sparc-sun-*)
|
||||
sparc_cpu=""
|
||||
AC_MSG_CHECKING([if gcc supports -mv8])
|
||||
old_cflags="$CFLAGS"
|
||||
CFLAGS="$CFLAGS -mv8"
|
||||
AC_TRY_COMPILE(, [return 0;], [
|
||||
AC_MSG_RESULT([yes])
|
||||
sparc_cpu="-mv8"
|
||||
])
|
||||
CFLAGS="$old_cflags"
|
||||
DEBUG="-g -Wall -Wextra -D__NO_MATH_INLINES -fsigned-char $sparc_cpu"
|
||||
CFLAGS="-O3 -Wall -Wextra -ffast-math -D__NO_MATH_INLINES -fsigned-char $sparc_cpu"
|
||||
PROFILE="-pg -g -O3 -D__NO_MATH_INLINES -fsigned-char $sparc_cpu" ;;
|
||||
*-*-darwin*)
|
||||
DEBUG="-DDARWIN -fno-common -force_cpusubtype_ALL -Wall -g -O0 -fsigned-char"
|
||||
CFLAGS="-DDARWIN -fno-common -force_cpusubtype_ALL -Wall -g -O3 -ffast-math -fsigned-char"
|
||||
PROFILE="-DDARWIN -fno-common -force_cpusubtype_ALL -Wall -g -pg -O3 -ffast-math -fsigned-char";;
|
||||
*-*-os2*)
|
||||
# Use -W instead of -Wextra because gcc on OS/2 is an old version.
|
||||
DEBUG="-g -Wall -W -D_REENTRANT -D__NO_MATH_INLINES -fsigned-char"
|
||||
CFLAGS="-O3 -Wall -W -ffast-math -D_REENTRANT -fsigned-char"
|
||||
PROFILE="-pg -g -O3 -ffast-math -D_REENTRANT -fsigned-char";;
|
||||
*)
|
||||
DEBUG="-g -Wall -Wextra -D__NO_MATH_INLINES -fsigned-char"
|
||||
CFLAGS="-O3 -Wall -Wextra -D__NO_MATH_INLINES -fsigned-char"
|
||||
PROFILE="-O3 -g -pg -D__NO_MATH_INLINES -fsigned-char" ;;
|
||||
esac
|
||||
|
||||
AC_ADD_CFLAGS([-Wdeclaration-after-statement])
|
||||
fi
|
||||
CFLAGS="$CFLAGS $cflags_save"
|
||||
|
||||
dnl --------------------------------------------------
|
||||
dnl Check for headers
|
||||
dnl --------------------------------------------------
|
||||
|
||||
AC_CHECK_HEADER(memory.h,CFLAGS="$CFLAGS -DUSE_MEMORY_H",:)
|
||||
|
||||
dnl --------------------------------------------------
|
||||
dnl Check for typedefs, structures, etc
|
||||
dnl --------------------------------------------------
|
||||
|
||||
dnl none
|
||||
|
||||
dnl --------------------------------------------------
|
||||
dnl Check for libraries
|
||||
dnl --------------------------------------------------
|
||||
|
||||
AC_CHECK_LIB(m, cos, VORBIS_LIBS="-lm", VORBIS_LIBS="")
|
||||
AC_CHECK_LIB(pthread, pthread_create, pthread_lib="-lpthread", :)
|
||||
|
||||
PKG_PROG_PKG_CONFIG
|
||||
|
||||
HAVE_OGG=no
|
||||
if test "x$PKG_CONFIG" != "x"
|
||||
then
|
||||
PKG_CHECK_MODULES(OGG, ogg >= 1.0, HAVE_OGG=yes, HAVE_OGG=no)
|
||||
fi
|
||||
if test "x$HAVE_OGG" = "xno"
|
||||
then
|
||||
dnl fall back to the old school test
|
||||
XIPH_PATH_OGG(, AC_MSG_ERROR(must have Ogg installed!))
|
||||
libs_save=$LIBS
|
||||
LIBS="$OGG_LIBS $VORBIS_LIBS"
|
||||
AC_CHECK_FUNC(oggpack_writealign, , AC_MSG_ERROR(Ogg >= 1.0 required !))
|
||||
LIBS=$libs_save
|
||||
fi
|
||||
|
||||
dnl --------------------------------------------------
|
||||
dnl Check for library functions
|
||||
dnl --------------------------------------------------
|
||||
|
||||
AC_FUNC_ALLOCA
|
||||
AC_FUNC_MEMCMP
|
||||
|
||||
dnl --------------------------------------------------
|
||||
dnl Do substitutions
|
||||
dnl --------------------------------------------------
|
||||
|
||||
AC_SUBST(VORBIS_LIBS)
|
||||
AC_SUBST(DEBUG)
|
||||
AC_SUBST(PROFILE)
|
||||
AC_SUBST(pthread_lib)
|
||||
|
||||
dnl The following line causes the libtool distributed with the source
|
||||
dnl to be replaced if the build system has a more recent version.
|
||||
AC_SUBST(LIBTOOL_DEPS)
|
||||
|
||||
AC_CONFIG_FILES([
|
||||
Makefile
|
||||
m4/Makefile
|
||||
lib/Makefile
|
||||
lib/modes/Makefile
|
||||
lib/books/Makefile
|
||||
lib/books/coupled/Makefile
|
||||
lib/books/uncoupled/Makefile
|
||||
lib/books/floor/Makefile
|
||||
doc/Makefile doc/vorbisfile/Makefile doc/vorbisenc/Makefile doc/libvorbis/Makefile
|
||||
doc/Doxyfile
|
||||
include/Makefile include/vorbis/Makefile
|
||||
examples/Makefile
|
||||
test/Makefile
|
||||
vq/Makefile
|
||||
libvorbis.spec
|
||||
vorbis.pc
|
||||
vorbisenc.pc
|
||||
vorbisfile.pc
|
||||
vorbis-uninstalled.pc
|
||||
vorbisenc-uninstalled.pc
|
||||
vorbisfile-uninstalled.pc
|
||||
])
|
||||
AC_CONFIG_HEADERS([config.h])
|
||||
|
||||
AC_OUTPUT
|
|
@ -0,0 +1,208 @@
|
|||
libvorbis (1.2.0.dfsg-3.1) unstable; urgency=high
|
||||
|
||||
* Non-maintainer upload by the security team
|
||||
* Fix integer overflows (and possible DoS attacks) via crafted
|
||||
OGG files (Closes: #482518)
|
||||
Fixes: CVE-2008-1423, CVE-2008-1420, CVE-2008-1419
|
||||
|
||||
-- Steffen Joeris <white@debian.org> Mon, 26 May 2008 12:48:06 +0000
|
||||
|
||||
libvorbis (1.2.0.dfsg-3) unstable; urgency=low
|
||||
|
||||
* Use dpkg-gensymbols, with symbol files obtained from Mole (stripping
|
||||
debian revision and .dfsg suffix).
|
||||
|
||||
* Install upstream CHANGES file as changelog.gz. (Closes: #302037)
|
||||
|
||||
* Bump debian/compat to 5, and Standards-Version to 3.7.3 (no changes
|
||||
needed).
|
||||
|
||||
* Use quilt.make in debian/rules.
|
||||
|
||||
-- Adeodato Simó <dato@net.com.org.es> Thu, 27 Dec 2007 14:33:45 +0100
|
||||
|
||||
libvorbis (1.2.0.dfsg-2) unstable; urgency=high
|
||||
|
||||
* Bump shlibs for libvorbis0a due to new vorbis_synthesis_idheader header.
|
||||
(Closes: #436083)
|
||||
|
||||
-- Adeodato Simó <dato@net.com.org.es> Tue, 14 Aug 2007 20:55:54 +0200
|
||||
|
||||
libvorbis (1.2.0.dfsg-1) unstable; urgency=low
|
||||
|
||||
[ Adeodato Simó ]
|
||||
* Use ${binary:Version} instead of ${Source-Version}.
|
||||
|
||||
[ Clint Adams ]
|
||||
* New upstream release.
|
||||
- Remove upstream_r13198-fix_segfault_in_ov_time_seek.diff .
|
||||
* Bump shlibs for libvorbisfile3 to >= 1.2.0 due to new ov_fopen
|
||||
function.
|
||||
|
||||
-- Clint Adams <schizo@debian.org> Fri, 27 Jul 2007 02:57:44 -0400
|
||||
|
||||
libvorbis (1.1.2.dfsg-2) unstable; urgency=low
|
||||
|
||||
* Bump to Standards-Version 3.7.2.
|
||||
* Add upstream_r13198-fix_segfault_in_ov_time_seek.diff. closes: #281995.
|
||||
|
||||
-- Clint Adams <schizo@debian.org> Fri, 29 Jun 2007 09:46:12 -0400
|
||||
|
||||
libvorbis (1.1.2.dfsg-1.2) unstable; urgency=high
|
||||
|
||||
* Fix shlibs files for libvorbisenc and libvorbisfile, which were broken
|
||||
by my first NMU to have dependencies for libvorbis0a. Closes: #395048
|
||||
|
||||
-- Joey Hess <joeyh@debian.org> Tue, 24 Oct 2006 19:55:19 -0400
|
||||
|
||||
libvorbis (1.1.2.dfsg-1.1) unstable; urgency=low
|
||||
|
||||
* NMU
|
||||
* Remove draft RFC files, as they are not under a free license.
|
||||
Closes: #390660
|
||||
* Repackage the source package without these files.
|
||||
* Add README.Source documenting how the upstream source is repackaged.
|
||||
* Modify dh_makeshlibs call to avoid generating a shlibs file that has
|
||||
an unncessarily tight versioned dependency on this new pseudo-version
|
||||
of libvorbis.
|
||||
|
||||
-- Joey Hess <joeyh@debian.org> Sun, 15 Oct 2006 17:21:37 -0400
|
||||
|
||||
libvorbis (1.1.2-1) unstable; urgency=low
|
||||
|
||||
* Switch maintenance to the Debian Xiph.org Maintainers (alioth/pkg-xiph).
|
||||
|
||||
* New upstream release packaged. (Closes: #327586)
|
||||
|
||||
* Move HTML documentation from /usr/share/doc/libvorbis-dev itself to an
|
||||
html/ subdirectory of it.
|
||||
|
||||
* Update debian/control:
|
||||
+ drop unnecessary build-dependency on devscripts.
|
||||
+ drop version restriction on debhelper and libogg-dev build-dependencies,
|
||||
since they're already satisfied with stable.
|
||||
|
||||
* Overhaul debian/rules, and switch to quilt for patch management.
|
||||
|
||||
* Add debian/compat file, instead of exporting DH_COMPAT.
|
||||
|
||||
* Update download URL in debian/copyright.
|
||||
|
||||
* Add debian/watch file.
|
||||
|
||||
* Bumped Standards-Version to 3.6.2 (no changes required).
|
||||
|
||||
-- Adeodato Simó <dato@net.com.org.es> Thu, 26 Jan 2006 01:35:39 +0100
|
||||
|
||||
libvorbis (1.1.0-1) unstable; urgency=low
|
||||
|
||||
* New upstream.
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Thu, 17 Mar 2005 21:30:00 -0600
|
||||
|
||||
libvorbis (1.0.1-1) unstable; urgency=low
|
||||
|
||||
* New upstream.
|
||||
* Improved descriptions. (Closes: #166649)
|
||||
* Updated DEB_BUILD_OPTIONS support. (Closes: #188464)
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Tue, 9 Dec 2003 01:00:00 -0600
|
||||
|
||||
libvorbis (1.0.0-3) unstable; urgency=low
|
||||
|
||||
* Add libvorbis0 conflict to libvorbis0a.
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Wed, 12 Mar 2003 17:00:00 -0600
|
||||
|
||||
libvorbis (1.0.0-2) unstable; urgency=low
|
||||
|
||||
* Rename libvorbis0 -> libvorbis0a to keep packages from upgrading to it
|
||||
by mistake. (Closes: #156227, #156365, #161961, #171548, #172466,
|
||||
#172469, #178756)
|
||||
* GNU config automated update: config.sub (20020621 to 20030103),
|
||||
config.guess (20020529 to 20030110)
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Sat, 8 Mar 2003 13:00:00 -0600
|
||||
|
||||
libvorbis (1.0.0-1) unstable; urgency=low
|
||||
|
||||
* New upstream.
|
||||
* Split libvorbis package into libvorbis libvorbisenc libvorbisfile due to
|
||||
shared object major versions going out of sync.
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Fri, 19 Jul 2002 09:00:00 -0500
|
||||
|
||||
libvorbis (1.0rc3-1) unstable; urgency=low
|
||||
|
||||
* New upstream. (Closes: #121995, #123472)
|
||||
* added autotools target (config.* updater) to rules
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Mon, 24 Dec 2001 11:00:00 -0600
|
||||
|
||||
libvorbis (1.0rc2-1) unstable; urgency=low
|
||||
|
||||
* New upstream.
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Sun, 12 Aug 2001 22:00:00 -0500
|
||||
|
||||
libvorbis (1.0rc1-1) unstable; urgency=low
|
||||
|
||||
* New upstream. (Closes: #84977, #95330)
|
||||
* Upstream says lame at fault. See bug details. (Closes: #98010)
|
||||
* Fixed versioned depends.
|
||||
* Changed clean method to distclean.
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Sun, 17 Jun 2001 20:00:00 -0500
|
||||
|
||||
libvorbis (1.0beta4-1) unstable; urgency=low
|
||||
|
||||
* New upstream.
|
||||
* Appears to be fixed, can't reproduce bug (closes: #78848)
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Mon, 26 Feb 2001 08:00:00 -0600
|
||||
|
||||
libvorbis (1.0beta3-3) unstable; urgency=low
|
||||
|
||||
* Fixed Build-Depends libogg-dev version dependency.
|
||||
* Fixed Sections.
|
||||
* Updated to Standards-Version to 3.5.1.0
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Sat, 17 Feb 2001 18:14:53 -0600
|
||||
|
||||
libvorbis (1.0beta3-2) unstable; urgency=low
|
||||
|
||||
* Added dependency for libogg-dev (closes: #78262)
|
||||
* Added dependency for libogg-dev (closes: #81432)
|
||||
* Corrected development library package name (closes: #82464)
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Sat, 3 Feb 2001 13:29:30 -0600
|
||||
|
||||
libvorbis (1.0beta3-1) unstable; urgency=low
|
||||
|
||||
* New Maintainer.
|
||||
* Upstream source was reorganized.
|
||||
* Package split according to the upstream reorganization.
|
||||
|
||||
-- Christopher L Cheney <ccheney@debian.org> Tue, 31 Oct 2000 15:08:22 -0600
|
||||
|
||||
vorbis (1.0beta2-1) unstable; urgency=low
|
||||
|
||||
* New upstream version. Closes: #67326, #68416
|
||||
* Changed xmms-vorbis to Architechture: any. Closes: #67395
|
||||
* Added Build-deps. Closes: #66628
|
||||
* Moved vorbize to vorbis-tools along with oggenc and vorbiscomment
|
||||
|
||||
-- Michael Beattie <mjb@debian.org> Wed, 9 Aug 2000 00:30:15 +1200
|
||||
|
||||
vorbis (1.0beta1-1) unstable; urgency=low
|
||||
|
||||
* First Beta, Ready for debian release.
|
||||
|
||||
-- Michael Beattie <mickyb@es.co.nz> Fri, 30 Jun 2000 19:26:59 +1200
|
||||
|
||||
vorbis (0.0-1) unstable; urgency=low
|
||||
|
||||
* Initial Release.
|
||||
* Initial package, not placed in archive.
|
||||
|
||||
-- Michael Beattie <mickyb@es.co.nz> Mon, 26 Jun 2000 18:59:56 +1200
|
|
@ -0,0 +1,60 @@
|
|||
Source: libvorbis
|
||||
Section: libs
|
||||
Priority: optional
|
||||
Maintainer: Christopher L Cheney <ccheney@debian.org>
|
||||
Build-Depends: autotools-dev, debhelper (>> 4.0.18), devscripts, libogg-dev (>> 1.1.0)
|
||||
Standards-Version: 3.6.1.0
|
||||
|
||||
Package: libvorbis0a
|
||||
Architecture: any
|
||||
Section: libs
|
||||
Depends: ${shlibs:Depends}
|
||||
Conflicts: libvorbis0
|
||||
Replaces: libvorbis0
|
||||
Description: The Vorbis General Audio Compression Codec
|
||||
Ogg Vorbis is a fully open, non-proprietary, patent-and-royalty-free,
|
||||
general-purpose compressed audio format for audio and music at fixed
|
||||
and variable bitrates from 16 to 128 kbps/channel.
|
||||
.
|
||||
The Vorbis library is the primary Ogg Vorbis library.
|
||||
|
||||
Package: libvorbisenc2
|
||||
Architecture: any
|
||||
Section: libs
|
||||
Depends: ${shlibs:Depends}
|
||||
Conflicts: libvorbis0 (<< 1.0.0)
|
||||
Replaces: libvorbis0 (<< 1.0.0)
|
||||
Description: The Vorbis General Audio Compression Codec
|
||||
Ogg Vorbis is a fully open, non-proprietary, patent-and-royalty-free,
|
||||
general-purpose compressed audio format for audio and music at fixed
|
||||
and variable bitrates from 16 to 128 kbps/channel.
|
||||
.
|
||||
The Vorbisenc library provides a convenient API for setting up an encoding
|
||||
environment using libvorbis.
|
||||
|
||||
Package: libvorbisfile3
|
||||
Architecture: any
|
||||
Section: libs
|
||||
Depends: ${shlibs:Depends}
|
||||
Conflicts: libvorbis0 (<< 1.0.0)
|
||||
Replaces: libvorbis0 (<< 1.0.0)
|
||||
Description: The Vorbis General Audio Compression Codec
|
||||
Ogg Vorbis is a fully open, non-proprietary, patent-and-royalty-free,
|
||||
general-purpose compressed audio format for audio and music at fixed
|
||||
and variable bitrates from 16 to 128 kbps/channel.
|
||||
.
|
||||
The Vorbisfile library provides a convenient high-level API for decoding
|
||||
and basic manipulation of all Vorbis I audio streams.
|
||||
|
||||
Package: libvorbis-dev
|
||||
Architecture: any
|
||||
Section: libdevel
|
||||
Depends: libogg-dev, libvorbis0a (= ${Source-Version}), libvorbisenc2 (= ${Source-Version}), libvorbisfile3 (= ${Source-Version})
|
||||
Description: The Vorbis General Audio Compression Codec (development files)
|
||||
Ogg Vorbis is a fully open, non-proprietary, patent-and-royalty-free,
|
||||
general-purpose compressed audio format for audio and music at fixed
|
||||
and variable bitrates from 16 to 128 kbps/channel.
|
||||
.
|
||||
This package contains the header files and documentation needed to develop
|
||||
applications with libvorbis.
|
||||
|
|
@ -0,0 +1,38 @@
|
|||
This package was debianized by Christopher L Cheney <ccheney@debian.org> on
|
||||
Tue, 31 Oct 2000 15:08:22 -0600.
|
||||
|
||||
It was downloaded from http://www.vorbis.com/download_unix.psp
|
||||
|
||||
Upstream Author: Monty <monty@xiph.org>
|
||||
|
||||
Copyright:
|
||||
|
||||
Copyright (c) 2002, Xiph.org Foundation
|
||||
|
||||
Redistribution and use in source and binary forms, with or without
|
||||
modification, are permitted provided that the following conditions
|
||||
are met:
|
||||
|
||||
- Redistributions of source code must retain the above copyright
|
||||
notice, this list of conditions and the following disclaimer.
|
||||
|
||||
- Redistributions in binary form must reproduce the above copyright
|
||||
notice, this list of conditions and the following disclaimer in the
|
||||
documentation and/or other materials provided with the distribution.
|
||||
|
||||
- Neither the name of the Xiph.org Foundation nor the names of its
|
||||
contributors may be used to endorse or promote products derived from
|
||||
this software without specific prior written permission.
|
||||
|
||||
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||||
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
|
||||
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
|
||||
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
|
||||
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
|
||||
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
|
||||
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
||||
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
||||
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
|
|
@ -0,0 +1 @@
|
|||
debian/tmp/usr/share/doc/libvorbis-*/*
|
|
@ -0,0 +1,2 @@
|
|||
examples/*.c
|
||||
examples/*.pl
|
|
@ -0,0 +1,16 @@
|
|||
debian/tmp/usr/include/vorbis/codec.h
|
||||
debian/tmp/usr/include/vorbis/vorbisenc.h
|
||||
debian/tmp/usr/include/vorbis/vorbisfile.h
|
||||
debian/tmp/usr/lib/libvorbis.a
|
||||
debian/tmp/usr/lib/libvorbis.la
|
||||
debian/tmp/usr/lib/libvorbis.so
|
||||
debian/tmp/usr/lib/libvorbisenc.a
|
||||
debian/tmp/usr/lib/libvorbisenc.la
|
||||
debian/tmp/usr/lib/libvorbisenc.so
|
||||
debian/tmp/usr/lib/libvorbisfile.a
|
||||
debian/tmp/usr/lib/libvorbisfile.la
|
||||
debian/tmp/usr/lib/libvorbisfile.so
|
||||
debian/tmp/usr/lib/pkgconfig/vorbis.pc
|
||||
debian/tmp/usr/lib/pkgconfig/vorbisenc.pc
|
||||
debian/tmp/usr/lib/pkgconfig/vorbisfile.pc
|
||||
debian/tmp/usr/share/aclocal/vorbis.m4
|
|
@ -0,0 +1 @@
|
|||
debian/tmp/usr/lib/libvorbis.so.*
|
|
@ -0,0 +1 @@
|
|||
debian/tmp/usr/lib/libvorbisenc.so.*
|
|
@ -0,0 +1 @@
|
|||
debian/tmp/usr/lib/libvorbisfile.so.*
|
|
@ -0,0 +1,154 @@
|
|||
#!/usr/bin/make -f
|
||||
# Sample debian/rules that uses debhelper.
|
||||
# GNU copyright 1997 to 1999 by Joey Hess.
|
||||
#
|
||||
# Modified to make a template file for a multi-binary package with separated
|
||||
# build-arch and build-indep targets by Bill Allombert 2001
|
||||
|
||||
# Uncomment this to turn on verbose mode.
|
||||
#export DH_VERBOSE=1
|
||||
|
||||
# This is the debhelper compatibility version to use.
|
||||
export DH_COMPAT=4
|
||||
|
||||
# This has to be exported to make some magic below work.
|
||||
export DH_OPTIONS
|
||||
|
||||
# These are used for cross-compiling and for saving the configure script
|
||||
# from having to guess our platform (since we know it already)
|
||||
DEB_HOST_GNU_TYPE ?= $(shell dpkg-architecture -qDEB_HOST_GNU_TYPE)
|
||||
DEB_BUILD_GNU_TYPE ?= $(shell dpkg-architecture -qDEB_BUILD_GNU_TYPE)
|
||||
|
||||
objdir = $(CURDIR)/obj-$(DEB_BUILD_GNU_TYPE)
|
||||
|
||||
CFLAGS = -Wall -g
|
||||
|
||||
ifneq (,$(findstring noopt,$(DEB_BUILD_OPTIONS)))
|
||||
CFLAGS += -O0
|
||||
else
|
||||
CFLAGS += -O2
|
||||
endif
|
||||
ifeq (,$(findstring nostrip,$(DEB_BUILD_OPTIONS)))
|
||||
INSTALL_PROGRAM += -s
|
||||
endif
|
||||
|
||||
configure: configure-stamp
|
||||
configure-stamp:
|
||||
dh_testdir
|
||||
|
||||
# make build directory
|
||||
mkdir $(objdir)
|
||||
|
||||
# run configure with build tree $(objdir)
|
||||
# change ../configure to ../autogen.sh for CVS build
|
||||
cd $(objdir) && \
|
||||
../configure --build=$(DEB_BUILD_GNU_TYPE) --host=$(DEB_HOST_GNU_TYPE) \
|
||||
--prefix=/usr --enable-static
|
||||
|
||||
touch configure-stamp
|
||||
|
||||
#Architecture
|
||||
build: build-arch build-indep
|
||||
|
||||
build-arch: build-arch-stamp
|
||||
build-arch-stamp: configure-stamp
|
||||
|
||||
cd $(objdir) && \
|
||||
$(MAKE)
|
||||
|
||||
touch build-arch-stamp
|
||||
|
||||
build-indep: build-indep-stamp
|
||||
build-indep-stamp: configure-stamp
|
||||
|
||||
# Add here commands to compile the indep part of the package.
|
||||
#$(MAKE) doc
|
||||
touch build-indep-stamp
|
||||
|
||||
debian-clean:
|
||||
dh_testdir
|
||||
dh_testroot
|
||||
|
||||
dh_clean
|
||||
|
||||
clean:
|
||||
dh_testdir
|
||||
dh_testroot
|
||||
rm -f build-arch-stamp build-indep-stamp configure-stamp
|
||||
|
||||
# Remove build tree
|
||||
rm -rf $(objdir)
|
||||
|
||||
# if Makefile exists run distclean
|
||||
if test -f Makefile; then \
|
||||
$(MAKE) distclean; \
|
||||
fi
|
||||
|
||||
#if test -d CVS; then \
|
||||
$(MAKE) cvs-clean ;\
|
||||
fi
|
||||
|
||||
dh_clean
|
||||
|
||||
install: install-indep install-arch
|
||||
install-indep:
|
||||
dh_testdir
|
||||
dh_testroot
|
||||
# dh_clean -k -i
|
||||
# dh_installdirs -i
|
||||
|
||||
# dh_install -i --list-missing
|
||||
|
||||
install-arch:
|
||||
dh_testdir
|
||||
dh_testroot
|
||||
dh_clean -k -s
|
||||
dh_installdirs -s
|
||||
|
||||
cd $(objdir) && \
|
||||
$(MAKE) install DESTDIR=$(CURDIR)/debian/tmp
|
||||
|
||||
dh_install -s --list-missing
|
||||
|
||||
# Must not depend on anything. This is to be called by
|
||||
# binary-arch/binary-indep
|
||||
# in another 'make' thread.
|
||||
binary-common:
|
||||
dh_testdir
|
||||
dh_testroot
|
||||
dh_installchangelogs CHANGES
|
||||
dh_installdocs
|
||||
dh_installexamples
|
||||
# dh_installmenu
|
||||
# dh_installdebconf
|
||||
# dh_installlogrotate
|
||||
# dh_installemacsen
|
||||
# dh_installpam
|
||||
# dh_installmime
|
||||
# dh_installinit
|
||||
# dh_installcron
|
||||
# dh_installinfo
|
||||
dh_installman
|
||||
dh_link
|
||||
dh_strip
|
||||
dh_compress
|
||||
dh_fixperms
|
||||
# dh_perl
|
||||
# dh_python
|
||||
dh_makeshlibs -V
|
||||
dh_installdeb
|
||||
dh_shlibdeps -ldebian/libvorbis0a/usr/lib
|
||||
dh_gencontrol
|
||||
dh_md5sums
|
||||
dh_builddeb
|
||||
|
||||
# Build architecture independant packages using the common target.
|
||||
binary-indep: build-indep install-indep
|
||||
# $(MAKE) -f debian/rules DH_OPTIONS=-i binary-common
|
||||
|
||||
# Build architecture dependant packages using the common target.
|
||||
binary-arch: build-arch install-arch
|
||||
$(MAKE) -f debian/rules DH_OPTIONS=-a binary-common
|
||||
|
||||
binary: binary-arch binary-indep
|
||||
.PHONY: build clean binary-indep binary-arch binary install install-indep install-arch configure
|
|
@ -0,0 +1,3 @@
|
|||
version=2
|
||||
|
||||
http://downloads.xiph.org/releases/vorbis/libvorbis-(.*)\.tar\.gz debian uupdate
|
|
@ -0,0 +1,528 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Introduction and Description} \label{vorbis:spec:intro}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
This document provides a high level description of the Vorbis codec's
|
||||
construction. A bit-by-bit specification appears beginning in
|
||||
\xref{vorbis:spec:codec}.
|
||||
The later sections assume a high-level
|
||||
understanding of the Vorbis decode process, which is
|
||||
provided here.
|
||||
|
||||
\subsubsection{Application}
|
||||
Vorbis is a general purpose perceptual audio CODEC intended to allow
|
||||
maximum encoder flexibility, thus allowing it to scale competitively
|
||||
over an exceptionally wide range of bitrates. At the high
|
||||
quality/bitrate end of the scale (CD or DAT rate stereo, 16/24 bits)
|
||||
it is in the same league as MPEG-2 and MPC. Similarly, the 1.0
|
||||
encoder can encode high-quality CD and DAT rate stereo at below 48kbps
|
||||
without resampling to a lower rate. Vorbis is also intended for
|
||||
lower and higher sample rates (from 8kHz telephony to 192kHz digital
|
||||
masters) and a range of channel representations (monaural,
|
||||
polyphonic, stereo, quadraphonic, 5.1, ambisonic, or up to 255
|
||||
discrete channels).
|
||||
|
||||
|
||||
\subsubsection{Classification}
|
||||
Vorbis I is a forward-adaptive monolithic transform CODEC based on the
|
||||
Modified Discrete Cosine Transform. The codec is structured to allow
|
||||
addition of a hybrid wavelet filterbank in Vorbis II to offer better
|
||||
transient response and reproduction using a transform better suited to
|
||||
localized time events.
|
||||
|
||||
|
||||
\subsubsection{Assumptions}
|
||||
|
||||
The Vorbis CODEC design assumes a complex, psychoacoustically-aware
|
||||
encoder and simple, low-complexity decoder. Vorbis decode is
|
||||
computationally simpler than mp3, although it does require more
|
||||
working memory as Vorbis has no static probability model; the vector
|
||||
codebooks used in the first stage of decoding from the bitstream are
|
||||
packed in their entirety into the Vorbis bitstream headers. In
|
||||
packed form, these codebooks occupy only a few kilobytes; the extent
|
||||
to which they are pre-decoded into a cache is the dominant factor in
|
||||
decoder memory usage.
|
||||
|
||||
|
||||
Vorbis provides none of its own framing, synchronization or protection
|
||||
against errors; it is solely a method of accepting input audio,
|
||||
dividing it into individual frames and compressing these frames into
|
||||
raw, unformatted 'packets'. The decoder then accepts these raw
|
||||
packets in sequence, decodes them, synthesizes audio frames from
|
||||
them, and reassembles the frames into a facsimile of the original
|
||||
audio stream. Vorbis is a free-form variable bit rate (VBR) codec and packets have no
|
||||
minimum size, maximum size, or fixed/expected size. Packets
|
||||
are designed that they may be truncated (or padded) and remain
|
||||
decodable; this is not to be considered an error condition and is used
|
||||
extensively in bitrate management in peeling. Both the transport
|
||||
mechanism and decoder must allow that a packet may be any size, or
|
||||
end before or after packet decode expects.
|
||||
|
||||
Vorbis packets are thus intended to be used with a transport mechanism
|
||||
that provides free-form framing, sync, positioning and error correction
|
||||
in accordance with these design assumptions, such as Ogg (for file
|
||||
transport) or RTP (for network multicast). For purposes of a few
|
||||
examples in this document, we will assume that Vorbis is to be
|
||||
embedded in an Ogg stream specifically, although this is by no means a
|
||||
requirement or fundamental assumption in the Vorbis design.
|
||||
|
||||
The specification for embedding Vorbis into
|
||||
an Ogg transport stream is in \xref{vorbis:over:ogg}.
|
||||
|
||||
|
||||
|
||||
\subsubsection{Codec Setup and Probability Model}
|
||||
|
||||
Vorbis' heritage is as a research CODEC and its current design
|
||||
reflects a desire to allow multiple decades of continuous encoder
|
||||
improvement before running out of room within the codec specification.
|
||||
For these reasons, configurable aspects of codec setup intentionally
|
||||
lean toward the extreme of forward adaptive.
|
||||
|
||||
The single most controversial design decision in Vorbis (and the most
|
||||
unusual for a Vorbis developer to keep in mind) is that the entire
|
||||
probability model of the codec, the Huffman and VQ codebooks, is
|
||||
packed into the bitstream header along with extensive CODEC setup
|
||||
parameters (often several hundred fields). This makes it impossible,
|
||||
as it would be with MPEG audio layers, to embed a simple frame type
|
||||
flag in each audio packet, or begin decode at any frame in the stream
|
||||
without having previously fetched the codec setup header.
|
||||
|
||||
|
||||
\begin{note}
|
||||
Vorbis \emph{can} initiate decode at any arbitrary packet within a
|
||||
bitstream so long as the codec has been initialized/setup with the
|
||||
setup headers.
|
||||
\end{note}
|
||||
|
||||
Thus, Vorbis headers are both required for decode to begin and
|
||||
relatively large as bitstream headers go. The header size is
|
||||
unbounded, although for streaming a rule-of-thumb of 4kB or less is
|
||||
recommended (and Xiph.Org's Vorbis encoder follows this suggestion).
|
||||
|
||||
Our own design work indicates the primary liability of the
|
||||
required header is in mindshare; it is an unusual design and thus
|
||||
causes some amount of complaint among engineers as this runs against
|
||||
current design trends (and also points out limitations in some
|
||||
existing software/interface designs, such as Windows' ACM codec
|
||||
framework). However, we find that it does not fundamentally limit
|
||||
Vorbis' suitable application space.
|
||||
|
||||
|
||||
\subsubsection{Format Specification}
|
||||
The Vorbis format is well-defined by its decode specification; any
|
||||
encoder that produces packets that are correctly decoded by the
|
||||
reference Vorbis decoder described below may be considered a proper
|
||||
Vorbis encoder. A decoder must faithfully and completely implement
|
||||
the specification defined below (except where noted) to be considered
|
||||
a proper Vorbis decoder.
|
||||
|
||||
\subsubsection{Hardware Profile}
|
||||
Although Vorbis decode is computationally simple, it may still run
|
||||
into specific limitations of an embedded design. For this reason,
|
||||
embedded designs are allowed to deviate in limited ways from the
|
||||
`full' decode specification yet still be certified compliant. These
|
||||
optional omissions are labelled in the spec where relevant.
|
||||
|
||||
|
||||
\subsection{Decoder Configuration}
|
||||
|
||||
Decoder setup consists of configuration of multiple, self-contained
|
||||
component abstractions that perform specific functions in the decode
|
||||
pipeline. Each different component instance of a specific type is
|
||||
semantically interchangeable; decoder configuration consists both of
|
||||
internal component configuration, as well as arrangement of specific
|
||||
instances into a decode pipeline. Componentry arrangement is roughly
|
||||
as follows:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=\textwidth]{components}
|
||||
\captionof{figure}{decoder pipeline configuration}
|
||||
\end{center}
|
||||
|
||||
\subsubsection{Global Config}
|
||||
Global codec configuration consists of a few audio related fields
|
||||
(sample rate, channels), Vorbis version (always '0' in Vorbis I),
|
||||
bitrate hints, and the lists of component instances. All other
|
||||
configuration is in the context of specific components.
|
||||
|
||||
\subsubsection{Mode}
|
||||
|
||||
Each Vorbis frame is coded according to a master 'mode'. A bitstream
|
||||
may use one or many modes.
|
||||
|
||||
The mode mechanism is used to encode a frame according to one of
|
||||
multiple possible methods with the intention of choosing a method best
|
||||
suited to that frame. Different modes are, e.g. how frame size
|
||||
is changed from frame to frame. The mode number of a frame serves as a
|
||||
top level configuration switch for all other specific aspects of frame
|
||||
decode.
|
||||
|
||||
A 'mode' configuration consists of a frame size setting, window type
|
||||
(always 0, the Vorbis window, in Vorbis I), transform type (always
|
||||
type 0, the MDCT, in Vorbis I) and a mapping number. The mapping
|
||||
number specifies which mapping configuration instance to use for
|
||||
low-level packet decode and synthesis.
|
||||
|
||||
|
||||
\subsubsection{Mapping}
|
||||
|
||||
A mapping contains a channel coupling description and a list of
|
||||
'submaps' that bundle sets of channel vectors together for grouped
|
||||
encoding and decoding. These submaps are not references to external
|
||||
components; the submap list is internal and specific to a mapping.
|
||||
|
||||
A 'submap' is a configuration/grouping that applies to a subset of
|
||||
floor and residue vectors within a mapping. The submap functions as a
|
||||
last layer of indirection such that specific special floor or residue
|
||||
settings can be applied not only to all the vectors in a given mode,
|
||||
but also specific vectors in a specific mode. Each submap specifies
|
||||
the proper floor and residue instance number to use for decoding that
|
||||
submap's spectral floor and spectral residue vectors.
|
||||
|
||||
As an example:
|
||||
|
||||
Assume a Vorbis stream that contains six channels in the standard 5.1
|
||||
format. The sixth channel, as is normal in 5.1, is bass only.
|
||||
Therefore it would be wasteful to encode a full-spectrum version of it
|
||||
as with the other channels. The submapping mechanism can be used to
|
||||
apply a full range floor and residue encoding to channels 0 through 4,
|
||||
and a bass-only representation to the bass channel, thus saving space.
|
||||
In this example, channels 0-4 belong to submap 0 (which indicates use
|
||||
of a full-range floor) and channel 5 belongs to submap 1, which uses a
|
||||
bass-only representation.
|
||||
|
||||
|
||||
\subsubsection{Floor}
|
||||
|
||||
Vorbis encodes a spectral 'floor' vector for each PCM channel. This
|
||||
vector is a low-resolution representation of the audio spectrum for
|
||||
the given channel in the current frame, generally used akin to a
|
||||
whitening filter. It is named a 'floor' because the Xiph.Org
|
||||
reference encoder has historically used it as a unit-baseline for
|
||||
spectral resolution.
|
||||
|
||||
A floor encoding may be of two types. Floor 0 uses a packed LSP
|
||||
representation on a dB amplitude scale and Bark frequency scale.
|
||||
Floor 1 represents the curve as a piecewise linear interpolated
|
||||
representation on a dB amplitude scale and linear frequency scale.
|
||||
The two floors are semantically interchangeable in
|
||||
encoding/decoding. However, floor type 1 provides more stable
|
||||
inter-frame behavior, and so is the preferred choice in all
|
||||
coupled-stereo and high bitrate modes. Floor 1 is also considerably
|
||||
less expensive to decode than floor 0.
|
||||
|
||||
Floor 0 is not to be considered deprecated, but it is of limited
|
||||
modern use. No known Vorbis encoder past Xiph.Org's own beta 4 makes
|
||||
use of floor 0.
|
||||
|
||||
The values coded/decoded by a floor are both compactly formatted and
|
||||
make use of entropy coding to save space. For this reason, a floor
|
||||
configuration generally refers to multiple codebooks in the codebook
|
||||
component list. Entropy coding is thus provided as an abstraction,
|
||||
and each floor instance may choose from any and all available
|
||||
codebooks when coding/decoding.
|
||||
|
||||
|
||||
\subsubsection{Residue}
|
||||
The spectral residue is the fine structure of the audio spectrum
|
||||
once the floor curve has been subtracted out. In simplest terms, it
|
||||
is coded in the bitstream using cascaded (multi-pass) vector
|
||||
quantization according to one of three specific packing/coding
|
||||
algorithms numbered 0 through 2. The packing algorithm details are
|
||||
configured by residue instance. As with the floor components, the
|
||||
final VQ/entropy encoding is provided by external codebook instances
|
||||
and each residue instance may choose from any and all available
|
||||
codebooks.
|
||||
|
||||
\subsubsection{Codebooks}
|
||||
|
||||
Codebooks are a self-contained abstraction that perform entropy
|
||||
decoding and, optionally, use the entropy-decoded integer value as an
|
||||
offset into an index of output value vectors, returning the indicated
|
||||
vector of values.
|
||||
|
||||
The entropy coding in a Vorbis I codebook is provided by a standard
|
||||
Huffman binary tree representation. This tree is tightly packed using
|
||||
one of several methods, depending on whether codeword lengths are
|
||||
ordered or unordered, or the tree is sparse.
|
||||
|
||||
The codebook vector index is similarly packed according to index
|
||||
characteristic. Most commonly, the vector index is encoded as a
|
||||
single list of values of possible values that are then permuted into
|
||||
a list of n-dimensional rows (lattice VQ).
|
||||
|
||||
|
||||
|
||||
\subsection{High-level Decode Process}
|
||||
|
||||
\subsubsection{Decode Setup}
|
||||
|
||||
Before decoding can begin, a decoder must initialize using the
|
||||
bitstream headers matching the stream to be decoded. Vorbis uses
|
||||
three header packets; all are required, in-order, by this
|
||||
specification. Once set up, decode may begin at any audio packet
|
||||
belonging to the Vorbis stream. In Vorbis I, all packets after the
|
||||
three initial headers are audio packets.
|
||||
|
||||
The header packets are, in order, the identification
|
||||
header, the comments header, and the setup header.
|
||||
|
||||
\paragraph{Identification Header}
|
||||
The identification header identifies the bitstream as Vorbis, Vorbis
|
||||
version, and the simple audio characteristics of the stream such as
|
||||
sample rate and number of channels.
|
||||
|
||||
\paragraph{Comment Header}
|
||||
The comment header includes user text comments (``tags'') and a vendor
|
||||
string for the application/library that produced the bitstream. The
|
||||
encoding and proper use of the comment header is described in \xref{vorbis:spec:comment}.
|
||||
|
||||
\paragraph{Setup Header}
|
||||
The setup header includes extensive CODEC setup information as well as
|
||||
the complete VQ and Huffman codebooks needed for decode.
|
||||
|
||||
|
||||
\subsubsection{Decode Procedure}
|
||||
|
||||
The decoding and synthesis procedure for all audio packets is
|
||||
fundamentally the same.
|
||||
\begin{enumerate}
|
||||
\item decode packet type flag
|
||||
\item decode mode number
|
||||
\item decode window shape (long windows only)
|
||||
\item decode floor
|
||||
\item decode residue into residue vectors
|
||||
\item inverse channel coupling of residue vectors
|
||||
\item generate floor curve from decoded floor data
|
||||
\item compute dot product of floor and residue, producing audio spectrum vector
|
||||
\item inverse monolithic transform of audio spectrum vector, always an MDCT in Vorbis I
|
||||
\item overlap/add left-hand output of transform with right-hand output of previous frame
|
||||
\item store right hand-data from transform of current frame for future lapping
|
||||
\item if not first frame, return results of overlap/add as audio result of current frame
|
||||
\end{enumerate}
|
||||
|
||||
Note that clever rearrangement of the synthesis arithmetic is
|
||||
possible; as an example, one can take advantage of symmetries in the
|
||||
MDCT to store the right-hand transform data of a partial MDCT for a
|
||||
50\% inter-frame buffer space savings, and then complete the transform
|
||||
later before overlap/add with the next frame. This optimization
|
||||
produces entirely equivalent output and is naturally perfectly legal.
|
||||
The decoder must be \emph{entirely mathematically equivalent} to the
|
||||
specification, it need not be a literal semantic implementation.
|
||||
|
||||
\paragraph{Packet type decode}
|
||||
|
||||
Vorbis I uses four packet types. The first three packet types mark each
|
||||
of the three Vorbis headers described above. The fourth packet type
|
||||
marks an audio packet. All other packet types are reserved; packets
|
||||
marked with a reserved type should be ignored.
|
||||
|
||||
Following the three header packets, all packets in a Vorbis I stream
|
||||
are audio. The first step of audio packet decode is to read and
|
||||
verify the packet type; \emph{a non-audio packet when audio is expected
|
||||
indicates stream corruption or a non-compliant stream. The decoder
|
||||
must ignore the packet and not attempt decoding it to
|
||||
audio}.
|
||||
|
||||
|
||||
|
||||
|
||||
\paragraph{Mode decode}
|
||||
Vorbis allows an encoder to set up multiple, numbered packet 'modes',
|
||||
as described earlier, all of which may be used in a given Vorbis
|
||||
stream. The mode is encoded as an integer used as a direct offset into
|
||||
the mode instance index.
|
||||
|
||||
|
||||
\paragraph{Window shape decode (long windows only)} \label{vorbis:spec:window}
|
||||
|
||||
Vorbis frames may be one of two PCM sample sizes specified during
|
||||
codec setup. In Vorbis I, legal frame sizes are powers of two from 64
|
||||
to 8192 samples. Aside from coupling, Vorbis handles channels as
|
||||
independent vectors and these frame sizes are in samples per channel.
|
||||
|
||||
Vorbis uses an overlapping transform, namely the MDCT, to blend one
|
||||
frame into the next, avoiding most inter-frame block boundary
|
||||
artifacts. The MDCT output of one frame is windowed according to MDCT
|
||||
requirements, overlapped 50\% with the output of the previous frame and
|
||||
added. The window shape assures seamless reconstruction.
|
||||
|
||||
This is easy to visualize in the case of equal sized-windows:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=\textwidth]{window1}
|
||||
\captionof{figure}{overlap of two equal-sized windows}
|
||||
\end{center}
|
||||
|
||||
And slightly more complex in the case of overlapping unequal sized
|
||||
windows:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=\textwidth]{window2}
|
||||
\captionof{figure}{overlap of a long and a short window}
|
||||
\end{center}
|
||||
|
||||
In the unequal-sized window case, the window shape of the long window
|
||||
must be modified for seamless lapping as above. It is possible to
|
||||
correctly infer window shape to be applied to the current window from
|
||||
knowing the sizes of the current, previous and next window. It is
|
||||
legal for a decoder to use this method. However, in the case of a long
|
||||
window (short windows require no modification), Vorbis also codes two
|
||||
flag bits to specify pre- and post- window shape. Although not
|
||||
strictly necessary for function, this minor redundancy allows a packet
|
||||
to be fully decoded to the point of lapping entirely independently of
|
||||
any other packet, allowing easier abstraction of decode layers as well
|
||||
as allowing a greater level of easy parallelism in encode and
|
||||
decode.
|
||||
|
||||
A description of valid window functions for use with an inverse MDCT
|
||||
can be found in \cite{Sporer/Brandenburg/Edler}. Vorbis windows
|
||||
all use the slope function
|
||||
\[ y = \sin(.5*\pi \, \sin^2((x+.5)/n*\pi)) . \]
|
||||
|
||||
|
||||
|
||||
\paragraph{floor decode}
|
||||
Each floor is encoded/decoded in channel order, however each floor
|
||||
belongs to a 'submap' that specifies which floor configuration to
|
||||
use. All floors are decoded before residue decode begins.
|
||||
|
||||
|
||||
\paragraph{residue decode}
|
||||
|
||||
Although the number of residue vectors equals the number of channels,
|
||||
channel coupling may mean that the raw residue vectors extracted
|
||||
during decode do not map directly to specific channels. When channel
|
||||
coupling is in use, some vectors will correspond to coupled magnitude
|
||||
or angle. The coupling relationships are described in the codec setup
|
||||
and may differ from frame to frame, due to different mode numbers.
|
||||
|
||||
Vorbis codes residue vectors in groups by submap; the coding is done
|
||||
in submap order from submap 0 through n-1. This differs from floors
|
||||
which are coded using a configuration provided by submap number, but
|
||||
are coded individually in channel order.
|
||||
|
||||
|
||||
|
||||
\paragraph{inverse channel coupling}
|
||||
|
||||
A detailed discussion of stereo in the Vorbis codec can be found in
|
||||
the document \href{stereo.html}{Stereo Channel Coupling in the
|
||||
Vorbis CODEC}. Vorbis is not limited to only stereo coupling, but
|
||||
the stereo document also gives a good overview of the generic coupling
|
||||
mechanism.
|
||||
|
||||
Vorbis coupling applies to pairs of residue vectors at a time;
|
||||
decoupling is done in-place a pair at a time in the order and using
|
||||
the vectors specified in the current mapping configuration. The
|
||||
decoupling operation is the same for all pairs, converting square
|
||||
polar representation (where one vector is magnitude and the second
|
||||
angle) back to Cartesian representation.
|
||||
|
||||
After decoupling, in order, each pair of vectors on the coupling list,
|
||||
the resulting residue vectors represent the fine spectral detail
|
||||
of each output channel.
|
||||
|
||||
|
||||
|
||||
\paragraph{generate floor curve}
|
||||
|
||||
The decoder may choose to generate the floor curve at any appropriate
|
||||
time. It is reasonable to generate the output curve when the floor
|
||||
data is decoded from the raw packet, or it can be generated after
|
||||
inverse coupling and applied to the spectral residue directly,
|
||||
combining generation and the dot product into one step and eliminating
|
||||
some working space.
|
||||
|
||||
Both floor 0 and floor 1 generate a linear-range, linear-domain output
|
||||
vector to be multiplied (dot product) by the linear-range,
|
||||
linear-domain spectral residue.
|
||||
|
||||
|
||||
|
||||
\paragraph{compute floor/residue dot product}
|
||||
|
||||
This step is straightforward; for each output channel, the decoder
|
||||
multiplies the floor curve and residue vectors element by element,
|
||||
producing the finished audio spectrum of each channel.
|
||||
|
||||
% TODO/FIXME: The following two paragraphs have identical twins
|
||||
% in section 4 (under "dot product")
|
||||
One point is worth mentioning about this dot product; a common mistake
|
||||
in a fixed point implementation might be to assume that a 32 bit
|
||||
fixed-point representation for floor and residue and direct
|
||||
multiplication of the vectors is sufficient for acceptable spectral
|
||||
depth in all cases because it happens to mostly work with the current
|
||||
Xiph.Org reference encoder.
|
||||
|
||||
However, floor vector values can span \~{}140dB (\~{}24 bits unsigned), and
|
||||
the audio spectrum vector should represent a minimum of 120dB (\~{}21
|
||||
bits with sign), even when output is to a 16 bit PCM device. For the
|
||||
residue vector to represent full scale if the floor is nailed to
|
||||
$-140$dB, it must be able to span 0 to $+140$dB. For the residue vector
|
||||
to reach full scale if the floor is nailed at 0dB, it must be able to
|
||||
represent $-140$dB to $+0$dB. Thus, in order to handle full range
|
||||
dynamics, a residue vector may span $-140$dB to $+140$dB entirely within
|
||||
spec. A 280dB range is approximately 48 bits with sign; thus the
|
||||
residue vector must be able to represent a 48 bit range and the dot
|
||||
product must be able to handle an effective 48 bit times 24 bit
|
||||
multiplication. This range may be achieved using large (64 bit or
|
||||
larger) integers, or implementing a movable binary point
|
||||
representation.
|
||||
|
||||
|
||||
|
||||
\paragraph{inverse monolithic transform (MDCT)}
|
||||
|
||||
The audio spectrum is converted back into time domain PCM audio via an
|
||||
inverse Modified Discrete Cosine Transform (MDCT). A detailed
|
||||
description of the MDCT is available in \cite{Sporer/Brandenburg/Edler}.
|
||||
|
||||
Note that the PCM produced directly from the MDCT is not yet finished
|
||||
audio; it must be lapped with surrounding frames using an appropriate
|
||||
window (such as the Vorbis window) before the MDCT can be considered
|
||||
orthogonal.
|
||||
|
||||
|
||||
|
||||
\paragraph{overlap/add data}
|
||||
Windowed MDCT output is overlapped and added with the right hand data
|
||||
of the previous window such that the 3/4 point of the previous window
|
||||
is aligned with the 1/4 point of the current window (as illustrated in
|
||||
the window overlap diagram). At this point, the audio data between the
|
||||
center of the previous frame and the center of the current frame is
|
||||
now finished and ready to be returned.
|
||||
|
||||
|
||||
\paragraph{cache right hand data}
|
||||
The decoder must cache the right hand portion of the current frame to
|
||||
be lapped with the left hand portion of the next frame.
|
||||
|
||||
|
||||
|
||||
\paragraph{return finished audio data}
|
||||
|
||||
The overlapped portion produced from overlapping the previous and
|
||||
current frame data is finished data to be returned by the decoder.
|
||||
This data spans from the center of the previous window to the center
|
||||
of the current window. In the case of same-sized windows, the amount
|
||||
of data to return is one-half block consisting of and only of the
|
||||
overlapped portions. When overlapping a short and long window, much of
|
||||
the returned range is not actually overlap. This does not damage
|
||||
transform orthogonality. Pay attention however to returning the
|
||||
correct data range; the amount of data to be returned is:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
window\_blocksize(previous\_window)/4+window\_blocksize(current\_window)/4
|
||||
\end{Verbatim}
|
||||
|
||||
from the center of the previous window to the center of the current
|
||||
window.
|
||||
|
||||
Data is not returned from the first frame; it must be used to 'prime'
|
||||
the decode engine. The encoder accounts for this priming when
|
||||
calculating PCM offsets; after the first frame, the proper PCM output
|
||||
offset is '0' (as no data has been returned yet).
|
|
@ -0,0 +1,246 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Bitpacking Convention} \label{vorbis:spec:bitpacking}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
The Vorbis codec uses relatively unstructured raw packets containing
|
||||
arbitrary-width binary integer fields. Logically, these packets are a
|
||||
bitstream in which bits are coded one-by-one by the encoder and then
|
||||
read one-by-one in the same monotonically increasing order by the
|
||||
decoder. Most current binary storage arrangements group bits into a
|
||||
native word size of eight bits (octets), sixteen bits, thirty-two bits
|
||||
or, less commonly other fixed word sizes. The Vorbis bitpacking
|
||||
convention specifies the correct mapping of the logical packet
|
||||
bitstream into an actual representation in fixed-width words.
|
||||
|
||||
|
||||
\subsubsection{octets, bytes and words}
|
||||
|
||||
In most contemporary architectures, a 'byte' is synonymous with an
|
||||
'octet', that is, eight bits. This has not always been the case;
|
||||
seven, ten, eleven and sixteen bit 'bytes' have been used. For
|
||||
purposes of the bitpacking convention, a byte implies the native,
|
||||
smallest integer storage representation offered by a platform. On
|
||||
modern platforms, this is generally assumed to be eight bits (not
|
||||
necessarily because of the processor but because of the
|
||||
filesystem/memory architecture. Modern filesystems invariably offer
|
||||
bytes as the fundamental atom of storage). A 'word' is an integer
|
||||
size that is a grouped multiple of this smallest size.
|
||||
|
||||
The most ubiquitous architectures today consider a 'byte' to be an
|
||||
octet (eight bits) and a word to be a group of two, four or eight
|
||||
bytes (16, 32 or 64 bits). Note however that the Vorbis bitpacking
|
||||
convention is still well defined for any native byte size; Vorbis uses
|
||||
the native bit-width of a given storage system. This document assumes
|
||||
that a byte is one octet for purposes of example.
|
||||
|
||||
\subsubsection{bit order}
|
||||
|
||||
A byte has a well-defined 'least significant' bit (LSb), which is the
|
||||
only bit set when the byte is storing the two's complement integer
|
||||
value +1. A byte's 'most significant' bit (MSb) is at the opposite
|
||||
end of the byte. Bits in a byte are numbered from zero at the LSb to
|
||||
$n$ ($n=7$ in an octet) for the
|
||||
MSb.
|
||||
|
||||
|
||||
|
||||
\subsubsection{byte order}
|
||||
|
||||
Words are native groupings of multiple bytes. Several byte orderings
|
||||
are possible in a word; the common ones are 3-2-1-0 ('big endian' or
|
||||
'most significant byte first' in which the highest-valued byte comes
|
||||
first), 0-1-2-3 ('little endian' or 'least significant byte first' in
|
||||
which the lowest value byte comes first) and less commonly 3-1-2-0 and
|
||||
0-2-1-3 ('mixed endian').
|
||||
|
||||
The Vorbis bitpacking convention specifies storage and bitstream
|
||||
manipulation at the byte, not word, level, thus host word ordering is
|
||||
of a concern only during optimization when writing high performance
|
||||
code that operates on a word of storage at a time rather than by byte.
|
||||
Logically, bytes are always coded and decoded in order from byte zero
|
||||
through byte $n$.
|
||||
|
||||
|
||||
|
||||
\subsubsection{coding bits into byte sequences}
|
||||
|
||||
The Vorbis codec has need to code arbitrary bit-width integers, from
|
||||
zero to 32 bits wide, into packets. These integer fields are not
|
||||
aligned to the boundaries of the byte representation; the next field
|
||||
is written at the bit position at which the previous field ends.
|
||||
|
||||
The encoder logically packs integers by writing the LSb of a binary
|
||||
integer to the logical bitstream first, followed by next least
|
||||
significant bit, etc, until the requested number of bits have been
|
||||
coded. When packing the bits into bytes, the encoder begins by
|
||||
placing the LSb of the integer to be written into the least
|
||||
significant unused bit position of the destination byte, followed by
|
||||
the next-least significant bit of the source integer and so on up to
|
||||
the requested number of bits. When all bits of the destination byte
|
||||
have been filled, encoding continues by zeroing all bits of the next
|
||||
byte and writing the next bit into the bit position 0 of that byte.
|
||||
Decoding follows the same process as encoding, but by reading bits
|
||||
from the byte stream and reassembling them into integers.
|
||||
|
||||
|
||||
|
||||
\subsubsection{signedness}
|
||||
|
||||
The signedness of a specific number resulting from decode is to be
|
||||
interpreted by the decoder given decode context. That is, the three
|
||||
bit binary pattern 'b111' can be taken to represent either 'seven' as
|
||||
an unsigned integer, or '-1' as a signed, two's complement integer.
|
||||
The encoder and decoder are responsible for knowing if fields are to
|
||||
be treated as signed or unsigned.
|
||||
|
||||
|
||||
|
||||
\subsubsection{coding example}
|
||||
|
||||
Code the 4 bit integer value '12' [b1100] into an empty bytestream.
|
||||
Bytestream result:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
|
||||
V
|
||||
|
||||
7 6 5 4 3 2 1 0
|
||||
byte 0 [0 0 0 0 1 1 0 0] <-
|
||||
byte 1 [ ]
|
||||
byte 2 [ ]
|
||||
byte 3 [ ]
|
||||
...
|
||||
byte n [ ] bytestream length == 1 byte
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
Continue by coding the 3 bit integer value '-1' [b111]:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
|
||||
V
|
||||
|
||||
7 6 5 4 3 2 1 0
|
||||
byte 0 [0 1 1 1 1 1 0 0] <-
|
||||
byte 1 [ ]
|
||||
byte 2 [ ]
|
||||
byte 3 [ ]
|
||||
...
|
||||
byte n [ ] bytestream length == 1 byte
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
Continue by coding the 7 bit integer value '17' [b0010001]:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
|
||||
V
|
||||
|
||||
7 6 5 4 3 2 1 0
|
||||
byte 0 [1 1 1 1 1 1 0 0]
|
||||
byte 1 [0 0 0 0 1 0 0 0] <-
|
||||
byte 2 [ ]
|
||||
byte 3 [ ]
|
||||
...
|
||||
byte n [ ] bytestream length == 2 bytes
|
||||
bit cursor == 6
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
Continue by coding the 13 bit integer value '6969' [b110 11001110 01]:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
|
||||
V
|
||||
|
||||
7 6 5 4 3 2 1 0
|
||||
byte 0 [1 1 1 1 1 1 0 0]
|
||||
byte 1 [0 1 0 0 1 0 0 0]
|
||||
byte 2 [1 1 0 0 1 1 1 0]
|
||||
byte 3 [0 0 0 0 0 1 1 0] <-
|
||||
...
|
||||
byte n [ ] bytestream length == 4 bytes
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{decoding example}
|
||||
|
||||
Reading from the beginning of the bytestream encoded in the above example:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
|
||||
V
|
||||
|
||||
7 6 5 4 3 2 1 0
|
||||
byte 0 [1 1 1 1 1 1 0 0] <-
|
||||
byte 1 [0 1 0 0 1 0 0 0]
|
||||
byte 2 [1 1 0 0 1 1 1 0]
|
||||
byte 3 [0 0 0 0 0 1 1 0] bytestream length == 4 bytes
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
We read two, two-bit integer fields, resulting in the returned numbers
|
||||
'b00' and 'b11'. Two things are worth noting here:
|
||||
|
||||
\begin{itemize}
|
||||
\item Although these four bits were originally written as a single
|
||||
four-bit integer, reading some other combination of bit-widths from the
|
||||
bitstream is well defined. There are no artificial alignment
|
||||
boundaries maintained in the bitstream.
|
||||
|
||||
\item The second value is the
|
||||
two-bit-wide integer 'b11'. This value may be interpreted either as
|
||||
the unsigned value '3', or the signed value '-1'. Signedness is
|
||||
dependent on decode context.
|
||||
\end{itemize}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{end-of-packet alignment}
|
||||
|
||||
The typical use of bitpacking is to produce many independent
|
||||
byte-aligned packets which are embedded into a larger byte-aligned
|
||||
container structure, such as an Ogg transport bitstream. Externally,
|
||||
each bytestream (encoded bitstream) must begin and end on a byte
|
||||
boundary. Often, the encoded bitstream is not an integer number of
|
||||
bytes, and so there is unused (uncoded) space in the last byte of a
|
||||
packet.
|
||||
|
||||
Unused space in the last byte of a bytestream is always zeroed during
|
||||
the coding process. Thus, should this unused space be read, it will
|
||||
return binary zeroes.
|
||||
|
||||
Attempting to read past the end of an encoded packet results in an
|
||||
'end-of-packet' condition. End-of-packet is not to be considered an
|
||||
error; it is merely a state indicating that there is insufficient
|
||||
remaining data to fulfill the desired read size. Vorbis uses truncated
|
||||
packets as a normal mode of operation, and as such, decoders must
|
||||
handle reading past the end of a packet as a typical mode of
|
||||
operation. Any further read operations after an 'end-of-packet'
|
||||
condition shall also return 'end-of-packet'.
|
||||
|
||||
|
||||
|
||||
\subsubsection{reading zero bits}
|
||||
|
||||
Reading a zero-bit-wide integer returns the value '0' and does not
|
||||
increment the stream cursor. Reading to the end of the packet (but
|
||||
not past, such that an 'end-of-packet' condition has not triggered)
|
||||
and then reading a zero bit integer shall succeed, returning 0, and
|
||||
not trigger an end-of-packet condition. Reading a zero-bit-wide
|
||||
integer after a previous read sets 'end-of-packet' shall also fail
|
||||
with 'end-of-packet'.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,456 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Probability Model and Codebooks} \label{vorbis:spec:codebook}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
Unlike practically every other mainstream audio codec, Vorbis has no
|
||||
statically configured probability model, instead packing all entropy
|
||||
decoding configuration, VQ and Huffman, into the bitstream itself in
|
||||
the third header, the codec setup header. This packed configuration
|
||||
consists of multiple 'codebooks', each containing a specific
|
||||
Huffman-equivalent representation for decoding compressed codewords as
|
||||
well as an optional lookup table of output vector values to which a
|
||||
decoded Huffman value is applied as an offset, generating the final
|
||||
decoded output corresponding to a given compressed codeword.
|
||||
|
||||
\subsubsection{Bitwise operation}
|
||||
The codebook mechanism is built on top of the vorbis bitpacker. Both
|
||||
the codebooks themselves and the codewords they decode are unrolled
|
||||
from a packet as a series of arbitrary-width values read from the
|
||||
stream according to \xref{vorbis:spec:bitpacking}.
|
||||
|
||||
|
||||
|
||||
|
||||
\subsection{Packed codebook format}
|
||||
|
||||
For purposes of the examples below, we assume that the storage
|
||||
system's native byte width is eight bits. This is not universally
|
||||
true; see \xref{vorbis:spec:bitpacking} for discussion
|
||||
relating to non-eight-bit bytes.
|
||||
|
||||
\subsubsection{codebook decode}
|
||||
|
||||
A codebook begins with a 24 bit sync pattern, 0x564342:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
byte 0: [ 0 1 0 0 0 0 1 0 ] (0x42)
|
||||
byte 1: [ 0 1 0 0 0 0 1 1 ] (0x43)
|
||||
byte 2: [ 0 1 0 1 0 1 1 0 ] (0x56)
|
||||
\end{Verbatim}
|
||||
|
||||
16 bit \varname{[codebook\_dimensions]} and 24 bit \varname{[codebook\_entries]} fields:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
||||
byte 3: [ X X X X X X X X ]
|
||||
byte 4: [ X X X X X X X X ] [codebook\_dimensions] (16 bit unsigned)
|
||||
|
||||
byte 5: [ X X X X X X X X ]
|
||||
byte 6: [ X X X X X X X X ]
|
||||
byte 7: [ X X X X X X X X ] [codebook\_entries] (24 bit unsigned)
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
Next is the \varname{[ordered]} bit flag:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
||||
byte 8: [ X ] [ordered] (1 bit)
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
Each entry, numbering a
|
||||
total of \varname{[codebook\_entries]}, is assigned a codeword length.
|
||||
We now read the list of codeword lengths and store these lengths in
|
||||
the array \varname{[codebook\_codeword\_lengths]}. Decode of lengths is
|
||||
according to whether the \varname{[ordered]} flag is set or unset.
|
||||
|
||||
\begin{itemize}
|
||||
\item
|
||||
If the \varname{[ordered]} flag is unset, the codeword list is not
|
||||
length ordered and the decoder needs to read each codeword length
|
||||
one-by-one.
|
||||
|
||||
The decoder first reads one additional bit flag, the
|
||||
\varname{[sparse]} flag. This flag determines whether or not the
|
||||
codebook contains unused entries that are not to be included in the
|
||||
codeword decode tree:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
byte 8: [ X 1 ] [sparse] flag (1 bit)
|
||||
\end{Verbatim}
|
||||
|
||||
The decoder now performs for each of the \varname{[codebook\_entries]}
|
||||
codebook entries:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
||||
1) if([sparse] is set) \{
|
||||
|
||||
2) [flag] = read one bit;
|
||||
3) if([flag] is set) \{
|
||||
|
||||
4) [length] = read a five bit unsigned integer;
|
||||
5) codeword length for this entry is [length]+1;
|
||||
|
||||
\} else \{
|
||||
|
||||
6) this entry is unused. mark it as such.
|
||||
|
||||
\}
|
||||
|
||||
\} else the sparse flag is not set \{
|
||||
|
||||
7) [length] = read a five bit unsigned integer;
|
||||
8) the codeword length for this entry is [length]+1;
|
||||
|
||||
\}
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
\item
|
||||
If the \varname{[ordered]} flag is set, the codeword list for this
|
||||
codebook is encoded in ascending length order. Rather than reading
|
||||
a length for every codeword, the encoder reads the number of
|
||||
codewords per length. That is, beginning at entry zero:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [current\_entry] = 0;
|
||||
2) [current\_length] = read a five bit unsigned integer and add 1;
|
||||
3) [number] = read \link{vorbis:spec:ilog}{ilog}([codebook\_entries] - [current\_entry]) bits as an unsigned integer
|
||||
4) set the entries [current\_entry] through [current\_entry]+[number]-1, inclusive,
|
||||
of the [codebook\_codeword\_lengths] array to [current\_length]
|
||||
5) set [current\_entry] to [number] + [current\_entry]
|
||||
6) increment [current\_length] by 1
|
||||
7) if [current\_entry] is greater than [codebook\_entries] ERROR CONDITION;
|
||||
the decoder will not be able to read this stream.
|
||||
8) if [current\_entry] is less than [codebook\_entries], repeat process starting at 3)
|
||||
9) done.
|
||||
\end{Verbatim}
|
||||
|
||||
\end{itemize}
|
||||
|
||||
After all codeword lengths have been decoded, the decoder reads the
|
||||
vector lookup table. Vorbis I supports three lookup types:
|
||||
\begin{enumerate}
|
||||
\item
|
||||
No lookup
|
||||
\item
|
||||
Implicitly populated value mapping (lattice VQ)
|
||||
\item
|
||||
Explicitly populated value mapping (tessellated or 'foam'
|
||||
VQ)
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
The lookup table type is read as a four bit unsigned integer:
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [codebook\_lookup\_type] = read four bits as an unsigned integer
|
||||
\end{Verbatim}
|
||||
|
||||
Codebook decode precedes according to \varname{[codebook\_lookup\_type]}:
|
||||
\begin{itemize}
|
||||
\item
|
||||
Lookup type zero indicates no lookup to be read. Proceed past
|
||||
lookup decode.
|
||||
\item
|
||||
Lookup types one and two are similar, differing only in the
|
||||
number of lookup values to be read. Lookup type one reads a list of
|
||||
values that are permuted in a set pattern to build a list of vectors,
|
||||
each vector of order \varname{[codebook\_dimensions]} scalars. Lookup
|
||||
type two builds the same vector list, but reads each scalar for each
|
||||
vector explicitly, rather than building vectors from a smaller list of
|
||||
possible scalar values. Lookup decode proceeds as follows:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [codebook\_minimum\_value] = \link{vorbis:spec:float32:unpack}{float32\_unpack}( read 32 bits as an unsigned integer)
|
||||
2) [codebook\_delta\_value] = \link{vorbis:spec:float32:unpack}{float32\_unpack}( read 32 bits as an unsigned integer)
|
||||
3) [codebook\_value\_bits] = read 4 bits as an unsigned integer and add 1
|
||||
4) [codebook\_sequence\_p] = read 1 bit as a boolean flag
|
||||
|
||||
if ( [codebook\_lookup\_type] is 1 ) \{
|
||||
|
||||
5) [codebook\_lookup\_values] = \link{vorbis:spec:lookup1:values}{lookup1\_values}(\varname{[codebook\_entries]}, \varname{[codebook\_dimensions]} )
|
||||
|
||||
\} else \{
|
||||
|
||||
6) [codebook\_lookup\_values] = \varname{[codebook\_entries]} * \varname{[codebook\_dimensions]}
|
||||
|
||||
\}
|
||||
|
||||
7) read a total of [codebook\_lookup\_values] unsigned integers of [codebook\_value\_bits] each;
|
||||
store these in order in the array [codebook\_multiplicands]
|
||||
\end{Verbatim}
|
||||
\item
|
||||
A \varname{[codebook\_lookup\_type]} of greater than two is reserved
|
||||
and indicates a stream that is not decodable by the specification in this
|
||||
document.
|
||||
|
||||
\end{itemize}
|
||||
|
||||
|
||||
An 'end of packet' during any read operation in the above steps is
|
||||
considered an error condition rendering the stream undecodable.
|
||||
|
||||
\paragraph{Huffman decision tree representation}
|
||||
|
||||
The \varname{[codebook\_codeword\_lengths]} array and
|
||||
\varname{[codebook\_entries]} value uniquely define the Huffman decision
|
||||
tree used for entropy decoding.
|
||||
|
||||
Briefly, each used codebook entry (recall that length-unordered
|
||||
codebooks support unused codeword entries) is assigned, in order, the
|
||||
lowest valued unused binary Huffman codeword possible. Assume the
|
||||
following codeword length list:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
entry 0: length 2
|
||||
entry 1: length 4
|
||||
entry 2: length 4
|
||||
entry 3: length 4
|
||||
entry 4: length 4
|
||||
entry 5: length 2
|
||||
entry 6: length 3
|
||||
entry 7: length 3
|
||||
\end{Verbatim}
|
||||
|
||||
Assigning codewords in order (lowest possible value of the appropriate
|
||||
length to highest) results in the following codeword list:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
entry 0: length 2 codeword 00
|
||||
entry 1: length 4 codeword 0100
|
||||
entry 2: length 4 codeword 0101
|
||||
entry 3: length 4 codeword 0110
|
||||
entry 4: length 4 codeword 0111
|
||||
entry 5: length 2 codeword 10
|
||||
entry 6: length 3 codeword 110
|
||||
entry 7: length 3 codeword 111
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
\begin{note}
|
||||
Unlike most binary numerical values in this document, we
|
||||
intend the above codewords to be read and used bit by bit from left to
|
||||
right, thus the codeword '001' is the bit string 'zero, zero, one'.
|
||||
When determining 'lowest possible value' in the assignment definition
|
||||
above, the leftmost bit is the MSb.
|
||||
\end{note}
|
||||
|
||||
It is clear that the codeword length list represents a Huffman
|
||||
decision tree with the entry numbers equivalent to the leaves numbered
|
||||
left-to-right:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=10cm]{hufftree}
|
||||
\captionof{figure}{huffman tree illustration}
|
||||
\end{center}
|
||||
|
||||
|
||||
As we assign codewords in order, we see that each choice constructs a
|
||||
new leaf in the leftmost possible position.
|
||||
|
||||
Note that it's possible to underspecify or overspecify a Huffman tree
|
||||
via the length list. In the above example, if codeword seven were
|
||||
eliminated, it's clear that the tree is unfinished:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=10cm]{hufftree-under}
|
||||
\captionof{figure}{underspecified huffman tree illustration}
|
||||
\end{center}
|
||||
|
||||
|
||||
Similarly, in the original codebook, it's clear that the tree is fully
|
||||
populated and a ninth codeword is impossible. Both underspecified and
|
||||
overspecified trees are an error condition rendering the stream
|
||||
undecodable.
|
||||
|
||||
Codebook entries marked 'unused' are simply skipped in the assigning
|
||||
process. They have no codeword and do not appear in the decision
|
||||
tree, thus it's impossible for any bit pattern read from the stream to
|
||||
decode to that entry number.
|
||||
|
||||
\paragraph{Errata 20150226: Single entry codebooks}
|
||||
|
||||
A 'single-entry codebook' is a codebook with one active codeword
|
||||
entry. A single-entry codebook may be either a fully populated
|
||||
codebook with only one declared entry, or a sparse codebook with only
|
||||
one entry marked used. The Vorbis I spec provides no means to specify
|
||||
a codeword length of zero, and as a result, a single-entry codebook is
|
||||
inherently malformed because it is underpopulated. The original
|
||||
specification did not address directly the matter of single-entry
|
||||
codebooks; they were implicitly illegal as it was not possible to
|
||||
write such a codebook with a valid tree structure.
|
||||
|
||||
In r14811 of the libvorbis reference implementation, Xiph added an
|
||||
additional check to the codebook implementation to reject
|
||||
underpopulated Huffman trees. This change led to the discovery of
|
||||
single-entry books used 'in the wild' when the new, stricter checks
|
||||
rejected a number of apparently working streams.
|
||||
|
||||
In order to minimize breakage of deployed (if technically erroneous)
|
||||
streams, r16073 of the reference implementation explicitly
|
||||
special-cased single-entry codebooks to tolerate the single-entry
|
||||
case. Commit r16073 also added the following to the specification:
|
||||
|
||||
\blockquote{\sout{Take special care that a codebook with a single used
|
||||
entry is handled properly; it consists of a single codework of
|
||||
zero bits and ’reading’ a value out of such a codebook always
|
||||
returns the single used value and sinks zero bits.
|
||||
}}
|
||||
|
||||
The intent was to clarify the spec and codify current practice.
|
||||
However, this addition is erroneously at odds with the intent of preserving
|
||||
usability of existing streams using single-entry codebooks, disagrees
|
||||
with the code changes that reinstated decoding, and does not address how
|
||||
single-entry codebooks should be encoded.
|
||||
|
||||
As such, the above addition made in r16037 is struck from the
|
||||
specification and replaced by the following:
|
||||
|
||||
\blockquote{It is possible to declare a Vorbis codebook containing a
|
||||
single codework entry. A single-entry codebook may be either a
|
||||
fully populated codebook with \varname{[codebook\_entries]} set to
|
||||
1, or a sparse codebook marking only one entry used. Note that it
|
||||
is not possible to also encode a \varname{[codeword\_length]} of
|
||||
zero for the single used codeword, as the unsigned value written to
|
||||
the stream is \varname{[codeword\_length]-1}. Instead, encoder
|
||||
implementations should indicate a \varname{[codeword\_length]} of 1
|
||||
and 'write' the codeword to a stream during audio encoding by
|
||||
writing a single zero bit.
|
||||
|
||||
Decoder implementations shall reject a codebook if it contains only
|
||||
one used entry and the encoded \varname{[codeword\_length]} of that
|
||||
entry is not 1. 'Reading' a value from single-entry codebook always
|
||||
returns the single used codeword value and sinks one bit. Decoders
|
||||
should tolerate that the bit read from the stream be '1' instead of
|
||||
'0'; both values shall return the single used codeword.}
|
||||
|
||||
\paragraph{VQ lookup table vector representation}
|
||||
|
||||
Unpacking the VQ lookup table vectors relies on the following values:
|
||||
\begin{programlisting}
|
||||
the [codebook\_multiplicands] array
|
||||
[codebook\_minimum\_value]
|
||||
[codebook\_delta\_value]
|
||||
[codebook\_sequence\_p]
|
||||
[codebook\_lookup\_type]
|
||||
[codebook\_entries]
|
||||
[codebook\_dimensions]
|
||||
[codebook\_lookup\_values]
|
||||
\end{programlisting}
|
||||
|
||||
\bigskip
|
||||
|
||||
Decoding (unpacking) a specific vector in the vector lookup table
|
||||
proceeds according to \varname{[codebook\_lookup\_type]}. The unpacked
|
||||
vector values are what a codebook would return during audio packet
|
||||
decode in a VQ context.
|
||||
|
||||
\paragraph{Vector value decode: Lookup type 1}
|
||||
|
||||
Lookup type one specifies a lattice VQ lookup table built
|
||||
algorithmically from a list of scalar values. Calculate (unpack) the
|
||||
final values of a codebook entry vector from the entries in
|
||||
\varname{[codebook\_multiplicands]} as follows (\varname{[value\_vector]}
|
||||
is the output vector representing the vector of values for entry number
|
||||
\varname{[lookup\_offset]} in this codebook):
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [last] = 0;
|
||||
2) [index\_divisor] = 1;
|
||||
3) iterate [i] over the range 0 ... [codebook\_dimensions]-1 (once for each scalar value in the value vector) \{
|
||||
|
||||
4) [multiplicand\_offset] = ( [lookup\_offset] divided by [index\_divisor] using integer
|
||||
division ) integer modulo [codebook\_lookup\_values]
|
||||
|
||||
5) vector [value\_vector] element [i] =
|
||||
( [codebook\_multiplicands] array element number [multiplicand\_offset] ) *
|
||||
[codebook\_delta\_value] + [codebook\_minimum\_value] + [last];
|
||||
|
||||
6) if ( [codebook\_sequence\_p] is set ) then set [last] = vector [value\_vector] element [i]
|
||||
|
||||
7) [index\_divisor] = [index\_divisor] * [codebook\_lookup\_values]
|
||||
|
||||
\}
|
||||
|
||||
8) vector calculation completed.
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
|
||||
\paragraph{Vector value decode: Lookup type 2}
|
||||
|
||||
Lookup type two specifies a VQ lookup table in which each scalar in
|
||||
each vector is explicitly set by the \varname{[codebook\_multiplicands]}
|
||||
array in a one-to-one mapping. Calculate [unpack] the
|
||||
final values of a codebook entry vector from the entries in
|
||||
\varname{[codebook\_multiplicands]} as follows (\varname{[value\_vector]}
|
||||
is the output vector representing the vector of values for entry number
|
||||
\varname{[lookup\_offset]} in this codebook):
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [last] = 0;
|
||||
2) [multiplicand\_offset] = [lookup\_offset] * [codebook\_dimensions]
|
||||
3) iterate [i] over the range 0 ... [codebook\_dimensions]-1 (once for each scalar value in the value vector) \{
|
||||
|
||||
4) vector [value\_vector] element [i] =
|
||||
( [codebook\_multiplicands] array element number [multiplicand\_offset] ) *
|
||||
[codebook\_delta\_value] + [codebook\_minimum\_value] + [last];
|
||||
|
||||
5) if ( [codebook\_sequence\_p] is set ) then set [last] = vector [value\_vector] element [i]
|
||||
|
||||
6) increment [multiplicand\_offset]
|
||||
|
||||
\}
|
||||
|
||||
7) vector calculation completed.
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
\subsection{Use of the codebook abstraction}
|
||||
|
||||
The decoder uses the codebook abstraction much as it does the
|
||||
bit-unpacking convention; a specific codebook reads a
|
||||
codeword from the bitstream, decoding it into an entry number, and then
|
||||
returns that entry number to the decoder (when used in a scalar
|
||||
entropy coding context), or uses that entry number as an offset into
|
||||
the VQ lookup table, returning a vector of values (when used in a context
|
||||
desiring a VQ value). Scalar or VQ context is always explicit; any call
|
||||
to the codebook mechanism requests either a scalar entry number or a
|
||||
lookup vector.
|
||||
|
||||
Note that VQ lookup type zero indicates that there is no lookup table;
|
||||
requesting decode using a codebook of lookup type 0 in any context
|
||||
expecting a vector return value (even in a case where a vector of
|
||||
dimension one) is forbidden. If decoder setup or decode requests such
|
||||
an action, that is an error condition rendering the packet
|
||||
undecodable.
|
||||
|
||||
Using a codebook to read from the packet bitstream consists first of
|
||||
reading and decoding the next codeword in the bitstream. The decoder
|
||||
reads bits until the accumulated bits match a codeword in the
|
||||
codebook. This process can be though of as logically walking the
|
||||
Huffman decode tree by reading one bit at a time from the bitstream,
|
||||
and using the bit as a decision boolean to take the 0 branch (left in
|
||||
the above examples) or the 1 branch (right in the above examples).
|
||||
Walking the tree finishes when the decode process hits a leaf in the
|
||||
decision tree; the result is the entry number corresponding to that
|
||||
leaf. Reading past the end of a packet propagates the 'end-of-stream'
|
||||
condition to the decoder.
|
||||
|
||||
When used in a scalar context, the resulting codeword entry is the
|
||||
desired return value.
|
||||
|
||||
When used in a VQ context, the codeword entry number is used as an
|
||||
offset into the VQ lookup table. The value returned to the decoder is
|
||||
the vector of scalars corresponding to this offset.
|
|
@ -0,0 +1,660 @@
|
|||
|
||||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Codec Setup and Packet Decode} \label{vorbis:spec:codec}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
This document serves as the top-level reference document for the
|
||||
bit-by-bit decode specification of Vorbis I. This document assumes a
|
||||
high-level understanding of the Vorbis decode process, which is
|
||||
provided in \xref{vorbis:spec:intro}. \xref{vorbis:spec:bitpacking} covers reading and writing bit fields from
|
||||
and to bitstream packets.
|
||||
|
||||
|
||||
|
||||
\subsection{Header decode and decode setup}
|
||||
|
||||
A Vorbis bitstream begins with three header packets. The header
|
||||
packets are, in order, the identification header, the comments header,
|
||||
and the setup header. All are required for decode compliance. An
|
||||
end-of-packet condition during decoding the first or third header
|
||||
packet renders the stream undecodable. End-of-packet decoding the
|
||||
comment header is a non-fatal error condition.
|
||||
|
||||
\subsubsection{Common header decode}
|
||||
|
||||
Each header packet begins with the same header fields.
|
||||
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [packet\_type] : 8 bit value
|
||||
2) 0x76, 0x6f, 0x72, 0x62, 0x69, 0x73: the characters 'v','o','r','b','i','s' as six octets
|
||||
\end{Verbatim}
|
||||
|
||||
Decode continues according to packet type; the identification header
|
||||
is type 1, the comment header type 3 and the setup header type 5
|
||||
(these types are all odd as a packet with a leading single bit of '0'
|
||||
is an audio packet). The packets must occur in the order of
|
||||
identification, comment, setup.
|
||||
|
||||
|
||||
|
||||
\subsubsection{Identification header}
|
||||
|
||||
The identification header is a short header of only a few fields used
|
||||
to declare the stream definitively as Vorbis, and provide a few externally
|
||||
relevant pieces of information about the audio stream. The
|
||||
identification header is coded as follows:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [vorbis\_version] = read 32 bits as unsigned integer
|
||||
2) [audio\_channels] = read 8 bit integer as unsigned
|
||||
3) [audio\_sample\_rate] = read 32 bits as unsigned integer
|
||||
4) [bitrate\_maximum] = read 32 bits as signed integer
|
||||
5) [bitrate\_nominal] = read 32 bits as signed integer
|
||||
6) [bitrate\_minimum] = read 32 bits as signed integer
|
||||
7) [blocksize\_0] = 2 exponent (read 4 bits as unsigned integer)
|
||||
8) [blocksize\_1] = 2 exponent (read 4 bits as unsigned integer)
|
||||
9) [framing\_flag] = read one bit
|
||||
\end{Verbatim}
|
||||
|
||||
\varname{[vorbis\_version]} is to read '0' in order to be compatible
|
||||
with this document. Both \varname{[audio\_channels]} and
|
||||
\varname{[audio\_sample\_rate]} must read greater than zero. Allowed final
|
||||
blocksize values are 64, 128, 256, 512, 1024, 2048, 4096 and 8192 in
|
||||
Vorbis I. \varname{[blocksize\_0]} must be less than or equal to
|
||||
\varname{[blocksize\_1]}. The framing bit must be nonzero. Failure to
|
||||
meet any of these conditions renders a stream undecodable.
|
||||
|
||||
The bitrate fields above are used only as hints. The nominal bitrate
|
||||
field especially may be considerably off in purely VBR streams. The
|
||||
fields are meaningful only when greater than zero.
|
||||
|
||||
\begin{itemize}
|
||||
\item All three fields set to the same value implies a fixed rate, or tightly bounded, nearly fixed-rate bitstream
|
||||
\item Only nominal set implies a VBR or ABR stream that averages the nominal bitrate
|
||||
\item Maximum and or minimum set implies a VBR bitstream that obeys the bitrate limits
|
||||
\item None set indicates the encoder does not care to speculate.
|
||||
\end{itemize}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{Comment header}
|
||||
Comment header decode and data specification is covered in
|
||||
\xref{vorbis:spec:comment}.
|
||||
|
||||
|
||||
\subsubsection{Setup header}
|
||||
|
||||
Vorbis codec setup is configurable to an extreme degree:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=\textwidth]{components}
|
||||
\captionof{figure}{decoder pipeline configuration}
|
||||
\end{center}
|
||||
|
||||
|
||||
The setup header contains the bulk of the codec setup information
|
||||
needed for decode. The setup header contains, in order, the lists of
|
||||
codebook configurations, time-domain transform configurations
|
||||
(placeholders in Vorbis I), floor configurations, residue
|
||||
configurations, channel mapping configurations and mode
|
||||
configurations. It finishes with a framing bit of '1'. Header decode
|
||||
proceeds in the following order:
|
||||
|
||||
\paragraph{Codebooks}
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[vorbis\_codebook\_count]} = read eight bits as unsigned integer and add one
|
||||
\item Decode \varname{[vorbis\_codebook\_count]} codebooks in order as defined
|
||||
in \xref{vorbis:spec:codebook}. Save each configuration, in
|
||||
order, in an array of
|
||||
codebook configurations \varname{[vorbis\_codebook\_configurations]}.
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
\paragraph{Time domain transforms}
|
||||
|
||||
These hooks are placeholders in Vorbis I. Nevertheless, the
|
||||
configuration placeholder values must be read to maintain bitstream
|
||||
sync.
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[vorbis\_time\_count]} = read 6 bits as unsigned integer and add one
|
||||
\item read \varname{[vorbis\_time\_count]} 16 bit values; each value should be zero. If any value is nonzero, this is an error condition and the stream is undecodable.
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
\paragraph{Floors}
|
||||
|
||||
Vorbis uses two floor types; header decode is handed to the decode
|
||||
abstraction of the appropriate type.
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[vorbis\_floor\_count]} = read 6 bits as unsigned integer and add one
|
||||
\item For each \varname{[i]} of \varname{[vorbis\_floor\_count]} floor numbers:
|
||||
\begin{enumerate}
|
||||
\item read the floor type: vector \varname{[vorbis\_floor\_types]} element \varname{[i]} =
|
||||
read 16 bits as unsigned integer
|
||||
\item If the floor type is zero, decode the floor
|
||||
configuration as defined in \xref{vorbis:spec:floor0}; save
|
||||
this
|
||||
configuration in slot \varname{[i]} of the floor configuration array \varname{[vorbis\_floor\_configurations]}.
|
||||
\item If the floor type is one,
|
||||
decode the floor configuration as defined in \xref{vorbis:spec:floor1}; save this configuration in slot \varname{[i]} of the floor configuration array \varname{[vorbis\_floor\_configurations]}.
|
||||
\item If the the floor type is greater than one, this stream is undecodable; ERROR CONDITION
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
\paragraph{Residues}
|
||||
|
||||
Vorbis uses three residue types; header decode of each type is identical.
|
||||
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[vorbis\_residue\_count]} = read 6 bits as unsigned integer and add one
|
||||
|
||||
\item For each of \varname{[vorbis\_residue\_count]} residue numbers:
|
||||
\begin{enumerate}
|
||||
\item read the residue type; vector \varname{[vorbis\_residue\_types]} element \varname{[i]} = read 16 bits as unsigned integer
|
||||
\item If the residue type is zero,
|
||||
one or two, decode the residue configuration as defined in \xref{vorbis:spec:residue}; save this configuration in slot \varname{[i]} of the residue configuration array \varname{[vorbis\_residue\_configurations]}.
|
||||
\item If the the residue type is greater than two, this stream is undecodable; ERROR CONDITION
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
\paragraph{Mappings}
|
||||
|
||||
Mappings are used to set up specific pipelines for encoding
|
||||
multichannel audio with varying channel mapping applications. Vorbis I
|
||||
uses a single mapping type (0), with implicit PCM channel mappings.
|
||||
|
||||
% FIXME/TODO: LaTeX cannot nest enumerate that deeply, so I have to use
|
||||
% itemize at the innermost level. However, it would be much better to
|
||||
% rewrite this pseudocode using listings or algoritmicx or some other
|
||||
% package geared towards this.
|
||||
\begin{enumerate}
|
||||
\item \varname{[vorbis\_mapping\_count]} = read 6 bits as unsigned integer and add one
|
||||
\item For each \varname{[i]} of \varname{[vorbis\_mapping\_count]} mapping numbers:
|
||||
\begin{enumerate}
|
||||
\item read the mapping type: 16 bits as unsigned integer. There's no reason to save the mapping type in Vorbis I.
|
||||
\item If the mapping type is nonzero, the stream is undecodable
|
||||
\item If the mapping type is zero:
|
||||
\begin{enumerate}
|
||||
\item read 1 bit as a boolean flag
|
||||
\begin{enumerate}
|
||||
\item if set, \varname{[vorbis\_mapping\_submaps]} = read 4 bits as unsigned integer and add one
|
||||
\item if unset, \varname{[vorbis\_mapping\_submaps]} = 1
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
\item read 1 bit as a boolean flag
|
||||
\begin{enumerate}
|
||||
\item if set, square polar channel mapping is in use:
|
||||
\begin{itemize}
|
||||
\item \varname{[vorbis\_mapping\_coupling\_steps]} = read 8 bits as unsigned integer and add one
|
||||
\item for \varname{[j]} each of \varname{[vorbis\_mapping\_coupling\_steps]} steps:
|
||||
\begin{itemize}
|
||||
\item vector \varname{[vorbis\_mapping\_magnitude]} element \varname{[j]}= read \link{vorbis:spec:ilog}{ilog}(\varname{[audio\_channels]} - 1) bits as unsigned integer
|
||||
\item vector \varname{[vorbis\_mapping\_angle]} element \varname{[j]}= read \link{vorbis:spec:ilog}{ilog}(\varname{[audio\_channels]} - 1) bits as unsigned integer
|
||||
\item the numbers read in the above two steps are channel numbers representing the channel to treat as magnitude and the channel to treat as angle, respectively. If for any coupling step the angle channel number equals the magnitude channel number, the magnitude channel number is greater than \varname{[audio\_channels]}-1, or the angle channel is greater than \varname{[audio\_channels]}-1, the stream is undecodable.
|
||||
\end{itemize}
|
||||
|
||||
|
||||
\end{itemize}
|
||||
|
||||
|
||||
\item if unset, \varname{[vorbis\_mapping\_coupling\_steps]} = 0
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
\item read 2 bits (reserved field); if the value is nonzero, the stream is undecodable
|
||||
\item if \varname{[vorbis\_mapping\_submaps]} is greater than one, we read channel multiplex settings. For each \varname{[j]} of \varname{[audio\_channels]} channels:
|
||||
\begin{enumerate}
|
||||
\item vector \varname{[vorbis\_mapping\_mux]} element \varname{[j]} = read 4 bits as unsigned integer
|
||||
\item if the value is greater than the highest numbered submap (\varname{[vorbis\_mapping\_submaps]} - 1), this in an error condition rendering the stream undecodable
|
||||
\end{enumerate}
|
||||
|
||||
\item for each submap \varname{[j]} of \varname{[vorbis\_mapping\_submaps]} submaps, read the floor and residue numbers for use in decoding that submap:
|
||||
\begin{enumerate}
|
||||
\item read and discard 8 bits (the unused time configuration placeholder)
|
||||
\item read 8 bits as unsigned integer for the floor number; save in vector \varname{[vorbis\_mapping\_submap\_floor]} element \varname{[j]}
|
||||
\item verify the floor number is not greater than the highest number floor configured for the bitstream. If it is, the bitstream is undecodable
|
||||
\item read 8 bits as unsigned integer for the residue number; save in vector \varname{[vorbis\_mapping\_submap\_residue]} element \varname{[j]}
|
||||
\item verify the residue number is not greater than the highest number residue configured for the bitstream. If it is, the bitstream is undecodable
|
||||
\end{enumerate}
|
||||
|
||||
\item save this mapping configuration in slot \varname{[i]} of the mapping configuration array \varname{[vorbis\_mapping\_configurations]}.
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
\paragraph{Modes}
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[vorbis\_mode\_count]} = read 6 bits as unsigned integer and add one
|
||||
\item For each of \varname{[vorbis\_mode\_count]} mode numbers:
|
||||
\begin{enumerate}
|
||||
\item \varname{[vorbis\_mode\_blockflag]} = read 1 bit
|
||||
\item \varname{[vorbis\_mode\_windowtype]} = read 16 bits as unsigned integer
|
||||
\item \varname{[vorbis\_mode\_transformtype]} = read 16 bits as unsigned integer
|
||||
\item \varname{[vorbis\_mode\_mapping]} = read 8 bits as unsigned integer
|
||||
\item verify ranges; zero is the only legal value in Vorbis I for
|
||||
\varname{[vorbis\_mode\_windowtype]}
|
||||
and \varname{[vorbis\_mode\_transformtype]}. \varname{[vorbis\_mode\_mapping]} must not be greater than the highest number mapping in use. Any illegal values render the stream undecodable.
|
||||
\item save this mode configuration in slot \varname{[i]} of the mode configuration array
|
||||
\varname{[vorbis\_mode\_configurations]}.
|
||||
\end{enumerate}
|
||||
|
||||
\item read 1 bit as a framing flag. If unset, a framing error occurred and the stream is not
|
||||
decodable.
|
||||
\end{enumerate}
|
||||
|
||||
After reading mode descriptions, setup header decode is complete.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
\subsection{Audio packet decode and synthesis}
|
||||
|
||||
Following the three header packets, all packets in a Vorbis I stream
|
||||
are audio. The first step of audio packet decode is to read and
|
||||
verify the packet type. \emph{A non-audio packet when audio is expected
|
||||
indicates stream corruption or a non-compliant stream. The decoder
|
||||
must ignore the packet and not attempt decoding it to audio}.
|
||||
|
||||
|
||||
\subsubsection{packet type, mode and window decode}
|
||||
|
||||
\begin{enumerate}
|
||||
\item read 1 bit \varname{[packet\_type]}; check that packet type is 0 (audio)
|
||||
\item read \link{vorbis:spec:ilog}{ilog}([vorbis\_mode\_count]-1) bits
|
||||
\varname{[mode\_number]}
|
||||
\item decode blocksize \varname{[n]} is equal to \varname{[blocksize\_0]} if
|
||||
\varname{[vorbis\_mode\_blockflag]} is 0, else \varname{[n]} is equal to \varname{[blocksize\_1]}.
|
||||
\item perform window selection and setup; this window is used later by the inverse MDCT:
|
||||
\begin{enumerate}
|
||||
\item if this is a long window (the \varname{[vorbis\_mode\_blockflag]} flag of this mode is
|
||||
set):
|
||||
\begin{enumerate}
|
||||
\item read 1 bit for \varname{[previous\_window\_flag]}
|
||||
\item read 1 bit for \varname{[next\_window\_flag]}
|
||||
\item if \varname{[previous\_window\_flag]} is not set, the left half
|
||||
of the window will be a hybrid window for lapping with a
|
||||
short block. See \xref{vorbis:spec:window} for an illustration of overlapping
|
||||
dissimilar
|
||||
windows. Else, the left half window will have normal long
|
||||
shape.
|
||||
\item if \varname{[next\_window\_flag]} is not set, the right half of
|
||||
the window will be a hybrid window for lapping with a short
|
||||
block. See \xref{vorbis:spec:window} for an
|
||||
illustration of overlapping dissimilar
|
||||
windows. Else, the left right window will have normal long
|
||||
shape.
|
||||
\end{enumerate}
|
||||
|
||||
\item if this is a short window, the window is always the same
|
||||
short-window shape.
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
Vorbis windows all use the slope function $y=\sin(\frac{\pi}{2} * \sin^2((x+0.5)/n * \pi))$,
|
||||
where $n$ is window size and $x$ ranges $0 \ldots n-1$, but dissimilar
|
||||
lapping requirements can affect overall shape. Window generation
|
||||
proceeds as follows:
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[window\_center]} = \varname{[n]} / 2
|
||||
\item if (\varname{[vorbis\_mode\_blockflag]} is set and \varname{[previous\_window\_flag]} is
|
||||
not set) then
|
||||
\begin{enumerate}
|
||||
\item \varname{[left\_window\_start]} = \varname{[n]}/4 -
|
||||
\varname{[blocksize\_0]}/4
|
||||
\item \varname{[left\_window\_end]} = \varname{[n]}/4 + \varname{[blocksize\_0]}/4
|
||||
\item \varname{[left\_n]} = \varname{[blocksize\_0]}/2
|
||||
\end{enumerate}
|
||||
else
|
||||
\begin{enumerate}
|
||||
\item \varname{[left\_window\_start]} = 0
|
||||
\item \varname{[left\_window\_end]} = \varname{[window\_center]}
|
||||
\item \varname{[left\_n]} = \varname{[n]}/2
|
||||
\end{enumerate}
|
||||
|
||||
\item if (\varname{[vorbis\_mode\_blockflag]} is set and \varname{[next\_window\_flag]} is not
|
||||
set) then
|
||||
\begin{enumerate}
|
||||
\item \varname{[right\_window\_start]} = \varname{[n]*3}/4 -
|
||||
\varname{[blocksize\_0]}/4
|
||||
\item \varname{[right\_window\_end]} = \varname{[n]*3}/4 +
|
||||
\varname{[blocksize\_0]}/4
|
||||
\item \varname{[right\_n]} = \varname{[blocksize\_0]}/2
|
||||
\end{enumerate}
|
||||
else
|
||||
\begin{enumerate}
|
||||
\item \varname{[right\_window\_start]} = \varname{[window\_center]}
|
||||
\item \varname{[right\_window\_end]} = \varname{[n]}
|
||||
\item \varname{[right\_n]} = \varname{[n]}/2
|
||||
\end{enumerate}
|
||||
|
||||
\item window from range 0 ... \varname{[left\_window\_start]}-1 inclusive is zero
|
||||
\item for \varname{[i]} in range \varname{[left\_window\_start]} ...
|
||||
\varname{[left\_window\_end]}-1, window(\varname{[i]}) = $\sin(\frac{\pi}{2} * \sin^2($ (\varname{[i]}-\varname{[left\_window\_start]}+0.5) / \varname{[left\_n]} $* \frac{\pi}{2})$ )
|
||||
\item window from range \varname{[left\_window\_end]} ... \varname{[right\_window\_start]}-1
|
||||
inclusive is one\item for \varname{[i]} in range \varname{[right\_window\_start]} ... \varname{[right\_window\_end]}-1, window(\varname{[i]}) = $\sin(\frac{\pi}{2} * \sin^2($ (\varname{[i]}-\varname{[right\_window\_start]}+0.5) / \varname{[right\_n]} $ * \frac{\pi}{2} + \frac{\pi}{2})$ )
|
||||
\item window from range \varname{[right\_window\_start]} ... \varname{[n]}-1 is
|
||||
zero
|
||||
\end{enumerate}
|
||||
|
||||
An end-of-packet condition up to this point should be considered an
|
||||
error that discards this packet from the stream. An end of packet
|
||||
condition past this point is to be considered a possible nominal
|
||||
occurrence.
|
||||
|
||||
|
||||
|
||||
\subsubsection{floor curve decode}
|
||||
|
||||
From this point on, we assume out decode context is using mode number
|
||||
\varname{[mode\_number]} from configuration array
|
||||
\varname{[vorbis\_mode\_configurations]} and the map number
|
||||
\varname{[vorbis\_mode\_mapping]} (specified by the current mode) taken
|
||||
from the mapping configuration array
|
||||
\varname{[vorbis\_mapping\_configurations]}.
|
||||
|
||||
Floor curves are decoded one-by-one in channel order.
|
||||
|
||||
For each floor \varname{[i]} of \varname{[audio\_channels]}
|
||||
\begin{enumerate}
|
||||
\item \varname{[submap\_number]} = element \varname{[i]} of vector [vorbis\_mapping\_mux]
|
||||
\item \varname{[floor\_number]} = element \varname{[submap\_number]} of vector
|
||||
[vorbis\_submap\_floor]
|
||||
\item if the floor type of this
|
||||
floor (vector \varname{[vorbis\_floor\_types]} element
|
||||
\varname{[floor\_number]}) is zero then decode the floor for
|
||||
channel \varname{[i]} according to the
|
||||
\xref{vorbis:spec:floor0-decode}
|
||||
\item if the type of this floor
|
||||
is one then decode the floor for channel \varname{[i]} according
|
||||
to the \xref{vorbis:spec:floor1-decode}
|
||||
\item save the needed decoded floor information for channel for later synthesis
|
||||
\item if the decoded floor returned 'unused', set vector \varname{[no\_residue]} element
|
||||
\varname{[i]} to true, else set vector \varname{[no\_residue]} element \varname{[i]} to
|
||||
false
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
An end-of-packet condition during floor decode shall result in packet
|
||||
decode zeroing all channel output vectors and skipping to the
|
||||
add/overlap output stage.
|
||||
|
||||
|
||||
|
||||
\subsubsection{nonzero vector propagate}
|
||||
|
||||
A possible result of floor decode is that a specific vector is marked
|
||||
'unused' which indicates that that final output vector is all-zero
|
||||
values (and the floor is zero). The residue for that vector is not
|
||||
coded in the stream, save for one complication. If some vectors are
|
||||
used and some are not, channel coupling could result in mixing a
|
||||
zeroed and nonzeroed vector to produce two nonzeroed vectors.
|
||||
|
||||
for each \varname{[i]} from 0 ... \varname{[vorbis\_mapping\_coupling\_steps]}-1
|
||||
|
||||
\begin{enumerate}
|
||||
\item if either \varname{[no\_residue]} entry for channel
|
||||
(\varname{[vorbis\_mapping\_magnitude]} element \varname{[i]})
|
||||
or channel
|
||||
(\varname{[vorbis\_mapping\_angle]} element \varname{[i]})
|
||||
are set to false, then both must be set to false. Note that an 'unused'
|
||||
floor has no decoded floor information; it is important that this is
|
||||
remembered at floor curve synthesis time.
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{residue decode}
|
||||
|
||||
Unlike floors, which are decoded in channel order, the residue vectors
|
||||
are decoded in submap order.
|
||||
|
||||
for each submap \varname{[i]} in order from 0 ... \varname{[vorbis\_mapping\_submaps]}-1
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[ch]} = 0
|
||||
\item for each channel \varname{[j]} in order from 0 ... \varname{[audio\_channels]} - 1
|
||||
\begin{enumerate}
|
||||
\item if channel \varname{[j]} in submap \varname{[i]} (vector \varname{[vorbis\_mapping\_mux]} element \varname{[j]} is equal to \varname{[i]})
|
||||
\begin{enumerate}
|
||||
\item if vector \varname{[no\_residue]} element \varname{[j]} is true
|
||||
\begin{enumerate}
|
||||
\item vector \varname{[do\_not\_decode\_flag]} element \varname{[ch]} is set
|
||||
\end{enumerate}
|
||||
else
|
||||
\begin{enumerate}
|
||||
\item vector \varname{[do\_not\_decode\_flag]} element \varname{[ch]} is unset
|
||||
\end{enumerate}
|
||||
|
||||
\item increment \varname{[ch]}
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
\item \varname{[residue\_number]} = vector \varname{[vorbis\_mapping\_submap\_residue]} element \varname{[i]}
|
||||
\item \varname{[residue\_type]} = vector \varname{[vorbis\_residue\_types]} element \varname{[residue\_number]}
|
||||
\item decode \varname{[ch]} vectors using residue \varname{[residue\_number]}, according to type \varname{[residue\_type]}, also passing vector \varname{[do\_not\_decode\_flag]} to indicate which vectors in the bundle should not be decoded. Correct per-vector decode length is \varname{[n]}/2.
|
||||
\item \varname{[ch]} = 0
|
||||
\item for each channel \varname{[j]} in order from 0 ... \varname{[audio\_channels]}
|
||||
\begin{enumerate}
|
||||
\item if channel \varname{[j]} is in submap \varname{[i]} (vector \varname{[vorbis\_mapping\_mux]} element \varname{[j]} is equal to \varname{[i]})
|
||||
\begin{enumerate}
|
||||
\item residue vector for channel \varname{[j]} is set to decoded residue vector \varname{[ch]}
|
||||
\item increment \varname{[ch]}
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
\subsubsection{inverse coupling}
|
||||
|
||||
for each \varname{[i]} from \varname{[vorbis\_mapping\_coupling\_steps]}-1 descending to 0
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[magnitude\_vector]} = the residue vector for channel
|
||||
(vector \varname{[vorbis\_mapping\_magnitude]} element \varname{[i]})
|
||||
\item \varname{[angle\_vector]} = the residue vector for channel (vector
|
||||
\varname{[vorbis\_mapping\_angle]} element \varname{[i]})
|
||||
\item for each scalar value \varname{[M]} in vector \varname{[magnitude\_vector]} and the corresponding scalar value \varname{[A]} in vector \varname{[angle\_vector]}:
|
||||
\begin{enumerate}
|
||||
\item if (\varname{[M]} is greater than zero)
|
||||
\begin{enumerate}
|
||||
\item if (\varname{[A]} is greater than zero)
|
||||
\begin{enumerate}
|
||||
\item \varname{[new\_M]} = \varname{[M]}
|
||||
\item \varname{[new\_A]} = \varname{[M]}-\varname{[A]}
|
||||
\end{enumerate}
|
||||
else
|
||||
\begin{enumerate}
|
||||
\item \varname{[new\_A]} = \varname{[M]}
|
||||
\item \varname{[new\_M]} = \varname{[M]}+\varname{[A]}
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
else
|
||||
\begin{enumerate}
|
||||
\item if (\varname{[A]} is greater than zero)
|
||||
\begin{enumerate}
|
||||
\item \varname{[new\_M]} = \varname{[M]}
|
||||
\item \varname{[new\_A]} = \varname{[M]}+\varname{[A]}
|
||||
\end{enumerate}
|
||||
else
|
||||
\begin{enumerate}
|
||||
\item \varname{[new\_A]} = \varname{[M]}
|
||||
\item \varname{[new\_M]} = \varname{[M]}-\varname{[A]}
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
\item set scalar value \varname{[M]} in vector \varname{[magnitude\_vector]} to \varname{[new\_M]}
|
||||
\item set scalar value \varname{[A]} in vector \varname{[angle\_vector]} to \varname{[new\_A]}
|
||||
\end{enumerate}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{dot product}
|
||||
|
||||
For each channel, synthesize the floor curve from the decoded floor
|
||||
information, according to packet type. Note that the vector synthesis
|
||||
length for floor computation is \varname{[n]}/2.
|
||||
|
||||
For each channel, multiply each element of the floor curve by each
|
||||
element of that channel's residue vector. The result is the dot
|
||||
product of the floor and residue vectors for each channel; the produced
|
||||
vectors are the length \varname{[n]}/2 audio spectrum for each
|
||||
channel.
|
||||
|
||||
% TODO/FIXME: The following two paragraphs have identical twins
|
||||
% in section 1 (under "compute floor/residue dot product")
|
||||
One point is worth mentioning about this dot product; a common mistake
|
||||
in a fixed point implementation might be to assume that a 32 bit
|
||||
fixed-point representation for floor and residue and direct
|
||||
multiplication of the vectors is sufficient for acceptable spectral
|
||||
depth in all cases because it happens to mostly work with the current
|
||||
Xiph.Org reference encoder.
|
||||
|
||||
However, floor vector values can span \~140dB (\~24 bits unsigned), and
|
||||
the audio spectrum vector should represent a minimum of 120dB (\~21
|
||||
bits with sign), even when output is to a 16 bit PCM device. For the
|
||||
residue vector to represent full scale if the floor is nailed to
|
||||
$-140$dB, it must be able to span 0 to $+140$dB. For the residue vector
|
||||
to reach full scale if the floor is nailed at 0dB, it must be able to
|
||||
represent $-140$dB to $+0$dB. Thus, in order to handle full range
|
||||
dynamics, a residue vector may span $-140$dB to $+140$dB entirely within
|
||||
spec. A 280dB range is approximately 48 bits with sign; thus the
|
||||
residue vector must be able to represent a 48 bit range and the dot
|
||||
product must be able to handle an effective 48 bit times 24 bit
|
||||
multiplication. This range may be achieved using large (64 bit or
|
||||
larger) integers, or implementing a movable binary point
|
||||
representation.
|
||||
|
||||
|
||||
|
||||
\subsubsection{inverse MDCT}
|
||||
|
||||
Convert the audio spectrum vector of each channel back into time
|
||||
domain PCM audio via an inverse Modified Discrete Cosine Transform
|
||||
(MDCT). A detailed description of the MDCT is available in \cite{Sporer/Brandenburg/Edler}. The window
|
||||
function used for the MDCT is the function described earlier.
|
||||
|
||||
|
||||
|
||||
\subsubsection{overlap\_add}
|
||||
|
||||
Windowed MDCT output is overlapped and added with the right hand data
|
||||
of the previous window such that the 3/4 point of the previous window
|
||||
is aligned with the 1/4 point of the current window (as illustrated in
|
||||
\xref{vorbis:spec:window}). The overlapped portion
|
||||
produced from overlapping the previous and current frame data is
|
||||
finished data to be returned by the decoder. This data spans from the
|
||||
center of the previous window to the center of the current window. In
|
||||
the case of same-sized windows, the amount of data to return is
|
||||
one-half block consisting of and only of the overlapped portions. When
|
||||
overlapping a short and long window, much of the returned range does not
|
||||
actually overlap. This does not damage transform orthogonality. Pay
|
||||
attention however to returning the correct data range; the amount of
|
||||
data to be returned is:
|
||||
|
||||
\begin{programlisting}
|
||||
window_blocksize(previous_window)/4+window_blocksize(current_window)/4
|
||||
\end{programlisting}
|
||||
|
||||
from the center (element windowsize/2) of the previous window to the
|
||||
center (element windowsize/2-1, inclusive) of the current window.
|
||||
|
||||
Data is not returned from the first frame; it must be used to 'prime'
|
||||
the decode engine. The encoder accounts for this priming when
|
||||
calculating PCM offsets; after the first frame, the proper PCM output
|
||||
offset is '0' (as no data has been returned yet).
|
||||
|
||||
|
||||
|
||||
\subsubsection{output channel order}
|
||||
|
||||
Vorbis I specifies only a channel mapping type 0. In mapping type 0,
|
||||
channel mapping is implicitly defined as follows for standard audio
|
||||
applications. As of revision 16781 (20100113), the specification adds
|
||||
defined channel locations for 6.1 and 7.1 surround. Ordering/location
|
||||
for greater-than-eight channels remains 'left to the implementation'.
|
||||
|
||||
These channel orderings refer to order within the encoded stream. It
|
||||
is naturally possible for a decoder to produce output with channels in
|
||||
any order. Any such decoder should explicitly document channel
|
||||
reordering behavior.
|
||||
|
||||
\begin{description} %[style=nextline]
|
||||
\item[one channel]
|
||||
the stream is monophonic
|
||||
|
||||
\item[two channels]
|
||||
the stream is stereo. channel order: left, right
|
||||
|
||||
\item[three channels]
|
||||
the stream is a 1d-surround encoding. channel order: left,
|
||||
center, right
|
||||
|
||||
\item[four channels]
|
||||
the stream is quadraphonic surround. channel order: front left,
|
||||
front right, rear left, rear right
|
||||
|
||||
\item[five channels]
|
||||
the stream is five-channel surround. channel order: front left,
|
||||
center, front right, rear left, rear right
|
||||
|
||||
\item[six channels]
|
||||
the stream is 5.1 surround. channel order: front left, center,
|
||||
front right, rear left, rear right, LFE
|
||||
|
||||
\item[seven channels]
|
||||
the stream is 6.1 surround. channel order: front left, center,
|
||||
front right, side left, side right, rear center, LFE
|
||||
|
||||
\item[eight channels]
|
||||
the stream is 7.1 surround. channel order: front left, center,
|
||||
front right, side left, side right, rear left, rear right,
|
||||
LFE
|
||||
|
||||
\item[greater than eight channels]
|
||||
channel use and order is defined by the application
|
||||
|
||||
\end{description}
|
||||
|
||||
Applications using Vorbis for dedicated purposes may define channel
|
||||
mapping as seen fit. Future channel mappings (such as three and four
|
||||
channel \href{http://www.ambisonic.net/}{Ambisonics}) will
|
||||
make use of channel mappings other than mapping 0.
|
||||
|
||||
|
|
@ -0,0 +1,239 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{comment field and header specification} \label{vorbis:spec:comment}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
The Vorbis text comment header is the second (of three) header
|
||||
packets that begin a Vorbis bitstream. It is meant for short text
|
||||
comments, not arbitrary metadata; arbitrary metadata belongs in a
|
||||
separate logical bitstream (usually an XML stream type) that provides
|
||||
greater structure and machine parseability.
|
||||
|
||||
The comment field is meant to be used much like someone jotting a
|
||||
quick note on the bottom of a CDR. It should be a little information to
|
||||
remember the disc by and explain it to others; a short, to-the-point
|
||||
text note that need not only be a couple words, but isn't going to be
|
||||
more than a short paragraph. The essentials, in other words, whatever
|
||||
they turn out to be, eg:
|
||||
|
||||
\begin{quote}
|
||||
Honest Bob and the Factory-to-Dealer-Incentives, \textit{``I'm Still
|
||||
Around''}, opening for Moxy Fr\"{u}vous, 1997.
|
||||
\end{quote}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsection{Comment encoding}
|
||||
|
||||
\subsubsection{Structure}
|
||||
|
||||
The comment header is logically a list of eight-bit-clean vectors; the
|
||||
number of vectors is bounded to $2^{32}-1$ and the length of each vector
|
||||
is limited to $2^{32}-1$ bytes. The vector length is encoded; the vector
|
||||
contents themselves are not null terminated. In addition to the vector
|
||||
list, there is a single vector for vendor name (also 8 bit clean,
|
||||
length encoded in 32 bits). For example, the 1.0 release of libvorbis
|
||||
set the vendor string to ``Xiph.Org libVorbis I 20020717''.
|
||||
|
||||
The vector lengths and number of vectors are stored lsb first, according
|
||||
to the bit packing conventions of the vorbis codec. However, since data
|
||||
in the comment header is octet-aligned, they can simply be read as
|
||||
unaligned 32 bit little endian unsigned integers.
|
||||
|
||||
The comment header is decoded as follows:
|
||||
|
||||
\begin{programlisting}
|
||||
1) [vendor\_length] = read an unsigned integer of 32 bits
|
||||
2) [vendor\_string] = read a UTF-8 vector as [vendor\_length] octets
|
||||
3) [user\_comment\_list\_length] = read an unsigned integer of 32 bits
|
||||
4) iterate [user\_comment\_list\_length] times {
|
||||
5) [length] = read an unsigned integer of 32 bits
|
||||
6) this iteration's user comment = read a UTF-8 vector as [length] octets
|
||||
}
|
||||
7) [framing\_bit] = read a single bit as boolean
|
||||
8) if ( [framing\_bit] unset or end-of-packet ) then ERROR
|
||||
9) done.
|
||||
\end{programlisting}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{Content vector format}
|
||||
|
||||
The comment vectors are structured similarly to a UNIX environment variable.
|
||||
That is, comment fields consist of a field name and a corresponding value and
|
||||
look like:
|
||||
|
||||
\begin{quote}
|
||||
\begin{programlisting}
|
||||
comment[0]="ARTIST=me";
|
||||
comment[1]="TITLE=the sound of Vorbis";
|
||||
\end{programlisting}
|
||||
\end{quote}
|
||||
|
||||
The field name is case-insensitive and may consist of ASCII 0x20
|
||||
through 0x7D, 0x3D ('=') excluded. ASCII 0x41 through 0x5A inclusive
|
||||
(characters A-Z) is to be considered equivalent to ASCII 0x61 through
|
||||
0x7A inclusive (characters a-z).
|
||||
|
||||
|
||||
The field name is immediately followed by ASCII 0x3D ('=');
|
||||
this equals sign is used to terminate the field name.
|
||||
|
||||
|
||||
0x3D is followed by 8 bit clean UTF-8 encoded value of the
|
||||
field contents to the end of the field.
|
||||
|
||||
|
||||
\paragraph{Field names}
|
||||
|
||||
Below is a proposed, minimal list of standard field names with a
|
||||
description of intended use. No single or group of field names is
|
||||
mandatory; a comment header may contain one, all or none of the names
|
||||
in this list.
|
||||
|
||||
\begin{description} %[style=nextline]
|
||||
\item[TITLE]
|
||||
Track/Work name
|
||||
|
||||
\item[VERSION]
|
||||
The version field may be used to differentiate multiple
|
||||
versions of the same track title in a single collection. (e.g. remix
|
||||
info)
|
||||
|
||||
\item[ALBUM]
|
||||
The collection name to which this track belongs
|
||||
|
||||
\item[TRACKNUMBER]
|
||||
The track number of this piece if part of a specific larger collection or album
|
||||
|
||||
\item[ARTIST]
|
||||
The artist generally considered responsible for the work. In popular music this is usually the performing band or singer. For classical music it would be the composer. For an audio book it would be the author of the original text.
|
||||
|
||||
\item[PERFORMER]
|
||||
The artist(s) who performed the work. In classical music this would be the conductor, orchestra, soloists. In an audio book it would be the actor who did the reading. In popular music this is typically the same as the ARTIST and is omitted.
|
||||
|
||||
\item[COPYRIGHT]
|
||||
Copyright attribution, e.g., '2001 Nobody's Band' or '1999 Jack Moffitt'
|
||||
|
||||
\item[LICENSE]
|
||||
License information, eg, 'All Rights Reserved', 'Any
|
||||
Use Permitted', a URL to a license such as a Creative Commons license
|
||||
("www.creativecommons.org/blahblah/license.html") or the EFF Open
|
||||
Audio License ('distributed under the terms of the Open Audio
|
||||
License. see http://www.eff.org/IP/Open\_licenses/eff\_oal.html for
|
||||
details'), etc.
|
||||
|
||||
\item[ORGANIZATION]
|
||||
Name of the organization producing the track (i.e.
|
||||
the 'record label')
|
||||
|
||||
\item[DESCRIPTION]
|
||||
A short text description of the contents
|
||||
|
||||
\item[GENRE]
|
||||
A short text indication of music genre
|
||||
|
||||
\item[DATE]
|
||||
Date the track was recorded
|
||||
|
||||
\item[LOCATION]
|
||||
Location where track was recorded
|
||||
|
||||
\item[CONTACT]
|
||||
Contact information for the creators or distributors of the track. This could be a URL, an email address, the physical address of the producing label.
|
||||
|
||||
\item[ISRC]
|
||||
International Standard Recording Code for the
|
||||
track; see \href{http://www.ifpi.org/isrc/}{the ISRC
|
||||
intro page} for more information on ISRC numbers.
|
||||
|
||||
\end{description}
|
||||
|
||||
|
||||
|
||||
\paragraph{Implications}
|
||||
|
||||
Field names should not be 'internationalized'; this is a
|
||||
concession to simplicity not an attempt to exclude the majority of
|
||||
the world that doesn't speak English. Field \emph{contents},
|
||||
however, use the UTF-8 character encoding to allow easy representation
|
||||
of any language.
|
||||
|
||||
We have the length of the entirety of the field and restrictions on
|
||||
the field name so that the field name is bounded in a known way. Thus
|
||||
we also have the length of the field contents.
|
||||
|
||||
Individual 'vendors' may use non-standard field names within
|
||||
reason. The proper use of comment fields should be clear through
|
||||
context at this point. Abuse will be discouraged.
|
||||
|
||||
There is no vendor-specific prefix to 'nonstandard' field names.
|
||||
Vendors should make some effort to avoid arbitrarily polluting the
|
||||
common namespace. We will generally collect the more useful tags
|
||||
here to help with standardization.
|
||||
|
||||
Field names are not required to be unique (occur once) within a
|
||||
comment header. As an example, assume a track was recorded by three
|
||||
well know artists; the following is permissible, and encouraged:
|
||||
|
||||
\begin{quote}
|
||||
\begin{programlisting}
|
||||
ARTIST=Dizzy Gillespie
|
||||
ARTIST=Sonny Rollins
|
||||
ARTIST=Sonny Stitt
|
||||
\end{programlisting}
|
||||
\end{quote}
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{Encoding}
|
||||
|
||||
The comment header comprises the entirety of the second bitstream
|
||||
header packet. Unlike the first bitstream header packet, it is not
|
||||
generally the only packet on the second page and may not be restricted
|
||||
to within the second bitstream page. The length of the comment header
|
||||
packet is (practically) unbounded. The comment header packet is not
|
||||
optional; it must be present in the bitstream even if it is
|
||||
effectively empty.
|
||||
|
||||
The comment header is encoded as follows (as per Ogg's standard
|
||||
bitstream mapping which renders least-significant-bit of the word to be
|
||||
coded into the least significant available bit of the current
|
||||
bitstream octet first):
|
||||
|
||||
\begin{enumerate}
|
||||
\item
|
||||
Vendor string length (32 bit unsigned quantity specifying number of octets)
|
||||
|
||||
\item
|
||||
Vendor string ([vendor string length] octets coded from beginning of string to end of string, not null terminated)
|
||||
|
||||
\item
|
||||
Number of comment fields (32 bit unsigned quantity specifying number of fields)
|
||||
|
||||
\item
|
||||
Comment field 0 length (if [Number of comment fields] $>0$; 32 bit unsigned quantity specifying number of octets)
|
||||
|
||||
\item
|
||||
Comment field 0 ([Comment field 0 length] octets coded from beginning of string to end of string, not null terminated)
|
||||
|
||||
\item
|
||||
Comment field 1 length (if [Number of comment fields] $>1$...)...
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
This is actually somewhat easier to describe in code; implementation of the above can be found in \filename{vorbis/lib/info.c}, \function{\_vorbis\_pack\_comment()} and \function{\_vorbis\_unpack\_comment()}.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,201 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Floor type 0 setup and decode} \label{vorbis:spec:floor0}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
Vorbis floor type zero uses Line Spectral Pair (LSP, also alternately
|
||||
known as Line Spectral Frequency or LSF) representation to encode a
|
||||
smooth spectral envelope curve as the frequency response of the LSP
|
||||
filter. This representation is equivalent to a traditional all-pole
|
||||
infinite impulse response filter as would be used in linear predictive
|
||||
coding; LSP representation may be converted to LPC representation and
|
||||
vice-versa.
|
||||
|
||||
|
||||
|
||||
\subsection{Floor 0 format}
|
||||
|
||||
Floor zero configuration consists of six integer fields and a list of
|
||||
VQ codebooks for use in coding/decoding the LSP filter coefficient
|
||||
values used by each frame.
|
||||
|
||||
\subsubsection{header decode}
|
||||
|
||||
Configuration information for instances of floor zero decodes from the
|
||||
codec setup header (third packet). configuration decode proceeds as
|
||||
follows:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [floor0\_order] = read an unsigned integer of 8 bits
|
||||
2) [floor0\_rate] = read an unsigned integer of 16 bits
|
||||
3) [floor0\_bark\_map\_size] = read an unsigned integer of 16 bits
|
||||
4) [floor0\_amplitude\_bits] = read an unsigned integer of six bits
|
||||
5) [floor0\_amplitude\_offset] = read an unsigned integer of eight bits
|
||||
6) [floor0\_number\_of\_books] = read an unsigned integer of four bits and add 1
|
||||
7) array [floor0\_book\_list] = read a list of [floor0\_number\_of\_books] unsigned integers of eight bits each;
|
||||
\end{Verbatim}
|
||||
|
||||
An end-of-packet condition during any of these bitstream reads renders
|
||||
this stream undecodable. In addition, any element of the array
|
||||
\varname{[floor0\_book\_list]} that is greater than the maximum codebook
|
||||
number for this bitstream is an error condition that also renders the
|
||||
stream undecodable.
|
||||
|
||||
|
||||
|
||||
\subsubsection{packet decode} \label{vorbis:spec:floor0-decode}
|
||||
|
||||
Extracting a floor0 curve from an audio packet consists of first
|
||||
decoding the curve amplitude and \varname{[floor0\_order]} LSP
|
||||
coefficient values from the bitstream, and then computing the floor
|
||||
curve, which is defined as the frequency response of the decoded LSP
|
||||
filter.
|
||||
|
||||
Packet decode proceeds as follows:
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [amplitude] = read an unsigned integer of [floor0\_amplitude\_bits] bits
|
||||
2) if ( [amplitude] is greater than zero ) \{
|
||||
3) [coefficients] is an empty, zero length vector
|
||||
4) [booknumber] = read an unsigned integer of \link{vorbis:spec:ilog}{ilog}( [floor0\_number\_of\_books] ) bits
|
||||
5) if ( [booknumber] is greater than the highest number decode codebook ) then packet is undecodable
|
||||
6) [last] = zero;
|
||||
7) vector [temp\_vector] = read vector from bitstream using codebook number [floor0\_book\_list] element [booknumber] in VQ context.
|
||||
8) add the scalar value [last] to each scalar in vector [temp\_vector]
|
||||
9) [last] = the value of the last scalar in vector [temp\_vector]
|
||||
10) concatenate [temp\_vector] onto the end of the [coefficients] vector
|
||||
11) if (length of vector [coefficients] is less than [floor0\_order], continue at step 6
|
||||
|
||||
\}
|
||||
|
||||
12) done.
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
Take note of the following properties of decode:
|
||||
\begin{itemize}
|
||||
\item An \varname{[amplitude]} value of zero must result in a return code that indicates this channel is unused in this frame (the output of the channel will be all-zeroes in synthesis). Several later stages of decode don't occur for an unused channel.
|
||||
\item An end-of-packet condition during decode should be considered a
|
||||
nominal occruence; if end-of-packet is reached during any read
|
||||
operation above, floor decode is to return 'unused' status as if the
|
||||
\varname{[amplitude]} value had read zero at the beginning of decode.
|
||||
|
||||
\item The book number used for decode
|
||||
can, in fact, be stored in the bitstream in \link{vorbis:spec:ilog}{ilog}( \varname{[floor0\_number\_of\_books]} -
|
||||
1 ) bits. Nevertheless, the above specification is correct and values
|
||||
greater than the maximum possible book value are reserved.
|
||||
|
||||
\item The number of scalars read into the vector \varname{[coefficients]}
|
||||
may be greater than \varname{[floor0\_order]}, the number actually
|
||||
required for curve computation. For example, if the VQ codebook used
|
||||
for the floor currently being decoded has a
|
||||
\varname{[codebook\_dimensions]} value of three and
|
||||
\varname{[floor0\_order]} is ten, the only way to fill all the needed
|
||||
scalars in \varname{[coefficients]} is to to read a total of twelve
|
||||
scalars as four vectors of three scalars each. This is not an error
|
||||
condition, and care must be taken not to allow a buffer overflow in
|
||||
decode. The extra values are not used and may be ignored or discarded.
|
||||
\end{itemize}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{curve computation} \label{vorbis:spec:floor0-synth}
|
||||
|
||||
Given an \varname{[amplitude]} integer and \varname{[coefficients]}
|
||||
vector from packet decode as well as the [floor0\_order],
|
||||
[floor0\_rate], [floor0\_bark\_map\_size], [floor0\_amplitude\_bits] and
|
||||
[floor0\_amplitude\_offset] values from floor setup, and an output
|
||||
vector size \varname{[n]} specified by the decode process, we compute a
|
||||
floor output vector.
|
||||
|
||||
If the value \varname{[amplitude]} is zero, the return value is a
|
||||
length \varname{[n]} vector with all-zero scalars. Otherwise, begin by
|
||||
assuming the following definitions for the given vector to be
|
||||
synthesized:
|
||||
|
||||
\begin{displaymath}
|
||||
\mathrm{map}_i = \left\{
|
||||
\begin{array}{ll}
|
||||
\min (
|
||||
\mathtt{floor0\texttt{\_}bark\texttt{\_}map\texttt{\_}size} - 1,
|
||||
foobar
|
||||
) & \textrm{for } i \in [0,n-1] \\
|
||||
-1 & \textrm{for } i = n
|
||||
\end{array}
|
||||
\right.
|
||||
\end{displaymath}
|
||||
|
||||
where
|
||||
|
||||
\begin{displaymath}
|
||||
foobar =
|
||||
\left\lfloor
|
||||
\mathrm{bark}\left(\frac{\mathtt{floor0\texttt{\_}rate} \cdot i}{2n}\right) \cdot \frac{\mathtt{floor0\texttt{\_}bark\texttt{\_}map\texttt{\_}size}} {\mathrm{bark}(.5 \cdot \mathtt{floor0\texttt{\_}rate})}
|
||||
\right\rfloor
|
||||
\end{displaymath}
|
||||
|
||||
and
|
||||
|
||||
\begin{displaymath}
|
||||
\mathrm{bark}(x) = 13.1 \arctan (.00074x) + 2.24 \arctan (.0000000185x^2) + .0001x
|
||||
\end{displaymath}
|
||||
|
||||
The above is used to synthesize the LSP curve on a Bark-scale frequency
|
||||
axis, then map the result to a linear-scale frequency axis.
|
||||
Similarly, the below calculation synthesizes the output LSP curve \varname{[output]} on a log
|
||||
(dB) amplitude scale, mapping it to linear amplitude in the last step:
|
||||
|
||||
\begin{enumerate}
|
||||
\item \varname{[i]} = 0
|
||||
\item \varname{[$\omega$]} = $\pi$ * map element \varname{[i]} / \varname{[floor0\_bark\_map\_size]}
|
||||
\item if ( \varname{[floor0\_order]} is odd ) {
|
||||
\begin{enumerate}
|
||||
\item calculate \varname{[p]} and \varname{[q]} according to:
|
||||
\begin{eqnarray*}
|
||||
p & = & (1 - \cos^2\omega)\prod_{j=0}^{\frac{\mathtt{floor0\texttt{\_}order}-3}{2}} 4 (\cos([\mathtt{coefficients}]_{2j+1}) - \cos \omega)^2 \\
|
||||
q & = & \frac{1}{4} \prod_{j=0}^{\frac{\mathtt{floor0\texttt{\_}order}-1}{2}} 4 (\cos([\mathtt{coefficients}]_{2j}) - \cos \omega)^2
|
||||
\end{eqnarray*}
|
||||
|
||||
\end{enumerate}
|
||||
} else \varname{[floor0\_order]} is even {
|
||||
\begin{enumerate}[resume]
|
||||
\item calculate \varname{[p]} and \varname{[q]} according to:
|
||||
\begin{eqnarray*}
|
||||
p & = & \frac{(1 - \cos\omega)}{2} \prod_{j=0}^{\frac{\mathtt{floor0\texttt{\_}order}-2}{2}} 4 (\cos([\mathtt{coefficients}]_{2j+1}) - \cos \omega)^2 \\
|
||||
q & = & \frac{(1 + \cos\omega)}{2} \prod_{j=0}^{\frac{\mathtt{floor0\texttt{\_}order}-2}{2}} 4 (\cos([\mathtt{coefficients}]_{2j}) - \cos \omega)^2
|
||||
\end{eqnarray*}
|
||||
|
||||
\end{enumerate}
|
||||
}
|
||||
|
||||
\item calculate \varname{[linear\_floor\_value]} according to:
|
||||
\begin{displaymath}
|
||||
\exp \left( .11512925 \left(\frac{\mathtt{amplitude} \cdot \mathtt{floor0\texttt{\_}amplitute\texttt{\_}offset}}{(2^{\mathtt{floor0\texttt{\_}amplitude\texttt{\_}bits}}-1)\sqrt{p+q}}
|
||||
- \mathtt{floor0\texttt{\_}amplitude\texttt{\_}offset} \right) \right)
|
||||
\end{displaymath}
|
||||
|
||||
\item \varname{[iteration\_condition]} = map element \varname{[i]}
|
||||
\item \varname{[output]} element \varname{[i]} = \varname{[linear\_floor\_value]}
|
||||
\item increment \varname{[i]}
|
||||
\item if ( map element \varname{[i]} is equal to \varname{[iteration\_condition]} ) continue at step 5
|
||||
\item if ( \varname{[i]} is less than \varname{[n]} ) continue at step 2
|
||||
\item done
|
||||
\end{enumerate}
|
||||
|
||||
\paragraph{Errata 20150227: Bark scale computation}
|
||||
|
||||
Due to a typo when typesetting this version of the specification from the original HTML document, the Bark scale computation previously erroneously read:
|
||||
|
||||
\begin{displaymath}
|
||||
\hbox{\sout{$
|
||||
\mathrm{bark}(x) = 13.1 \arctan (.00074x) + 2.24 \arctan (.0000000185x^2 + .0001x)
|
||||
$}}
|
||||
\end{displaymath}
|
||||
|
||||
Note that the last parenthesis is misplaced. This document now uses the correct equation as it appeared in the original HTML spec document:
|
||||
|
||||
\begin{displaymath}
|
||||
\mathrm{bark}(x) = 13.1 \arctan (.00074x) + 2.24 \arctan (.0000000185x^2) + .0001x
|
||||
\end{displaymath}
|
||||
|
|
@ -0,0 +1,404 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Floor type 1 setup and decode} \label{vorbis:spec:floor1}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
Vorbis floor type one uses a piecewise straight-line representation to
|
||||
encode a spectral envelope curve. The representation plots this curve
|
||||
mechanically on a linear frequency axis and a logarithmic (dB)
|
||||
amplitude axis. The integer plotting algorithm used is similar to
|
||||
Bresenham's algorithm.
|
||||
|
||||
|
||||
|
||||
\subsection{Floor 1 format}
|
||||
|
||||
\subsubsection{model}
|
||||
|
||||
Floor type one represents a spectral curve as a series of
|
||||
line segments. Synthesis constructs a floor curve using iterative
|
||||
prediction in a process roughly equivalent to the following simplified
|
||||
description:
|
||||
|
||||
\begin{itemize}
|
||||
\item the first line segment (base case) is a logical line spanning
|
||||
from x_0,y_0 to x_1,y_1 where in the base case x_0=0 and x_1=[n], the
|
||||
full range of the spectral floor to be computed.
|
||||
|
||||
\item the induction step chooses a point x_new within an existing
|
||||
logical line segment and produces a y_new value at that point computed
|
||||
from the existing line's y value at x_new (as plotted by the line) and
|
||||
a difference value decoded from the bitstream packet.
|
||||
|
||||
\item floor computation produces two new line segments, one running from
|
||||
x_0,y_0 to x_new,y_new and from x_new,y_new to x_1,y_1. This step is
|
||||
performed logically even if y_new represents no change to the
|
||||
amplitude value at x_new so that later refinement is additionally
|
||||
bounded at x_new.
|
||||
|
||||
\item the induction step repeats, using a list of x values specified in
|
||||
the codec setup header at floor 1 initialization time. Computation
|
||||
is completed at the end of the x value list.
|
||||
|
||||
\end{itemize}
|
||||
|
||||
|
||||
Consider the following example, with values chosen for ease of
|
||||
understanding rather than representing typical configuration:
|
||||
|
||||
For the below example, we assume a floor setup with an [n] of 128.
|
||||
The list of selected X values in increasing order is
|
||||
0,16,32,48,64,80,96,112 and 128. In list order, the values interleave
|
||||
as 0, 128, 64, 32, 96, 16, 48, 80 and 112. The corresponding
|
||||
list-order Y values as decoded from an example packet are 110, 20, -5,
|
||||
-45, 0, -25, -10, 30 and -10. We compute the floor in the following
|
||||
way, beginning with the first line:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=8cm]{floor1-1}
|
||||
\captionof{figure}{graph of example floor}
|
||||
\end{center}
|
||||
|
||||
We now draw new logical lines to reflect the correction to new_Y, and
|
||||
iterate for X positions 32 and 96:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=8cm]{floor1-2}
|
||||
\captionof{figure}{graph of example floor}
|
||||
\end{center}
|
||||
|
||||
Although the new Y value at X position 96 is unchanged, it is still
|
||||
used later as an endpoint for further refinement. From here on, the
|
||||
pattern should be clear; we complete the floor computation as follows:
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=8cm]{floor1-3}
|
||||
\captionof{figure}{graph of example floor}
|
||||
\end{center}
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=8cm]{floor1-4}
|
||||
\captionof{figure}{graph of example floor}
|
||||
\end{center}
|
||||
|
||||
A more efficient algorithm with carefully defined integer rounding
|
||||
behavior is used for actual decode, as described later. The actual
|
||||
algorithm splits Y value computation and line plotting into two steps
|
||||
with modifications to the above algorithm to eliminate noise
|
||||
accumulation through integer roundoff/truncation.
|
||||
|
||||
|
||||
|
||||
\subsubsection{header decode}
|
||||
|
||||
A list of floor X values is stored in the packet header in interleaved
|
||||
format (used in list order during packet decode and synthesis). This
|
||||
list is split into partitions, and each partition is assigned to a
|
||||
partition class. X positions 0 and [n] are implicit and do not belong
|
||||
to an explicit partition or partition class.
|
||||
|
||||
A partition class consists of a representation vector width (the
|
||||
number of Y values which the partition class encodes at once), a
|
||||
'subclass' value representing the number of alternate entropy books
|
||||
the partition class may use in representing Y values, the list of
|
||||
[subclass] books and a master book used to encode which alternate
|
||||
books were chosen for representation in a given packet. The
|
||||
master/subclass mechanism is meant to be used as a flexible
|
||||
representation cascade while still using codebooks only in a scalar
|
||||
context.
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
|
||||
1) [floor1\_partitions] = read 5 bits as unsigned integer
|
||||
2) [maximum\_class] = -1
|
||||
3) iterate [i] over the range 0 ... [floor1\_partitions]-1 \{
|
||||
|
||||
4) vector [floor1\_partition\_class\_list] element [i] = read 4 bits as unsigned integer
|
||||
|
||||
\}
|
||||
|
||||
5) [maximum\_class] = largest integer scalar value in vector [floor1\_partition\_class\_list]
|
||||
6) iterate [i] over the range 0 ... [maximum\_class] \{
|
||||
|
||||
7) vector [floor1\_class\_dimensions] element [i] = read 3 bits as unsigned integer and add 1
|
||||
8) vector [floor1\_class\_subclasses] element [i] = read 2 bits as unsigned integer
|
||||
9) if ( vector [floor1\_class\_subclasses] element [i] is nonzero ) \{
|
||||
|
||||
10) vector [floor1\_class\_masterbooks] element [i] = read 8 bits as unsigned integer
|
||||
|
||||
\}
|
||||
|
||||
11) iterate [j] over the range 0 ... (2 exponent [floor1\_class\_subclasses] element [i]) - 1 \{
|
||||
|
||||
12) array [floor1\_subclass\_books] element [i],[j] =
|
||||
read 8 bits as unsigned integer and subtract one
|
||||
\}
|
||||
\}
|
||||
|
||||
13) [floor1\_multiplier] = read 2 bits as unsigned integer and add one
|
||||
14) [rangebits] = read 4 bits as unsigned integer
|
||||
15) vector [floor1\_X\_list] element [0] = 0
|
||||
16) vector [floor1\_X\_list] element [1] = 2 exponent [rangebits];
|
||||
17) [floor1\_values] = 2
|
||||
18) iterate [i] over the range 0 ... [floor1\_partitions]-1 \{
|
||||
|
||||
19) [current\_class\_number] = vector [floor1\_partition\_class\_list] element [i]
|
||||
20) iterate [j] over the range 0 ... ([floor1\_class\_dimensions] element [current\_class\_number])-1 \{
|
||||
21) vector [floor1\_X\_list] element ([floor1\_values]) =
|
||||
read [rangebits] bits as unsigned integer
|
||||
22) increment [floor1\_values] by one
|
||||
\}
|
||||
\}
|
||||
|
||||
23) done
|
||||
\end{Verbatim}
|
||||
|
||||
An end-of-packet condition while reading any aspect of a floor 1
|
||||
configuration during setup renders a stream undecodable. In addition,
|
||||
a \varname{[floor1\_class\_masterbooks]} or
|
||||
\varname{[floor1\_subclass\_books]} scalar element greater than the
|
||||
highest numbered codebook configured in this stream is an error
|
||||
condition that renders the stream undecodable. Vector
|
||||
[floor1\_x\_list] is limited to a maximum length of 65 elements; a
|
||||
setup indicating more than 65 total elements (including elements 0 and
|
||||
1 set prior to the read loop) renders the stream undecodable. All
|
||||
vector [floor1\_x\_list] element values must be unique within the
|
||||
vector; a non-unique value renders the stream undecodable.
|
||||
|
||||
\subsubsection{packet decode} \label{vorbis:spec:floor1-decode}
|
||||
|
||||
Packet decode begins by checking the \varname{[nonzero]} flag:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [nonzero] = read 1 bit as boolean
|
||||
\end{Verbatim}
|
||||
|
||||
If \varname{[nonzero]} is unset, that indicates this channel contained
|
||||
no audio energy in this frame. Decode immediately returns a status
|
||||
indicating this floor curve (and thus this channel) is unused this
|
||||
frame. (A return status of 'unused' is different from decoding a
|
||||
floor that has all points set to minimum representation amplitude,
|
||||
which happens to be approximately -140dB).
|
||||
|
||||
|
||||
Assuming \varname{[nonzero]} is set, decode proceeds as follows:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [range] = vector \{ 256, 128, 86, 64 \} element ([floor1\_multiplier]-1)
|
||||
2) vector [floor1\_Y] element [0] = read \link{vorbis:spec:ilog}{ilog}([range]-1) bits as unsigned integer
|
||||
3) vector [floor1\_Y] element [1] = read \link{vorbis:spec:ilog}{ilog}([range]-1) bits as unsigned integer
|
||||
4) [offset] = 2;
|
||||
5) iterate [i] over the range 0 ... [floor1\_partitions]-1 \{
|
||||
|
||||
6) [class] = vector [floor1\_partition\_class] element [i]
|
||||
7) [cdim] = vector [floor1\_class\_dimensions] element [class]
|
||||
8) [cbits] = vector [floor1\_class\_subclasses] element [class]
|
||||
9) [csub] = (2 exponent [cbits])-1
|
||||
10) [cval] = 0
|
||||
11) if ( [cbits] is greater than zero ) \{
|
||||
|
||||
12) [cval] = read from packet using codebook number
|
||||
(vector [floor1\_class\_masterbooks] element [class]) in scalar context
|
||||
\}
|
||||
|
||||
13) iterate [j] over the range 0 ... [cdim]-1 \{
|
||||
|
||||
14) [book] = array [floor1\_subclass\_books] element [class],([cval] bitwise AND [csub])
|
||||
15) [cval] = [cval] right shifted [cbits] bits
|
||||
16) if ( [book] is not less than zero ) \{
|
||||
|
||||
17) vector [floor1\_Y] element ([j]+[offset]) = read from packet using codebook
|
||||
[book] in scalar context
|
||||
|
||||
\} else [book] is less than zero \{
|
||||
|
||||
18) vector [floor1\_Y] element ([j]+[offset]) = 0
|
||||
|
||||
\}
|
||||
\}
|
||||
|
||||
19) [offset] = [offset] + [cdim]
|
||||
|
||||
\}
|
||||
|
||||
20) done
|
||||
\end{Verbatim}
|
||||
|
||||
An end-of-packet condition during curve decode should be considered a
|
||||
nominal occurrence; if end-of-packet is reached during any read
|
||||
operation above, floor decode is to return 'unused' status as if the
|
||||
\varname{[nonzero]} flag had been unset at the beginning of decode.
|
||||
|
||||
|
||||
Vector \varname{[floor1\_Y]} contains the values from packet decode
|
||||
needed for floor 1 synthesis.
|
||||
|
||||
|
||||
|
||||
\subsubsection{curve computation} \label{vorbis:spec:floor1-synth}
|
||||
|
||||
Curve computation is split into two logical steps; the first step
|
||||
derives final Y amplitude values from the encoded, wrapped difference
|
||||
values taken from the bitstream. The second step plots the curve
|
||||
lines. Also, although zero-difference values are used in the
|
||||
iterative prediction to find final Y values, these points are
|
||||
conditionally skipped during final line computation in step two.
|
||||
Skipping zero-difference values allows a smoother line fit.
|
||||
|
||||
Although some aspects of the below algorithm look like inconsequential
|
||||
optimizations, implementors are warned to follow the details closely.
|
||||
Deviation from implementing a strictly equivalent algorithm can result
|
||||
in serious decoding errors.
|
||||
|
||||
{\em Additional note:} Although \varname{[floor1\_final\_Y]} values in
|
||||
the prediction loop and at the end of step 1 are inherently limited by
|
||||
the prediction algorithm to [0, \varname{[range]}), it is possible to
|
||||
abuse the setup and codebook machinery to produce negative or
|
||||
over-range results. We suggest that decoder implementations guard
|
||||
the values in vector \varname{[floor1\_final\_Y]} by clamping each
|
||||
element to [0, \varname{[range]}) after step 1. Variants of this
|
||||
suggestion are acceptable as valid floor1 setups cannot produce
|
||||
out of range values.
|
||||
|
||||
\begin{description}
|
||||
\item[step 1: amplitude value synthesis]
|
||||
|
||||
Unwrap the always-positive-or-zero values read from the packet into
|
||||
+/- difference values, then apply to line prediction.
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [range] = vector \{ 256, 128, 86, 64 \} element ([floor1\_multiplier]-1)
|
||||
2) vector [floor1\_step2\_flag] element [0] = set
|
||||
3) vector [floor1\_step2\_flag] element [1] = set
|
||||
4) vector [floor1\_final\_Y] element [0] = vector [floor1\_Y] element [0]
|
||||
5) vector [floor1\_final\_Y] element [1] = vector [floor1\_Y] element [1]
|
||||
6) iterate [i] over the range 2 ... [floor1\_values]-1 \{
|
||||
|
||||
7) [low\_neighbor\_offset] = \link{vorbis:spec:low:neighbor}{low\_neighbor}([floor1\_X\_list],[i])
|
||||
8) [high\_neighbor\_offset] = \link{vorbis:spec:high:neighbor}{high\_neighbor}([floor1\_X\_list],[i])
|
||||
|
||||
9) [predicted] = \link{vorbis:spec:render:point}{render\_point}( vector [floor1\_X\_list] element [low\_neighbor\_offset],
|
||||
vector [floor1\_final\_Y] element [low\_neighbor\_offset],
|
||||
vector [floor1\_X\_list] element [high\_neighbor\_offset],
|
||||
vector [floor1\_final\_Y] element [high\_neighbor\_offset],
|
||||
vector [floor1\_X\_list] element [i] )
|
||||
|
||||
10) [val] = vector [floor1\_Y] element [i]
|
||||
11) [highroom] = [range] - [predicted]
|
||||
12) [lowroom] = [predicted]
|
||||
13) if ( [highroom] is less than [lowroom] ) \{
|
||||
|
||||
14) [room] = [highroom] * 2
|
||||
|
||||
\} else [highroom] is not less than [lowroom] \{
|
||||
|
||||
15) [room] = [lowroom] * 2
|
||||
|
||||
\}
|
||||
|
||||
16) if ( [val] is nonzero ) \{
|
||||
|
||||
17) vector [floor1\_step2\_flag] element [low\_neighbor\_offset] = set
|
||||
18) vector [floor1\_step2\_flag] element [high\_neighbor\_offset] = set
|
||||
19) vector [floor1\_step2\_flag] element [i] = set
|
||||
20) if ( [val] is greater than or equal to [room] ) \{
|
||||
|
||||
21) if ( [highroom] is greater than [lowroom] ) \{
|
||||
|
||||
22) vector [floor1\_final\_Y] element [i] = [val] - [lowroom] + [predicted]
|
||||
|
||||
\} else [highroom] is not greater than [lowroom] \{
|
||||
|
||||
23) vector [floor1\_final\_Y] element [i] = [predicted] - [val] + [highroom] - 1
|
||||
|
||||
\}
|
||||
|
||||
\} else [val] is less than [room] \{
|
||||
|
||||
24) if ([val] is odd) \{
|
||||
|
||||
25) vector [floor1\_final\_Y] element [i] =
|
||||
[predicted] - (([val] + 1) divided by 2 using integer division)
|
||||
|
||||
\} else [val] is even \{
|
||||
|
||||
26) vector [floor1\_final\_Y] element [i] =
|
||||
[predicted] + ([val] / 2 using integer division)
|
||||
|
||||
\}
|
||||
|
||||
\}
|
||||
|
||||
\} else [val] is zero \{
|
||||
|
||||
27) vector [floor1\_step2\_flag] element [i] = unset
|
||||
28) vector [floor1\_final\_Y] element [i] = [predicted]
|
||||
|
||||
\}
|
||||
|
||||
\}
|
||||
|
||||
29) done
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
|
||||
|
||||
\item[step 2: curve synthesis]
|
||||
|
||||
Curve synthesis generates a return vector \varname{[floor]} of length
|
||||
\varname{[n]} (where \varname{[n]} is provided by the decode process
|
||||
calling to floor decode). Floor 1 curve synthesis makes use of the
|
||||
\varname{[floor1\_X\_list]}, \varname{[floor1\_final\_Y]} and
|
||||
\varname{[floor1\_step2\_flag]} vectors, as well as [floor1\_multiplier]
|
||||
and [floor1\_values] values.
|
||||
|
||||
Decode begins by sorting the scalars from vectors
|
||||
\varname{[floor1\_X\_list]}, \varname{[floor1\_final\_Y]} and
|
||||
\varname{[floor1\_step2\_flag]} together into new vectors
|
||||
\varname{[floor1\_X\_list]'}, \varname{[floor1\_final\_Y]'} and
|
||||
\varname{[floor1\_step2\_flag]'} according to ascending sort order of the
|
||||
values in \varname{[floor1\_X\_list]}. That is, sort the values of
|
||||
\varname{[floor1\_X\_list]} and then apply the same permutation to
|
||||
elements of the other two vectors so that the X, Y and step2\_flag
|
||||
values still match.
|
||||
|
||||
Then compute the final curve in one pass:
|
||||
|
||||
\begin{Verbatim}[commandchars=\\\{\}]
|
||||
1) [hx] = 0
|
||||
2) [lx] = 0
|
||||
3) [ly] = vector [floor1\_final\_Y]' element [0] * [floor1\_multiplier]
|
||||
4) iterate [i] over the range 1 ... [floor1\_values]-1 \{
|
||||
|
||||
5) if ( [floor1\_step2\_flag]' element [i] is set ) \{
|
||||
|
||||
6) [hy] = [floor1\_final\_Y]' element [i] * [floor1\_multiplier]
|
||||
7) [hx] = [floor1\_X\_list]' element [i]
|
||||
8) \link{vorbis:spec:render:line}{render\_line}( [lx], [ly], [hx], [hy], [floor] )
|
||||
9) [lx] = [hx]
|
||||
10) [ly] = [hy]
|
||||
\}
|
||||
\}
|
||||
|
||||
11) if ( [hx] is less than [n] ) \{
|
||||
|
||||
12) \link{vorbis:spec:render:line}{render\_line}( [hx], [hy], [n], [hy], [floor] )
|
||||
|
||||
\}
|
||||
|
||||
13) if ( [hx] is greater than [n] ) \{
|
||||
|
||||
14) truncate vector [floor] to [n] elements
|
||||
|
||||
\}
|
||||
|
||||
15) for each scalar in vector [floor], perform a lookup substitution using
|
||||
the scalar value from [floor] as an offset into the vector \link{vorbis:spec:floor1:inverse:dB:table}{[floor1\_inverse\_dB\_static\_table]}
|
||||
|
||||
16) done
|
||||
|
||||
\end{Verbatim}
|
||||
|
||||
\end{description}
|
|
@ -0,0 +1,451 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Residue setup and decode} \label{vorbis:spec:residue}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
A residue vector represents the fine detail of the audio spectrum of
|
||||
one channel in an audio frame after the encoder subtracts the floor
|
||||
curve and performs any channel coupling. A residue vector may
|
||||
represent spectral lines, spectral magnitude, spectral phase or
|
||||
hybrids as mixed by channel coupling. The exact semantic content of
|
||||
the vector does not matter to the residue abstraction.
|
||||
|
||||
Whatever the exact qualities, the Vorbis residue abstraction codes the
|
||||
residue vectors into the bitstream packet, and then reconstructs the
|
||||
vectors during decode. Vorbis makes use of three different encoding
|
||||
variants (numbered 0, 1 and 2) of the same basic vector encoding
|
||||
abstraction.
|
||||
|
||||
|
||||
|
||||
\subsection{Residue format}
|
||||
|
||||
Residue format partitions each vector in the vector bundle into chunks,
|
||||
classifies each chunk, encodes the chunk classifications and finally
|
||||
encodes the chunks themselves using the the specific VQ arrangement
|
||||
defined for each selected classification.
|
||||
The exact interleaving and partitioning vary by residue encoding number,
|
||||
however the high-level process used to classify and encode the residue
|
||||
vector is the same in all three variants.
|
||||
|
||||
A set of coded residue vectors are all of the same length. High level
|
||||
coding structure, ignoring for the moment exactly how a partition is
|
||||
encoded and simply trusting that it is, is as follows:
|
||||
|
||||
\begin{itemize}
|
||||
\item Each vector is partitioned into multiple equal sized chunks
|
||||
according to configuration specified. If we have a vector size of
|
||||
\emph{n}, a partition size \emph{residue\_partition\_size}, and a total
|
||||
of \emph{ch} residue vectors, the total number of partitioned chunks
|
||||
coded is \emph{n}/\emph{residue\_partition\_size}*\emph{ch}. It is
|
||||
important to note that the integer division truncates. In the below
|
||||
example, we assume an example \emph{residue\_partition\_size} of 8.
|
||||
|
||||
\item Each partition in each vector has a classification number that
|
||||
specifies which of multiple configured VQ codebook setups are used to
|
||||
decode that partition. The classification numbers of each partition
|
||||
can be thought of as forming a vector in their own right, as in the
|
||||
illustration below. Just as the residue vectors are coded in grouped
|
||||
partitions to increase encoding efficiency, the classification vector
|
||||
is also partitioned into chunks. The integer elements of each scalar
|
||||
in a classification chunk are built into a single scalar that
|
||||
represents the classification numbers in that chunk. In the below
|
||||
example, the classification codeword encodes two classification
|
||||
numbers.
|
||||
|
||||
\item The values in a residue vector may be encoded monolithically in a
|
||||
single pass through the residue vector, but more often efficient
|
||||
codebook design dictates that each vector is encoded as the additive
|
||||
sum of several passes through the residue vector using more than one
|
||||
VQ codebook. Thus, each residue value potentially accumulates values
|
||||
from multiple decode passes. The classification value associated with
|
||||
a partition is the same in each pass, thus the classification codeword
|
||||
is coded only in the first pass.
|
||||
|
||||
\end{itemize}
|
||||
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=\textwidth]{residue-pack}
|
||||
\captionof{figure}{illustration of residue vector format}
|
||||
\end{center}
|
||||
|
||||
|
||||
|
||||
\subsection{residue 0}
|
||||
|
||||
Residue 0 and 1 differ only in the way the values within a residue
|
||||
partition are interleaved during partition encoding (visually treated
|
||||
as a black box--or cyan box or brown box--in the above figure).
|
||||
|
||||
Residue encoding 0 interleaves VQ encoding according to the
|
||||
dimension of the codebook used to encode a partition in a specific
|
||||
pass. The dimension of the codebook need not be the same in multiple
|
||||
passes, however the partition size must be an even multiple of the
|
||||
codebook dimension.
|
||||
|
||||
As an example, assume a partition vector of size eight, to be encoded
|
||||
by residue 0 using codebook sizes of 8, 4, 2 and 1:
|
||||
|
||||
\begin{programlisting}
|
||||
|
||||
original residue vector: [ 0 1 2 3 4 5 6 7 ]
|
||||
|
||||
codebook dimensions = 8 encoded as: [ 0 1 2 3 4 5 6 7 ]
|
||||
|
||||
codebook dimensions = 4 encoded as: [ 0 2 4 6 ], [ 1 3 5 7 ]
|
||||
|
||||
codebook dimensions = 2 encoded as: [ 0 4 ], [ 1 5 ], [ 2 6 ], [ 3 7 ]
|
||||
|
||||
codebook dimensions = 1 encoded as: [ 0 ], [ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ]
|
||||
|
||||
\end{programlisting}
|
||||
|
||||
It is worth mentioning at this point that no configurable value in the
|
||||
residue coding setup is restricted to a power of two.
|
||||
|
||||
|
||||
|
||||
\subsection{residue 1}
|
||||
|
||||
Residue 1 does not interleave VQ encoding. It represents partition
|
||||
vector scalars in order. As with residue 0, however, partition length
|
||||
must be an integer multiple of the codebook dimension, although
|
||||
dimension may vary from pass to pass.
|
||||
|
||||
As an example, assume a partition vector of size eight, to be encoded
|
||||
by residue 0 using codebook sizes of 8, 4, 2 and 1:
|
||||
|
||||
\begin{programlisting}
|
||||
|
||||
original residue vector: [ 0 1 2 3 4 5 6 7 ]
|
||||
|
||||
codebook dimensions = 8 encoded as: [ 0 1 2 3 4 5 6 7 ]
|
||||
|
||||
codebook dimensions = 4 encoded as: [ 0 1 2 3 ], [ 4 5 6 7 ]
|
||||
|
||||
codebook dimensions = 2 encoded as: [ 0 1 ], [ 2 3 ], [ 4 5 ], [ 6 7 ]
|
||||
|
||||
codebook dimensions = 1 encoded as: [ 0 ], [ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ]
|
||||
|
||||
\end{programlisting}
|
||||
|
||||
|
||||
|
||||
\subsection{residue 2}
|
||||
|
||||
Residue type two can be thought of as a variant of residue type 1.
|
||||
Rather than encoding multiple passed-in vectors as in residue type 1,
|
||||
the \emph{ch} passed in vectors of length \emph{n} are first
|
||||
interleaved and flattened into a single vector of length
|
||||
\emph{ch}*\emph{n}. Encoding then proceeds as in type 1. Decoding is
|
||||
as in type 1 with decode interleave reversed. If operating on a single
|
||||
vector to begin with, residue type 1 and type 2 are equivalent.
|
||||
|
||||
\begin{center}
|
||||
\includegraphics[width=\textwidth]{residue2}
|
||||
\captionof{figure}{illustration of residue type 2}
|
||||
\end{center}
|
||||
|
||||
|
||||
\subsection{Residue decode}
|
||||
|
||||
\subsubsection{header decode}
|
||||
|
||||
Header decode for all three residue types is identical.
|
||||
\begin{programlisting}
|
||||
1) [residue\_begin] = read 24 bits as unsigned integer
|
||||
2) [residue\_end] = read 24 bits as unsigned integer
|
||||
3) [residue\_partition\_size] = read 24 bits as unsigned integer and add one
|
||||
4) [residue\_classifications] = read 6 bits as unsigned integer and add one
|
||||
5) [residue\_classbook] = read 8 bits as unsigned integer
|
||||
\end{programlisting}
|
||||
|
||||
\varname{[residue\_begin]} and
|
||||
\varname{[residue\_end]} select the specific sub-portion of
|
||||
each vector that is actually coded; it implements akin to a bandpass
|
||||
where, for coding purposes, the vector effectively begins at element
|
||||
\varname{[residue\_begin]} and ends at
|
||||
\varname{[residue\_end]}. Preceding and following values in
|
||||
the unpacked vectors are zeroed. Note that for residue type 2, these
|
||||
values as well as \varname{[residue\_partition\_size]}apply to
|
||||
the interleaved vector, not the individual vectors before interleave.
|
||||
\varname{[residue\_partition\_size]} is as explained above,
|
||||
\varname{[residue\_classifications]} is the number of possible
|
||||
classification to which a partition can belong and
|
||||
\varname{[residue\_classbook]} is the codebook number used to
|
||||
code classification codewords. The number of dimensions in book
|
||||
\varname{[residue\_classbook]} determines how many
|
||||
classification values are grouped into a single classification
|
||||
codeword. Note that the number of entries and dimensions in book
|
||||
\varname{[residue\_classbook]}, along with
|
||||
\varname{[residue\_classifications]}, overdetermines to
|
||||
possible number of classification codewords.
|
||||
If \varname{[residue\_classifications]}\^{}\varname{[residue\_classbook]}.dimensions
|
||||
exceeds \varname{[residue\_classbook]}.entries, the
|
||||
bitstream should be regarded to be undecodable.
|
||||
|
||||
Next we read a bitmap pattern that specifies which partition classes
|
||||
code values in which passes.
|
||||
|
||||
\begin{programlisting}
|
||||
1) iterate [i] over the range 0 ... [residue\_classifications]-1 {
|
||||
|
||||
2) [high\_bits] = 0
|
||||
3) [low\_bits] = read 3 bits as unsigned integer
|
||||
4) [bitflag] = read one bit as boolean
|
||||
5) if ( [bitflag] is set ) then [high\_bits] = read five bits as unsigned integer
|
||||
6) vector [residue\_cascade] element [i] = [high\_bits] * 8 + [low\_bits]
|
||||
}
|
||||
7) done
|
||||
\end{programlisting}
|
||||
|
||||
Finally, we read in a list of book numbers, each corresponding to
|
||||
specific bit set in the cascade bitmap. We loop over the possible
|
||||
codebook classifications and the maximum possible number of encoding
|
||||
stages (8 in Vorbis I, as constrained by the elements of the cascade
|
||||
bitmap being eight bits):
|
||||
|
||||
\begin{programlisting}
|
||||
1) iterate [i] over the range 0 ... [residue\_classifications]-1 {
|
||||
|
||||
2) iterate [j] over the range 0 ... 7 {
|
||||
|
||||
3) if ( vector [residue\_cascade] element [i] bit [j] is set ) {
|
||||
|
||||
4) array [residue\_books] element [i][j] = read 8 bits as unsigned integer
|
||||
|
||||
} else {
|
||||
|
||||
5) array [residue\_books] element [i][j] = unused
|
||||
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
6) done
|
||||
\end{programlisting}
|
||||
|
||||
An end-of-packet condition at any point in header decode renders the
|
||||
stream undecodable. In addition, any codebook number greater than the
|
||||
maximum numbered codebook set up in this stream also renders the
|
||||
stream undecodable. All codebooks in array [residue\_books] are
|
||||
required to have a value mapping. The presence of codebook in array
|
||||
[residue\_books] without a value mapping (maptype equals zero) renders
|
||||
the stream undecodable.
|
||||
|
||||
|
||||
|
||||
\subsubsection{packet decode}
|
||||
|
||||
Format 0 and 1 packet decode is identical except for specific
|
||||
partition interleave. Format 2 packet decode can be built out of the
|
||||
format 1 decode process. Thus we describe first the decode
|
||||
infrastructure identical to all three formats.
|
||||
|
||||
In addition to configuration information, the residue decode process
|
||||
is passed the number of vectors in the submap bundle and a vector of
|
||||
flags indicating if any of the vectors are not to be decoded. If the
|
||||
passed in number of vectors is 3 and vector number 1 is marked 'do not
|
||||
decode', decode skips vector 1 during the decode loop. However, even
|
||||
'do not decode' vectors are allocated and zeroed.
|
||||
|
||||
Depending on the values of \varname{[residue\_begin]} and
|
||||
\varname{[residue\_end]}, it is obvious that the encoded
|
||||
portion of a residue vector may be the entire possible residue vector
|
||||
or some other strict subset of the actual residue vector size with
|
||||
zero padding at either uncoded end. However, it is also possible to
|
||||
set \varname{[residue\_begin]} and
|
||||
\varname{[residue\_end]} to specify a range partially or
|
||||
wholly beyond the maximum vector size. Before beginning residue
|
||||
decode, limit \varname{[residue\_begin]} and
|
||||
\varname{[residue\_end]} to the maximum possible vector size
|
||||
as follows. We assume that the number of vectors being encoded,
|
||||
\varname{[ch]} is provided by the higher level decoding
|
||||
process.
|
||||
|
||||
\begin{programlisting}
|
||||
1) [actual\_size] = current blocksize/2;
|
||||
2) if residue encoding is format 2
|
||||
3) [actual\_size] = [actual\_size] * [ch];
|
||||
4) [limit\_residue\_begin] = minimum of ([residue\_begin],[actual\_size]);
|
||||
5) [limit\_residue\_end] = minimum of ([residue\_end],[actual\_size]);
|
||||
\end{programlisting}
|
||||
|
||||
The following convenience values are conceptually useful to clarifying
|
||||
the decode process:
|
||||
|
||||
\begin{programlisting}
|
||||
1) [classwords\_per\_codeword] = [codebook\_dimensions] value of codebook [residue\_classbook]
|
||||
2) [n\_to\_read] = [limit\_residue\_end] - [limit\_residue\_begin]
|
||||
3) [partitions\_to\_read] = [n\_to\_read] / [residue\_partition\_size]
|
||||
\end{programlisting}
|
||||
|
||||
Packet decode proceeds as follows, matching the description offered earlier in the document.
|
||||
\begin{programlisting}
|
||||
1) allocate and zero all vectors that will be returned.
|
||||
2) if ([n\_to\_read] is zero), stop; there is no residue to decode.
|
||||
3) iterate [pass] over the range 0 ... 7 {
|
||||
|
||||
4) [partition\_count] = 0
|
||||
|
||||
5) while [partition\_count] is less than [partitions\_to\_read]
|
||||
|
||||
6) if ([pass] is zero) {
|
||||
|
||||
7) iterate [j] over the range 0 .. [ch]-1 {
|
||||
|
||||
8) if vector [j] is not marked 'do not decode' {
|
||||
|
||||
9) [temp] = read from packet using codebook [residue\_classbook] in scalar context
|
||||
10) iterate [i] descending over the range [classwords\_per\_codeword]-1 ... 0 {
|
||||
|
||||
11) array [classifications] element [j],([i]+[partition\_count]) =
|
||||
[temp] integer modulo [residue\_classifications]
|
||||
12) [temp] = [temp] / [residue\_classifications] using integer division
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
13) iterate [i] over the range 0 .. ([classwords\_per\_codeword] - 1) while [partition\_count]
|
||||
is also less than [partitions\_to\_read] {
|
||||
|
||||
14) iterate [j] over the range 0 .. [ch]-1 {
|
||||
|
||||
15) if vector [j] is not marked 'do not decode' {
|
||||
|
||||
16) [vqclass] = array [classifications] element [j],[partition\_count]
|
||||
17) [vqbook] = array [residue\_books] element [vqclass],[pass]
|
||||
18) if ([vqbook] is not 'unused') {
|
||||
|
||||
19) decode partition into output vector number [j], starting at scalar
|
||||
offset [limit\_residue\_begin]+[partition\_count]*[residue\_partition\_size] using
|
||||
codebook number [vqbook] in VQ context
|
||||
}
|
||||
}
|
||||
|
||||
20) increment [partition\_count] by one
|
||||
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
21) done
|
||||
|
||||
\end{programlisting}
|
||||
|
||||
An end-of-packet condition during packet decode is to be considered a
|
||||
nominal occurrence. Decode returns the result of vector decode up to
|
||||
that point.
|
||||
|
||||
|
||||
|
||||
\subsubsection{format 0 specifics}
|
||||
|
||||
Format zero decodes partitions exactly as described earlier in the
|
||||
'Residue Format: residue 0' section. The following pseudocode
|
||||
presents the same algorithm. Assume:
|
||||
|
||||
\begin{itemize}
|
||||
\item \varname{[n]} is the value in \varname{[residue\_partition\_size]}
|
||||
\item \varname{[v]} is the residue vector
|
||||
\item \varname{[offset]} is the beginning read offset in [v]
|
||||
\end{itemize}
|
||||
|
||||
|
||||
\begin{programlisting}
|
||||
1) [step] = [n] / [codebook\_dimensions]
|
||||
2) iterate [i] over the range 0 ... [step]-1 {
|
||||
|
||||
3) vector [entry\_temp] = read vector from packet using current codebook in VQ context
|
||||
4) iterate [j] over the range 0 ... [codebook\_dimensions]-1 {
|
||||
|
||||
5) vector [v] element ([offset]+[i]+[j]*[step]) =
|
||||
vector [v] element ([offset]+[i]+[j]*[step]) +
|
||||
vector [entry\_temp] element [j]
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
6) done
|
||||
|
||||
\end{programlisting}
|
||||
|
||||
|
||||
|
||||
\subsubsection{format 1 specifics}
|
||||
|
||||
Format 1 decodes partitions exactly as described earlier in the
|
||||
'Residue Format: residue 1' section. The following pseudocode
|
||||
presents the same algorithm. Assume:
|
||||
|
||||
\begin{itemize}
|
||||
\item \varname{[n]} is the value in
|
||||
\varname{[residue\_partition\_size]}
|
||||
\item \varname{[v]} is the residue vector
|
||||
\item \varname{[offset]} is the beginning read offset in [v]
|
||||
\end{itemize}
|
||||
|
||||
|
||||
\begin{programlisting}
|
||||
1) [i] = 0
|
||||
2) vector [entry\_temp] = read vector from packet using current codebook in VQ context
|
||||
3) iterate [j] over the range 0 ... [codebook\_dimensions]-1 {
|
||||
|
||||
4) vector [v] element ([offset]+[i]) =
|
||||
vector [v] element ([offset]+[i]) +
|
||||
vector [entry\_temp] element [j]
|
||||
5) increment [i]
|
||||
|
||||
}
|
||||
|
||||
6) if ( [i] is less than [n] ) continue at step 2
|
||||
7) done
|
||||
\end{programlisting}
|
||||
|
||||
|
||||
|
||||
\subsubsection{format 2 specifics}
|
||||
|
||||
Format 2 is reducible to format 1. It may be implemented as an additional step prior to and an additional post-decode step after a normal format 1 decode.
|
||||
|
||||
|
||||
Format 2 handles 'do not decode' vectors differently than residue 0 or
|
||||
1; if all vectors are marked 'do not decode', no decode occurrs.
|
||||
However, if at least one vector is to be decoded, all the vectors are
|
||||
decoded. We then request normal format 1 to decode a single vector
|
||||
representing all output channels, rather than a vector for each
|
||||
channel. After decode, deinterleave the vector into independent vectors, one for each output channel. That is:
|
||||
|
||||
\begin{enumerate}
|
||||
\item If all vectors 0 through \emph{ch}-1 are marked 'do not decode', allocate and clear a single vector \varname{[v]}of length \emph{ch*n} and skip step 2 below; proceed directly to the post-decode step.
|
||||
\item Rather than performing format 1 decode to produce \emph{ch} vectors of length \emph{n} each, call format 1 decode to produce a single vector \varname{[v]} of length \emph{ch*n}.
|
||||
\item Post decode: Deinterleave the single vector \varname{[v]} returned by format 1 decode as described above into \emph{ch} independent vectors, one for each outputchannel, according to:
|
||||
\begin{programlisting}
|
||||
1) iterate [i] over the range 0 ... [n]-1 {
|
||||
|
||||
2) iterate [j] over the range 0 ... [ch]-1 {
|
||||
|
||||
3) output vector number [j] element [i] = vector [v] element ([i] * [ch] + [j])
|
||||
|
||||
}
|
||||
}
|
||||
|
||||
4) done
|
||||
\end{programlisting}
|
||||
|
||||
\end{enumerate}
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,180 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Helper equations} \label{vorbis:spec:helper}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
The equations below are used in multiple places by the Vorbis codec
|
||||
specification. Rather than cluttering up the main specification
|
||||
documents, they are defined here and referenced where appropriate.
|
||||
|
||||
|
||||
\subsection{Functions}
|
||||
|
||||
\subsubsection{ilog} \label{vorbis:spec:ilog}
|
||||
|
||||
The "ilog(x)" function returns the position number (1 through n) of the highest set bit in the two's complement integer value
|
||||
\varname{[x]}. Values of \varname{[x]} less than zero are defined to return zero.
|
||||
|
||||
\begin{programlisting}
|
||||
1) [return\_value] = 0;
|
||||
2) if ( [x] is greater than zero ) {
|
||||
|
||||
3) increment [return\_value];
|
||||
4) logical shift [x] one bit to the right, padding the MSb with zero
|
||||
5) repeat at step 2)
|
||||
|
||||
}
|
||||
|
||||
6) done
|
||||
\end{programlisting}
|
||||
|
||||
Examples:
|
||||
|
||||
\begin{itemize}
|
||||
\item ilog(0) = 0;
|
||||
\item ilog(1) = 1;
|
||||
\item ilog(2) = 2;
|
||||
\item ilog(3) = 2;
|
||||
\item ilog(4) = 3;
|
||||
\item ilog(7) = 3;
|
||||
\item ilog(negative number) = 0;
|
||||
\end{itemize}
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{float32\_unpack} \label{vorbis:spec:float32:unpack}
|
||||
|
||||
"float32\_unpack(x)" is intended to translate the packed binary
|
||||
representation of a Vorbis codebook float value into the
|
||||
representation used by the decoder for floating point numbers. For
|
||||
purposes of this example, we will unpack a Vorbis float32 into a
|
||||
host-native floating point number.
|
||||
|
||||
\begin{programlisting}
|
||||
1) [mantissa] = [x] bitwise AND 0x1fffff (unsigned result)
|
||||
2) [sign] = [x] bitwise AND 0x80000000 (unsigned result)
|
||||
3) [exponent] = ( [x] bitwise AND 0x7fe00000) shifted right 21 bits (unsigned result)
|
||||
4) if ( [sign] is nonzero ) then negate [mantissa]
|
||||
5) return [mantissa] * ( 2 ^ ( [exponent] - 788 ) )
|
||||
\end{programlisting}
|
||||
|
||||
|
||||
|
||||
\subsubsection{lookup1\_values} \label{vorbis:spec:lookup1:values}
|
||||
|
||||
"lookup1\_values(codebook\_entries,codebook\_dimensions)" is used to
|
||||
compute the correct length of the value index for a codebook VQ lookup
|
||||
table of lookup type 1. The values on this list are permuted to
|
||||
construct the VQ vector lookup table of size
|
||||
\varname{[codebook\_entries]}.
|
||||
|
||||
The return value for this function is defined to be 'the greatest
|
||||
integer value for which \varname{[return\_value]} to the power of
|
||||
\varname{[codebook\_dimensions]} is less than or equal to
|
||||
\varname{[codebook\_entries]}'.
|
||||
|
||||
|
||||
|
||||
\subsubsection{low\_neighbor} \label{vorbis:spec:low:neighbor}
|
||||
|
||||
"low\_neighbor(v,x)" finds the position \varname{n} in vector \varname{[v]} of
|
||||
the greatest value scalar element for which \varname{n} is less than
|
||||
\varname{[x]} and vector \varname{[v]} element \varname{n} is less
|
||||
than vector \varname{[v]} element \varname{[x]}.
|
||||
|
||||
\subsubsection{high\_neighbor} \label{vorbis:spec:high:neighbor}
|
||||
|
||||
"high\_neighbor(v,x)" finds the position \varname{n} in vector [v] of
|
||||
the lowest value scalar element for which \varname{n} is less than
|
||||
\varname{[x]} and vector \varname{[v]} element \varname{n} is greater
|
||||
than vector \varname{[v]} element \varname{[x]}.
|
||||
|
||||
|
||||
|
||||
\subsubsection{render\_point} \label{vorbis:spec:render:point}
|
||||
|
||||
"render\_point(x0,y0,x1,y1,X)" is used to find the Y value at point X
|
||||
along the line specified by x0, x1, y0 and y1. This function uses an
|
||||
integer algorithm to solve for the point directly without calculating
|
||||
intervening values along the line.
|
||||
|
||||
\begin{programlisting}
|
||||
1) [dy] = [y1] - [y0]
|
||||
2) [adx] = [x1] - [x0]
|
||||
3) [ady] = absolute value of [dy]
|
||||
4) [err] = [ady] * ([X] - [x0])
|
||||
5) [off] = [err] / [adx] using integer division
|
||||
6) if ( [dy] is less than zero ) {
|
||||
|
||||
7) [Y] = [y0] - [off]
|
||||
|
||||
} else {
|
||||
|
||||
8) [Y] = [y0] + [off]
|
||||
|
||||
}
|
||||
|
||||
9) done
|
||||
\end{programlisting}
|
||||
|
||||
|
||||
|
||||
\subsubsection{render\_line} \label{vorbis:spec:render:line}
|
||||
|
||||
Floor decode type one uses the integer line drawing algorithm of
|
||||
"render\_line(x0, y0, x1, y1, v)" to construct an integer floor
|
||||
curve for contiguous piecewise line segments. Note that it has not
|
||||
been relevant elsewhere, but here we must define integer division as
|
||||
rounding division of both positive and negative numbers toward zero.
|
||||
|
||||
|
||||
\begin{programlisting}
|
||||
1) [dy] = [y1] - [y0]
|
||||
2) [adx] = [x1] - [x0]
|
||||
3) [ady] = absolute value of [dy]
|
||||
4) [base] = [dy] / [adx] using integer division
|
||||
5) [x] = [x0]
|
||||
6) [y] = [y0]
|
||||
7) [err] = 0
|
||||
|
||||
8) if ( [dy] is less than 0 ) {
|
||||
|
||||
9) [sy] = [base] - 1
|
||||
|
||||
} else {
|
||||
|
||||
10) [sy] = [base] + 1
|
||||
|
||||
}
|
||||
|
||||
11) [ady] = [ady] - (absolute value of [base]) * [adx]
|
||||
12) vector [v] element [x] = [y]
|
||||
|
||||
13) iterate [x] over the range [x0]+1 ... [x1]-1 {
|
||||
|
||||
14) [err] = [err] + [ady];
|
||||
15) if ( [err] >= [adx] ) {
|
||||
|
||||
16) [err] = [err] - [adx]
|
||||
17) [y] = [y] + [sy]
|
||||
|
||||
} else {
|
||||
|
||||
18) [y] = [y] + [base]
|
||||
|
||||
}
|
||||
|
||||
19) vector [v] element [x] = [y]
|
||||
|
||||
}
|
||||
\end{programlisting}
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,76 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Tables} \label{vorbis:spec:tables}
|
||||
|
||||
\subsection{floor1\_inverse\_dB\_table} \label{vorbis:spec:floor1:inverse:dB:table}
|
||||
|
||||
The vector \varname{[floor1\_inverse\_dB\_table]} is a 256 element static
|
||||
lookup table consisting of the following values (read left to right
|
||||
then top to bottom):
|
||||
|
||||
\begin{Verbatim}
|
||||
1.0649863e-07, 1.1341951e-07, 1.2079015e-07, 1.2863978e-07,
|
||||
1.3699951e-07, 1.4590251e-07, 1.5538408e-07, 1.6548181e-07,
|
||||
1.7623575e-07, 1.8768855e-07, 1.9988561e-07, 2.1287530e-07,
|
||||
2.2670913e-07, 2.4144197e-07, 2.5713223e-07, 2.7384213e-07,
|
||||
2.9163793e-07, 3.1059021e-07, 3.3077411e-07, 3.5226968e-07,
|
||||
3.7516214e-07, 3.9954229e-07, 4.2550680e-07, 4.5315863e-07,
|
||||
4.8260743e-07, 5.1396998e-07, 5.4737065e-07, 5.8294187e-07,
|
||||
6.2082472e-07, 6.6116941e-07, 7.0413592e-07, 7.4989464e-07,
|
||||
7.9862701e-07, 8.5052630e-07, 9.0579828e-07, 9.6466216e-07,
|
||||
1.0273513e-06, 1.0941144e-06, 1.1652161e-06, 1.2409384e-06,
|
||||
1.3215816e-06, 1.4074654e-06, 1.4989305e-06, 1.5963394e-06,
|
||||
1.7000785e-06, 1.8105592e-06, 1.9282195e-06, 2.0535261e-06,
|
||||
2.1869758e-06, 2.3290978e-06, 2.4804557e-06, 2.6416497e-06,
|
||||
2.8133190e-06, 2.9961443e-06, 3.1908506e-06, 3.3982101e-06,
|
||||
3.6190449e-06, 3.8542308e-06, 4.1047004e-06, 4.3714470e-06,
|
||||
4.6555282e-06, 4.9580707e-06, 5.2802740e-06, 5.6234160e-06,
|
||||
5.9888572e-06, 6.3780469e-06, 6.7925283e-06, 7.2339451e-06,
|
||||
7.7040476e-06, 8.2047000e-06, 8.7378876e-06, 9.3057248e-06,
|
||||
9.9104632e-06, 1.0554501e-05, 1.1240392e-05, 1.1970856e-05,
|
||||
1.2748789e-05, 1.3577278e-05, 1.4459606e-05, 1.5399272e-05,
|
||||
1.6400004e-05, 1.7465768e-05, 1.8600792e-05, 1.9809576e-05,
|
||||
2.1096914e-05, 2.2467911e-05, 2.3928002e-05, 2.5482978e-05,
|
||||
2.7139006e-05, 2.8902651e-05, 3.0780908e-05, 3.2781225e-05,
|
||||
3.4911534e-05, 3.7180282e-05, 3.9596466e-05, 4.2169667e-05,
|
||||
4.4910090e-05, 4.7828601e-05, 5.0936773e-05, 5.4246931e-05,
|
||||
5.7772202e-05, 6.1526565e-05, 6.5524908e-05, 6.9783085e-05,
|
||||
7.4317983e-05, 7.9147585e-05, 8.4291040e-05, 8.9768747e-05,
|
||||
9.5602426e-05, 0.00010181521, 0.00010843174, 0.00011547824,
|
||||
0.00012298267, 0.00013097477, 0.00013948625, 0.00014855085,
|
||||
0.00015820453, 0.00016848555, 0.00017943469, 0.00019109536,
|
||||
0.00020351382, 0.00021673929, 0.00023082423, 0.00024582449,
|
||||
0.00026179955, 0.00027881276, 0.00029693158, 0.00031622787,
|
||||
0.00033677814, 0.00035866388, 0.00038197188, 0.00040679456,
|
||||
0.00043323036, 0.00046138411, 0.00049136745, 0.00052329927,
|
||||
0.00055730621, 0.00059352311, 0.00063209358, 0.00067317058,
|
||||
0.00071691700, 0.00076350630, 0.00081312324, 0.00086596457,
|
||||
0.00092223983, 0.00098217216, 0.0010459992, 0.0011139742,
|
||||
0.0011863665, 0.0012634633, 0.0013455702, 0.0014330129,
|
||||
0.0015261382, 0.0016253153, 0.0017309374, 0.0018434235,
|
||||
0.0019632195, 0.0020908006, 0.0022266726, 0.0023713743,
|
||||
0.0025254795, 0.0026895994, 0.0028643847, 0.0030505286,
|
||||
0.0032487691, 0.0034598925, 0.0036847358, 0.0039241906,
|
||||
0.0041792066, 0.0044507950, 0.0047400328, 0.0050480668,
|
||||
0.0053761186, 0.0057254891, 0.0060975636, 0.0064938176,
|
||||
0.0069158225, 0.0073652516, 0.0078438871, 0.0083536271,
|
||||
0.0088964928, 0.009474637, 0.010090352, 0.010746080,
|
||||
0.011444421, 0.012188144, 0.012980198, 0.013823725,
|
||||
0.014722068, 0.015678791, 0.016697687, 0.017782797,
|
||||
0.018938423, 0.020169149, 0.021479854, 0.022875735,
|
||||
0.024362330, 0.025945531, 0.027631618, 0.029427276,
|
||||
0.031339626, 0.033376252, 0.035545228, 0.037855157,
|
||||
0.040315199, 0.042935108, 0.045725273, 0.048696758,
|
||||
0.051861348, 0.055231591, 0.058820850, 0.062643361,
|
||||
0.066714279, 0.071049749, 0.075666962, 0.080584227,
|
||||
0.085821044, 0.091398179, 0.097337747, 0.10366330,
|
||||
0.11039993, 0.11757434, 0.12521498, 0.13335215,
|
||||
0.14201813, 0.15124727, 0.16107617, 0.17154380,
|
||||
0.18269168, 0.19456402, 0.20720788, 0.22067342,
|
||||
0.23501402, 0.25028656, 0.26655159, 0.28387361,
|
||||
0.30232132, 0.32196786, 0.34289114, 0.36517414,
|
||||
0.38890521, 0.41417847, 0.44109412, 0.46975890,
|
||||
0.50028648, 0.53279791, 0.56742212, 0.60429640,
|
||||
0.64356699, 0.68538959, 0.72993007, 0.77736504,
|
||||
0.82788260, 0.88168307, 0.9389798, 1.
|
||||
\end{Verbatim}
|
|
@ -0,0 +1,148 @@
|
|||
## Process this with automake to create Makefile.in
|
||||
|
||||
SUBDIRS = libvorbis vorbisfile vorbisenc
|
||||
|
||||
docdir = $(datadir)/doc/$(PACKAGE)-$(VERSION)
|
||||
|
||||
### all of the static docs, commited to SVN and included as is
|
||||
static_docs = \
|
||||
rfc5215.xml \
|
||||
rfc5215.txt \
|
||||
eightphase.png \
|
||||
fish_xiph_org.png \
|
||||
floor1_inverse_dB_table.html \
|
||||
floorval.png \
|
||||
fourphase.png \
|
||||
framing.html \
|
||||
helper.html \
|
||||
index.html \
|
||||
oggstream.html \
|
||||
programming.html \
|
||||
squarepolar.png \
|
||||
stereo.html \
|
||||
stream.png \
|
||||
v-comment.html \
|
||||
vorbis-clip.txt \
|
||||
vorbis-errors.txt \
|
||||
vorbis-fidelity.html
|
||||
|
||||
# bits needed by the spec
|
||||
SPEC_PNG = \
|
||||
components.png \
|
||||
floor1-1.png \
|
||||
floor1-2.png \
|
||||
floor1-3.png \
|
||||
floor1-4.png \
|
||||
hufftree.png \
|
||||
hufftree-under.png \
|
||||
residue-pack.png \
|
||||
residue2.png \
|
||||
window1.png \
|
||||
window2.png \
|
||||
Vorbis_I_spec0x.png \
|
||||
Vorbis_I_spec1x.png \
|
||||
Vorbis_I_spec2x.png \
|
||||
Vorbis_I_spec3x.png \
|
||||
Vorbis_I_spec4x.png \
|
||||
Vorbis_I_spec5x.png \
|
||||
Vorbis_I_spec6x.png \
|
||||
Vorbis_I_spec7x.png \
|
||||
Vorbis_I_spec8x.png \
|
||||
Vorbis_I_spec9x.png \
|
||||
Vorbis_I_spec10x.png \
|
||||
Vorbis_I_spec11x.png \
|
||||
Vorbis_I_spec12x.png \
|
||||
Vorbis_I_spec13x.png \
|
||||
Vorbis_I_spec14x.png
|
||||
|
||||
SPEC_TEX = \
|
||||
Vorbis_I_spec.tex \
|
||||
01-introduction.tex \
|
||||
02-bitpacking.tex \
|
||||
03-codebook.tex \
|
||||
04-codec.tex \
|
||||
05-comment.tex \
|
||||
06-floor0.tex \
|
||||
07-floor1.tex \
|
||||
08-residue.tex \
|
||||
09-helper.tex \
|
||||
10-tables.tex \
|
||||
a1-encapsulation-ogg.tex \
|
||||
a2-encapsulation-rtp.tex \
|
||||
footer.tex
|
||||
|
||||
built_docs = Vorbis_I_spec.pdf Vorbis_I_spec.html Vorbis_I_spec.css
|
||||
|
||||
# conditionally make the generated documentation
|
||||
if BUILD_DOCS
|
||||
doc_DATA = $(static_docs) $(SPEC_PNG) $(built_docs) doxygen-build.stamp
|
||||
else
|
||||
doc_DATA = $(static_docs) doxygen-build.stamp
|
||||
endif
|
||||
|
||||
EXTRA_DIST = $(static_docs) $(built_docs) \
|
||||
$(SPEC_TEX) $(SPEC_PNG) $(SPEC_PDF) Vorbis_I_spec.cfg Doxyfile.in
|
||||
|
||||
# these are expensive; only remove if we have to
|
||||
MAINTAINERCLEANFILES = $(built_docs)
|
||||
CLEANFILES = $(SPEC_TEX:%.tex=%.aux) \
|
||||
Vorbis_I_spec.4ct Vorbis_I_spec.4tc \
|
||||
Vorbis_I_spec.dvi Vorbis_I_spec.idv \
|
||||
Vorbis_I_spec.lg Vorbis_I_spec.log \
|
||||
Vorbis_I_spec.out Vorbis_I_spec.tmp \
|
||||
Vorbis_I_spec.toc Vorbis_I_spec.xref \
|
||||
zzVorbis_I_spec.ps
|
||||
DISTCLEANFILES = $(built_docs)
|
||||
|
||||
|
||||
# explicit rules for generating docs
|
||||
if BUILD_DOCS
|
||||
Vorbis_I_spec.html Vorbis_I_spec.css: $(SPEC_TEX) $(SPEC_PNG) fish_xiph_org.png
|
||||
htlatex $<
|
||||
|
||||
Vorbis_I_spec.pdf: $(SPEC_TEX) $(SPEC_PNG)
|
||||
pdflatex $<
|
||||
pdflatex $<
|
||||
pdflatex $<
|
||||
else
|
||||
Vorbis_I_spec.html: NO_DOCS_ERROR
|
||||
Vorbis_I_spec.pdf: NO_DOCS_ERROR
|
||||
NO_DOCS_ERROR:
|
||||
@echo
|
||||
@echo "*** Documentation has not been built! ***"
|
||||
@echo "Try re-running after passing --enable-docs to configure."
|
||||
@echo
|
||||
endif
|
||||
|
||||
if HAVE_DOXYGEN
|
||||
doxygen-build.stamp: Doxyfile $(top_srcdir)/include/vorbis/*.h
|
||||
doxygen
|
||||
touch doxygen-build.stamp
|
||||
else
|
||||
doxygen-build.stamp:
|
||||
echo "*** Warning: Documentation build is disabled."
|
||||
touch doxygen-build.stamp
|
||||
endif
|
||||
|
||||
install-data-local: doxygen-build.stamp
|
||||
$(mkinstalldirs) $(DESTDIR)$(docdir)
|
||||
if test -d vorbis; then \
|
||||
for dir in vorbis/*; do \
|
||||
if test -d $$dir; then \
|
||||
b=`basename $$dir`; \
|
||||
$(mkinstalldirs) $(DESTDIR)$(docdir)/$$b; \
|
||||
for f in $$dir/*; do \
|
||||
$(INSTALL_DATA) $$f $(DESTDIR)$(docdir)/$$b; \
|
||||
done \
|
||||
fi \
|
||||
done \
|
||||
fi
|
||||
|
||||
uninstall-local:
|
||||
rm -rf $(DESTDIR)$(docdir)
|
||||
|
||||
clean-local:
|
||||
if test -d vorbis; then rm -rf vorbis; fi
|
||||
if test -f doxygen-build.stamp; then rm -f doxygen-build.stamp; fi
|
||||
|
||||
|
|
@ -0,0 +1,4 @@
|
|||
\Preamble{html}
|
||||
\begin{document}
|
||||
\DeclareGraphicsExtensions{.png}
|
||||
\EndPreamble
|
|
@ -0,0 +1,144 @@
|
|||
|
||||
/* start css.sty */
|
||||
.cmex-10{font-size:83%;}
|
||||
.cmssbx-10x-x-120{ font-family: sans-serif; font-weight: bold;}
|
||||
.cmssbx-10x-x-120{ font-family: sans-serif; font-weight: bold;}
|
||||
.cmssbx-10x-x-248{font-size:206%; font-family: sans-serif; font-weight: bold;}
|
||||
.cmssbx-10x-x-248{ font-family: sans-serif; font-weight: bold;}
|
||||
.cmr-17{font-size:141%;}
|
||||
.cmmi-12{font-style: italic;}
|
||||
.cmtt-12{font-family: monospace;}
|
||||
.cmtt-12{font-family: monospace;}
|
||||
.cmtt-12{font-family: monospace;}
|
||||
.cmbx-12{ font-weight: bold;}
|
||||
.cmti-12{ font-style: italic;}
|
||||
.cmr-8{font-size:66%;}
|
||||
.cmr-6{font-size:50%;}
|
||||
.cmmi-8{font-size:66%;font-style: italic;}
|
||||
.cmsy-8{font-size:66%;}
|
||||
.cmsy-6{font-size:50%;}
|
||||
.cmtt-8{font-size:66%;font-family: monospace;}
|
||||
.cmtt-8{font-family: monospace;}
|
||||
.cmtt-8{font-family: monospace;}
|
||||
.cmtt-8x-x-75{font-size:50%;font-family: monospace;}
|
||||
.cmtt-8x-x-75{font-family: monospace;}
|
||||
.cmtt-8x-x-75{font-family: monospace;}
|
||||
p.noindent { text-indent: 0em }
|
||||
td p.noindent { text-indent: 0em; margin-top:0em; }
|
||||
p.nopar { text-indent: 0em; }
|
||||
p.indent{ text-indent: 1.5em }
|
||||
@media print {div.crosslinks {visibility:hidden;}}
|
||||
a img { border-top: 0; border-left: 0; border-right: 0; }
|
||||
center { margin-top:1em; margin-bottom:1em; }
|
||||
td center { margin-top:0em; margin-bottom:0em; }
|
||||
.Canvas { position:relative; }
|
||||
img.math{vertical-align:middle;}
|
||||
li p.indent { text-indent: 0em }
|
||||
li p:first-child{ margin-top:0em; }
|
||||
li p:last-child, li div:last-child { margin-bottom:0.5em; }
|
||||
li p~ul:last-child, li p~ol:last-child{ margin-bottom:0.5em; }
|
||||
.enumerate1 {list-style-type:decimal;}
|
||||
.enumerate2 {list-style-type:lower-alpha;}
|
||||
.enumerate3 {list-style-type:lower-roman;}
|
||||
.enumerate4 {list-style-type:upper-alpha;}
|
||||
div.newtheorem { margin-bottom: 2em; margin-top: 2em;}
|
||||
.obeylines-h,.obeylines-v {white-space: nowrap; }
|
||||
div.obeylines-v p { margin-top:0; margin-bottom:0; }
|
||||
.overline{ text-decoration:overline; }
|
||||
.overline img{ border-top: 1px solid black; }
|
||||
td.displaylines {text-align:center; white-space:nowrap;}
|
||||
.centerline {text-align:center;}
|
||||
.rightline {text-align:right;}
|
||||
div.verbatim {font-family: monospace; white-space: nowrap; text-align:left; clear:both; }
|
||||
.fbox {padding-left:3.0pt; padding-right:3.0pt; text-indent:0pt; border:solid black 0.4pt; }
|
||||
div.fbox {display:table}
|
||||
div.center div.fbox {text-align:center; clear:both; padding-left:3.0pt; padding-right:3.0pt; text-indent:0pt; border:solid black 0.4pt; }
|
||||
div.minipage{width:100%;}
|
||||
div.center, div.center div.center {text-align: center; margin-left:1em; margin-right:1em;}
|
||||
div.center div {text-align: left;}
|
||||
div.flushright, div.flushright div.flushright {text-align: right;}
|
||||
div.flushright div {text-align: left;}
|
||||
div.flushleft {text-align: left;}
|
||||
.underline{ text-decoration:underline; }
|
||||
.underline img{ border-bottom: 1px solid black; margin-bottom:1pt; }
|
||||
.framebox-c, .framebox-l, .framebox-r { padding-left:3.0pt; padding-right:3.0pt; text-indent:0pt; border:solid black 0.4pt; }
|
||||
.framebox-c {text-align:center;}
|
||||
.framebox-l {text-align:left;}
|
||||
.framebox-r {text-align:right;}
|
||||
span.thank-mark{ vertical-align: super }
|
||||
span.footnote-mark sup.textsuperscript, span.footnote-mark a sup.textsuperscript{ font-size:80%; }
|
||||
div.tabular, div.center div.tabular {text-align: center; margin-top:0.5em; margin-bottom:0.5em; }
|
||||
table.tabular td p{margin-top:0em;}
|
||||
table.tabular {margin-left: auto; margin-right: auto;}
|
||||
td p:first-child{ margin-top:0em; }
|
||||
td p:last-child{ margin-bottom:0em; }
|
||||
div.td00{ margin-left:0pt; margin-right:0pt; }
|
||||
div.td01{ margin-left:0pt; margin-right:5pt; }
|
||||
div.td10{ margin-left:5pt; margin-right:0pt; }
|
||||
div.td11{ margin-left:5pt; margin-right:5pt; }
|
||||
table[rules] {border-left:solid black 0.4pt; border-right:solid black 0.4pt; }
|
||||
td.td00{ padding-left:0pt; padding-right:0pt; }
|
||||
td.td01{ padding-left:0pt; padding-right:5pt; }
|
||||
td.td10{ padding-left:5pt; padding-right:0pt; }
|
||||
td.td11{ padding-left:5pt; padding-right:5pt; }
|
||||
table[rules] {border-left:solid black 0.4pt; border-right:solid black 0.4pt; }
|
||||
.hline hr, .cline hr{ height : 1px; margin:0px; }
|
||||
.tabbing-right {text-align:right;}
|
||||
span.TEX {letter-spacing: -0.125em; }
|
||||
span.TEX span.E{ position:relative;top:0.5ex;left:-0.0417em;}
|
||||
a span.TEX span.E {text-decoration: none; }
|
||||
span.LATEX span.A{ position:relative; top:-0.5ex; left:-0.4em; font-size:85%;}
|
||||
span.LATEX span.TEX{ position:relative; left: -0.4em; }
|
||||
div.float, div.figure {margin-left: auto; margin-right: auto;}
|
||||
div.float img {text-align:center;}
|
||||
div.figure img {text-align:center;}
|
||||
.marginpar {width:20%; float:right; text-align:left; margin-left:auto; margin-top:0.5em; font-size:85%; text-decoration:underline;}
|
||||
.marginpar p{margin-top:0.4em; margin-bottom:0.4em;}
|
||||
table.equation {width:100%;}
|
||||
.equation td{text-align:center; }
|
||||
td.equation { margin-top:1em; margin-bottom:1em; }
|
||||
td.equation-label { width:5%; text-align:center; }
|
||||
td.eqnarray4 { width:5%; white-space: normal; }
|
||||
td.eqnarray2 { width:5%; }
|
||||
table.eqnarray-star, table.eqnarray {width:100%;}
|
||||
div.eqnarray{text-align:center;}
|
||||
div.array {text-align:center;}
|
||||
div.pmatrix {text-align:center;}
|
||||
table.pmatrix {width:100%;}
|
||||
span.pmatrix img{vertical-align:middle;}
|
||||
div.pmatrix {text-align:center;}
|
||||
table.pmatrix {width:100%;}
|
||||
span.bar-css {text-decoration:overline;}
|
||||
img.cdots{vertical-align:middle;}
|
||||
.partToc a, .partToc, .likepartToc a, .likepartToc {line-height: 200%; font-weight:bold; font-size:110%;}
|
||||
.chapterToc a, .chapterToc, .likechapterToc a, .likechapterToc, .appendixToc a, .appendixToc {line-height: 200%; font-weight:bold;}
|
||||
.index-item, .index-subitem, .index-subsubitem {display:block}
|
||||
div.caption {text-indent:-2em; margin-left:3em; margin-right:1em; text-align:left;}
|
||||
div.caption span.id{font-weight: bold; white-space: nowrap; }
|
||||
h1.partHead{text-align: center}
|
||||
p.bibitem { text-indent: -2em; margin-left: 2em; margin-top:0.6em; margin-bottom:0.6em; }
|
||||
p.bibitem-p { text-indent: 0em; margin-left: 2em; margin-top:0.6em; margin-bottom:0.6em; }
|
||||
.paragraphHead, .likeparagraphHead { margin-top:2em; font-weight: bold;}
|
||||
.subparagraphHead, .likesubparagraphHead { font-weight: bold;}
|
||||
.quote {margin-bottom:0.25em; margin-top:0.25em; margin-left:1em; margin-right:1em; text-align:justify;}
|
||||
.verse{white-space:nowrap; margin-left:2em}
|
||||
div.maketitle {text-align:center;}
|
||||
h2.titleHead{text-align:center;}
|
||||
div.maketitle{ margin-bottom: 2em; }
|
||||
div.author, div.date {text-align:center;}
|
||||
div.thanks{text-align:left; margin-left:10%; font-size:85%; font-style:italic; }
|
||||
div.author{white-space: nowrap;}
|
||||
.quotation {margin-bottom:0.25em; margin-top:0.25em; margin-left:1em; }
|
||||
.abstract p {margin-left:5%; margin-right:5%;}
|
||||
div.abstract {width:100%;}
|
||||
span.footnote-mark sup.textsuperscript, span.footnote-mark a sup.textsuperscript{ font-size:80%; }
|
||||
.figure img.graphics {margin-left:10%;}
|
||||
P.fancyvrb {white-space: nowrap; margin:0em;}
|
||||
dt.enumerate-enumitem{float:left; clear:left; margin-left:1em; margin-right:1em;}
|
||||
.uline{ text-decoration:underline; }
|
||||
.uuline{ text-decoration:underline; }
|
||||
span.sout {text-decoration: line-through }
|
||||
span.xout {text-decoration: line-through }
|
||||
span.uwave {text-decoration:underline }
|
||||
/* end css.sty */
|
||||
|
|
@ -0,0 +1,141 @@
|
|||
\documentclass[12pt,paper=a4]{scrartcl}
|
||||
|
||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||
% Packages
|
||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||
|
||||
% ...
|
||||
%\usepackage[margin=3cm]{geometry}
|
||||
\usepackage{a4wide}
|
||||
|
||||
% ...
|
||||
\usepackage[english]{babel}
|
||||
|
||||
%\usepackage[latin1]{inputenc}
|
||||
%\usepackage[T1]{fontenc}
|
||||
|
||||
% Do not indent paragraphs, instead separate them via vertical spacing
|
||||
\usepackage{parskip}
|
||||
|
||||
% Support for graphics, provides \includegraphics
|
||||
\usepackage{graphicx}
|
||||
%\graphicspath{{images/}} % Specify subdir containing the images
|
||||
|
||||
% Hyperref enriches the generated PDF with clickable links,
|
||||
% and provides many other useful features.
|
||||
\usepackage{nameref}
|
||||
\usepackage[colorlinks]{hyperref}
|
||||
\def\sectionautorefname{Section} % Write section with capital 'S'
|
||||
\def\subsectionautorefname{Subsection} % Write subsection with capital 'S'
|
||||
|
||||
|
||||
% The fancyvrb package provides the "Verbatim" environment, which,
|
||||
% unlike the built-in "verbatim", allows embedding TeX commands, as
|
||||
% well as tons of other neat stuff (line numbers, formatting adjustments, ...)
|
||||
\usepackage{fancyvrb}
|
||||
\fvset{tabsize=4,fontsize=\scriptsize,numbers=left}
|
||||
|
||||
% Normally, one can not use the underscore character in LaTeX without
|
||||
% escaping it (\_ instead of _). Since the Vorbis specs use it a lot,
|
||||
% we use the underscore package to change this default behavior.
|
||||
\usepackage[nohyphen]{underscore}
|
||||
|
||||
\usepackage{enumitem}
|
||||
|
||||
% In LaTeX, pictures are normally put into floating environments, and it is
|
||||
% left to the typesetting engine to place them in the "optimal" spot. These
|
||||
% docs however expect pictures to be placed in a *specific* position. So we
|
||||
% don't use \begin{figure}...\end{figure}, but rather a center environment.
|
||||
% To still be able to use captions, we use the capt-of package.
|
||||
\usepackage{capt-of}
|
||||
|
||||
% strikeout support
|
||||
\usepackage[normalem]{ulem}
|
||||
|
||||
% blockquote support
|
||||
\usepackage{csquotes}
|
||||
|
||||
% allow 'special' characters in filenames, like undescore :-P
|
||||
\usepackage{grffile}
|
||||
|
||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||
% Custom commands
|
||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||
|
||||
% Custom ref command, using hyperrefs autoref & nameref, to simulate the
|
||||
% behavior of DocBook's '<xref>'.
|
||||
\newcommand{\xref}[1]{\autoref{#1}, ``\nameref{#1}''}
|
||||
|
||||
% Emulat DocBook's '<link>'.
|
||||
\newcommand{\link}[2]{\hyperref[#1]{#2}}
|
||||
|
||||
% Simple 'Note' environment. Can be customized later on.
|
||||
\newenvironment{note}{\subparagraph*{Note:}}{}
|
||||
|
||||
% Map DocBook's <programlisting> to fancyvrb's Verbatim environment
|
||||
\let\programlisting\Verbatim
|
||||
\let\endprogramlisting\endVerbatim
|
||||
|
||||
% Fake some more DocBook elements
|
||||
\newcommand{\function}[1]{\texttt{#1}}
|
||||
\newcommand{\filename}[1]{\texttt{#1}}
|
||||
\newcommand{\varname}[1]{\texttt{#1}}
|
||||
\newcommand{\literal}[1]{\texttt{#1}}
|
||||
|
||||
% Redefine \~ to generate something that looks more appropriate when used in text.
|
||||
\renewcommand{\~}{$\sim$}
|
||||
|
||||
% Useful helper macro that inserts TODO comments very visibly into the generated
|
||||
% file. Helps you to not forget to resolve those TODOs... :)
|
||||
\newcommand{\TODO}[1]{\textcolor{red}{*** #1 ***}}
|
||||
|
||||
% Configure graphics formats: Prefer PDF, fall back to PNG or JPG, as available.
|
||||
\DeclareGraphicsExtensions{.pdf,.png,.jpg,.jpeg}
|
||||
|
||||
|
||||
% NOTE: Things to watch out for: Some chars are reserved in LaTeX. You need to translate them...
|
||||
% ~ -> $\sim$ (or \~ which we defined above)
|
||||
% % -> \%
|
||||
% & -> \&
|
||||
% < -> $<$
|
||||
% > -> $>$
|
||||
% and others. Refer to any of the many LaTeX refs out there if in doubt!
|
||||
|
||||
\begin{document}
|
||||
|
||||
|
||||
\title{Vorbis I specification}
|
||||
\author{Xiph.Org Foundation}
|
||||
\maketitle
|
||||
|
||||
\tableofcontents
|
||||
|
||||
\include{01-introduction}
|
||||
\include{02-bitpacking}
|
||||
\include{03-codebook}
|
||||
\include{04-codec}
|
||||
\include{05-comment}
|
||||
\include{06-floor0}
|
||||
\include{07-floor1}
|
||||
\include{08-residue}
|
||||
\include{09-helper}
|
||||
\include{10-tables}
|
||||
|
||||
\appendix
|
||||
\include{a1-encapsulation-ogg}
|
||||
\include{a2-encapsulation-rtp}
|
||||
|
||||
\include{footer}
|
||||
|
||||
|
||||
% TODO: Use a bibliography, as in the example below?
|
||||
\begin{thebibliography}{99}
|
||||
|
||||
\bibitem{Sporer/Brandenburg/Edler} T.~Sporer, K.~Brandenburg and B.~Edler,
|
||||
The use of multirate filter banks for coding of high quality digital audio,
|
||||
\url{http://www.iocon.com/resource/docs/ps/eusipco_corrected.ps}.
|
||||
|
||||
|
||||
\end{thebibliography}
|
||||
|
||||
\end{document}
|
After Width: | Height: | Size: 1.3 KiB |
After Width: | Height: | Size: 3.7 KiB |
After Width: | Height: | Size: 3.7 KiB |
After Width: | Height: | Size: 3.3 KiB |
After Width: | Height: | Size: 1.7 KiB |
After Width: | Height: | Size: 1.8 KiB |
After Width: | Height: | Size: 556 B |
After Width: | Height: | Size: 556 B |
After Width: | Height: | Size: 556 B |
After Width: | Height: | Size: 556 B |
After Width: | Height: | Size: 556 B |
After Width: | Height: | Size: 557 B |
After Width: | Height: | Size: 2.4 KiB |
After Width: | Height: | Size: 2.5 KiB |
After Width: | Height: | Size: 1.8 KiB |
|
@ -0,0 +1,184 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Embedding Vorbis into an Ogg stream} \label{vorbis:over:ogg}
|
||||
|
||||
\subsection{Overview}
|
||||
|
||||
This document describes using Ogg logical and physical transport
|
||||
streams to encapsulate Vorbis compressed audio packet data into file
|
||||
form.
|
||||
|
||||
The \xref{vorbis:spec:intro} provides an overview of the construction
|
||||
of Vorbis audio packets.
|
||||
|
||||
The \href{oggstream.html}{Ogg
|
||||
bitstream overview} and \href{framing.html}{Ogg logical
|
||||
bitstream and framing spec} provide detailed descriptions of Ogg
|
||||
transport streams. This specification document assumes a working
|
||||
knowledge of the concepts covered in these named backround
|
||||
documents. Please read them first.
|
||||
|
||||
\subsubsection{Restrictions}
|
||||
|
||||
The Ogg/Vorbis I specification currently dictates that Ogg/Vorbis
|
||||
streams use Ogg transport streams in degenerate, unmultiplexed
|
||||
form only. That is:
|
||||
|
||||
\begin{itemize}
|
||||
\item
|
||||
A meta-headerless Ogg file encapsulates the Vorbis I packets
|
||||
|
||||
\item
|
||||
The Ogg stream may be chained, i.e., contain multiple, contigous logical streams (links).
|
||||
|
||||
\item
|
||||
The Ogg stream must be unmultiplexed (only one stream, a Vorbis audio stream, per link)
|
||||
|
||||
\end{itemize}
|
||||
|
||||
|
||||
This is not to say that it is not currently possible to multiplex
|
||||
Vorbis with other media types into a multi-stream Ogg file. At the
|
||||
time this document was written, Ogg was becoming a popular container
|
||||
for low-bitrate movies consisting of DivX video and Vorbis audio.
|
||||
However, a 'Vorbis I audio file' is taken to imply Vorbis audio
|
||||
existing alone within a degenerate Ogg stream. A compliant 'Vorbis
|
||||
audio player' is not required to implement Ogg support beyond the
|
||||
specific support of Vorbis within a degenrate Ogg stream (naturally,
|
||||
application authors are encouraged to support full multiplexed Ogg
|
||||
handling).
|
||||
|
||||
|
||||
|
||||
|
||||
\subsubsection{MIME type}
|
||||
|
||||
The MIME type of Ogg files depend on the context. Specifically, complex
|
||||
multimedia and applications should use \literal{application/ogg},
|
||||
while visual media should use \literal{video/ogg}, and audio
|
||||
\literal{audio/ogg}. Vorbis data encapsulated in Ogg may appear
|
||||
in any of those types. RTP encapsulated Vorbis should use
|
||||
\literal{audio/vorbis} + \literal{audio/vorbis-config}.
|
||||
|
||||
|
||||
\subsection{Encapsulation}
|
||||
|
||||
Ogg encapsulation of a Vorbis packet stream is straightforward.
|
||||
|
||||
\begin{itemize}
|
||||
|
||||
\item
|
||||
The first Vorbis packet (the identification header), which
|
||||
uniquely identifies a stream as Vorbis audio, is placed alone in the
|
||||
first page of the logical Ogg stream. This results in a first Ogg
|
||||
page of exactly 58 bytes at the very beginning of the logical stream.
|
||||
|
||||
|
||||
\item
|
||||
This first page is marked 'beginning of stream' in the page flags.
|
||||
|
||||
|
||||
\item
|
||||
The second and third vorbis packets (comment and setup
|
||||
headers) may span one or more pages beginning on the second page of
|
||||
the logical stream. However many pages they span, the third header
|
||||
packet finishes the page on which it ends. The next (first audio) packet
|
||||
must begin on a fresh page.
|
||||
|
||||
|
||||
\item
|
||||
The granule position of these first pages containing only headers is zero.
|
||||
|
||||
|
||||
\item
|
||||
The first audio packet of the logical stream begins a fresh Ogg page.
|
||||
|
||||
|
||||
\item
|
||||
Packets are placed into ogg pages in order until the end of stream.
|
||||
|
||||
|
||||
\item
|
||||
The last page is marked 'end of stream' in the page flags.
|
||||
|
||||
|
||||
\item
|
||||
Vorbis packets may span page boundaries.
|
||||
|
||||
|
||||
\item
|
||||
The granule position of pages containing Vorbis audio is in units
|
||||
of PCM audio samples (per channel; a stereo stream's granule position
|
||||
does not increment at twice the speed of a mono stream).
|
||||
|
||||
|
||||
\item
|
||||
The granule position of a page represents the end PCM sample
|
||||
position of the last packet \emph{completed} on that
|
||||
page. The 'last PCM sample' is the last complete sample returned by
|
||||
decode, not an internal sample awaiting lapping with a
|
||||
subsequent block. A page that is entirely spanned by a single
|
||||
packet (that completes on a subsequent page) has no granule
|
||||
position, and the granule position is set to '-1'.
|
||||
|
||||
|
||||
Note that the last decoded (fully lapped) PCM sample from a packet
|
||||
is not necessarily the middle sample from that block. If, eg, the
|
||||
current Vorbis packet encodes a "long block" and the next Vorbis
|
||||
packet encodes a "short block", the last decodable sample from the
|
||||
current packet be at position (3*long\_block\_length/4) -
|
||||
(short\_block\_length/4).
|
||||
|
||||
|
||||
\item
|
||||
The granule (PCM) position of the first page need not indicate
|
||||
that the stream started at position zero. Although the granule
|
||||
position belongs to the last completed packet on the page and a
|
||||
valid granule position must be positive, by
|
||||
inference it may indicate that the PCM position of the beginning
|
||||
of audio is positive or negative.
|
||||
|
||||
|
||||
\begin{itemize}
|
||||
\item
|
||||
A positive starting value simply indicates that this stream begins at
|
||||
some positive time offset, potentially within a larger
|
||||
program. This is a common case when connecting to the middle
|
||||
of broadcast stream.
|
||||
|
||||
\item
|
||||
A negative value indicates that
|
||||
output samples preceeding time zero should be discarded during
|
||||
decoding; this technique is used to allow sample-granularity
|
||||
editing of the stream start time of already-encoded Vorbis
|
||||
streams. The number of samples to be discarded must not exceed
|
||||
the overlap-add span of the first two audio packets.
|
||||
|
||||
\end{itemize}
|
||||
|
||||
|
||||
In both of these cases in which the initial audio PCM starting
|
||||
offset is nonzero, the second finished audio packet must flush the
|
||||
page on which it appears and the third packet begin a fresh page.
|
||||
This allows the decoder to always be able to perform PCM position
|
||||
adjustments before needing to return any PCM data from synthesis,
|
||||
resulting in correct positioning information without any aditional
|
||||
seeking logic.
|
||||
|
||||
|
||||
\begin{note}
|
||||
Failure to do so should, at worst, cause a
|
||||
decoder implementation to return incorrect positioning information
|
||||
for seeking operations at the very beginning of the stream.
|
||||
\end{note}
|
||||
|
||||
|
||||
\item
|
||||
A granule position on the final page in a stream that indicates
|
||||
less audio data than the final packet would normally return is used to
|
||||
end the stream on other than even frame boundaries. The difference
|
||||
between the actual available data returned and the declared amount
|
||||
indicates how many trailing samples to discard from the decoding
|
||||
process.
|
||||
|
||||
\end{itemize}
|
|
@ -0,0 +1,8 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section{Vorbis encapsulation in RTP} \label{vorbis:over:rtp}
|
||||
|
||||
% TODO: Include draft-rtp.xml somehow?
|
||||
|
||||
Please consult RFC 5215 \textit{``RTP Payload Format for Vorbis Encoded
|
||||
Audio''} for description of how to embed Vorbis audio in an RTP stream.
|
After Width: | Height: | Size: 9.5 KiB |
After Width: | Height: | Size: 11 KiB |
After Width: | Height: | Size: 2.4 KiB |
After Width: | Height: | Size: 3.3 KiB |
After Width: | Height: | Size: 3.7 KiB |
After Width: | Height: | Size: 4.5 KiB |
After Width: | Height: | Size: 4.1 KiB |
|
@ -0,0 +1,154 @@
|
|||
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
|
||||
<html>
|
||||
<head>
|
||||
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-15"/>
|
||||
<title>Ogg Vorbis Documentation</title>
|
||||
|
||||
<style type="text/css">
|
||||
body {
|
||||
margin: 0 18px 0 18px;
|
||||
padding-bottom: 30px;
|
||||
font-family: Verdana, Arial, Helvetica, sans-serif;
|
||||
color: #333333;
|
||||
font-size: .8em;
|
||||
}
|
||||
|
||||
a {
|
||||
color: #3366cc;
|
||||
}
|
||||
|
||||
img {
|
||||
border: 0;
|
||||
}
|
||||
|
||||
#xiphlogo {
|
||||
margin: 30px 0 16px 0;
|
||||
}
|
||||
|
||||
#content p {
|
||||
line-height: 1.4;
|
||||
}
|
||||
|
||||
h1, h1 a, h2, h2 a, h3, h3 a {
|
||||
font-weight: bold;
|
||||
color: #ff9900;
|
||||
margin: 1.3em 0 8px 0;
|
||||
}
|
||||
|
||||
h1 {
|
||||
font-size: 1.3em;
|
||||
}
|
||||
|
||||
h2 {
|
||||
font-size: 1.2em;
|
||||
}
|
||||
|
||||
h3 {
|
||||
font-size: 1.1em;
|
||||
}
|
||||
|
||||
li {
|
||||
line-height: 1.4;
|
||||
}
|
||||
|
||||
#copyright {
|
||||
margin-top: 30px;
|
||||
line-height: 1.5em;
|
||||
text-align: center;
|
||||
font-size: .8em;
|
||||
color: #888888;
|
||||
clear: both;
|
||||
}
|
||||
</style>
|
||||
|
||||
</head>
|
||||
|
||||
<body>
|
||||
|
||||
<div id="xiphlogo">
|
||||
<a href="http://www.xiph.org/"><img src="fish_xiph_org.png" alt="Fish Logo and Xiph.Org"/></a>
|
||||
</div>
|
||||
|
||||
<h1>Ogg Vorbis I format specification: floor1_inverse_dB_table</h1>
|
||||
|
||||
<p>The vector <tt>[floor1_inverse_dB_table]</tt> is a 256 element static
|
||||
lookup table consiting of the following values (read left to right
|
||||
then top to bottom):</p>
|
||||
|
||||
<pre>
|
||||
1.0649863e-07, 1.1341951e-07, 1.2079015e-07, 1.2863978e-07,
|
||||
1.3699951e-07, 1.4590251e-07, 1.5538408e-07, 1.6548181e-07,
|
||||
1.7623575e-07, 1.8768855e-07, 1.9988561e-07, 2.1287530e-07,
|
||||
2.2670913e-07, 2.4144197e-07, 2.5713223e-07, 2.7384213e-07,
|
||||
2.9163793e-07, 3.1059021e-07, 3.3077411e-07, 3.5226968e-07,
|
||||
3.7516214e-07, 3.9954229e-07, 4.2550680e-07, 4.5315863e-07,
|
||||
4.8260743e-07, 5.1396998e-07, 5.4737065e-07, 5.8294187e-07,
|
||||
6.2082472e-07, 6.6116941e-07, 7.0413592e-07, 7.4989464e-07,
|
||||
7.9862701e-07, 8.5052630e-07, 9.0579828e-07, 9.6466216e-07,
|
||||
1.0273513e-06, 1.0941144e-06, 1.1652161e-06, 1.2409384e-06,
|
||||
1.3215816e-06, 1.4074654e-06, 1.4989305e-06, 1.5963394e-06,
|
||||
1.7000785e-06, 1.8105592e-06, 1.9282195e-06, 2.0535261e-06,
|
||||
2.1869758e-06, 2.3290978e-06, 2.4804557e-06, 2.6416497e-06,
|
||||
2.8133190e-06, 2.9961443e-06, 3.1908506e-06, 3.3982101e-06,
|
||||
3.6190449e-06, 3.8542308e-06, 4.1047004e-06, 4.3714470e-06,
|
||||
4.6555282e-06, 4.9580707e-06, 5.2802740e-06, 5.6234160e-06,
|
||||
5.9888572e-06, 6.3780469e-06, 6.7925283e-06, 7.2339451e-06,
|
||||
7.7040476e-06, 8.2047000e-06, 8.7378876e-06, 9.3057248e-06,
|
||||
9.9104632e-06, 1.0554501e-05, 1.1240392e-05, 1.1970856e-05,
|
||||
1.2748789e-05, 1.3577278e-05, 1.4459606e-05, 1.5399272e-05,
|
||||
1.6400004e-05, 1.7465768e-05, 1.8600792e-05, 1.9809576e-05,
|
||||
2.1096914e-05, 2.2467911e-05, 2.3928002e-05, 2.5482978e-05,
|
||||
2.7139006e-05, 2.8902651e-05, 3.0780908e-05, 3.2781225e-05,
|
||||
3.4911534e-05, 3.7180282e-05, 3.9596466e-05, 4.2169667e-05,
|
||||
4.4910090e-05, 4.7828601e-05, 5.0936773e-05, 5.4246931e-05,
|
||||
5.7772202e-05, 6.1526565e-05, 6.5524908e-05, 6.9783085e-05,
|
||||
7.4317983e-05, 7.9147585e-05, 8.4291040e-05, 8.9768747e-05,
|
||||
9.5602426e-05, 0.00010181521, 0.00010843174, 0.00011547824,
|
||||
0.00012298267, 0.00013097477, 0.00013948625, 0.00014855085,
|
||||
0.00015820453, 0.00016848555, 0.00017943469, 0.00019109536,
|
||||
0.00020351382, 0.00021673929, 0.00023082423, 0.00024582449,
|
||||
0.00026179955, 0.00027881276, 0.00029693158, 0.00031622787,
|
||||
0.00033677814, 0.00035866388, 0.00038197188, 0.00040679456,
|
||||
0.00043323036, 0.00046138411, 0.00049136745, 0.00052329927,
|
||||
0.00055730621, 0.00059352311, 0.00063209358, 0.00067317058,
|
||||
0.00071691700, 0.00076350630, 0.00081312324, 0.00086596457,
|
||||
0.00092223983, 0.00098217216, 0.0010459992, 0.0011139742,
|
||||
0.0011863665, 0.0012634633, 0.0013455702, 0.0014330129,
|
||||
0.0015261382, 0.0016253153, 0.0017309374, 0.0018434235,
|
||||
0.0019632195, 0.0020908006, 0.0022266726, 0.0023713743,
|
||||
0.0025254795, 0.0026895994, 0.0028643847, 0.0030505286,
|
||||
0.0032487691, 0.0034598925, 0.0036847358, 0.0039241906,
|
||||
0.0041792066, 0.0044507950, 0.0047400328, 0.0050480668,
|
||||
0.0053761186, 0.0057254891, 0.0060975636, 0.0064938176,
|
||||
0.0069158225, 0.0073652516, 0.0078438871, 0.0083536271,
|
||||
0.0088964928, 0.009474637, 0.010090352, 0.010746080,
|
||||
0.011444421, 0.012188144, 0.012980198, 0.013823725,
|
||||
0.014722068, 0.015678791, 0.016697687, 0.017782797,
|
||||
0.018938423, 0.020169149, 0.021479854, 0.022875735,
|
||||
0.024362330, 0.025945531, 0.027631618, 0.029427276,
|
||||
0.031339626, 0.033376252, 0.035545228, 0.037855157,
|
||||
0.040315199, 0.042935108, 0.045725273, 0.048696758,
|
||||
0.051861348, 0.055231591, 0.058820850, 0.062643361,
|
||||
0.066714279, 0.071049749, 0.075666962, 0.080584227,
|
||||
0.085821044, 0.091398179, 0.097337747, 0.10366330,
|
||||
0.11039993, 0.11757434, 0.12521498, 0.13335215,
|
||||
0.14201813, 0.15124727, 0.16107617, 0.17154380,
|
||||
0.18269168, 0.19456402, 0.20720788, 0.22067342,
|
||||
0.23501402, 0.25028656, 0.26655159, 0.28387361,
|
||||
0.30232132, 0.32196786, 0.34289114, 0.36517414,
|
||||
0.38890521, 0.41417847, 0.44109412, 0.46975890,
|
||||
0.50028648, 0.53279791, 0.56742212, 0.60429640,
|
||||
0.64356699, 0.68538959, 0.72993007, 0.77736504,
|
||||
0.82788260, 0.88168307, 0.9389798, 1.
|
||||
</pre>
|
||||
|
||||
<div id="copyright">
|
||||
The Xiph Fish Logo is a
|
||||
trademark (™) of Xiph.Org.<br/>
|
||||
|
||||
These pages © 1994 - 2005 Xiph.Org. All rights reserved.
|
||||
</div>
|
||||
|
||||
</body>
|
||||
</html>
|
After Width: | Height: | Size: 2.5 KiB |
|
@ -0,0 +1,31 @@
|
|||
% -*- mode: latex; TeX-master: "Vorbis_I_spec"; -*-
|
||||
%!TEX root = Vorbis_I_spec.tex
|
||||
\section*{Colophon}
|
||||
|
||||
\includegraphics[width=5cm]{fish_xiph_org}
|
||||
\label{footer}
|
||||
|
||||
Ogg is a \href{http://www.xiph.org/}{Xiph.Org Foundation} effort
|
||||
to protect essential tenets of Internet multimedia from corporate
|
||||
hostage-taking; Open Source is the net's greatest tool to keep
|
||||
everyone honest. See \href{http://www.xiph.org/about.html}{About
|
||||
the Xiph.Org Foundation} for details.
|
||||
|
||||
|
||||
Ogg Vorbis is the first Ogg audio CODEC. Anyone may freely use and
|
||||
distribute the Ogg and Vorbis specification, whether in a private,
|
||||
public or corporate capacity. However, the Xiph.Org Foundation and
|
||||
the Ogg project (xiph.org) reserve the right to set the Ogg Vorbis
|
||||
specification and certify specification compliance.
|
||||
|
||||
Xiph.Org's Vorbis software CODEC implementation is distributed under a
|
||||
BSD-like license. This does not restrict third parties from
|
||||
distributing independent implementations of Vorbis software under
|
||||
other licenses.
|
||||
|
||||
Ogg, Vorbis, Xiph.Org Foundation and their logos are trademarks (tm)
|
||||
of the \href{http://www.xiph.org/}{Xiph.Org Foundation}. These
|
||||
pages are copyright (C) 1994-2015 Xiph.Org Foundation. All rights
|
||||
reserved.
|
||||
|
||||
This document is set using \LaTeX.
|
After Width: | Height: | Size: 9.8 KiB |
|
@ -0,0 +1,431 @@
|
|||
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
|
||||
<html>
|
||||
<head>
|
||||
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-15"/>
|
||||
<title>Ogg Vorbis Documentation</title>
|
||||
|
||||
<style type="text/css">
|
||||
body {
|
||||
margin: 0 18px 0 18px;
|
||||
padding-bottom: 30px;
|
||||
font-family: Verdana, Arial, Helvetica, sans-serif;
|
||||
color: #333333;
|
||||
font-size: .8em;
|
||||
}
|
||||
|
||||
a {
|
||||
color: #3366cc;
|
||||
}
|
||||
|
||||
img {
|
||||
border: 0;
|
||||
}
|
||||
|
||||
#xiphlogo {
|
||||
margin: 30px 0 16px 0;
|
||||
}
|
||||
|
||||
#content p {
|
||||
line-height: 1.4;
|
||||
}
|
||||
|
||||
h1, h1 a, h2, h2 a, h3, h3 a {
|
||||
font-weight: bold;
|
||||
color: #ff9900;
|
||||
margin: 1.3em 0 8px 0;
|
||||
}
|
||||
|
||||
h1 {
|
||||
font-size: 1.3em;
|
||||
}
|
||||
|
||||
h2 {
|
||||
font-size: 1.2em;
|
||||
}
|
||||
|
||||
h3 {
|
||||
font-size: 1.1em;
|
||||
}
|
||||
|
||||
li {
|
||||
line-height: 1.4;
|
||||
}
|
||||
|
||||
#copyright {
|
||||
margin-top: 30px;
|
||||
line-height: 1.5em;
|
||||
text-align: center;
|
||||
font-size: .8em;
|
||||
color: #888888;
|
||||
clear: both;
|
||||
}
|
||||
</style>
|
||||
|
||||
</head>
|
||||
|
||||
<body>
|
||||
|
||||
<div id="xiphlogo">
|
||||
<a href="http://www.xiph.org/"><img src="fish_xiph_org.png" alt="Fish Logo and Xiph.Org"/></a>
|
||||
</div>
|
||||
|
||||
<h1>Ogg logical bitstream framing</h1>
|
||||
|
||||
<h2>Ogg bitstreams</h2>
|
||||
|
||||
<p>The Ogg transport bitstream is designed to provide framing, error
|
||||
protection and seeking structure for higher-level codec streams that
|
||||
consist of raw, unencapsulated data packets, such as the Vorbis audio
|
||||
codec or Theora video codec.</p>
|
||||
|
||||
<h2>Application example: Vorbis</h2>
|
||||
|
||||
<p>Vorbis encodes short-time blocks of PCM data into raw packets of
|
||||
bit-packed data. These raw packets may be used directly by transport
|
||||
mechanisms that provide their own framing and packet-separation
|
||||
mechanisms (such as UDP datagrams). For stream based storage (such as
|
||||
files) and transport (such as TCP streams or pipes), Vorbis uses the
|
||||
Ogg bitstream format to provide framing/sync, sync recapture
|
||||
after error, landmarks during seeking, and enough information to
|
||||
properly separate data back into packets at the original packet
|
||||
boundaries without relying on decoding to find packet boundaries.</p>
|
||||
|
||||
<h2>Design constraints for Ogg bitstreams</h2>
|
||||
|
||||
<ol>
|
||||
<li>True streaming; we must not need to seek to build a 100%
|
||||
complete bitstream.</li>
|
||||
<li>Use no more than approximately 1-2% of bitstream bandwidth for
|
||||
packet boundary marking, high-level framing, sync and seeking.</li>
|
||||
<li>Specification of absolute position within the original sample
|
||||
stream.</li>
|
||||
<li>Simple mechanism to ease limited editing, such as a simplified
|
||||
concatenation mechanism.</li>
|
||||
<li>Detection of corruption, recapture after error and direct, random
|
||||
access to data at arbitrary positions in the bitstream.</li>
|
||||
</ol>
|
||||
|
||||
<h2>Logical and Physical Bitstreams</h2>
|
||||
|
||||
<p>A <em>logical</em> Ogg bitstream is a contiguous stream of
|
||||
sequential pages belonging only to the logical bitstream. A
|
||||
<em>physical</em> Ogg bitstream is constructed from one or more
|
||||
than one logical Ogg bitstream (the simplest physical bitstream
|
||||
is simply a single logical bitstream). We describe below the exact
|
||||
formatting of an Ogg logical bitstream. Combining logical
|
||||
bitstreams into more complex physical bitstreams is described in the
|
||||
<a href="oggstream.html">Ogg bitstream overview</a>. The exact
|
||||
mapping of raw Vorbis packets into a valid Ogg Vorbis physical
|
||||
bitstream is described in the Vorbis I Specification.</p>
|
||||
|
||||
<h2>Bitstream structure</h2>
|
||||
|
||||
<p>An Ogg stream is structured by dividing incoming packets into
|
||||
segments of up to 255 bytes and then wrapping a group of contiguous
|
||||
packet segments into a variable length page preceded by a page
|
||||
header. Both the header size and page size are variable; the page
|
||||
header contains sizing information and checksum data to determine
|
||||
header/page size and data integrity.</p>
|
||||
|
||||
<p>The bitstream is captured (or recaptured) by looking for the beginning
|
||||
of a page, specifically the capture pattern. Once the capture pattern
|
||||
is found, the decoder verifies page sync and integrity by computing
|
||||
and comparing the checksum. At that point, the decoder can extract the
|
||||
packets themselves.</p>
|
||||
|
||||
<h3>Packet segmentation</h3>
|
||||
|
||||
<p>Packets are logically divided into multiple segments before encoding
|
||||
into a page. Note that the segmentation and fragmentation process is a
|
||||
logical one; it's used to compute page header values and the original
|
||||
page data need not be disturbed, even when a packet spans page
|
||||
boundaries.</p>
|
||||
|
||||
<p>The raw packet is logically divided into [n] 255 byte segments and a
|
||||
last fractional segment of < 255 bytes. A packet size may well
|
||||
consist only of the trailing fractional segment, and a fractional
|
||||
segment may be zero length. These values, called "lacing values" are
|
||||
then saved and placed into the header segment table.</p>
|
||||
|
||||
<p>An example should make the basic concept clear:</p>
|
||||
|
||||
<pre>
|
||||
<tt>
|
||||
raw packet:
|
||||
___________________________________________
|
||||
|______________packet data__________________| 753 bytes
|
||||
|
||||
lacing values for page header segment table: 255,255,243
|
||||
</tt>
|
||||
</pre>
|
||||
|
||||
<p>We simply add the lacing values for the total size; the last lacing
|
||||
value for a packet is always the value that is less than 255. Note
|
||||
that this encoding both avoids imposing a maximum packet size as well
|
||||
as imposing minimum overhead on small packets (as opposed to, eg,
|
||||
simply using two bytes at the head of every packet and having a max
|
||||
packet size of 32k. Small packets (<255, the typical case) are
|
||||
penalized with twice the segmentation overhead). Using the lacing
|
||||
values as suggested, small packets see the minimum possible
|
||||
byte-aligned overheade (1 byte) and large packets, over 512 bytes or
|
||||
so, see a fairly constant ~.5% overhead on encoding space.</p>
|
||||
|
||||
<p>Note that a lacing value of 255 implies that a second lacing value
|
||||
follows in the packet, and a value of < 255 marks the end of the
|
||||
packet after that many additional bytes. A packet of 255 bytes (or a
|
||||
multiple of 255 bytes) is terminated by a lacing value of 0:</p>
|
||||
|
||||
<pre><tt>
|
||||
raw packet:
|
||||
_______________________________
|
||||
|________packet data____________| 255 bytes
|
||||
|
||||
lacing values: 255, 0
|
||||
</tt></pre>
|
||||
|
||||
<p>Note also that a 'nil' (zero length) packet is not an error; it
|
||||
consists of nothing more than a lacing value of zero in the header.</p>
|
||||
|
||||
<h3>Packets spanning pages</h3>
|
||||
|
||||
<p>Packets are not restricted to beginning and ending within a page,
|
||||
although individual segments are, by definition, required to do so.
|
||||
Packets are not restricted to a maximum size, although excessively
|
||||
large packets in the data stream are discouraged; the Ogg
|
||||
bitstream specification strongly recommends nominal page size of
|
||||
approximately 4-8kB (large packets are foreseen as being useful for
|
||||
initialization data at the beginning of a logical bitstream).</p>
|
||||
|
||||
<p>After segmenting a packet, the encoder may decide not to place all the
|
||||
resulting segments into the current page; to do so, the encoder places
|
||||
the lacing values of the segments it wishes to belong to the current
|
||||
page into the current segment table, then finishes the page. The next
|
||||
page is begun with the first value in the segment table belonging to
|
||||
the next packet segment, thus continuing the packet (data in the
|
||||
packet body must also correspond properly to the lacing values in the
|
||||
spanned pages. The segment data in the first packet corresponding to
|
||||
the lacing values of the first page belong in that page; packet
|
||||
segments listed in the segment table of the following page must begin
|
||||
the page body of the subsequent page).</p>
|
||||
|
||||
<p>The last mechanic to spanning a page boundary is to set the header
|
||||
flag in the new page to indicate that the first lacing value in the
|
||||
segment table continues rather than begins a packet; a header flag of
|
||||
0x01 is set to indicate a continued packet. Although mandatory, it
|
||||
is not actually algorithmically necessary; one could inspect the
|
||||
preceding segment table to determine if the packet is new or
|
||||
continued. Adding the information to the packet_header flag allows a
|
||||
simpler design (with no overhead) that needs only inspect the current
|
||||
page header after frame capture. This also allows faster error
|
||||
recovery in the event that the packet originates in a corrupt
|
||||
preceding page, implying that the previous page's segment table
|
||||
cannot be trusted.</p>
|
||||
|
||||
<p>Note that a packet can span an arbitrary number of pages; the above
|
||||
spanning process is repeated for each spanned page boundary. Also a
|
||||
'zero termination' on a packet size that is an even multiple of 255
|
||||
must appear even if the lacing value appears in the next page as a
|
||||
zero-length continuation of the current packet. The header flag
|
||||
should be set to 0x01 to indicate that the packet spanned, even though
|
||||
the span is a nil case as far as data is concerned.</p>
|
||||
|
||||
<p>The encoding looks odd, but is properly optimized for speed and the
|
||||
expected case of the majority of packets being between 50 and 200
|
||||
bytes (note that it is designed such that packets of wildly different
|
||||
sizes can be handled within the model; placing packet size
|
||||
restrictions on the encoder would have only slightly simplified design
|
||||
in page generation and increased overall encoder complexity).</p>
|
||||
|
||||
<p>The main point behind tracking individual packets (and packet
|
||||
segments) is to allow more flexible encoding tricks that requiring
|
||||
explicit knowledge of packet size. An example is simple bandwidth
|
||||
limiting, implemented by simply truncating packets in the nominal case
|
||||
if the packet is arranged so that the least sensitive portion of the
|
||||
data comes last.</p>
|
||||
|
||||
<h3>Page header</h3>
|
||||
|
||||
<p>The headering mechanism is designed to avoid copying and re-assembly
|
||||
of the packet data (ie, making the packet segmentation process a
|
||||
logical one); the header can be generated directly from incoming
|
||||
packet data. The encoder buffers packet data until it finishes a
|
||||
complete page at which point it writes the header followed by the
|
||||
buffered packet segments.</p>
|
||||
|
||||
<h4>capture_pattern</h4>
|
||||
|
||||
<p>A header begins with a capture pattern that simplifies identifying
|
||||
pages; once the decoder has found the capture pattern it can do a more
|
||||
intensive job of verifying that it has in fact found a page boundary
|
||||
(as opposed to an inadvertent coincidence in the byte stream).</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
0 0x4f 'O'
|
||||
1 0x67 'g'
|
||||
2 0x67 'g'
|
||||
3 0x53 'S'
|
||||
</tt></pre>
|
||||
|
||||
<h4>stream_structure_version</h4>
|
||||
|
||||
<p>The capture pattern is followed by the stream structure revision:</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
4 0x00
|
||||
</tt></pre>
|
||||
|
||||
<h4>header_type_flag</h4>
|
||||
|
||||
<p>The header type flag identifies this page's context in the bitstream:</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
5 bitflags: 0x01: unset = fresh packet
|
||||
set = continued packet
|
||||
0x02: unset = not first page of logical bitstream
|
||||
set = first page of logical bitstream (bos)
|
||||
0x04: unset = not last page of logical bitstream
|
||||
set = last page of logical bitstream (eos)
|
||||
</tt></pre>
|
||||
|
||||
<h4>absolute granule position</h4>
|
||||
|
||||
<p>(This is packed in the same way the rest of Ogg data is packed; LSb
|
||||
of LSB first. Note that the 'position' data specifies a 'sample'
|
||||
number (eg, in a CD quality sample is four octets, 16 bits for left
|
||||
and 16 bits for right; in video it would likely be the frame number.
|
||||
It is up to the specific codec in use to define the semantic meaning
|
||||
of the granule position value). The position specified is the total
|
||||
samples encoded after including all packets finished on this page
|
||||
(packets begun on this page but continuing on to the next page do not
|
||||
count). The rationale here is that the position specified in the
|
||||
frame header of the last page tells how long the data coded by the
|
||||
bitstream is. A truncated stream will still return the proper number
|
||||
of samples that can be decoded fully.</p>
|
||||
|
||||
<p>A special value of '-1' (in two's complement) indicates that no packets
|
||||
finish on this page.</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
6 0xXX LSB
|
||||
7 0xXX
|
||||
8 0xXX
|
||||
9 0xXX
|
||||
10 0xXX
|
||||
11 0xXX
|
||||
12 0xXX
|
||||
13 0xXX MSB
|
||||
</tt></pre>
|
||||
|
||||
<h4>stream serial number</h4>
|
||||
|
||||
<p>Ogg allows for separate logical bitstreams to be mixed at page
|
||||
granularity in a physical bitstream. The most common case would be
|
||||
sequential arrangement, but it is possible to interleave pages for
|
||||
two separate bitstreams to be decoded concurrently. The serial
|
||||
number is the means by which pages physical pages are associated with
|
||||
a particular logical stream. Each logical stream must have a unique
|
||||
serial number within a physical stream:</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
14 0xXX LSB
|
||||
15 0xXX
|
||||
16 0xXX
|
||||
17 0xXX MSB
|
||||
</tt></pre>
|
||||
|
||||
<h4>page sequence no</h4>
|
||||
|
||||
<p>Page counter; lets us know if a page is lost (useful where packets
|
||||
span page boundaries).</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
18 0xXX LSB
|
||||
19 0xXX
|
||||
20 0xXX
|
||||
21 0xXX MSB
|
||||
</tt></pre>
|
||||
|
||||
<h4>page checksum</h4>
|
||||
|
||||
<p>32 bit CRC value (direct algorithm, initial val and final XOR = 0,
|
||||
generator polynomial=0x04c11db7). The value is computed over the
|
||||
entire header (with the CRC field in the header set to zero) and then
|
||||
continued over the page. The CRC field is then filled with the
|
||||
computed value.</p>
|
||||
|
||||
<p>(A thorough discussion of CRC algorithms can be found in <a
|
||||
href="http://www.ross.net/crc/download/crc_v3.txt">"A
|
||||
Painless Guide to CRC Error Detection Algorithms"</a> by Ross
|
||||
Williams <a href="mailto:ross@ross.net">ross@ross.net</a>.)</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
22 0xXX LSB
|
||||
23 0xXX
|
||||
24 0xXX
|
||||
25 0xXX MSB
|
||||
</tt></pre>
|
||||
|
||||
<h4>page_segments</h4>
|
||||
|
||||
<p>The number of segment entries to appear in the segment table. The
|
||||
maximum number of 255 segments (255 bytes each) sets the maximum
|
||||
possible physical page size at 65307 bytes or just under 64kB (thus
|
||||
we know that a header corrupted so as destroy sizing/alignment
|
||||
information will not cause a runaway bitstream. We'll read in the
|
||||
page according to the corrupted size information that's guaranteed to
|
||||
be a reasonable size regardless, notice the checksum mismatch, drop
|
||||
sync and then look for recapture).</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
26 0x00-0xff (0-255)
|
||||
</tt></pre>
|
||||
|
||||
<h4>segment_table (containing packet lacing values)</h4>
|
||||
|
||||
<p>The lacing values for each packet segment physically appearing in
|
||||
this page are listed in contiguous order.</p>
|
||||
|
||||
<pre><tt>
|
||||
byte value
|
||||
|
||||
27 0x00-0xff (0-255)
|
||||
[...]
|
||||
n 0x00-0xff (0-255, n=page_segments+26)
|
||||
</tt></pre>
|
||||
|
||||
<p>Total page size is calculated directly from the known header size and
|
||||
lacing values in the segment table. Packet data segments follow
|
||||
immediately after the header.</p>
|
||||
|
||||
<p>Page headers typically impose a flat .25-.5% space overhead assuming
|
||||
nominal ~8k page sizes. The segmentation table needed for exact
|
||||
packet recovery in the streaming layer adds approximately .5-1%
|
||||
nominal assuming expected encoder behavior in the 44.1kHz, 128kbps
|
||||
stereo encodings.</p>
|
||||
|
||||
<div id="copyright">
|
||||
The Xiph Fish Logo is a
|
||||
trademark (™) of Xiph.Org.<br/>
|
||||
|
||||
These pages © 1994 - 2005 Xiph.Org. All rights reserved.
|
||||
</div>
|
||||
|
||||
</body>
|
||||
</html>
|
|
@ -0,0 +1,239 @@
|
|||
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
|
||||
<html>
|
||||
<head>
|
||||
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-15"/>
|
||||
<title>Ogg Vorbis Documentation</title>
|
||||
|
||||
<style type="text/css">
|
||||
body {
|
||||
margin: 0 18px 0 18px;
|
||||
padding-bottom: 30px;
|
||||
font-family: Verdana, Arial, Helvetica, sans-serif;
|
||||
color: #333333;
|
||||
font-size: .8em;
|
||||
}
|
||||
|
||||
a {
|
||||
color: #3366cc;
|
||||
}
|
||||
|
||||
img {
|
||||
border: 0;
|
||||
}
|
||||
|
||||
#xiphlogo {
|
||||
margin: 30px 0 16px 0;
|
||||
}
|
||||
|
||||
#content p {
|
||||
line-height: 1.4;
|
||||
}
|
||||
|
||||
h1, h1 a, h2, h2 a, h3, h3 a {
|
||||
font-weight: bold;
|
||||
color: #ff9900;
|
||||
margin: 1.3em 0 8px 0;
|
||||
}
|
||||
|
||||
h1 {
|
||||
font-size: 1.3em;
|
||||
}
|
||||
|
||||
h2 {
|
||||
font-size: 1.2em;
|
||||
}
|
||||
|
||||
h3 {
|
||||
font-size: 1.1em;
|
||||
}
|
||||
|
||||
li {
|
||||
line-height: 1.4;
|
||||
}
|
||||
|
||||
#copyright {
|
||||
margin-top: 30px;
|
||||
line-height: 1.5em;
|
||||
text-align: center;
|
||||
font-size: .8em;
|
||||
color: #888888;
|
||||
clear: both;
|
||||
}
|
||||
</style>
|
||||
|
||||
</head>
|
||||
|
||||
<body>
|
||||
|
||||
<div id="xiphlogo">
|
||||
<a href="http://www.xiph.org/"><img src="fish_xiph_org.png" alt="Fish Logo and Xiph.Org"/></a>
|
||||
</div>
|
||||
|
||||
<h1>Ogg Vorbis I format specification: helper equations</h1>
|
||||
|
||||
<h1>Overview</h1>
|
||||
|
||||
<p>The equations below are used in multiple places by the Vorbis codec
|
||||
specification. Rather than cluttering up the main specification
|
||||
documents, they are defined here and linked in the main documents
|
||||
where appropriate.</p>
|
||||
|
||||
<h2><a name="log">ilog</a></h2>
|
||||
|
||||
<p>The "ilog(x)" function returns the position number (1 through n) of the
|
||||
highest set bit in the two's complement integer value
|
||||
<tt>[x]</tt>. Values of <tt>[x]</tt> less than zero are defined to return zero.</p>
|
||||
|
||||
<pre>
|
||||
1) [return_value] = 0;
|
||||
2) if ( [x] is greater than zero ){
|
||||
|
||||
3) increment [return_value];
|
||||
4) logical shift [x] one bit to the right, padding the MSb with zero
|
||||
5) repeat at step 2)
|
||||
|
||||
}
|
||||
|
||||
6) done
|
||||
</pre>
|
||||
|
||||
<p>Examples:</p>
|
||||
|
||||
<ul>
|
||||
<li>ilog(0) = 0;</li>
|
||||
<li>ilog(1) = 1;</li>
|
||||
<li>ilog(2) = 2;</li>
|
||||
<li>ilog(3) = 2;</li>
|
||||
<li>ilog(4) = 3;</li>
|
||||
<li>ilog(7) = 3;</li>
|
||||
<li>ilog(negative number) = 0;</li>
|
||||
</ul>
|
||||
|
||||
<h2><a name="float32_unpack">float32_unpack</a></h2>
|
||||
|
||||
<p>"float32_unpack(x)" is intended to translate the packed binary
|
||||
representation of a Vorbis codebook float value into the
|
||||
representation used by the decoder for floating point numbers. For
|
||||
purposes of this example, we will unpack a Vorbis float32 into a
|
||||
host-native floating point number.</p>
|
||||
|
||||
<pre>
|
||||
1) [mantissa] = [x] bitwise AND 0x1fffff (unsigned result)
|
||||
2) [sign] = [x] bitwise AND 0x80000000 (unsigned result)
|
||||
3) [exponent] = ( [x] bitwise AND 0x7fe00000) shifted right 21 bits (unsigned result)
|
||||
4) if ( [sign] is nonzero ) then negate [mantissa]
|
||||
5) return [mantissa] * ( 2 ^ ( [exponent] - 788 ) )
|
||||
</pre>
|
||||
|
||||
<h2><a name="lookup1_values">lookup1_values</a></h2>
|
||||
|
||||
<p>"lookup1_values(codebook_entries,codebook_dimensions)" is used to
|
||||
compute the correct length of the value index for a codebook VQ lookup
|
||||
table of lookup type 1. The values on this list are permuted to
|
||||
construct the VQ vector lookup table of size
|
||||
<tt>[codebook_entries]</tt>.</p>
|
||||
|
||||
<p>The return value for this function is defined to be 'the greatest
|
||||
integer value for which <tt>[return_value] to the power of
|
||||
[codebook_dimensions] is less than or equal to
|
||||
[codebook_entries]</tt>'.</p>
|
||||
|
||||
<h2><a name="low_neighbor">low_neighbor</a></h2>
|
||||
|
||||
<p>"low_neighbor(v,x)" finds the position <i>n</i> in vector [v] of
|
||||
the greatest value scalar element for which <i>n</i> is less than
|
||||
<tt>[x]</tt> and <tt>vector [v] element <i>n</i> is less
|
||||
than vector [v] element [x]</tt>.</p>
|
||||
|
||||
<h2><a name="high_neighbor">high_neighbor</a></h2>
|
||||
|
||||
<p>"high_neighbor(v,x)" finds the position <i>n</i> in vector [v] of
|
||||
the lowest value scalar element for which <i>n</i> is less than
|
||||
<tt>[x]</tt> and <tt>vector [v] element <i>n</i> is greater
|
||||
than vector [v] element [x]</tt>.</p>
|
||||
|
||||
<h2><a name="render_point">render_point</a></h2>
|
||||
|
||||
<p>"render_point(x0,y0,x1,y1,X)" is used to find the Y value at point X
|
||||
along the line specified by x0, x1, y0 and y1. This function uses an
|
||||
integer algorithm to solve for the point directly without calculating
|
||||
intervening values along the line.</p>
|
||||
|
||||
<pre>
|
||||
1) [dy] = [y1] - [y0]
|
||||
2) [adx] = [x1] - [x0]
|
||||
3) [ady] = absolute value of [dy]
|
||||
4) [err] = [ady] * ([X] - [x0])
|
||||
5) [off] = [err] / [adx] using integer division
|
||||
6) if ( [dy] is less than zero ) {
|
||||
|
||||
7) [Y] = [y0] - [off]
|
||||
|
||||
} else {
|
||||
|
||||
8) [Y] = [y0] + [off]
|
||||
|
||||
}
|
||||
|
||||
9) done
|
||||
</pre>
|
||||
|
||||
<h2><a name="render_line">render_line</a></h2>
|
||||
|
||||
<p>Floor decode type one uses the integer line drawing algorithm of
|
||||
"render_line(x0, y0, x1, y1, v)" to construct an integer floor
|
||||
curve for contiguous piecewise line segments. Note that it has not
|
||||
been relevant elsewhere, but here we must define integer division as
|
||||
rounding division of both positive and negative numbers toward zero.</p>
|
||||
|
||||
<pre>
|
||||
1) [dy] = [y1] - [y0]
|
||||
2) [adx] = [x1] - [x0]
|
||||
3) [ady] = absolute value of [dy]
|
||||
4) [base] = [dy] / [adx] using integer division
|
||||
5) [x] = [x0]
|
||||
6) [y] = [y0]
|
||||
7) [err] = 0
|
||||
|
||||
8) if ( [dy] is less than 0 ) {
|
||||
|
||||
9) [sy] = [base] - 1
|
||||
|
||||
} else {
|
||||
|
||||
10) [sy] = [base] + 1
|
||||
|
||||
}
|
||||
|
||||
11) [ady] = [ady] - (absolute value of [base]) * [adx]
|
||||
12) vector [v] element [x] = [y]
|
||||
|
||||
13) iterate [x] over the range [x0]+1 ... [x1]-1 {
|
||||
|
||||
14) [err] = [err] + [ady];
|
||||
15) if ( [err] >= [adx] ) {
|
||||
|
||||
15) [err] = [err] - [adx]
|
||||
16) [y] = [y] + [sy]
|
||||
|
||||
} else {
|
||||
|
||||
17) [y] = [y] + [base]
|
||||
|
||||
}
|
||||
|
||||
18) vector [v] element [x] = [y]
|
||||
|
||||
}
|
||||
</pre>
|
||||
|
||||
<div id="copyright">
|
||||
The Xiph Fish Logo is a
|
||||
trademark (™) of Xiph.Org.<br/>
|
||||
|
||||
These pages © 1994 - 2005 Xiph.Org. All rights reserved.
|
||||
</div>
|
||||
|
||||
</body>
|
||||
</html>
|
After Width: | Height: | Size: 1.2 KiB |
After Width: | Height: | Size: 1.2 KiB |
|
@ -0,0 +1,114 @@
|
|||
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
|
||||
<html>
|
||||
<head>
|
||||
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-15"/>
|
||||
<title>Ogg Vorbis Documentation</title>
|
||||
|
||||
<style type="text/css">
|
||||
body {
|
||||
margin: 0 18px 0 18px;
|
||||
padding-bottom: 30px;
|
||||
font-family: Verdana, Arial, Helvetica, sans-serif;
|
||||
color: #333333;
|
||||
font-size: .8em;
|
||||
}
|
||||
|
||||
a {
|
||||
color: #3366cc;
|
||||
}
|
||||
|
||||
img {
|
||||
border: 0;
|
||||
}
|
||||
|
||||
#xiphlogo {
|
||||
margin: 30px 0 16px 0;
|
||||
}
|
||||
|
||||
#content p {
|
||||
line-height: 1.4;
|
||||
}
|
||||
|
||||
h1, h1 a, h2, h2 a, h3, h3 a {
|
||||
font-weight: bold;
|
||||
color: #ff9900;
|
||||
margin: 1.3em 0 8px 0;
|
||||
}
|
||||
|
||||
h1 {
|
||||
font-size: 1.3em;
|
||||
}
|
||||
|
||||
h2 {
|
||||
font-size: 1.2em;
|
||||
}
|
||||
|
||||
h3 {
|
||||
font-size: 1.1em;
|
||||
}
|
||||
|
||||
li {
|
||||
line-height: 1.4;
|
||||
}
|
||||
|
||||
#copyright {
|
||||
margin-top: 30px;
|
||||
line-height: 1.5em;
|
||||
text-align: center;
|
||||
font-size: .8em;
|
||||
color: #888888;
|
||||
clear: both;
|
||||
}
|
||||
</style>
|
||||
|
||||
</head>
|
||||
|
||||
<body>
|
||||
|
||||
<div id="xiphlogo">
|
||||
<a href="http://www.xiph.org/"><img src="fish_xiph_org.png" alt="Fish Logo and Xiph.Org"/></a>
|
||||
</div>
|
||||
|
||||
<h1>Ogg Vorbis Documentation</h1>
|
||||
|
||||
<h2>Vorbis technical discussion documents</h2>
|
||||
<ul>
|
||||
<li><a href="vorbis-fidelity.html">Fidelity measurement terminology</a></li>
|
||||
<li><a href="stereo.html">Vorbis channel coupling and stereo-specific application</a></li>
|
||||
</ul>
|
||||
|
||||
<h2>Ogg Vorbis I specification</h2>
|
||||
|
||||
<ul>
|
||||
<li>Vorbis I specification [<a href="Vorbis_I_spec.html">html</a>]
|
||||
[<a href="Vorbis_I_spec.pdf">pdf</a>]</li>
|
||||
<li><a href="v-comment.html">Vorbis comment header specification</a></li>
|
||||
<li><a href="rfc5215.txt">Embedding Vorbis encoded
|
||||
audio in an RTP payload format</a></li>
|
||||
</ul>
|
||||
|
||||
<h2>Ogg Vorbis programming documents</h2>
|
||||
|
||||
<ul>
|
||||
<li><a href="libvorbis/index.html">Programming with libvorbis</a></li>
|
||||
<li><a href="vorbisfile/index.html">Programming with vorbisfile</a></li>
|
||||
<li><a href="vorbisenc/index.html">Programming with vorbisenc</a></li>
|
||||
</ul>
|
||||
|
||||
<h2>Ogg bitstream documentation</h2>
|
||||
|
||||
<ul>
|
||||
<li><a href="oggstream.html">Ogg bitstream overview</a></li>
|
||||
<li><a href="framing.html">Ogg logical bitstream and framing spec</a></li>
|
||||
</ul>
|
||||
|
||||
<div id="copyright">
|
||||
The Xiph Fish Logo is a
|
||||
trademark (™) of Xiph.Org.<br/>
|
||||
|
||||
These pages © 1994 - 2010 Xiph.Org. All rights reserved.
|
||||
</div>
|
||||
|
||||
</body>
|
||||
</html>
|
|
@ -0,0 +1,24 @@
|
|||
## Process this file with automake to produce Makefile.in
|
||||
|
||||
docdir = $(datadir)/doc/$(PACKAGE)-$(VERSION)/libvorbis
|
||||
|
||||
doc_DATA = index.html reference.html style.css vorbis_comment.html\
|
||||
vorbis_info.html vorbis_analysis_blockout.html vorbis_analysis_buffer.html\
|
||||
vorbis_analysis_headerout.html vorbis_analysis_init.html \
|
||||
vorbis_analysis_wrote.html vorbis_analysis.html vorbis_bitrate_addblock.html\
|
||||
vorbis_bitrate_flushpacket.html vorbis_block_init.html \
|
||||
vorbis_block_clear.html vorbis_dsp_clear.html vorbis_granule_time.html \
|
||||
vorbis_version_string.html vorbis_info_blocksize.html vorbis_info_clear.html\
|
||||
vorbis_info_init.html vorbis_comment_add.html vorbis_comment_add_tag.html\
|
||||
vorbis_comment_clear.html vorbis_comment_init.html vorbis_comment_query.html\
|
||||
vorbis_comment_query_count.html vorbis_commentheader_out.html\
|
||||
vorbis_packet_blocksize.html vorbis_synthesis.html \
|
||||
vorbis_synthesis_blockin.html vorbis_synthesis_halfrate.html \
|
||||
vorbis_synthesis_halfrate_p.html vorbis_synthesis_headerin.html \
|
||||
vorbis_synthesis_idheader.html vorbis_synthesis_init.html \
|
||||
vorbis_synthesis_lapout.html vorbis_synthesis_pcmout.html \
|
||||
vorbis_synthesis_read.html vorbis_synthesis_restart.html \
|
||||
vorbis_synthesis_trackonly.html vorbis_block.html vorbis_dsp_state.html \
|
||||
return.html overview.html
|
||||
|
||||
EXTRA_DIST = $(doc_DATA)
|
|
@ -0,0 +1,44 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - Documentation</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>Libvorbis Documentation</h1>
|
||||
|
||||
<p>
|
||||
Libvorbis contains the Vorbis reference encoder and decoder.
|
||||
<p>
|
||||
This is the lowest-level interface to the Vorbis encoder and decoder. If
|
||||
you're just looking for a simple way to extract the
|
||||
audio from an Ogg Vorbis file, you probably want to use <a
|
||||
href="../vorbisfile/index.html">vorbisfile</a> rather than using libogg
|
||||
and libvorbis directly.
|
||||
<p>
|
||||
<a href="overview.html">Libvorbis API overview</a><br>
|
||||
<a href="reference.html">Libvorbis API reference</a><br>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2000-2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,136 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - API Overview</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>Libvorbis API Overview</h1>
|
||||
|
||||
<p>Libvorbis is the reference implementation of the Vorbis codec. It is
|
||||
the lowest-level interface to the Vorbis encoder and decoder, working
|
||||
with packets directly.</p>
|
||||
|
||||
<p>All libvorbis routines and structures are declared in "vorbis/codec.h".</p>
|
||||
|
||||
<h2>Encoding workflow</h2>
|
||||
|
||||
<ol>
|
||||
<li>Initialize a <a href="vorbis_info.html">vorbis_info</a> structure
|
||||
by calling <a href="vorbis_info_init.html">vorbis_info_init</a> and
|
||||
then functions from <a href="../vorbisenc/index.html">libvorbisenc</a>
|
||||
on it.</li>
|
||||
<li>Initialize a <a href="vorbis_dsp_state.html">vorbis_dsp_state</a>
|
||||
for encoding based on the parameters in the vorbis_info by using <a
|
||||
href="vorbis_analysis_init.html">vorbis_analysis_init</a>.</li>
|
||||
<li>Initialize a <a href="vorbis_comment.html">vorbis_comment</a>
|
||||
structure using <a href="vorbis_comment_init.html">vorbis_comment_init</a>,
|
||||
populate it with any comments you wish to store in the stream, and call
|
||||
<a href="vorbis_analysis_headerout.html">vorbis_analysis_headerout</a> to
|
||||
get the three Vorbis stream header packets. Output the packets.</li>
|
||||
<li>Initialize a <a href="vorbis_block.html">vorbis_block</a> structure
|
||||
using <a href="vorbis_block_init.html">vorbis_block_init</a>.</li>
|
||||
<li>While there is more audio to encode:<ol>
|
||||
<li>Submit a chunk of audio data using <a
|
||||
href="vorbis_analysis_buffer.html">vorbis_analysis_buffer</a> and <a
|
||||
href="vorbis_analysis_wrote.html">vorbis_analysis_wrote</a>.</li>
|
||||
<li>Obtain all available blocks using <a
|
||||
href="vorbis_analysis_blockout.html">vorbis_analysis_blockout</a>
|
||||
in a loop. For each block obtained:<ol>
|
||||
<li>Encode the block into a packet (or prepare it for bitrate management)
|
||||
using <a href="vorbis_analysis.html">vorbis_analysis</a>. (It's a good
|
||||
idea to always pass the blocks through the bitrate
|
||||
management mechanism; more information is on the <a
|
||||
href="vorbis_analysis.html">vorbis_analysis</a> page. It does not affect
|
||||
the resulting packets unless you are actually using a bitrate-managed
|
||||
mode.)</li>
|
||||
<li>If you are using bitrate management, submit the block using <a
|
||||
href="vorbis_bitrate_addblock.html">vorbis_bitrate_addblock</a> and obtain
|
||||
packets using <a
|
||||
href="vorbis_bitrate_flushpacket.html">vorbis_bitrate_flushpacket</a>.</li>
|
||||
<li>Output any obtained packets.</li>
|
||||
</ol></li>
|
||||
</ol></li>
|
||||
<li>Submit an empty buffer to indicate the end of input; this will result
|
||||
in an end-of-stream packet after all encoding steps are done to it.</li>
|
||||
<li>Destroy the structures using the appropriate vorbis_*_clear routines.</li>
|
||||
</ol>
|
||||
|
||||
<h2>Decoding workflow</h2>
|
||||
|
||||
<em>Note: if you do not need to do anything more involved than just
|
||||
decoding the audio from an Ogg Vorbis file, you can use the far simpler
|
||||
<a href="../vorbisfile/index.html">libvorbisfile</a> interface, which
|
||||
will take care of all of the demuxing and low-level decoding operations
|
||||
(and even the I/O, if you want) for you.</em>
|
||||
|
||||
<ol>
|
||||
<li>When reading the header packets of an Ogg stream, you can use <a
|
||||
href="vorbis_synthesis_idheader.html">vorbis_synthesis_idheader</a> to
|
||||
check whether a stream might be Vorbis.</li>
|
||||
<li>Initialize a <a href="vorbis_info.html">vorbis_info</a> and a <a
|
||||
href="vorbis_comment.html">vorbis_comment</a> structure using the
|
||||
appropriate vorbis_*_init routines, then pass the first three packets
|
||||
from the stream (the Vorbis stream header packets) to <a
|
||||
href="vorbis_synthesis_headerin.html">vorbis_synthesis_headerin</a> in
|
||||
order. At this point, you can see the comments and basic parameters of
|
||||
the Vorbis stream.</li>
|
||||
<li>Initialize a <a href="vorbis_dsp_state.html">vorbis_dsp_state</a>
|
||||
for decoding based on the parameters in the vorbis_info by using <a
|
||||
href="vorbis_synthesis_init.html">vorbis_synthesis_init</a>.</li>
|
||||
<li>Initialize a <a href="vorbis_block.html">vorbis_block</a> structure
|
||||
using <a href="vorbis_block_init.html">vorbis_block_init</a>.</li>
|
||||
<li>While there are more packets to decode:<ol>
|
||||
<li>Decode the next packet into a block using <a
|
||||
href="vorbis_synthesis.html">vorbis_synthesis</a>.</li>
|
||||
<li>Submit the block to the reassembly layer using <a
|
||||
href="vorbis_synthesis_blockin.html">vorbis_synthesis_blockin</a>.</li>
|
||||
<li>Obtain some decoded audio using <a
|
||||
href="vorbis_synthesis_pcmout.html">vorbis_synthesis_pcmout</a> and <a
|
||||
href="vorbis_synthesis_read.html">vorbis_synthesis_read</a>. Any audio data
|
||||
returned but not marked as consumed using vorbis_synthesis_read carries
|
||||
over to the next call to vorbis_synthesis_pcmout.</li>
|
||||
</ol></li>
|
||||
<li>Destroy the structures using the appropriate vorbis_*_clear routines.</li>
|
||||
</ol>
|
||||
|
||||
<h2>Metadata workflow</h2>
|
||||
|
||||
<em>Note: if you do not need to do anything more involved than just
|
||||
reading the metadata from an Ogg Vorbis file, <a
|
||||
href="../vorbisfile/index.html">libvorbisfile</a> can do this for you.</em>
|
||||
|
||||
<ol>
|
||||
<li>Follow the decoding workflow above until you have access to the comments
|
||||
and basic parameters of the Vorbis stream.</li>
|
||||
<li>If you want to alter the comments, copy the first packet to the output
|
||||
file, then create a packet for the modified comments using <a
|
||||
href="vorbis_commentheader_out.html">vorbis_commentheader_out</a> and output
|
||||
it, then copy the third packet and all subsequent packets into the output
|
||||
file.</li>
|
||||
</ol>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
||||
|
|
@ -0,0 +1,86 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>Libvorbis API Reference</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>Libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>Libvorbis API Reference</h1>
|
||||
|
||||
<p>
|
||||
<b>Data Structures</b><br>
|
||||
<a href="vorbis_block.html">vorbis_block</a><br>
|
||||
<a href="vorbis_comment.html">vorbis_comment</a><br>
|
||||
<a href="vorbis_dsp_state.html">vorbis_dsp_state</a><br>
|
||||
<a href="vorbis_info.html">vorbis_info</a><br>
|
||||
<br>
|
||||
<b>Functions used by both decode and encode</b><br>
|
||||
<a href="vorbis_block_clear.html">vorbis_block_clear()</a><br>
|
||||
<a href="vorbis_block_init.html">vorbis_block_init()</a><br>
|
||||
<a href="vorbis_dsp_clear.html">vorbis_dsp_clear()</a><br>
|
||||
<a href="vorbis_granule_time.html">vorbis_granule_time()</a><br>
|
||||
<a href="vorbis_info_blocksize.html">vorbis_info_blocksize()</a><br>
|
||||
<a href="vorbis_info_clear.html">vorbis_info_clear()</a><br>
|
||||
<a href="vorbis_info_init.html">vorbis_info_init()</a><br>
|
||||
<a href="vorbis_version_string.html">vorbis_version_string()</a><br>
|
||||
<br>
|
||||
<b>Decoding</b><br>
|
||||
<a href="vorbis_packet_blocksize.html">vorbis_packet_blocksize()</a><br>
|
||||
<a href="vorbis_synthesis.html">vorbis_synthesis()</a><br>
|
||||
<a href="vorbis_synthesis_blockin.html">vorbis_synthesis_blockin()</a><br>
|
||||
<a href="vorbis_synthesis_halfrate.html">vorbis_synthesis_halfrate()</a><br>
|
||||
<a href="vorbis_synthesis_halfrate_p.html">vorbis_synthesis_halfrate_p()</a><br>
|
||||
<a href="vorbis_synthesis_headerin.html">vorbis_synthesis_headerin()</a><br>
|
||||
<a href="vorbis_synthesis_idheader.html">vorbis_synthesis_idheader()</a><br>
|
||||
<a href="vorbis_synthesis_init.html">vorbis_synthesis_init()</a><br>
|
||||
<a href="vorbis_synthesis_lapout.html">vorbis_synthesis_lapout()</a><br>
|
||||
<a href="vorbis_synthesis_pcmout.html">vorbis_synthesis_pcmout()</a><br>
|
||||
<a href="vorbis_synthesis_read.html">vorbis_synthesis_read()</a><br>
|
||||
<a href="vorbis_synthesis_restart.html">vorbis_synthesis_restart()</a><br>
|
||||
<a href="vorbis_synthesis_trackonly.html">vorbis_synthesis_trackonly()</a><br>
|
||||
<br>
|
||||
<b>Encoding</b><br>
|
||||
<a href="vorbis_analysis.html">vorbis_analysis()</a><br>
|
||||
<a href="vorbis_analysis_blockout.html">vorbis_analysis_blockout()</a><br>
|
||||
<a href="vorbis_analysis_buffer.html">vorbis_analysis_buffer()</a><br>
|
||||
<a href="vorbis_analysis_headerout.html">vorbis_analysis_headerout()</a><br>
|
||||
<a href="vorbis_analysis_init.html">vorbis_analysis_init()</a><br>
|
||||
<a href="vorbis_analysis_wrote.html">vorbis_analysis_wrote()</a><br>
|
||||
<a href="vorbis_bitrate_addblock.html">vorbis_bitrate_addblock()</a><br>
|
||||
<a href="vorbis_bitrate_flushpacket.html">vorbis_bitrate_flushpacket()</a><br>
|
||||
<br>
|
||||
<b>Metadata</b><br>
|
||||
<a href="vorbis_comment_add.html">vorbis_comment_add()</a><br>
|
||||
<a href="vorbis_comment_add_tag.html">vorbis_comment_add_tag()</a><br>
|
||||
<a href="vorbis_comment_clear.html">vorbis_comment_clear()</a><br>
|
||||
<a href="vorbis_comment_init.html">vorbis_comment_init()</a><br>
|
||||
<a href="vorbis_comment_query.html">vorbis_comment_query()</a><br>
|
||||
<a href="vorbis_comment_query_count.html">vorbis_comment_query_count()</a><br>
|
||||
<a href="vorbis_commentheader_out.html">vorbis_commentheader_out()</a><br>
|
||||
<br>
|
||||
<b><a href="return.html">Return Codes</a></b><br>
|
||||
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,79 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - Return Codes</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>Return Codes</h1>
|
||||
|
||||
<p>
|
||||
|
||||
The following return codes are <tt>#define</tt>d in "vorbis/codec.h" and
|
||||
may be returned by functions from libvorbis, <a
|
||||
href="../vorbisfile/index.html">libvorbisfile</a>, and <a
|
||||
href="../vorbisenc/index.html">libvorbisenc</a>. Descriptions of a code
|
||||
relevant to a specific function are found in the reference description
|
||||
of that function.
|
||||
|
||||
<dl>
|
||||
|
||||
<dt>OV_FALSE</dt>
|
||||
<dd>Not true, or no data available</dd>
|
||||
|
||||
<dt>OV_HOLE</dt>
|
||||
<dd>Vorbisfile encoutered missing or corrupt data in the bitstream. Recovery
|
||||
is normally automatic and this return code is for informational purposes only.</dd>
|
||||
|
||||
<dt>OV_EREAD</dt>
|
||||
<dd>Read error while fetching compressed data for decode</dd>
|
||||
|
||||
<dt>OV_EFAULT</dt>
|
||||
<dd>Internal inconsistency in encode or decode state. Continuing is likely not possible.</dd>
|
||||
|
||||
<dt>OV_EIMPL</dt>
|
||||
<dd>Feature not implemented</dd>
|
||||
|
||||
<dt>OV_EINVAL</dt>
|
||||
<dd>Either an invalid argument, or incompletely initialized argument passed to a call</dd>
|
||||
|
||||
<dt>OV_ENOTVORBIS</dt>
|
||||
<dd>The given file/data was not recognized as Ogg Vorbis data.</dd>
|
||||
|
||||
<dt>OV_EBADHEADER</dt>
|
||||
<dd>The file/data is apparently an Ogg Vorbis stream, but contains a corrupted or undecipherable header.</dd>
|
||||
|
||||
<dt>OV_EVERSION</dt>
|
||||
<dd>The bitstream format revision of the given stream is not supported.</dd>
|
||||
|
||||
<dt>OV_EBADLINK</dt>
|
||||
<dd>The given link exists in the Vorbis data stream, but is not decipherable due to garbacge or corruption.</dd>
|
||||
|
||||
<dt>OV_ENOSEEK</dt>
|
||||
<dd>The given stream is not seekable</dd>
|
||||
|
||||
</dl>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2000-2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,7 @@
|
|||
BODY { font-family: Helvetica, sans-serif }
|
||||
TD { font-family: Helvetica, sans-serif }
|
||||
P { font-family: Helvetica, sans-serif }
|
||||
H1 { font-family: Helvetica, sans-serif }
|
||||
H2 { font-family: Helvetica, sans-serif }
|
||||
H4 { font-family: Helvetica, sans-serif }
|
||||
P.tiny { font-size: 8pt }
|
|
@ -0,0 +1,86 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_analysis</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_analysis</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>Once the uncompressed audio data has been divided into blocks, this
|
||||
function is called on each block. It looks up the encoding mode and
|
||||
dispatches the block to the forward transform provided by that mode.
|
||||
</p>
|
||||
<p>When using a basic encoding mode, with no bitrate management,
|
||||
an ogg_packet pointer can be given, and the coded block is returned
|
||||
directly through that structure and can be placed in the output stream.
|
||||
</p>
|
||||
<p>Otherwise, NULL should be passed for the ogg_packet pointer. In
|
||||
that case, after the transform has been applied, the block must passed
|
||||
to vorbis_bitrate_addblock() for further coding. This method works with
|
||||
both basic and managed encoding modes, so it's recommended for new code.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_analysis(vorbis_block *vb,ogg_packet *op);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vb</i></dt>
|
||||
<dd>Pointer to the vorbis_block to be encoded.</dd>
|
||||
<dt><i>op</i></dt>
|
||||
<dd>Optional pointer to an ogg_packet. This is normally NULL,
|
||||
and the final output is obtained by passing <i>vb</i> though the
|
||||
vorbis_bitrate_*() interface to perform further refinement.
|
||||
However, when not using a bitrate managed encoding mode, it
|
||||
is possible to skip that step by providing an ogg_packet pointer
|
||||
here, obtaining the compressed data directly.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<ul>
|
||||
<li>0 for success</li>
|
||||
<li>negative values for failure:
|
||||
<ul>
|
||||
<li>OV_EINVAL - Invalid request; a non-NULL value was passed for <i>op</i> when the encoder is using a bitrate managed mode.</li>
|
||||
<li>OV_EFAULT - Internal fault; indicates a bug or memory corruption.</li>
|
||||
<li>OV_EIMPL - Unimplemented; not supported by this version of the library.</li>
|
||||
</ul>
|
||||
</li>
|
||||
</ul>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,79 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_analysis_blockout</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_analysis_blockout</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This fuction examines the available uncompressed data and tries to
|
||||
break it into appropriate sized blocks. It should be called in a loop
|
||||
after adding new data with vorbis_analysis_buffer()/vorbis_analysis_wrote()
|
||||
until it returns zero (need more data) or an negative value (error).
|
||||
</p>
|
||||
<p>
|
||||
Each block returned should be passed to vorbis_analysis() for transform
|
||||
and coding.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_analysis_blockout(vorbis_dsp_state *v,vorbis_block *vb);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>v</i></dt>
|
||||
<dd>Pointer to the vorbis_dsp_state representing the encoder.</dd>
|
||||
<dt><i>vb</i></dt>
|
||||
<dd>Pointer to a previously initialized vorbis_block object to hold the
|
||||
returned data.
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<ul>
|
||||
<li>1 for success when more blocks are available.</li>
|
||||
<li>0 for success when this is the last block available from the current input.</li>
|
||||
<li>negative values for failure:
|
||||
<ul>
|
||||
<li>OV_EINVAL - Invalid parameters.</li>
|
||||
<li>OV_EFAULT - Internal fault; indicates a bug or memory corruption.</li>
|
||||
<li>OV_EIMPL - Unimplemented; not supported by this version of the library.</li>
|
||||
</ul>
|
||||
</li>
|
||||
|
||||
</ul>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,74 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_analysis_buffer</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_analysis_buffer</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This fuction requests a buffer array for delivering audio to the
|
||||
encoder for compression.</p>
|
||||
|
||||
<p>The Vorbis encoder expects the caller to write audio data as
|
||||
non-interleaved floating point samples into its internal buffers.
|
||||
</p>
|
||||
<p>
|
||||
The general procedure is to call this function with the number of samples
|
||||
you have available. The encoder will arrange for that much internal storage
|
||||
and return an array of buffer pointers, one for each channel of audio.
|
||||
The caller must then write the audio samples into those buffers, as
|
||||
float values, and finally call vorbis_analysis_wrote() to tell the
|
||||
encoder the data is available for analysis.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern float **vorbis_analysis_buffer(vorbis_dsp_state *v,int vals);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>v</i></dt>
|
||||
<dd>Pointer to the vorbis_dsp_state representing the encoder.</dd>
|
||||
<dt><i>vals</i></dt>
|
||||
<dd>Number of samples to provide space for in the returned buffer. 1024 is a reasonable choice.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<p>Returns an array of floating point buffers which can accept data.
|
||||
A (**float) where the first index is the channel, and the second is
|
||||
the sample index.<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,83 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_analysis_headerout</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_analysis_headerout</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function creates and returns the three header packets needed
|
||||
to configure a decoder to accept compressed data. I should be called
|
||||
after all encoder initialization and configuration is complete. The
|
||||
output packets should be placed in order at the start of the compressed
|
||||
vorbis stream, prior to the first data packet.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_analysis_headerout(vorbis_dsp_state *v,
|
||||
vorbis_comment *vc,
|
||||
ogg_packet *op,
|
||||
ogg_packet *op_comm,
|
||||
ogg_packet *op_code);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>v</i></dt>
|
||||
<dd>Pointer to an initialized vorbis_dsp_state which holds the encoder configuration.</dd>
|
||||
<dt><i>vc</i></dt>
|
||||
<dd>Pointer to an initialized vorbis_comment structure which holds the metadata associated with the stream being encoded.</dd>
|
||||
<dt><i>op</i></dt>
|
||||
<dd>Pointer to an ogg_packet structure to be filled out with the stream identification header.</dd>
|
||||
<dt><i>op_comm</i></dt>
|
||||
<dd>Pointer to an ogg_packet structure to be filled out with the serialied vorbis_comment data.</dd>
|
||||
<dt><i>op_code</i></dt>
|
||||
<dd>Pointer to an ogg_packet structure to be filled out with the codebooks, mode descriptions, etc. which will be used encoding the stream.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<ul>
|
||||
<li>0 for success</li>
|
||||
<li>negative values for failure:
|
||||
<ul>
|
||||
<li>OV_EFAULT - Internal fault; indicates a bug or memory corruption.</li>
|
||||
<li>OV_EIMPL - Unimplemented; not supported by this version of the library.</li>
|
||||
</ul>
|
||||
</li>
|
||||
</ul>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,66 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_analysis_init</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_analysis_init</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function allocates and initializes the encoder's analysis state
|
||||
inside a is vorbis_dsp_state, based on the configuration in a vorbis_info
|
||||
struct.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_analysis_init(vorbis_dsp_state *v,vorbis_info *vi);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>v</i</dt>
|
||||
<dd>Pointer to the vorbis_dsp_state structure to be initialized for encoding.</dd>
|
||||
<dt><i>vi</i></dt>
|
||||
<dd>Pointer to an initialized <a href="vorbis_info.html">vorbis_info</a> struct describing the encoder configuration.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>
|
||||
0 for success</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,80 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_analysis_wrote</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_analysis_wrote</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function tells the encoder new data is available for compression.
|
||||
Call this after writing new audio into the buffer array returned by
|
||||
vorbis_analysis_buffer().
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Call with the <i>vals</i> parameter set to zero to signal the end
|
||||
of the input data.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_analysis_wrote(vorbis_dsp_state *v,int vals);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>v</i></dt>
|
||||
<dd>Pointer to the vorbis_dsp_state representing the encoder.</dd>
|
||||
<dt><i>vals</i></dt>
|
||||
<dd>Number of samples successfully written. This must be less than
|
||||
or equal to the value passed to vorbis_analysis_buffer(). A value
|
||||
of zero means all input data has been provided and the compressed
|
||||
stream should be finalized.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<ul>
|
||||
<li>0 for success</li>
|
||||
<li>negative values for failure:
|
||||
<ul>
|
||||
<li>OV_EINVAL - Invalid request; e.g. vals overflows the allocated space.</li>
|
||||
<li>OV_EFAULT - Internal fault; indicates a bug or memory corruption.</li>
|
||||
<li>OV_EIMPL - Unimplemented; not supported by this version of the library.</li>
|
||||
</ul>
|
||||
</li>
|
||||
</ul>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,74 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_bitrate_addblock</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_bitrate_addblock</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This fuction submits a transformed block to the bitrate management
|
||||
engine for final encoding. Packets are buffered and the packet boundaries
|
||||
adjusted and padded to meet the target bitrate, if any.</p>
|
||||
|
||||
<p>After calling vorbis_bitrate_addblock(), the passed vorbis_block
|
||||
structure can be reused in another call to vorbis_analysis_blockout().
|
||||
Call vorbis_bitrate_flushpacket() to obtain the final compressed data.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_bitrate_addblock(vorbis_block *vb);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vb</i></dt>
|
||||
<dd>Pointer to the vorbis_block to be submitted.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<ul>
|
||||
<li>0 for success.</li>
|
||||
<li>negative values for failure:
|
||||
<ul>
|
||||
<li>OV_EINVAL - Invalid parameters.</li>
|
||||
<li>OV_EFAULT - Internal fault; indicates a bug or memory corruption.</li>
|
||||
<li>OV_EIMPL - Unimplemented; not supported by this version of the library.</li>
|
||||
</ul>
|
||||
</li>
|
||||
|
||||
</ul>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,80 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_bitrate_flushpacket</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_bitrate_flushpacket</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function returns the next available completed packet from the
|
||||
bitrate management engine. It should be called in a loop after any call
|
||||
to vorbis_bitrate_addblock() until it returns either 0 (more data needed)
|
||||
or a negative value (error).
|
||||
</p>
|
||||
|
||||
<p>
|
||||
The data returned in the ogg_packet structure can be copied to the
|
||||
final compressed output stream.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_bitrate_flushpacket(vorbis_dsp_state *vd,
|
||||
ogg_packet *op);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vd</i></dt>
|
||||
<dd>Pointer to the vorbis_dsp_state represending the encoder.</dd>
|
||||
<dt><i>op</i></dt>
|
||||
<dd>Pointer to an ogg_packet to be filled out with the compressed data.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<ul>
|
||||
<li>1 for success when more packets are available.
|
||||
<li>0 for success when this is the last packet available from the current input.</li>
|
||||
<li>negative values for failure:
|
||||
<ul>
|
||||
<li>OV_EINVAL - Invalid parameters.</li>
|
||||
<li>OV_EFAULT - Internal fault; indicates a bug or memory corruption.</li>
|
||||
<li>OV_EIMPL - Unimplemented; not supported by this version of the library.</li>
|
||||
</ul>
|
||||
</li>
|
||||
|
||||
</ul>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,60 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - datatype - vorbis_block</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_block</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h"</i></p>
|
||||
|
||||
<p>
|
||||
The vorbis_block structure holds the data for a single block of audio. One
|
||||
vorbis_block translates to one codec packet. The encoding process consists
|
||||
of splitting the audio into blocks and encoding the blocks into packets;
|
||||
decoding consists of decoding the packets into blocks and reassembling
|
||||
the audio from the blocks.
|
||||
<p>
|
||||
This structure is intended to be private. Although the fields are given
|
||||
in the header file, they should not be directly modified or relied upon
|
||||
in any way.
|
||||
<p>
|
||||
|
||||
<table border=0 width=100% color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>typedef struct vorbis_block{
|
||||
/* private */
|
||||
} vorbis_block;</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<ul><li>None public.</li></ul>
|
||||
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,61 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_block_clear</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_block_clear</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function frees the internal storage for a vorbis_block structure.</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_block_clear(vorbis_block *vb);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vb</i></dt>
|
||||
<dd>Pointer to a vorbis_block struct to be cleared.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>
|
||||
0 for success</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,66 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_block_init</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_block_init</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function initializes a vorbis_block structure and allocates its
|
||||
internal storage. A vorbis_block is used to represent a particular block
|
||||
of input audio which can be analyzed and coded as a unit.
|
||||
</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_block_init(vorbis_dsp_state *v, vorbis_block *vb);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>v</i</dt>
|
||||
<dd>Pointer to an initialized vorbis_dsp_state with which to associate the new block.</dd>
|
||||
<dt><i>vb</i></dt>
|
||||
<dd>Pointer to a vorbis_block struct to be initialized.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>
|
||||
0 for success</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,80 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - datatype - vorbis_comment</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_comment</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h"</i></p>
|
||||
|
||||
<p>
|
||||
The vorbis_comment structure defines an Ogg Vorbis comment.
|
||||
<p>
|
||||
Only the fields the program needs must be defined. If a field isn't
|
||||
defined by the application, it will either be blank (if it's a string value)
|
||||
or set to some reasonable default (usually 0).
|
||||
<p>
|
||||
<i>Note:</i> When encoding, while it <i>is</i> supported to modify a
|
||||
vorbis_comment structure directly, be sure to read the notes on the
|
||||
<a href="vorbis_comment_init.html">vorbis_comment_init</a> and
|
||||
<a href="vorbis_comment_clear.html">vorbis_comment_clear</a> pages for
|
||||
considerations on memory allocation and freeing before you do so. Rule of
|
||||
thumb: call vorbis_comment_init, then <i>either</i> do all allocation,
|
||||
freeing, and modification yourself and <i>do not</i> call
|
||||
vorbis_comment_clear, <i>or</i> do all modification using libvorbis
|
||||
functions and <i>do</i> call vorbis_comment_clear.
|
||||
<p>
|
||||
|
||||
<table border=0 width=100% color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>typedef struct vorbis_comment{
|
||||
/* unlimited user comment fields. */
|
||||
char **user_comments;
|
||||
int *comment_lengths;
|
||||
int comments;
|
||||
char *vendor;
|
||||
|
||||
} vorbis_comment;</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>user_comments</i></dt>
|
||||
<dd>Unlimited user comment array. The individual strings in the array are 8 bit clean, by the Vorbis specification, and as such the <tt>comment_lengths</tt> array should be consulted to determine string length. For convenience, each string is also NULL-terminated by the decode library (although Vorbis comments are not NULL terminated within the bitstream itself).</dd>
|
||||
<dt><i>comment_lengths</i></dt>
|
||||
<dd>An int array that stores the length of each comment string</dd>
|
||||
<dt><i>comments</i></dt>
|
||||
<dd>Int signifying number of user comments in user_comments field.</dd>
|
||||
<dt><i>vendor</i></dt>
|
||||
<dd>Information about the Vorbis implementation that encoded the file. Stored in a standard C 0-terminated string. Libvorbis will fill this in itself when encoding a comment packet from this structure; when decoding, this contains the vendor string that was in the comment packet.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2000-2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,70 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_comment_add</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_comment_add</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function adds a raw comment string to a
|
||||
<a href="vorbis_comment.html">vorbis_comment</a> structure.</p>
|
||||
|
||||
<p>This function should be used if the string is already in the
|
||||
form "KEY=value". If you have a separate key and value, use
|
||||
<a href="vorbis_comment_add_tag.html">vorbis_comment_add_tag</a>
|
||||
instead.</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern void vorbis_comment_add(vorbis_comment *vc, const char *comment);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vc</i></dt>
|
||||
<dd>Pointer to a vorbis_comment structure to add the comment to.</dd>
|
||||
<dt><i>comment</i></dt>
|
||||
<dd>Pointer to the null-terminated raw comment string. The string will
|
||||
be copied, so it can be freed or modified after this function returns
|
||||
without affecting the vorbis_comment structure's contents.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>None.</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,74 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_comment_add_tag</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_comment_add_tag</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function adds a tag-comment pair to a
|
||||
<a href="vorbis_comment.html">vorbis_comment</a> structure. There can
|
||||
be more than one comment value for the same tag; if a comment with the
|
||||
same tag already exists, another comment with the same tag is added.</p>
|
||||
|
||||
<p>If you already have a string in the form "KEY=value", see
|
||||
<a href="vorbis_comment_add.html">vorbis_comment_add</a> instead.</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern void vorbis_comment_add_tag(vorbis_comment *vc,
|
||||
const char *tag, const char *contents);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vc</i></dt>
|
||||
<dd>Pointer to a vorbis_comment structure to add the comment to.</dd>
|
||||
<dt><i>tag</i></dt>
|
||||
<dd>Pointer to the null-terminated tag string. The string will
|
||||
be copied, so it can be freed or modified after this function returns
|
||||
without affecting the vorbis_comment structure's contents.</dd>
|
||||
<dt><i>contents</i></dt>
|
||||
<dd>Pointer to the null-terminated comment contents string. This will
|
||||
also be copied.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>None.</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,69 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_comment_clear</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_comment_clear</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function frees the internal storage associated with a <a href="vorbis_comment.html">vorbis_comment</a> structure.</p>
|
||||
|
||||
<p><i>Note:</i> Be careful if you have modified the vorbis_comment
|
||||
structure yourself, as libvorbis will try to use its own wrappers of
|
||||
memory allocation functions to free the contents of the vorbis_comment
|
||||
structure. This will not work correctly unless all arrays and comment
|
||||
strings contained in the vorbis_comment structure were allocated by
|
||||
libvorbis itself. This function is only guaranteed to be safe if all
|
||||
modification to the vorbis_comment structure was done using libvorbis
|
||||
functions.</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern void vorbis_comment_clear(vorbis_comment *vc);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vc</i></dt>
|
||||
<dd>The vorbis_comment structure to clear.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>None.</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,72 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_comment_init</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_comment_init</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function initializes a <a href="vorbis_comment.html">vorbis_comment</a>
|
||||
structure for use. After calling this function, the vorbis_comment
|
||||
structure contains no comments.</p>
|
||||
|
||||
<p><i>Note:</i> No internal storage is allocated by this function;
|
||||
internal storage is allocated as needed by other libvorbis functions that
|
||||
modify the vorbis_comment structure. If you modify the vorbis_comment
|
||||
structure directly, without using libvorbis, you should <i>not</i>
|
||||
call <a href="vorbis_comment_clear.html">vorbis_comment_clear</a> when
|
||||
you are finished but instead clean up after it yourself. See the note
|
||||
on the <a href="vorbis_comment_clear.html">vorbis_comment_clear</a>
|
||||
page for more information.</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern void vorbis_comment_init(vorbis_comment *vc);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vc</i></dt>
|
||||
<dd>Pointer to the <a href="vorbis_comment.html">vorbis_comment</a>
|
||||
structure to initialize.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>None.</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,72 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_comment_query</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_comment_query</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function retrieves a comment string for a given tag in a
|
||||
<a href="vorbis_comment.html">vorbis_comment</a> structure.</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern char *vorbis_comment_query(vorbis_comment *vc, const char *tag, int count);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vc</i></dt>
|
||||
<dd>Pointer to the vorbis_comment structure.</dd>
|
||||
<dt><i>tag</i></dt>
|
||||
<dd>Pointer to a null-terminated string of the comment tag to look
|
||||
for. Tags are compared case-insensitively.</dd>
|
||||
<dt><i>count</i></dt>
|
||||
<dd>The index of the comment string to retrieve. A value of 0 indicates
|
||||
the first comment whose tag matches <i>tag</i>. Use
|
||||
<a href="vorbis_comment_query_count.html">vorbis_comment_query_count</a>
|
||||
to determine the number of matching comments.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>A pointer to the comment string. The underlying buffer is owned by
|
||||
the vorbis_comment structure.</li>
|
||||
<li>NULL on a nonexistent tag or if <i>count</i> is greater than or
|
||||
equal to the number of matching comments.</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,66 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_comment_query_count</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_comment_query_count</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function determines the number of comments with a given tag
|
||||
that are present in a <a href="vorbis_comment.html">vorbis_comment</a>
|
||||
structure.</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_comment_query_count(vorbis_comment *vc, const char *tag);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vc</i></dt>
|
||||
<dd>Pointer to the vorbis_comment structure.</dd>
|
||||
<dt><i>tag</i></dt>
|
||||
<dd>Pointer to a null-terminated string of the comment tag to look
|
||||
for. Tags are compared case-insensitively.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>The number of comments present with the given tag.</li>
|
||||
<li>0 if no such comments are present.</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
|
@ -0,0 +1,65 @@
|
|||
<html>
|
||||
|
||||
<head>
|
||||
<title>libvorbis - function - vorbis_commentheader_out</title>
|
||||
<link rel=stylesheet href="style.css" type="text/css">
|
||||
</head>
|
||||
|
||||
<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
|
||||
<table border=0 width=100%>
|
||||
<tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h1>vorbis_commentheader_out</h1>
|
||||
|
||||
<p><i>declared in "vorbis/codec.h";</i></p>
|
||||
|
||||
<p>This function encodes the contents of a
|
||||
<a href="vorbis_comment.html">vorbis_comment</a> structure into an
|
||||
ogg_packet.</p>
|
||||
|
||||
<table border=0 color=black cellspacing=0 cellpadding=7>
|
||||
<tr bgcolor=#cccccc>
|
||||
<td>
|
||||
<pre><b>
|
||||
extern int vorbis_commentheader_out(vorbis_comment *vc, ogg_packet *op);
|
||||
</b></pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<h3>Parameters</h3>
|
||||
<dl>
|
||||
<dt><i>vc</i></dt>
|
||||
<dd>The vorbis_comment structure to encode.</dd>
|
||||
<dt><i>op</i></dt>
|
||||
<dd>The ogg_packet to place the encoded comment packet into.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
<h3>Return Values</h3>
|
||||
<blockquote>
|
||||
<li>0 on success.</li>
|
||||
<li>OV_EIMPL on error.</li>
|
||||
</blockquote>
|
||||
<p>
|
||||
|
||||
<br><br>
|
||||
<hr noshade>
|
||||
<table border=0 width=100%>
|
||||
<tr valign=top>
|
||||
<td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
|
||||
<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a></p></td>
|
||||
</tr><tr>
|
||||
<td><p class=tiny>libvorbis documentation</p></td>
|
||||
<td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|