273 lines
12 KiB
Plaintext
273 lines
12 KiB
Plaintext
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Flite: a small run-time speech synthesis engine
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version 1.4-release
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Copyright Carnegie Mellon University 1999-2009
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All rights reserved
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http://cmuflite.org
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Flite is a small fast run-time speech synthesis engine. It is the
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latest addition to the suite of free software synthesis tools
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including University of Edinburgh's Festival Speech Synthesis System
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and Carnegie Mellon University's FestVox project, tools, scripts and
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documentation for building synthetic voices. However, flite itself
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does not require either of these systems to compile and run.
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The core Flite library was developed by Alan W Black <awb@cs.cmu.edu>
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(mostly in his so-called spare time) while employed in the Language
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Technologies Institute at Carnegie Mellon University. The name
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"flite", originally chosen to mean "festival-lite" is perhaps doubly
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appropriate as a substantial part of design and coding was done over
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30,000ft while awb was travelling, and (usually) isn't in meetings.
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The voices, lexicon and language components of flite, both their
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compression techniques and their actual contents were developed by
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Kevin A. Lenzo <lenzo@cs.cmu.edu> and Alan W Black <awb@cs.cmu.edu>.
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Flite is the answer to the complaint that Festival is too big, too slow,
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and not portable enough.
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o Flite is designed for very small devices, such as PDAs, and also
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for large server machines with lots of ports.
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o Flite is not a replacement for Festival but an alternative run time
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engine for voices developed in the FestVox framework where size and
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speed is crucial.
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o Flite is all in ANSI C, it contains no C++ or Scheme, thus requires
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more care in programming, and is harder to customize at run time.
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o It is thread safe
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o Voices, lexicons and language descriptions can be compiled
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(mostly automatically for voices and lexicons) into C representations
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from their FestVox formats
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o All voices, lexicons and language model data are const and in the
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text segment (i.e. they may be put in ROM). As they are linked in
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at compile time, there is virtually no startup delay.
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o Although the synthesized output is not exactly the same as the same
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voice in Festival they are effectively equivalent. That is flite
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doesn't sound better or worse than the equivalent voice in festival,
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just faster, smaller and scalable.
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o For standard diphone voices, maximum run time memory
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requirements are approximately less than twice the memory requirement
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for the waveform generated. For 32bit archtectures
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this effectively means under 1M.
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o The flite program supports, synthesis of individual strings or files
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(utterance by utterance) to direct audio devices or to waveform files.
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o The flite library offers simple functions suitable for use in specific
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applications.
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Flite is distributed with a single 8K diphone voice (derived from the
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cmu_us_kal voice), a pruned lexicon (derived from
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cmulex) and a set of models for US English. Here are comparisons
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with Festival using basically the same 8KHz diphone voice
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Flite Festival
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core code 60K 2.6M
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USEnglish 100K ??
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lexicon 600K 5M
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diphone 1.8M 2.1M
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runtime <1M 16-20M
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On a 500Mhz PIII, a timing test of the first two chapters of
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"Alice in Wonderland" (doc/alice) was done. This produces about
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1300 seconds of speech. With flite it takes 19.128 seconds (about
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70.6 times faster than real time) with Festival it takes 97 seconds
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(13.4 times faster than real time). On the ipaq (with the 16KHz diphones)
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flite synthesizes 9.79 time faster than real time.
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Requirements:
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o A good C compiler, some of these files are quite large and some C
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compilers might choke on these, gcc is fine. Sun CC 3.01 has been
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tested too. Visual C++ 6.0 is known to fail on the large diphone
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database files. We recommend you use GCC under Cygwin or mingw32
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instead.
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o GNU Make
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o An audio device isn't required as flite can write its output to
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a waveform file.
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Supported platforms:
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We have successfully compiled and run on
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o Various Intel Linux systems (and iPaq Linux), under various versions
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of GCC (2.7.2 to 4.x)
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o FreeBSD 3.x and 4.x
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o Solaris 5.7, and Solaris 9
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o Initial support for Mac OS X
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o Windows 2000/XP under Cygwin 1.3.5 and later
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o Support for WinCE (2.11 and 3.0) WM (5.x plus) is included
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o PalmOS 5.x devices (Treo 600, Zire 31 and Tungsten C)
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o Successfully compiles and runs under 64Bit Linux architectures
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o OSF1 V4.0 (gives an unimportant warning about sizes when compiled cst_val.c)
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Other similar platforms should just work, we have also cross compiled
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on a Linux machine for StrongARM. However note that new byte order
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architectures may not work directly as there is some careful
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byte order constraints in some structures. These are portable but may
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require reordering of some fields, contact us if you are moving to
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a new archiecture.
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News
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----
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New in 1.4 (December 2009)
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o crude multi-voice selection support (may change)
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o 4 basic voices are included 3 clustergen (awb, rms and slt) plus
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the kal diphone database
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o CMULEX now uses maximum onset for syllabification
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o alsa support
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o Clustergen support (including mlpg with mixed excitation)
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But is still slow on limited processors
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o Windows support with Visual Studio (specifically for the Olympus
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Spoken Dialog System)
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o WinCE support is redone with cegcc/mingw32ce with example
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example TTS app: Fluwm: Flite on Windows Mobile
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o Speed-ups in feature interpretation limiting calls to alloc
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o Speed-ups (and fixes) for converting clunits festvox voices
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New in 1.3-release (October 2005)
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o fixes to lpc residual extraction to give better quality output
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o An updated lexicon (festlex_CMU from festival-2.0) and better
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compression its about 30% of the previous size, with about
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the same accuracy
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o Fairly substantial code movements to better support PalmOS and
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multi-platform cross compilation builds
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o A PalmOS 5.0 port with an small example talking app ("flop")
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o runs under ix86_64 linux
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New in 1.2-release (February 2003)
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o A build process for diphone and clunits/ldom voices
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FestVox voices can be converted (sometimes) automatically
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o Various bug fixes
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o Initial support for Mac OS X (not talking to audio device yet)
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but compiles and runs
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o Text files can be synthesize to a single audio file
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o (optional) shared library support (Linux)
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Compilation
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-----------
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In general
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tar zxvf flite-1.4-release.tar.gz
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cd flite-1.4-release
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./configure
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make
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Where tar is gnu tar (gtar), and make is gnu make (gmake).
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Configuration should be automatic, but maybe doesn't work in all cases
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especially if you have some new compiler. You can explicitly set to
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compiler in config/config and add any options you see fit. Configure
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tries to guess these but it might be able for cross compilation cases
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Interesting options there are
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-DWORDS_BIGENDIAN=1 for bigendian machines (e.g. Sparc, M68x)
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-DNO_UNION_INITIALIZATION=1 For compilers without C 99 union inintialization
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-DCST_AUDIO_NONE if you don't need/want audio support
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There are different sets of voices and languages you can select between
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them (and your own sets if you make config/XXX.lv). For example
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./configure --with-langvox=transtac
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Will use the languages and voices defined in config/transtac.lv
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Usage:
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------
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The ./bin/flite voices contains all supported voices and you may
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choose between the voices with the -voice flag and list the supported
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voices with the -lw flag. Note the kal (diphone) voice is a different
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technology from the others and is much less computationally expensive
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but more robotic. For each voice additional binaries that contain
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only that voice are created in ./bin/flite_FULLVOICENAME,
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e.g. ./bin/flite_cmu_us_awb.
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If it compiles properly a binary will be put in bin/, note by
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default -g is on so it will be bigger than is actually required
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./bin/flite "Flite is a small fast run-time synthesis engine" flite.wav
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Will produce an 8KHz riff headered waveform file (riff is Microsoft's
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wave format often called .WAV).
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./bin/flite doc/alice
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Will play the text file doc/alice. If the first argument contains
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a space it is treated as text otherwise it is treated as a filename.
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If a second argument is given a waveform file is written to it,
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if no argument is given or "play" is given it will attempt to
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write directly to the audio device (if supported). if "none"
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is given the audio is simply thrown away (used for benchmarking).
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Explicit options are also available.
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./bin/flite -v doc/alice none
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Will synthesize the file without playing the audio and give a summary
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of the speed.
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./bin/flite doc/alice alice.wav
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will synthesize the whole of alice into a single file (previoous
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versions would only give the last utterance in the file, but
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that is fixed now).
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An additional set of feature setting options are available, these are
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*debug* options, Voices are represented as sets of feature values (see
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lang/cmu_us_kal/cmu_us_kal.c) and you can override values on the
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command line. This can stop flite from working if malicious values
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are set and therefor this facility is not intended to be made
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available for standard users. But these are useful for
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debugging. Some typical examples are
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./bin/flite --sets join_type=simple_join doc/intro
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Use simple concatenation of diphones without prosodic modification
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./bin/flite -pw doc/alice
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Print sentences as they are said
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./bin/flite --setf duration_stretch=1.5 doc/alice
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Make it speak slower
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./bin/flite --setf int_f0_target_mean=145 doc/alice
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Make it speak higher
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The talking clock is an example talking clode as discussed on
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http://festvox.org/ldom it requires a single argument HH:MM
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under Unix you can call it
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./bin/flite_time `date +%H:%M`
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./bin/flite -lv
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List the voices available in this build
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./bin/flite -voice rms -f doc/alice
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Speak with the US male rms voice
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./bin/flite -voice awb -f doc/alice
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Speak with the "Scottish" male awb voice
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./bin/flite -voice slt -f doc/alice
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Speak with the US female slt voice
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Voice quality
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-------------
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So you've eagerly downloaded flite, compiled it and run it, now you
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are disappointed that is doesn't sound wonderful, sure its fast and
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small but what you really hoped for was the dulcit tones of a deep
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baritone voice that would make you desperately hang on every phrase it
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sang. But instead you get an 8Khz diphone voice that sounds like it
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came from the last millenium.
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Well, first, you are right, it is an 8KHz diphone voice from the last
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millenium, and that was actually deliberate. As we developed flite we
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wanted a voice that was stable and that we could directly compare with
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that very same voice in Festival. Flite is an *engine*. We want to
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be able take voices built with the FestVox process and compile them
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for flite, the result should be exactly the same quality (though of
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course trading the size for quality in flite is also an option). The
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included voice is just an sample voice that was used in the testing
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process. We have better voices in Festival and are working on the
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coversion process to make it both more automatic and more robust and
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tunable, but we haven't done that yet, so in this first beta release.
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This old poor sounding voice is all we have, sorry, we'll provide you
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with free, high-quality, scalable, configurable, natural sounding
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voices for flite, in all languages and dialects, with the tools to
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built new voices efficiently and robustly as soon as we can. Though
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in the mean time, a few higher quality voices will be released with
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the next version.
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