153 lines
4.1 KiB
HTML
153 lines
4.1 KiB
HTML
|
<html>
|
||
|
|
|
||
|
|
<head>
|
||
|
|
<title>vorbisfile - Example Code</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>Vorbisfile documentation</p></td>
|
||
|
|
<td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
<h1>Example Code: seeking</h1>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
The following is a run-through of the seeking example program supplied
|
||
|
|
with vorbisfile - <a href="seeking_test_c.html">seeking_test.c</a>.
|
||
|
|
This program tests the vorbisfile <a href="ov_time_seek.html">ov_time_seek</a> function by seeking to random points within the file.
|
||
|
|
|
||
|
|
<p>
|
||
|
|
First, relevant headers, including vorbis-specific "codec.h" and "vorbisfile.h" have to be included.
|
||
|
|
|
||
|
|
<br><br>
|
||
|
|
<table border=0 width=100% color=black cellspacing=0 cellpadding=7>
|
||
|
|
<tr bgcolor=#cccccc>
|
||
|
|
<td>
|
||
|
|
<pre><b>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include "vorbis/codec.h"
|
||
|
|
#include "vorbis/vorbisfile.h"
|
||
|
|
</b></pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
<p>Inside main(), we declare our primary OggVorbis_File structure. We also declare other helpful variables to track our progress within the file.
|
||
|
|
<br><br>
|
||
|
|
<table border=0 width=100% color=black cellspacing=0 cellpadding=7>
|
||
|
|
<tr bgcolor=#cccccc>
|
||
|
|
<td>
|
||
|
|
<pre><b>
|
||
|
|
int main(){
|
||
|
|
OggVorbis_File ov;
|
||
|
|
int i;
|
||
|
|
</b></pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
<p>This example takes its input on stdin which is in 'text' mode by default under Windows; this will corrupt the input data unless set to binary mode. This applies only to Windows.
|
||
|
|
<br><br>
|
||
|
|
<table border=0 width=100% color=black cellspacing=0 cellpadding=7>
|
||
|
|
<tr bgcolor=#cccccc>
|
||
|
|
<td>
|
||
|
|
<pre><b>
|
||
|
|
#ifdef _WIN32 /* We need to set stdin to binary mode under Windows */
|
||
|
|
_setmode( _fileno( stdin ), _O_BINARY );
|
||
|
|
#endif
|
||
|
|
</b></pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
<p><a href="ov_open_callbacks.html">ov_open()</a> must be
|
||
|
|
called to initialize the <a href="OggVorbis_File.html">OggVorbis_File</a> structure with default values.
|
||
|
|
<a href="ov_open_callbacks.html">ov_open_callbacks()</a> also checks to ensure that we're reading Vorbis format and not something else.
|
||
|
|
|
||
|
|
<br><br>
|
||
|
|
<table border=0 width=100% color=black cellspacing=0 cellpadding=7>
|
||
|
|
<tr bgcolor=#cccccc>
|
||
|
|
<td>
|
||
|
|
<pre><b>
|
||
|
|
if(ov_open_callbacks(stdin,&ov,NULL,-1, OV_CALLBACKS_NOCLOSE)<0){
|
||
|
|
printf("Could not open input as an OggVorbis file.\n\n");
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
|
||
|
|
</b></pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
First we check to make sure the stream is seekable using <a href="ov_seekable.html">ov_seekable</a>.
|
||
|
|
|
||
|
|
<p>Then we seek to 100 random spots in the bitstream using <a href="ov_time_seek.html">ov_time_seek</a> with randomly generated values.
|
||
|
|
|
||
|
|
<br><br>
|
||
|
|
<table border=0 width=100% color=black cellspacing=0 cellpadding=7>
|
||
|
|
<tr bgcolor=#cccccc>
|
||
|
|
<td>
|
||
|
|
<pre><b>
|
||
|
|
|
||
|
|
/* print details about each logical bitstream in the input */
|
||
|
|
if(ov_seekable(&ov)){
|
||
|
|
double length=ov_time_total(&ov,-1);
|
||
|
|
printf("testing seeking to random places in %g seconds....\n",length);
|
||
|
|
for(i=0;i<100;i++){
|
||
|
|
double val=(double)rand()/RAND_MAX*length;
|
||
|
|
ov_time_seek(&ov,val);
|
||
|
|
printf("\r\t%d [%gs]... ",i,val);
|
||
|
|
fflush(stdout);
|
||
|
|
}
|
||
|
|
|
||
|
|
printf("\r \nOK.\n\n");
|
||
|
|
}else{
|
||
|
|
printf("Standard input was not seekable.\n");
|
||
|
|
}
|
||
|
|
|
||
|
|
</b></pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
<p>
|
||
|
|
When we're done seeking, we need to call <a href="ov_clear.html">ov_clear()</a> to release the bitstream.
|
||
|
|
|
||
|
|
<br><br>
|
||
|
|
<table border=0 width=100% color=black cellspacing=0 cellpadding=7>
|
||
|
|
<tr bgcolor=#cccccc>
|
||
|
|
<td>
|
||
|
|
<pre><b>
|
||
|
|
ov_clear(&ov);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
</b></pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
The full source for seeking_test.c can be found with the vorbis
|
||
|
|
distribution in <a href="seeking_test_c.html">seeking_test.c</a>.
|
||
|
|
|
||
|
|
<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>Vorbisfile documentation</p></td>
|
||
|
|
<td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
</body>
|
||
|
|
|
||
|
|
</html>
|