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diff src/libvorbis-1.3.3/doc/vorbisfile/chainingexample.html @ 86:98c1576536ae
Bring in flac, ogg, vorbis
| author | Chris Cannam <cannam@all-day-breakfast.com> |
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| date | Tue, 19 Mar 2013 17:37:49 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/libvorbis-1.3.3/doc/vorbisfile/chainingexample.html Tue Mar 19 17:37:49 2013 +0000 @@ -0,0 +1,175 @@ +<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>Chaining Example Code</h1> + +<p> +The following is a run-through of the chaining example program supplied +with vorbisfile - <a href="chaining_example_c.html">chaining_example.c</a>. +This program demonstrates how to work with a chained bitstream. + +<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 "vorbis/codec.h" +#include "vorbis/vorbisfile.h" +#include "../lib/misc.h" +</b></pre> + </td> +</tr> +</table> + +<p>Inside main(), we declare our primary OggVorbis_File structure. We also declare a 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>We call <a href="ov_open_callbacks.html">ov_open_callbacks()</a> to +initialize the <a href="OggVorbis_File.html">OggVorbis_File</a> +structure. <a href="ov_open_callbacks.html">ov_open_callbacks()</a> +also checks to ensure that we're reading Vorbis format and not +something else. The OV_CALLBACKS_NOCLOSE callbacks instruct +libvorbisfile not to close stdin later during cleanup.<p> + +<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're going to find the number of logical bitstreams in the physical bitstream using <a href="ov_streams.html">ov_streams</a>. + +<p>We use <a href="ov_time_total.html">ov_time_total</a> to determine the total length of the physical bitstream. We specify that we want the entire bitstream by using the argument <tt>-1</tt>. + +<br><br> +<table border=0 width=100% color=black cellspacing=0 cellpadding=7> +<tr bgcolor=#cccccc> + <td> +<pre><b> + if(ov_seekable(&ov)){ + printf("Input bitstream contained %ld logical bitstream section(s).\n", + ov_streams(&ov)); + printf("Total bitstream playing time: %ld seconds\n\n", + (long)ov_time_total(&ov,-1)); + + }else{ + printf("Standard input was not seekable.\n" + "First logical bitstream information:\n\n"); + } + +</b></pre> + </td> +</tr> +</table> + +<p>Now we're going to iterate through each logical bitstream and print information about that bitstream. + +<p>We use <a href="ov_info.html">ov_info</a> to pull out the <a href="../libvorbis/vorbis_info.html">vorbis_info</a> struct for each logical bitstream. This struct contains bitstream-specific info. + +<p><a href="ov_serialnumber.html">ov_serialnumber</a> retrieves the unique serial number for the logical bistream. <a href="ov_raw_total.html">ov_raw_total</a> gives the total compressed bytes for the logical bitstream, and <a href="ov_time_total.html">ov_time_total</a> gives the total time in the logical bitstream. + +<br><br> +<table border=0 width=100% color=black cellspacing=0 cellpadding=7> +<tr bgcolor=#cccccc> + <td> +<pre><b> + for(i=0;i<ov_streams(&ov);i++){ + vorbis_info *vi=ov_info(&ov,i); + printf("\tlogical bitstream section %d information:\n",i+1); + printf("\t\t%ldHz %d channels bitrate %ldkbps serial number=%ld\n", + vi->rate,vi->channels,ov_bitrate(&ov,i)/1000, + ov_serialnumber(&ov,i)); + printf("\t\tcompressed length: %ld bytes ",(long)(ov_raw_total(&ov,i))); + printf(" play time: %lds\n",(long)ov_time_total(&ov,i)); + } +</b></pre> + </td> +</tr> +</table> +<p> +When we're done with the entire physical bitstream, 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 chaining_example.c can be found with the vorbis +distribution in <a href="chaining_example_c.html">chaining_example.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>