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Bring in flac, ogg, vorbis
author Chris Cannam
date Tue, 19 Mar 2013 17:37:49 +0000
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Chris@1 1 <html>
Chris@1 2
Chris@1 3 <head>
Chris@1 4 <title>vorbisfile - Example Code</title>
Chris@1 5 <link rel=stylesheet href="style.css" type="text/css">
Chris@1 6 </head>
Chris@1 7
Chris@1 8 <body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
Chris@1 9 <table border=0 width=100%>
Chris@1 10 <tr>
Chris@1 11 <td><p class=tiny>Vorbisfile documentation</p></td>
Chris@1 12 <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
Chris@1 13 </tr>
Chris@1 14 </table>
Chris@1 15
Chris@1 16 <h1>Chaining Example Code</h1>
Chris@1 17
Chris@1 18 <p>
Chris@1 19 The following is a run-through of the chaining example program supplied
Chris@1 20 with vorbisfile - <a href="chaining_example_c.html">chaining_example.c</a>.
Chris@1 21 This program demonstrates how to work with a chained bitstream.
Chris@1 22
Chris@1 23 <p>
Chris@1 24 First, relevant headers, including vorbis-specific "codec.h" and "vorbisfile.h" have to be included.
Chris@1 25
Chris@1 26 <br><br>
Chris@1 27 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 28 <tr bgcolor=#cccccc>
Chris@1 29 <td>
Chris@1 30 <pre><b>
Chris@1 31 #include "vorbis/codec.h"
Chris@1 32 #include "vorbis/vorbisfile.h"
Chris@1 33 #include "../lib/misc.h"
Chris@1 34 </b></pre>
Chris@1 35 </td>
Chris@1 36 </tr>
Chris@1 37 </table>
Chris@1 38
Chris@1 39 <p>Inside main(), we declare our primary OggVorbis_File structure. We also declare a other helpful variables to track our progress within the file.
Chris@1 40 <br><br>
Chris@1 41 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 42 <tr bgcolor=#cccccc>
Chris@1 43 <td>
Chris@1 44 <pre><b>
Chris@1 45 int main(){
Chris@1 46 OggVorbis_File ov;
Chris@1 47 int i;
Chris@1 48 </b></pre>
Chris@1 49 </td>
Chris@1 50 </tr>
Chris@1 51 </table>
Chris@1 52
Chris@1 53 <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.
Chris@1 54 <br><br>
Chris@1 55 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 56 <tr bgcolor=#cccccc>
Chris@1 57 <td>
Chris@1 58 <pre><b>
Chris@1 59 #ifdef _WIN32 /* We need to set stdin to binary mode under Windows */
Chris@1 60 _setmode( _fileno( stdin ), _O_BINARY );
Chris@1 61 #endif
Chris@1 62 </b></pre>
Chris@1 63 </td>
Chris@1 64 </tr>
Chris@1 65 </table>
Chris@1 66
Chris@1 67 <p>We call <a href="ov_open_callbacks.html">ov_open_callbacks()</a> to
Chris@1 68 initialize the <a href="OggVorbis_File.html">OggVorbis_File</a>
Chris@1 69 structure. <a href="ov_open_callbacks.html">ov_open_callbacks()</a>
Chris@1 70 also checks to ensure that we're reading Vorbis format and not
Chris@1 71 something else. The OV_CALLBACKS_NOCLOSE callbacks instruct
Chris@1 72 libvorbisfile not to close stdin later during cleanup.<p>
Chris@1 73
Chris@1 74 <br><br>
Chris@1 75 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 76 <tr bgcolor=#cccccc>
Chris@1 77 <td>
Chris@1 78 <pre><b>
Chris@1 79 if(ov_open_callbacks(stdin,&ov,NULL,-1,OV_CALLBACKS_NOCLOSE)<0){
Chris@1 80 printf("Could not open input as an OggVorbis file.\n\n");
Chris@1 81 exit(1);
Chris@1 82 }
Chris@1 83
Chris@1 84 </b></pre>
Chris@1 85 </td>
Chris@1 86 </tr>
Chris@1 87 </table>
Chris@1 88
Chris@1 89 <p>
Chris@1 90 First we check to make sure the stream is seekable using <a href="ov_seekable.html">ov_seekable</a>.
Chris@1 91
Chris@1 92 <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>.
Chris@1 93
Chris@1 94 <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>.
Chris@1 95
Chris@1 96 <br><br>
Chris@1 97 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 98 <tr bgcolor=#cccccc>
Chris@1 99 <td>
Chris@1 100 <pre><b>
Chris@1 101 if(ov_seekable(&amp;ov)){
Chris@1 102 printf("Input bitstream contained %ld logical bitstream section(s).\n",
Chris@1 103 ov_streams(&amp;ov));
Chris@1 104 printf("Total bitstream playing time: %ld seconds\n\n",
Chris@1 105 (long)ov_time_total(&amp;ov,-1));
Chris@1 106
Chris@1 107 }else{
Chris@1 108 printf("Standard input was not seekable.\n"
Chris@1 109 "First logical bitstream information:\n\n");
Chris@1 110 }
Chris@1 111
Chris@1 112 </b></pre>
Chris@1 113 </td>
Chris@1 114 </tr>
Chris@1 115 </table>
Chris@1 116
Chris@1 117 <p>Now we're going to iterate through each logical bitstream and print information about that bitstream.
Chris@1 118
Chris@1 119 <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.
Chris@1 120
Chris@1 121 <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.
Chris@1 122
Chris@1 123 <br><br>
Chris@1 124 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 125 <tr bgcolor=#cccccc>
Chris@1 126 <td>
Chris@1 127 <pre><b>
Chris@1 128 for(i=0;i&lt;ov_streams(&amp;ov);i++){
Chris@1 129 vorbis_info *vi=ov_info(&amp;ov,i);
Chris@1 130 printf("\tlogical bitstream section %d information:\n",i+1);
Chris@1 131 printf("\t\t%ldHz %d channels bitrate %ldkbps serial number=%ld\n",
Chris@1 132 vi-&gt;rate,vi-&gt;channels,ov_bitrate(&amp;ov,i)/1000,
Chris@1 133 ov_serialnumber(&amp;ov,i));
Chris@1 134 printf("\t\tcompressed length: %ld bytes ",(long)(ov_raw_total(&amp;ov,i)));
Chris@1 135 printf(" play time: %lds\n",(long)ov_time_total(&amp;ov,i));
Chris@1 136 }
Chris@1 137 </b></pre>
Chris@1 138 </td>
Chris@1 139 </tr>
Chris@1 140 </table>
Chris@1 141 <p>
Chris@1 142 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.
Chris@1 143
Chris@1 144 <br><br>
Chris@1 145 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 146 <tr bgcolor=#cccccc>
Chris@1 147 <td>
Chris@1 148 <pre><b>
Chris@1 149 ov_clear(&amp;ov);
Chris@1 150 return 0;
Chris@1 151 }
Chris@1 152 </b></pre>
Chris@1 153 </td>
Chris@1 154 </tr>
Chris@1 155 </table>
Chris@1 156
Chris@1 157 <p>
Chris@1 158 The full source for chaining_example.c can be found with the vorbis
Chris@1 159 distribution in <a href="chaining_example_c.html">chaining_example.c</a>.
Chris@1 160
Chris@1 161 <br><br>
Chris@1 162 <hr noshade>
Chris@1 163 <table border=0 width=100%>
Chris@1 164 <tr valign=top>
Chris@1 165 <td><p class=tiny>copyright &copy; 2000-2010 Xiph.Org</p></td>
Chris@1 166 <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
Chris@1 167 </tr><tr>
Chris@1 168 <td><p class=tiny>Vorbisfile documentation</p></td>
Chris@1 169 <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
Chris@1 170 </tr>
Chris@1 171 </table>
Chris@1 172
Chris@1 173 </body>
Chris@1 174
Chris@1 175 </html>