Mercurial > hg > sv-dependency-builds

annotate src/libvorbis-1.3.3/doc/vorbisfile/seekexample.html @ 1:05aa0afa9217

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Bring in flac, ogg, vorbis
author Chris Cannam
date Tue, 19 Mar 2013 17:37:49 +0000
parents
children
rev   line source
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>Example Code: seeking</h1>
Chris@1 17
Chris@1 18 <p>
Chris@1 19 The following is a run-through of the seeking example program supplied
Chris@1 20 with vorbisfile - <a href="seeking_test_c.html">seeking_test.c</a>.
Chris@1 21 This program tests the vorbisfile <a href="ov_time_seek.html">ov_time_seek</a> function by seeking to random points within the file.
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 &lt;stdlib.h>
Chris@1 32 #include &lt;stdio.h>
Chris@1 33 #include "vorbis/codec.h"
Chris@1 34 #include "vorbis/vorbisfile.h"
Chris@1 35 </b></pre>
Chris@1 36 </td>
Chris@1 37 </tr>
Chris@1 38 </table>
Chris@1 39
Chris@1 40 <p>Inside main(), we declare our primary OggVorbis_File structure. We also declare other helpful variables to track our progress within the file.
Chris@1 41 <br><br>
Chris@1 42 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 43 <tr bgcolor=#cccccc>
Chris@1 44 <td>
Chris@1 45 <pre><b>
Chris@1 46 int main(){
Chris@1 47 OggVorbis_File ov;
Chris@1 48 int i;
Chris@1 49 </b></pre>
Chris@1 50 </td>
Chris@1 51 </tr>
Chris@1 52 </table>
Chris@1 53
Chris@1 54 <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 55 <br><br>
Chris@1 56 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 57 <tr bgcolor=#cccccc>
Chris@1 58 <td>
Chris@1 59 <pre><b>
Chris@1 60 #ifdef _WIN32 /* We need to set stdin to binary mode under Windows */
Chris@1 61 _setmode( _fileno( stdin ), _O_BINARY );
Chris@1 62 #endif
Chris@1 63 </b></pre>
Chris@1 64 </td>
Chris@1 65 </tr>
Chris@1 66 </table>
Chris@1 67
Chris@1 68 <p><a href="ov_open_callbacks.html">ov_open()</a> must be
Chris@1 69 called to initialize the <a href="OggVorbis_File.html">OggVorbis_File</a> structure with default values.
Chris@1 70 <a href="ov_open_callbacks.html">ov_open_callbacks()</a> also checks to ensure that we're reading Vorbis format and not something else.
Chris@1 71
Chris@1 72 <br><br>
Chris@1 73 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 74 <tr bgcolor=#cccccc>
Chris@1 75 <td>
Chris@1 76 <pre><b>
Chris@1 77 if(ov_open_callbacks(stdin,&ov,NULL,-1, OV_CALLBACKS_NOCLOSE)<0){
Chris@1 78 printf("Could not open input as an OggVorbis file.\n\n");
Chris@1 79 exit(1);
Chris@1 80 }
Chris@1 81
Chris@1 82 </b></pre>
Chris@1 83 </td>
Chris@1 84 </tr>
Chris@1 85 </table>
Chris@1 86
Chris@1 87 <p>
Chris@1 88 First we check to make sure the stream is seekable using <a href="ov_seekable.html">ov_seekable</a>.
Chris@1 89
Chris@1 90 <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.
Chris@1 91
Chris@1 92 <br><br>
Chris@1 93 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 94 <tr bgcolor=#cccccc>
Chris@1 95 <td>
Chris@1 96 <pre><b>
Chris@1 97
Chris@1 98 /* print details about each logical bitstream in the input */
Chris@1 99 if(ov_seekable(&ov)){
Chris@1 100 double length=ov_time_total(&ov,-1);
Chris@1 101 printf("testing seeking to random places in %g seconds....\n",length);
Chris@1 102 for(i=0;i<100;i++){
Chris@1 103 double val=(double)rand()/RAND_MAX*length;
Chris@1 104 ov_time_seek(&ov,val);
Chris@1 105 printf("\r\t%d [%gs]... ",i,val);
Chris@1 106 fflush(stdout);
Chris@1 107 }
Chris@1 108
Chris@1 109 printf("\r \nOK.\n\n");
Chris@1 110 }else{
Chris@1 111 printf("Standard input was not seekable.\n");
Chris@1 112 }
Chris@1 113
Chris@1 114 </b></pre>
Chris@1 115 </td>
Chris@1 116 </tr>
Chris@1 117 </table>
Chris@1 118 <p>
Chris@1 119 When we're done seeking, we need to call <a href="ov_clear.html">ov_clear()</a> to release the bitstream.
Chris@1 120
Chris@1 121 <br><br>
Chris@1 122 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
Chris@1 123 <tr bgcolor=#cccccc>
Chris@1 124 <td>
Chris@1 125 <pre><b>
Chris@1 126 ov_clear(&ov);
Chris@1 127 return 0;
Chris@1 128 }
Chris@1 129 </b></pre>
Chris@1 130 </td>
Chris@1 131 </tr>
Chris@1 132 </table>
Chris@1 133
Chris@1 134 <p>
Chris@1 135 The full source for seeking_test.c can be found with the vorbis
Chris@1 136 distribution in <a href="seeking_test_c.html">seeking_test.c</a>.
Chris@1 137
Chris@1 138 <br><br>
Chris@1 139 <hr noshade>
Chris@1 140 <table border=0 width=100%>
Chris@1 141 <tr valign=top>
Chris@1 142 <td><p class=tiny>copyright &copy; 2000-2010 Xiph.Org</p></td>
Chris@1 143 <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
Chris@1 144 </tr><tr>
Chris@1 145 <td><p class=tiny>Vorbisfile documentation</p></td>
Chris@1 146 <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
Chris@1 147 </tr>
Chris@1 148 </table>
Chris@1 149
Chris@1 150 </body>
Chris@1 151
Chris@1 152 </html>