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| 2 |
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| 3 | <head>
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| 4 | <title>vorbisfile - Example Code</title>
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| 5 | <link rel=stylesheet href="style.css" type="text/css">
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| 6 | </head>
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| 7 |
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| 8 | <body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
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| 9 | <table border=0 width=100%>
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| 10 | <tr>
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| 11 | <td><p class=tiny>Vorbisfile documentation</p></td>
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| 12 | <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
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| 13 | </tr>
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| 14 | </table>
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| 15 |
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| 16 | <h1>Example Code: seeking</h1>
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| 17 |
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| 18 | <p>
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| 19 | The following is a run-through of the seeking example program supplied
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| 20 | with vorbisfile - <a href="seeking_test_c.html">seeking_test.c</a>.
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| 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.
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| 22 |
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| 23 | <p>
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| 24 | First, relevant headers, including vorbis-specific "codec.h" and "vorbisfile.h" have to be included.
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| 25 |
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| 26 | <br><br>
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| 27 | <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
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| 28 | <tr bgcolor=#cccccc>
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| 29 | <td>
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| 30 | <pre><b>
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| 31 | #include <stdlib.h>
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| 32 | #include <stdio.h>
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| 33 | #include "vorbis/codec.h"
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| 34 | #include "vorbis/vorbisfile.h"
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| 35 | </b></pre>
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| 36 | </td>
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| 37 | </tr>
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| 38 | </table>
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| 39 |
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| 40 | <p>Inside main(), we declare our primary OggVorbis_File structure. We also declare other helpful variables to track our progress within the file.
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| 41 | <br><br>
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| 42 | <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
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| 43 | <tr bgcolor=#cccccc>
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| 44 | <td>
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| 45 | <pre><b>
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| 46 | int main(){
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| 47 | OggVorbis_File ov;
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| 48 | int i;
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| 49 | </b></pre>
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| 50 | </td>
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| 51 | </tr>
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| 52 | </table>
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| 53 |
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| 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.
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| 55 | <br><br>
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| 56 | <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
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| 57 | <tr bgcolor=#cccccc>
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| 58 | <td>
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| 59 | <pre><b>
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| 60 | #ifdef _WIN32 /* We need to set stdin to binary mode under Windows */
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| 61 | _setmode( _fileno( stdin ), _O_BINARY );
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| 62 | #endif
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| 63 | </b></pre>
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| 64 | </td>
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| 65 | </tr>
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| 66 | </table>
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| 67 |
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| 68 | <p><a href="ov_open_callbacks.html">ov_open()</a> must be
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| 69 | called to initialize the <a href="OggVorbis_File.html">OggVorbis_File</a> structure with default values.
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| 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.
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| 71 |
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| 72 | <br><br>
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| 73 | <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
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| 74 | <tr bgcolor=#cccccc>
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| 75 | <td>
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| 76 | <pre><b>
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| 77 | if(ov_open_callbacks(stdin,&ov,NULL,-1, OV_CALLBACKS_NOCLOSE)<0){
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| 78 | printf("Could not open input as an OggVorbis file.\n\n");
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| 79 | exit(1);
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| 80 | }
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| 81 |
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| 82 | </b></pre>
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| 83 | </td>
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| 84 | </tr>
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| 85 | </table>
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| 86 |
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| 87 | <p>
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| 88 | First we check to make sure the stream is seekable using <a href="ov_seekable.html">ov_seekable</a>.
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| 89 |
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| 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.
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| 91 |
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| 92 | <br><br>
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| 93 | <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
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| 94 | <tr bgcolor=#cccccc>
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| 95 | <td>
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| 96 | <pre><b>
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| 97 |
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| 98 | /* print details about each logical bitstream in the input */
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| 99 | if(ov_seekable(&ov)){
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| 100 | double length=ov_time_total(&ov,-1);
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| 101 | printf("testing seeking to random places in %g seconds....\n",length);
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| 102 | for(i=0;i<100;i++){
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| 103 | double val=(double)rand()/RAND_MAX*length;
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| 104 | ov_time_seek(&ov,val);
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| 105 | printf("\r\t%d [%gs]... ",i,val);
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| 106 | fflush(stdout);
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| 107 | }
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| 108 |
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| 109 | printf("\r \nOK.\n\n");
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| 110 | }else{
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| 111 | printf("Standard input was not seekable.\n");
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| 112 | }
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| 113 |
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| 114 | </b></pre>
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| 115 | </td>
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| 116 | </tr>
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| 117 | </table>
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| 118 | <p>
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| 119 | When we're done seeking, we need to call <a href="ov_clear.html">ov_clear()</a> to release the bitstream.
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| 120 |
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| 121 | <br><br>
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| 122 | <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
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| 123 | <tr bgcolor=#cccccc>
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| 124 | <td>
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| 125 | <pre><b>
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| 126 | ov_clear(&ov);
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| 127 | return 0;
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| 128 | }
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| 129 | </b></pre>
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| 130 | </td>
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| 131 | </tr>
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| 132 | </table>
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| 133 |
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| 134 | <p>
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| 135 | The full source for seeking_test.c can be found with the vorbis
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| 136 | distribution in <a href="seeking_test_c.html">seeking_test.c</a>.
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| 137 |
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| 138 | <br><br>
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| 139 | <hr noshade>
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| 140 | <table border=0 width=100%>
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| 141 | <tr valign=top>
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| 142 | <td><p class=tiny>copyright © 2000-2010 Xiph.Org</p></td>
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| 143 | <td align=right><p class=tiny><a href="https://xiph.org/vorbis/">Ogg Vorbis</a></p></td>
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| 144 | </tr><tr>
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| 145 | <td><p class=tiny>Vorbisfile documentation</p></td>
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| 146 | <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
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| 147 | </tr>
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| 148 | </table>
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| 149 |
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| 150 | </body>
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| 151 |
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| 152 | </html>
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