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