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- <html>
- <head>
- <title>Tremor - Decoding</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>Tremor documentation</p></td>
- <td align=right><p class=tiny>Tremor version 1.0 - 20020403</p></td>
- </tr>
- </table>
- <h1>Decoding</h1>
- <p>
- All libivorbisdec decoding routines are declared in "ivorbisfile.h".
- <p>
- After <a href="initialization.html">initialization</a>, decoding audio
- is as simple as calling <a href="ov_read.html">ov_read()</a>. This
- function works similarly to reading from a normal file using
- <tt>read()</tt>.<p>
- However, a few differences are worth noting:
- <h2>multiple stream links</h2>
- A Vorbis stream may consist of multiple sections (called links) that
- encode differing numbers of channels or sample rates. It is vitally
- important to pay attention to the link numbers returned by <a
- href="ov_read.html">ov_read</a> and handle audio changes that may
- occur at link boundaries. Such multi-section files do exist in the
- wild and are not merely a specification curiosity.
- <h2>returned data amount</h2>
- <a href="ov_read.html">ov_read</a> does not attempt to completely fill
- a large, passed in data buffer; it merely guarantees that the passed
- back data does not overflow the passed in buffer size. Large buffers
- may be filled by iteratively looping over calls to <a
- href="ov_read.html">ov_read</a> (incrementing the buffer pointer)
- until the original buffer is filled.
- <h2>file cursor position</h2>
- Vorbis files do not necessarily start at a sample number or time offset
- of zero. Do not be surprised if a file begins at a positive offset of
- several minutes or hours, such as would happen if a large stream (such
- as a concert recording) is chopped into multiple seperate files.
- <p>
- <table border=1 color=black width=50% cellspacing=0 cellpadding=7>
- <tr bgcolor=#cccccc>
- <td><b>function</b></td>
- <td><b>purpose</b></td>
- </tr>
- <tr valign=top>
- <td><a href="ov_read.html">ov_read</a></td>
- <td>This function makes up the main chunk of a decode loop. It takes an
- OggVorbis_File structure, which must have been initialized by a previous
- call to <a href="ov_open.html"><tt>ov_open()</tt></a>.</td>
- </tr>
- </table>
- <br><br>
- <hr noshade>
- <table border=0 width=100%>
- <tr valign=top>
- <td><p class=tiny>copyright © 2002 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>Tremor documentation</p></td>
- <td align=right><p class=tiny>Tremor version 1.0 - 20020403</p></td>
- </tr>
- </table>
- </body>
- </html>
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