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| 2 |
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| 3 | <head>
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| 4 | <title>libvorbis - function - vorbis_analysis</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>libvorbis documentation</p></td>
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| 12 | <td align=right><p class=tiny>libvorbis 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>vorbis_analysis</h1>
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| 17 |
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| 18 | <p><i>declared in "vorbis/codec.h";</i></p>
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| 19 |
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| 20 | <p>Once the uncompressed audio data has been divided into blocks, this
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| 21 | function is called on each block. It looks up the encoding mode and
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| 22 | dispatches the block to the forward transform provided by that mode.
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| 23 | </p>
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| 24 | <p>When using a basic encoding mode, with no bitrate management,
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| 25 | an ogg_packet pointer can be given, and the coded block is returned
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| 26 | directly through that structure and can be placed in the output stream.
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| 27 | </p>
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| 28 | <p>Otherwise, NULL should be passed for the ogg_packet pointer. In
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| 29 | that case, after the transform has been applied, the block must passed
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| 30 | to vorbis_bitrate_addblock() for further coding. This method works with
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| 31 | both basic and managed encoding modes, so it's recommended for new code.
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| 32 | </p>
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| 33 |
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| 34 | <table border=0 color=black cellspacing=0 cellpadding=7>
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| 35 | <tr bgcolor=#cccccc>
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| 36 | <td>
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| 37 | <pre><b>
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| 38 | extern int vorbis_analysis(vorbis_block *vb,ogg_packet *op);
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| 39 | </b></pre>
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| 40 | </td>
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| 41 | </tr>
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| 42 | </table>
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| 43 |
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| 44 | <h3>Parameters</h3>
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| 45 | <dl>
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| 46 | <dt><i>vb</i></dt>
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| 47 | <dd>Pointer to the vorbis_block to be encoded.</dd>
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| 48 | <dt><i>op</i></dt>
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| 49 | <dd>Optional pointer to an ogg_packet. This is normally NULL,
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| 50 | and the final output is obtained by passing <i>vb</i> though the
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| 51 | vorbis_bitrate_*() interface to perform further refinement.
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| 52 | However, when not using a bitrate managed encoding mode, it
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| 53 | is possible to skip that step by providing an ogg_packet pointer
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| 54 | here, obtaining the compressed data directly.</dd>
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| 55 | </dl>
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| 56 |
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| 57 |
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| 58 | <h3>Return Values</h3>
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| 59 | <ul>
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| 60 | <li>0 for success</li>
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| 61 | <li>negative values for failure:
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| 62 | <ul>
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| 63 | <li>OV_EINVAL - Invalid request; a non-NULL value was passed for <i>op</i> when the encoder is using a bitrate managed mode.</li>
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| 64 | <li>OV_EFAULT - Internal fault; indicates a bug or memory corruption.</li>
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| 65 | <li>OV_EIMPL - Unimplemented; not supported by this version of the library.</li>
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| 66 | </ul>
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| 67 | </li>
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| 68 | </ul>
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| 69 | <p>
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| 70 |
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| 71 | <br><br>
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| 72 | <hr noshade>
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| 73 | <table border=0 width=100%>
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| 74 | <tr valign=top>
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| 75 | <td><p class=tiny>copyright © 2010 Xiph.Org</p></td>
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| 76 | <td align=right><p class=tiny><a href="https://xiph.org/vorbis/">Ogg Vorbis</a></p></td>
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| 77 | </tr><tr>
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| 78 | <td><p class=tiny>libvorbis documentation</p></td>
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| 79 | <td align=right><p class=tiny>libvorbis version 1.3.2 - 20101101</p></td>
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| 80 | </tr>
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| 81 | </table>
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| 82 |
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| 83 |
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| 84 | </body>
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| 85 |
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| 86 | </html>
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