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comparison src/libogg-1.3.0/doc/libogg/decoding.html @ 1:05aa0afa9217
Bring in flac, ogg, vorbis
| author | Chris Cannam |
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| date | Tue, 19 Mar 2013 17:37:49 +0000 |
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| 0:c7265573341e | 1:05aa0afa9217 |
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| 1 <html> | |
| 2 | |
| 3 <head> | |
| 4 <title>libogg - Decoding</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>libogg documentation</p></td> | |
| 12 <td align=right><p class=tiny>libogg release 1.3.0 - 20110804</p></td> | |
| 13 </tr> | |
| 14 </table> | |
| 15 | |
| 16 <h1>Decoding</h1> | |
| 17 <p>Libogg contains a set of functions used in the decoding process. | |
| 18 <p> | |
| 19 All the <b>libogg</b> specific functions are declared in "ogg/ogg.h". | |
| 20 <p> | |
| 21 <p>Decoding is based around the ogg synchronization layer. The <a href="ogg_sync_state.html">ogg_sync_state</a> struct coordinates between incoming data and the decoder. We read data into the synchronization layer, submit the data to the stream, and output raw packets to the decoder. | |
| 22 <p>Decoding through the Ogg layer follows a specific logical sequence. A read loop follows these logical steps: | |
| 23 <ul> | |
| 24 <li>Expose a buffer using <a href="ogg_sync_buffer.html">ogg_sync_buffer()</a>. | |
| 25 <li>Read data into the buffer, using fread() or a similar function. | |
| 26 <li>Call <a href="ogg_sync_wrote.html">ogg_sync_wrote()</a> to tell the synchronization layer how many bytes you wrote into the buffer. | |
| 27 <li>Write out the data using <a href="ogg_sync_pageout.html">ogg_sync_pageout</a>. | |
| 28 <li>Submit the completed page to the streaming layer with <a href="ogg_stream_pagein.html">ogg_stream_pagein</a>. | |
| 29 <li>Output a packet of data to the codec-specific decoding layer using <a href="ogg_stream_packetout.html">ogg_stream_packetout</a>. | |
| 30 </ul> | |
| 31 <p>In practice, streams are more complex, and Ogg also must handle headers, incomplete or dropped pages, and other errors in input. | |
| 32 <br><br> | |
| 33 | |
| 34 <table border=1 color=black width=50% cellspacing=0 cellpadding=7> | |
| 35 <tr bgcolor=#cccccc> | |
| 36 <td><b>function</b></td> | |
| 37 <td><b>purpose</b></td> | |
| 38 </tr> | |
| 39 <tr valign=top> | |
| 40 <td><a href="ogg_sync_init.html">ogg_sync_init</a></td> | |
| 41 <td>Initializes an Ogg bitstream.</td> | |
| 42 </tr> | |
| 43 <tr valign=top> | |
| 44 <td><a href="ogg_sync_clear.html">ogg_sync_clear</a></td> | |
| 45 <td>Clears the status information from the synchronization struct.<td> | |
| 46 </tr> | |
| 47 <tr valign=top> | |
| 48 <td><a href="ogg_sync_reset.html">ogg_sync_reset</a></td> | |
| 49 <td>Resets the synchronization status to initial values.</td> | |
| 50 </tr> | |
| 51 <tr valign=top> | |
| 52 <td><a href="ogg_sync_destroy.html">ogg_sync_destroy</a></td> | |
| 53 <td>Frees the synchronization struct.</td> | |
| 54 </tr> | |
| 55 <tr valign=top> | |
| 56 <td><a href="ogg_sync_check.html">ogg_sync_check</a></td> | |
| 57 <td>Check for asynchronous errors.</td> | |
| 58 </tr> | |
| 59 <tr valign=top> | |
| 60 <td><a href="ogg_sync_buffer.html">ogg_sync_buffer</a></td> | |
| 61 <td>Exposes a buffer from the synchronization layer in order to read data.</td> | |
| 62 </tr> | |
| 63 <tr valign=top> | |
| 64 <td><a href="ogg_sync_wrote.html">ogg_sync_wrote</a></td> | |
| 65 <td>Tells the synchronization layer how many bytes were written into the buffer.</td> | |
| 66 </tr> | |
| 67 <tr valign=top> | |
| 68 <td><a href="ogg_sync_pageseek.html">ogg_sync_pageseek</a></td> | |
| 69 <td>Finds the borders of pages and resynchronizes the stream.</td> | |
| 70 </tr> | |
| 71 <tr valign=top> | |
| 72 <td><a href="ogg_sync_pageout.html">ogg_sync_pageout</a></td> | |
| 73 <td>Outputs a page from the synchronization layer.</td> | |
| 74 </tr> | |
| 75 <tr valign=top> | |
| 76 <td><a href="ogg_stream_pagein.html">ogg_stream_pagein</a></td> | |
| 77 <td>Submits a complete page to the stream layer.</td> | |
| 78 </tr> | |
| 79 <tr valign=top> | |
| 80 <td><a href="ogg_stream_packetout.html">ogg_stream_packetout</a></td> | |
| 81 <td>Outputs a packet to the codec-specific decoding engine.</td> | |
| 82 </tr> | |
| 83 <tr valign=top> | |
| 84 <td><a href="ogg_stream_packetpeek.html">ogg_stream_packetpeek</a></td> | |
| 85 <td>Provides access to the next packet in the bitstream without | |
| 86 advancing decoding.</td> | |
| 87 </tr> | |
| 88 </table> | |
| 89 | |
| 90 <br><br> | |
| 91 <hr noshade> | |
| 92 <table border=0 width=100%> | |
| 93 <tr valign=top> | |
| 94 <td><p class=tiny>copyright © 2000-2011 Xiph.Org</p></td> | |
| 95 <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/">Ogg Container Format</a></p></td> | |
| 96 </tr><tr> | |
| 97 <td><p class=tiny>libogg documentation</p></td> | |
| 98 <td align=right><p class=tiny>libogg release 1.3.0 - 20110804</p></td> | |
| 99 </tr> | |
| 100 </table> | |
| 101 | |
| 102 </body> | |
| 103 | |
| 104 </html> |