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| 3 | <head> |
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| 4 | <title>Vorbisfile - function - ov_pcm_seek_page_lap</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 1.2.0 - 20070723</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>ov_pcm_seek_page_lap</h1> |
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| 17 | |
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| 18 | <p><i>declared in "vorbis/vorbisfile.h";</i></p> |
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| 19 | |
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| 20 | <p>Seeks to the closest page preceding the specified location (in pcm |
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| 21 | samples) within the physical bitstream. This variant of <a |
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| 22 | href="ov_pcm_seek_page.html">ov_pcm_seek_page</a> also automatically |
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| 23 | crosslaps the transition from the previous playback position into the |
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| 24 | new playback position in order to eliminate clicking and boundary |
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| 25 | discontinuities. Otherwise, usage and behavior is identical to <a |
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| 26 | href="ov_pcm_seek_page.html">ov_pcm_seek_page</a>. |
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| 27 | |
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| 28 | <p>This function is faster than <a |
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| 29 | href="ov_pcm_seek_lap.html">ov_pcm_seek_lap</a> because the function |
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| 30 | can begin decoding at a page boundary rather than seeking through any |
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| 31 | remaining samples before the specified location. However, it is less |
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| 32 | accurate. |
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| 33 | |
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| 34 | <p>ov_pcm_seek_page_lap also updates everything needed within the |
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| 35 | decoder, so you can immediately call <a |
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| 36 | href="ov_read.html">ov_read()</a> and get data from the newly seeked |
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| 37 | to position. |
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| 38 | |
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| 39 | <p>ov_pcm_seek_page_lap will lap between logical stream links of |
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| 40 | differing numbers of channels. Any extra channels from the origin of |
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| 41 | the seek are ignored; playback of these channels simply ends. Extra |
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| 42 | channels at the destination are lapped from silence. |
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| 43 | ov_pcm_seek_page_lap will also lap between logical stream links of |
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| 44 | differing sample rates. In this case, the sample rates are ignored |
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| 45 | (no implicit resampling is done to match playback). It is up to the |
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| 46 | application developer to decide if this behavior makes any sense in a |
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| 47 | given context; in practical use, these default behaviors perform |
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| 48 | sensibly. |
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| 49 | |
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| 50 | <p>This function only works for seekable streams. |
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| 51 | |
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| 52 | <br><br> |
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| 53 | <table border=0 color=black cellspacing=0 cellpadding=7> |
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| 54 | <tr bgcolor=#cccccc> |
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| 55 | <td> |
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| 56 | <pre><b> |
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| 57 | int ov_pcm_seek_page_lap(OggVorbis_File *vf,ogg_int64_t pos); |
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| 58 | </b></pre> |
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| 59 | </td> |
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| 60 | </tr> |
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| 61 | </table> |
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| 62 | |
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| 63 | <h3>Parameters</h3> |
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| 64 | <dl> |
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| 65 | <dt><i>vf</i></dt> |
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| 66 | <dd>A pointer to the OggVorbis_File structure--this is used for ALL the externally visible libvorbisfile |
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| 67 | functions.</dd> |
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| 68 | <dt><i>pos</i></dt> |
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| 69 | <dd>Position in pcm samples to seek to in the bitstream.</dd> |
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| 70 | </dl> |
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| 71 | |
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| 72 | |
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| 73 | <h3>Return Values</h3> |
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| 74 | <blockquote> |
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| 75 | <ul> |
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| 76 | <li>0 for success</li> |
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| 77 | |
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| 78 | <li> |
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| 79 | nonzero indicates failure, described by several error codes: |
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| 80 | <ul> |
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| 81 | <li>OV_ENOSEEK - Bitstream is not seekable. |
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| 82 | </li> |
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| 83 | <li>OV_EINVAL - Invalid argument value; possibly called with an OggVorbis_File structure that isn't open. |
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| 84 | </li> |
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| 85 | <li>OV_EREAD - A read from media returned an error. |
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| 86 | </li> |
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| 87 | <li>OV_EFAULT - Internal logic fault; indicates a bug or heap/stack |
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| 88 | corruption. |
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| 89 | </li> |
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| 90 | <li>OV_EOF - Indicates stream is at end of file immediately after a seek |
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| 91 | (making crosslap impossible as there's no preceeding decode state to crosslap). |
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| 92 | </li> |
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| 93 | <li>OV_EBADLINK - Invalid stream section supplied to libvorbisfile, or the requested link is corrupt. |
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| 94 | </li> |
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| 95 | </ul></li> |
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| 96 | </ul></blockquote> |
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| 97 | |
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| 98 | <br><br> |
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| 99 | <hr noshade> |
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| 100 | <table border=0 width=100%> |
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| 101 | <tr valign=top> |
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| 102 | <td><p class=tiny>copyright © 2007 Xiph.org</p></td> |
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| 103 | <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td> |
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| 104 | </tr><tr> |
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| 105 | <td><p class=tiny>Vorbisfile documentation</p></td> |
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| 106 | <td align=right><p class=tiny>vorbisfile version 1.2.0 - 20070723</p></td> |
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| 107 | </tr> |
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| 108 | </table> |
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| 109 | |
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| 110 | </body> |
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| 111 | |
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| 112 | </html> |
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