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<title>Vorbisfile - function - ov_pcm_seek_page_lap</title>
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<td><p class=tiny>Vorbisfile documentation</p></td>
<td align=right><p class=tiny>vorbisfile version 1.2.0 - 20070723</p></td>
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<h1>ov_pcm_seek_page_lap</h1>

<p><i>declared in "vorbis/vorbisfile.h";</i></p>

<p>Seeks to the closest page preceding the specified location (in pcm
samples) within the physical bitstream.  This variant of <a
href="ov_pcm_seek_page.html">ov_pcm_seek_page</a> also automatically
crosslaps the transition from the previous playback position into the
new playback position in order to eliminate clicking and boundary
discontinuities.  Otherwise, usage and behavior is identical to <a
href="ov_pcm_seek_page.html">ov_pcm_seek_page</a>.

<p>This function is faster than <a
href="ov_pcm_seek_lap.html">ov_pcm_seek_lap</a> because the function
can begin decoding at a page boundary rather than seeking through any
remaining samples before the specified location.  However, it is less
accurate.

<p>ov_pcm_seek_page_lap also updates everything needed within the
decoder, so you can immediately call <a
href="ov_read.html">ov_read()</a> and get data from the newly seeked
to position.

<p>ov_pcm_seek_page_lap will lap between logical stream links of
differing numbers of channels. Any extra channels from the origin of
the seek are ignored; playback of these channels simply ends. Extra
channels at the destination are lapped from silence.
ov_pcm_seek_page_lap will also lap between logical stream links of
differing sample rates.  In this case, the sample rates are ignored
(no implicit resampling is done to match playback). It is up to the
application developer to decide if this behavior makes any sense in a
given context; in practical use, these default behaviors perform
sensibly.

<p>This function only works for seekable streams.

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<pre><b>
int ov_pcm_seek_page_lap(OggVorbis_File *vf,ogg_int64_t pos);
</b></pre>
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<h3>Parameters</h3>
<dl>
<dt><i>vf</i></dt>
<dd>A pointer to the OggVorbis_File structure--this is used for ALL the externally visible libvorbisfile
functions.</dd>
<dt><i>pos</i></dt>
<dd>Position in pcm samples to seek to in the bitstream.</dd>
</dl>


<h3>Return Values</h3>
<blockquote>
<ul>
<li>0 for success</li>

<li>
nonzero indicates failure, described by several error codes:
  <ul>
  <li>OV_ENOSEEK - Bitstream is not seekable.
  </li>
  <li>OV_EINVAL - Invalid argument value; possibly called with an OggVorbis_File structure that isn't open.
  </li>
  <li>OV_EREAD - A read from media returned an error.
  </li>
  <li>OV_EFAULT - Internal logic fault; indicates a bug or heap/stack 
		corruption.
  </li>
  <li>OV_EOF - Indicates stream is at end of file immediately after a seek 
  (making crosslap impossible as there's no preceeding decode state to crosslap).
  </li>
  <li>OV_EBADLINK - Invalid stream section supplied to libvorbisfile, or the requested link is corrupt. 
  </li>
  </ul></li>
</ul></blockquote>

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<td><p class=tiny>copyright &copy; 2007 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>Vorbisfile documentation</p></td>
<td align=right><p class=tiny>vorbisfile version 1.2.0 - 20070723</p></td>
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</table>

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