00001 <html>
00002
00003 <head>
00004 <title>Vorbisfile - function - ov_crosslap</title>
00005 <link rel=stylesheet href="style.css" type="text/css">
00006 </head>
00007
00008 <body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
00009 <table border=0 width=100%>
00010 <tr>
00011 <td><p class=tiny>Vorbisfile documentation</p></td>
00012 <td align=right><p class=tiny>vorbisfile version 1.68 - 20030307</p></td>
00013 </tr>
00014 </table>
00015
00016 <h1>ov_crosslap()</h1>
00017
00018 <p><i>declared in "vorbis/vorbisfile.h";</i></p>
00019
00020 <p>ov_crosslap overlaps and blends the boundary at a transition
00021 between two separate streams represented by separate <a
00022 href="OggVorbis_File.html">OggVorbis_File</a> structures. For lapping
00023 transitions due to seeking within a single stream represented by a
00024 single <a href="OggVorbis_File.html">OggVorbis_File</a> structure,
00025 consider using the lapping versions of the <a
00026 href="seeking.html">vorbisfile seeking functions</a> instead.
00027
00028 <p>ov_crosslap is used between the last (usually ov_read) call on
00029 the old stream and the first ov_read from the new stream. Any
00030 desired positioning of the new stream must occur before the call to
00031 ov_crosslap() as a seek dumps all prior lapping information from a
00032 stream's decode state. Crosslapping does not introduce or remove any
00033 extraneous samples; positioning works exactly as if ov_crosslap was not
00034 called.
00035
00036 <p>ov_crosslap will lap between streams of differing numbers of
00037 channels. Any extra channels from the old stream are ignored; playback
00038 of these channels simply ends. Extra channels in the new stream are
00039 lapped from silence. ov_crosslap will also lap between streams links
00040 of differing sample rates. In this case, the sample rates are ignored
00041 (no implicit resampling is done to match playback). It is up to the
00042 application developer to decide if this behavior makes any sense in a
00043 given context; in practical use, these default behaviors perform
00044 sensibly.
00045
00046 <br><br>
00047 <table border=0 color=black cellspacing=0 cellpadding=7>
00048 <tr bgcolor=#cccccc>
00049 <td>
00050 <pre><b>
00051 long ov_crosslap(<a href="OggVorbis_File.html">OggVorbis_File</a> *old, <a href="OggVorbis_File.html">OggVorbis_File</a> *new);
00052
00053 </b></pre>
00054 </td>
00055 </tr>
00056 </table>
00057
00058 <h3>Parameters</h3>
00059 <dl>
00060 <dt><i>old</i></dt>
00061 <dd>A pointer to the OggVorbis_File structure representing the origin stream from which to transition playback.</dd>
00062
00063 <dt><i>new</i></dt>
00064 <dd>A pointer to the OggVorbis_File structure representing the stream with which playback continues.</dd>
00065 </dl>
00066
00067
00068 <h3>Return Values</h3>
00069 <blockquote>
00070 <dl>
00071 <dt>OV_EINVAL</dt>
00072 <dd>crosslap called with an OggVorbis_File structure that isn't open.</dd>
00073 <dt>OV_EFAULT</dt>
00074 <dd>internal error; implies a library bug or external heap corruption.</dd>
00075 <dt>OV_EREAD</dt>
00076 <dd> A read from media returned an error.</dd>
00077 <dt>OV_EOF</dt>
00078 <dd>indicates stream <tt>vf2</tt> is at end of file, or that <tt>vf1</tt> is at end of file immediately after a seek (making crosslap impossible as there's no preceding decode state to crosslap).</dd>
00079 <dt><i>0</i></dt>
00080 <dd>success.</dd>
00081 </dl>
00082 </blockquote>
00083
00084
00085
00086 <br><br>
00087 <hr noshade>
00088 <table border=0 width=100%>
00089 <tr valign=top>
00090 <td><p class=tiny>copyright © 2003 Xiph.org</p></td>
00091 <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
00092 </tr><tr>
00093 <td><p class=tiny>Vorbisfile documentation</p></td>
00094 <td align=right><p class=tiny>vorbisfile version 1.68 - 20030307</p></td>
00095 </tr>
00096 </table>
00097
00098 </body>
00099
00100 </html>
