Tremor/doc/ov_open.html - platform/external/tremor - Git at Google

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 <td><p class=tiny>Tremor documentation</p></td>
 <td align=right><p class=tiny>Tremor version 1.0 - 20020403</p></td>
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 <h1>ov_open</h1>

 <p><i>declared in "ivorbisfile.h";</i></p>

 <p>This is the main function used to open and initialize an OggVorbis_File
 structure. It sets up all the related decoding structure.
 <p>The first argument must be a file pointer to an already opened file
 or pipe (it need not be seekable--though this obviously restricts what
 can be done with the bitstream). <tt>vf</tt> should be a pointer to the
 OggVorbis_File structure--this is used for ALL the externally visible libvorbisidec
 functions. Once this has been called, the same <a href="OggVorbis_File.html">OggVorbis_File</a>
 struct should be passed to all the libvorbisidec functions.
 <p>Also, you should be aware that ov_open(), once successful, takes complete possession of the file resource.  After you have opened a file using ov_open(), you MUST close it using <a href="ov_clear.html">ov_clear()</a>, not fclose() or any other function.
 <p>
 It is often useful to call <tt>ov_open()</tt>
 simply to determine whether a given file is a vorbis bitstream. If the
 <tt>ov_open()</tt>
 call fails, then the file is not recognizable as such.
 When you use <tt>ov_open()
 </tt>for
 this, you should <tt>fclose()</tt> the file pointer if, and only if, the
 <tt>ov_open()</tt>
 call fails. If it succeeds, you must call <a href="ov_clear.html">ov_clear()</a> to clear
 the decoder's buffers and close the file for you.<p>

 (Note that <a href="ov_test.html">ov_test()</a> provides a less expensive way to test a file for Vorbisness.)<p>

 <br><br>
 <table border=0 color=black cellspacing=0 cellpadding=7>
 <tr bgcolor=#cccccc>
 	<td>
 <pre><b>
 int ov_open(FILE *f,<a href="OggVorbis_File.html">OggVorbis_File</a> *vf,char *initial,long ibytes);
 </b></pre>
 	</td>
 </tr>
 </table>

 <h3>Parameters</h3>
 <dl>
 <dt><i>f</i></dt>
 <dd>File pointer to an already opened file
 or pipe (it need not be seekable--though this obviously restricts what
 can be done with the bitstream).</dd>
 <dt><i>vf</i></dt>
 <dd>A pointer to the OggVorbis_File structure--this is used for ALL the externally visible libvorbisidec
 functions. Once this has been called, the same <tt>OggVorbis_File</tt>
 struct should be passed to all the libvorbisidec functions.</dd>
 <dt><i>initial</i></dt>
 <dd>Typically set to NULL.  This parameter is useful if some data has already been
 read from the file and the stream is not seekable. It is used in conjunction with <tt>ibytes</tt>.  In this case, <tt>initial</tt>
 should be a pointer to a buffer containing the data read.</dd>
 <dt><i>ibytes</i></dt>
 <dd>Typically set to 0.  This parameter is useful if some data has already been
 read from the file and the stream is not seekable. In this case, <tt>ibytes</tt>
 should contain the length (in bytes) of the buffer.  Used together with <tt>initial</tt></dd>
 </dl>


 <h3>Return Values</h3>
 <blockquote>
 <li>0 indicates success</li>

 <li>less than zero for failure:</li>
 <ul>
 <li>OV_EREAD - A read from media returned an error.</li>
 <li>OV_ENOTVORBIS - Bitstream is not Vorbis data.</li>
 <li>OV_EVERSION - Vorbis version mismatch.</li>
 <li>OV_EBADHEADER - Invalid Vorbis bitstream header.</li>
 <li>OV_EFAULT - Internal logic fault; indicates a bug or heap/stack corruption.</li>
 </ul>
 </blockquote>
 <p>

 <h3>Notes</h3>
 <p>If your decoder is threaded, it is recommended that you NOT call
 <tt>ov_open()</tt>
 in the main control thread--instead, call <tt>ov_open()</tt> IN your decode/playback
 thread. This is important because <tt>ov_open()</tt> may be a fairly time-consuming
 call, given that the full structure of the file is determined at this point,
 which may require reading large parts of the file under certain circumstances
 (determining all the logical bitstreams in one physical bitstream, for
 example).  See <a href="threads.html">Thread Safety</a> for other information on using libvorbisidec with threads.


 <br><br>
 <hr noshade>
 <table border=0 width=100%>
 <tr valign=top>
 <td><p class=tiny>copyright &copy; 2002 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>Tremor documentation</p></td>
 <td align=right><p class=tiny>Tremor version 1.0 - 20020403</p></td>
 </tr>
 </table>

 </body>

 </html>
	<html>

	<head>
	<title>Tremor - function - ov_open</title>
	<link rel=stylesheet href="style.css" type="text/css">
	</head>

	<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
	<table border=0 width=100%>
	<tr>
	<td><p class=tiny>Tremor documentation</p></td>
	<td align=right><p class=tiny>Tremor version 1.0 - 20020403</p></td>
	</tr>
	</table>

	<h1>ov_open</h1>

	<p><i>declared in "ivorbisfile.h";</i></p>

	<p>This is the main function used to open and initialize an OggVorbis_File
	structure. It sets up all the related decoding structure.
	<p>The first argument must be a file pointer to an already opened file
	or pipe (it need not be seekable--though this obviously restricts what
	can be done with the bitstream). <tt>vf</tt> should be a pointer to the
	OggVorbis_File structure--this is used for ALL the externally visible libvorbisidec
	functions. Once this has been called, the same <a href="OggVorbis_File.html">OggVorbis_File</a>
	struct should be passed to all the libvorbisidec functions.
	<p>Also, you should be aware that ov_open(), once successful, takes complete possession of the file resource. After you have opened a file using ov_open(), you MUST close it using <a href="ov_clear.html">ov_clear()</a>, not fclose() or any other function.
	<p>
	It is often useful to call <tt>ov_open()</tt>
	simply to determine whether a given file is a vorbis bitstream. If the
	<tt>ov_open()</tt>
	call fails, then the file is not recognizable as such.
	When you use <tt>ov_open()
	</tt>for
	this, you should <tt>fclose()</tt> the file pointer if, and only if, the
	<tt>ov_open()</tt>
	call fails. If it succeeds, you must call <a href="ov_clear.html">ov_clear()</a> to clear
	the decoder's buffers and close the file for you.<p>

	(Note that <a href="ov_test.html">ov_test()</a> provides a less expensive way to test a file for Vorbisness.)<p>

	<br><br>
	<table border=0 color=black cellspacing=0 cellpadding=7>
	<tr bgcolor=#cccccc>
	<td>
	<pre><b>
	int ov_open(FILE f,<a href="OggVorbis_File.html">OggVorbis_File</a> vf,char *initial,long ibytes);
	</b></pre>
	</td>
	</tr>
	</table>

	<h3>Parameters</h3>
	<dl>
	<dt><i>f</i></dt>
	<dd>File pointer to an already opened file
	or pipe (it need not be seekable--though this obviously restricts what
	can be done with the bitstream).</dd>
	<dt><i>vf</i></dt>
	<dd>A pointer to the OggVorbis_File structure--this is used for ALL the externally visible libvorbisidec
	functions. Once this has been called, the same <tt>OggVorbis_File</tt>
	struct should be passed to all the libvorbisidec functions.</dd>
	<dt><i>initial</i></dt>
	<dd>Typically set to NULL. This parameter is useful if some data has already been
	read from the file and the stream is not seekable. It is used in conjunction with <tt>ibytes</tt>. In this case, <tt>initial</tt>
	should be a pointer to a buffer containing the data read.</dd>
	<dt><i>ibytes</i></dt>
	<dd>Typically set to 0. This parameter is useful if some data has already been
	read from the file and the stream is not seekable. In this case, <tt>ibytes</tt>
	should contain the length (in bytes) of the buffer. Used together with <tt>initial</tt></dd>
	</dl>


	<h3>Return Values</h3>
	<blockquote>
	<li>0 indicates success</li>

	<li>less than zero for failure:</li>
	<ul>
	<li>OV_EREAD - A read from media returned an error.</li>
	<li>OV_ENOTVORBIS - Bitstream is not Vorbis data.</li>
	<li>OV_EVERSION - Vorbis version mismatch.</li>
	<li>OV_EBADHEADER - Invalid Vorbis bitstream header.</li>
	<li>OV_EFAULT - Internal logic fault; indicates a bug or heap/stack corruption.</li>
	</ul>
	</blockquote>
	<p>

	<h3>Notes</h3>
	<p>If your decoder is threaded, it is recommended that you NOT call
	<tt>ov_open()</tt>
	in the main control thread--instead, call <tt>ov_open()</tt> IN your decode/playback
	thread. This is important because <tt>ov_open()</tt> may be a fairly time-consuming
	call, given that the full structure of the file is determined at this point,
	which may require reading large parts of the file under certain circumstances
	(determining all the logical bitstreams in one physical bitstream, for
	example). See <a href="threads.html">Thread Safety</a> for other information on using libvorbisidec with threads.


	<br><br>
	<hr noshade>
	<table border=0 width=100%>
	<tr valign=top>
	<td><p class=tiny>copyright © 2002 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>Tremor documentation</p></td>
	<td align=right><p class=tiny>Tremor version 1.0 - 20020403</p></td>
	</tr>
	</table>

	</body>

	</html>