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| author | Aki <please@ignore.pl> | 2021-09-29 22:52:49 +0200 |
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| committer | Aki <please@ignore.pl> | 2021-09-29 22:52:49 +0200 |
| commit | 74f4b1bc3b627ba4c7e03498234d88cacdfbe97b (patch) | |
| tree | 197b5978d6e38f44069ea92583098a1da04aa635 /doc/vorbisfile/ov_open_callbacks.html | |
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diff --git a/doc/vorbisfile/ov_open_callbacks.html b/doc/vorbisfile/ov_open_callbacks.html new file mode 100644 index 0000000..6d59e0b --- /dev/null +++ b/doc/vorbisfile/ov_open_callbacks.html @@ -0,0 +1,147 @@ +<html> + +<head> +<title>Vorbisfile - function - ov_open_callbacks</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>Vorbisfile documentation</p></td> +<td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td> +</tr> +</table> + +<h1>ov_open_callbacks</h1> + +<p><i>declared in "vorbis/vorbisfile.h";</i></p> + +<p>This is an alternative function used to open and initialize an +OggVorbis_File structure when using a data source other than a file, +when its necessary to modify default file access behavior, or to +initialize a Vorbis decode from a <tt>FILE *</tt> pointer under +Windows where <a href="ov_open.html">ov_open()</a> cannot be used. It +allows the application to specify custom file manipulation routines +and sets up all the related decoding structures. + +<p>Once ov_open_callbacks() has been called, the same +<tt>OggVorbis_File</tt> struct should be passed to all the +libvorbisfile functions. Unlike <a +href="ov_fopen.html">ov_fopen()</a> and <a +href="ov_open.html">ov_open()</a>, ov_open_callbacks() may be used to +instruct vorbisfile to either automatically close or not to close the +file/data access handle in <a href="ov_clear.html">ov_clear()</a>. +Automatic closure is disabled by passing NULL as the close callback, +or using one of the predefined callback sets that specify a NULL close +callback. The application is responsible for closing a file when a +call to ov_open_callbacks() is unsuccessful.<p> + +See also <a href="callbacks.html">Callbacks and Non-stdio I/O</a> for +information on designing and specifying custom callback functions.<p> + +<br><br> +<table border=0 color=black cellspacing=0 cellpadding=7> +<tr bgcolor=#cccccc> + <td> +<pre><b> +int ov_open_callbacks(void *datasource, <a href="OggVorbis_File.html">OggVorbis_File</a> *vf, char *initial, long ibytes, <a href="ov_callbacks.html">ov_callbacks</a> callbacks); +</b></pre> + </td> +</tr> +</table> + +<h3>Parameters</h3> +<dl> +<dt><i>datasource</i></dt> +<dd>Pointer to a data structure allocated by the calling application, containing any state needed by the callbacks provided.</dd> +<dt><i>vf</i></dt> +<dd>A pointer to the OggVorbis_File structure--this is used for ALL the externally visible libvorbisfile +functions. Once this has been called, the same <tt>OggVorbis_File</tt> +struct should be passed to all the libvorbisfile 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 stream 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 stream 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> +<dt><i>callbacks</i></dt> +<dd>A completed <a href="ov_callbacks.html">ov_callbacks</a> struct which indicates desired custom file manipulation routines. vorbisfile.h defines several preprovided callback sets; see <a href="ov_callbacks.html">ov_callbacks</a> for details.</dd> +</dl> + + +<h3>Return Values</h3> +<blockquote> +<li>0 for 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 does not contain any 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> +<dl> + +<dt><b>[a] Windows and use as an ov_open() substitute</b><p> Windows +applications should not use <a href="ov_open.html">ov_open()</a> due +to the likelihood of <a href="ov_open.html#winfoot">CRT linking +mismatches and runtime protection faults +[ov_open:a]</a>. ov_open_callbacks() is a safe substitute; specifically: + +<pre><tt>ov_open_callbacks(f, vf, initial, ibytes, OV_CALLBACKS_DEFAULT);</tt> +</pre> + +... provides exactly the same functionality as <a +href="ov_open.html">ov_open()</a> but will always work correctly under +Windows, regardless of linking setup details.<p> + +<dt><b>[b] Threaded decode</b><p> +<dd>If your decoder is threaded, it is recommended that you NOT call +<tt>ov_open_callbacks()</tt> +in the main control thread--instead, call <tt>ov_open_callbacks()</tt> in your decode/playback +thread. This is important because <tt>ov_open_callbacks()</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 libvorbisfile with threads. +<p> + +<dt><b>[c] Mixed media streams</b><p> +<dd> +As of Vorbisfile release 1.2.0, Vorbisfile is able to access the +Vorbis content in mixed-media Ogg streams, not just Vorbis-only +streams. For example, Vorbisfile may be used to open and access the +audio from an Ogg stream consisting of Theora video and Vorbis audio. +Vorbisfile 1.2.0 decodes the first logical audio stream of each +physical stream section.<p> + +<dt><b>[d] Faster testing for Vorbis files</b><p> +<dd><a href="ov_test.html">ov_test()</a> and <a +href="ov_test_callbacks.html">ov_test_callbacks()</a> provide less +computationally expensive ways to test a file for Vorbisness, but +require more setup code.<p> + +</dl> + +<br><br> +<hr noshade> +<table border=0 width=100%> +<tr valign=top> +<td><p class=tiny>copyright © 2000-2010 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 1.3.2 - 20101101</p></td> +</tr> +</table> + +</body> + +</html> |