vorbis/doc/vorbisfile/initialization.html

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   4 <title>Vorbisfile - Setup/Teardown</title>
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  11 <td><p class=tiny>Vorbisfile documentation</p></td>
  12 <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
  13 </tr>
  14 </table>
  15
  16 <H1>Setup/Teardown</h1> <p>In order to decode audio using
  17 libvorbisfile, a bitstream containing Vorbis audio must be properly
  18 initialized before decoding and cleared when decoding is finished.
  19 The simplest possible case is to use <a
  20 href="ov_fopen.html">ov_fopen()</a> to open the file for access, check
  21 it for Vorbis content, and prepare it for playback.  A successful <a
  22 href="../libvorbis/return.html">return code</a> from <a
  23 href="ov_fopen.html">ov_fopen()</a> indicates the file is ready for use.
  24 Once the file is no longer needed, <a
  25 href="ov_clear.html">ov_clear()</a> is used to close the file and
  26 deallocate decoding resources.<p>
  27
  28 On systems other than Windows<a href="ov_open.html#winfoot">[a]</a>, an
  29 application may also open a file itself using <tt>fopen()</tt>, then pass the
  30 <tt>FILE *</tt> to libvorbisfile using <a
  31 href="ov_open.html">ov_open()</a>. </b>Do not</b> call
  32 <tt>fclose()</tt> on a file handle successfully submitted to <a
  33 href="ov_open.html">ov_open()</a>; libvorbisfile does this in the <a
  34 href="ov_clear.html">ov_clear()</a> call.<p>
  35
  36 An application that requires more setup flexibility may open a data
  37 stream using <a href="ov_open_callbacks.html">ov_open_callbacks()</a>
  38 to change default libvorbis behavior or specify non-stdio data access
  39 mechanisms.<p>
  40
  41 <p>
  42 All libvorbisfile initialization and deallocation routines are declared in "vorbis/vorbisfile.h".
  43 <p>
  44
  45 <table border=1 color=black width=50% cellspacing=0 cellpadding=7>
  46 <tr bgcolor=#cccccc>
  47         <td><b>function</b></td>
  48         <td><b>purpose</b></td>
  49 </tr>
  50 <tr valign=top>
  51         <td><a href="ov_fopen.html">ov_fopen</a></td>
  52         <td>Opens a file and initializes the Ogg Vorbis bitstream with default values.  This must be called before other functions in the library may be
  53         used.</td>
  54 </tr>
  55 <tr valign=top>
  56         <td><a href="ov_open.html">ov_open</a></td>
  57         <td>Initializes the Ogg Vorbis bitstream with default values from a passed in file handle.  This must be called before other functions in the library may be
  58         used.  <a href="#winfoot"><em>Do not use this call under Windows [a];</em></a> Use <a href="ov_fopen.html">ov_fopen()</a> or <a href="ov_open_callbacks.html">ov_open_callbacks()</a> instead.</td>
  59 </tr>
  60 <tr valign=top>
  61         <td><a href="ov_open_callbacks.html">ov_open_callbacks</a></td>
  62         <td>Initializes the Ogg Vorbis bitstream from a file handle and custom file/bitstream manipulation routines.  Used instead of <a href="ov_open.html">ov_open()</a> or <a href="ov_fopen.html">ov_fopen()</a> when altering or replacing libvorbis's default stdio I/O behavior, or when a bitstream must be initialized from a <tt>FILE *</tt> under Windows.</td>
  63 </tr>
  64
  65 <tr valign=top>
  66 <td><a href="ov_test.html">ov_test</a></td>
  67
  68 <td>Partially opens a file just far enough to determine if the file
  69 is an Ogg Vorbis file or not.  A successful return indicates that the
  70 file appears to be an Ogg Vorbis file, but the <a
  71 href="OggVorbis_File.html">OggVorbis_File</a> struct is not yet fully
  72 initialized for actual decoding.  After a <a href="../libvorbis/return.html">successful return</a>, the file
  73 may be closed using <a href="ov_clear.html">ov_clear()</a> or fully
  74 opened for decoding using <a
  75 href="ov_test_open.html">ov_test_open()</a>.<p> This call is intended to
  76 be used as a less expensive file open test than a full <a
  77 href="ov_open.html">ov_open()</a>.<p>
  78 Note that libvorbisfile owns the passed in file resource is it returns success; do not <tt>fclose()</tt> files owned by libvorbisfile.</td>
  79
  80 </tr>
  81 <tr valign=top>
  82 <td><a href="ov_test_callbacks.html">ov_test_callbacks</a></td>
  83 <td>As above but allowing application-define I/O callbacks.<p>
  84 Note that libvorbisfile owns the passed in file resource is it returns success; do not <tt>fclose()</tt> files owned by libvorbisfile.</td>
  85
  86 </tr>
  87 <tr valign=top>
  88 <td><a href="ov_test_open.html">ov_test_open</a><td>
  89 Finish opening a file after a successful call to <a href="ov_test.html">ov_test()</a> or <a href="ov_test_callbacks.html">ov_test_callbacks()</a>.</td>
  90 </tr>
  91 <tr valign=top>
  92         <td><a href="ov_clear.html">ov_clear</a></td> <td>Closes the
  93         bitstream and cleans up loose ends.  Must be called when
  94         finished with the bitstream.  After return, the <a
  95         href="OggVorbis_File.html">OggVorbis_File</a> struct is
  96         invalid and may not be used before being initialized again
  97         before begin reinitialized.
  98
  99 </td>
 100 </tr>
 101 </table>
 102
 103 <br><br>
 104 <hr noshade>
 105
 106 <table border=0 width=100%>
 107 <tr valign=top>
 108 <td><p class=tiny>copyright &copy; 2000-2010 Xiph.Org</p></td>
 109 <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
 110 </tr><tr>
 111 <td><p class=tiny>Vorbisfile documentation</p></td>
 112 <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
 113 </tr>
 114 </table>
 115
 116 </body>
 117
 118 </html>