vorbis/doc/vorbisfile/OggVorbis_File.html

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   4 <title>Vorbisfile - datatype - OggVorbis_File</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>OggVorbis_File</h1>
  17
  18 <p><i>declared in "vorbis/vorbisfile.h"</i></p>
  19
  20 <p>
  21 The OggVorbis_File structure defines an Ogg Vorbis file.
  22 <p>
  23
  24 This structure is used in all libvorbisfile routines.  Before it can
  25 be used, it must be initialized by <a
  26 href="ov_open.html">ov_open()</a>, <a
  27 href="ov_fopen.html">ov_fopen()</a>, or <a
  28 href="ov_open_callbacks.html">ov_open_callbacks()</a>. <em>Important
  29 Note:</em> The use of <a href="ov_open.html">ov_open()</a> is
  30 discouraged under Windows due to a peculiarity of Windows linking
  31 convention; use <a href="ov_fopen.html">ov_fopen()</a> or <a
  32 href="ov_open_callbacks.html">ov_open_callbacks()</a> instead.  This
  33 caution only applies to Windows; use of <a
  34 href="ov_open.html">ov_open()</a> is appropriate for all other
  35 platforms.  See the <a href="ov_open.html">ov_open()</a> page for more
  36 information.
  37
  38 <p>
  39 After use, the OggVorbis_File structure must be deallocated with a
  40 call to <a href="ov_clear.html">ov_clear()</a>.
  41
  42 <p>
  43 Note that once a file handle is passed to a successful <a
  44 href="ov_open.html">ov_open()</a> call, the handle is owned by
  45 libvorbisfile and will be closed by libvorbisfile later during the
  46 call to <a href="ov_clear.html">ov_clear()</a>.  The handle should not
  47 be used or closed outside of the libvorbisfile API.  Similarly, files
  48 opened by <a href="ov_fopen.html">ov_fopen()</a> will also be closed
  49 internally by vorbisfile in <a href="ov_clear.html">ov_clear()</a>.<p>
  50
  51 <a href="ov_open_callbacks.html">ov_open_callbacks()</a> allows the
  52 application to choose whether libvorbisfile will or will not close the
  53 handle in <a href="ov_clear.html">ov_clear()</a>; see the <a
  54 href="ov_open_callbacks.html">ov_open_callbacks()</a> page for more information.<p>
  55
  56 If a call to <a href="ov_open.html">ov_open()</a> or <a
  57 href="ov_open_callbacks.html">ov_open_callbacks()</a> <b>fails</b>,
  58 libvorbisfile does <b>not</b> assume ownership of the handle and the
  59 application is expected to close it if necessary.  A failed <a
  60 href="ov_fopen.html">ov_fopen()</a> call will internally close the
  61 file handle if the open process fails.<p>
  62
  63 <br><br>
  64 <table border=0 width=100% color=black cellspacing=0 cellpadding=7>
  65 <tr bgcolor=#cccccc>
  66         <td>
  67 <pre><b>typedef struct {
  68   void             *datasource; /* Pointer to a FILE *, etc. */
  69   int              seekable;
  70   ogg_int64_t      offset;
  71   ogg_int64_t      end;
  72   ogg_sync_state   oy;
  73
  74   /* If the FILE handle isn't seekable (eg, a pipe), only the current
  75      stream appears */
  76   int              links;
  77   ogg_int64_t      *offsets;
  78   ogg_int64_t      *dataoffsets;
  79   long             *serialnos;
  80   ogg_int64_t      *pcmlengths;
  81   vorbis_info      *vi;
  82   vorbis_comment   *vc;
  83
  84   /* Decoding working state local storage */
  85   ogg_int64_t      pcm_offset;
  86   int              ready_state;
  87   long             current_serialno;
  88   int              current_link;
  89
  90   ogg_int64_t      bittrack;
  91   ogg_int64_t      samptrack;
  92
  93   ogg_stream_state os; /* take physical pages, weld into a logical
  94                           stream of packets */
  95   vorbis_dsp_state vd; /* central working state for the packet->PCM decoder */
  96   vorbis_block     vb; /* local working space for packet->PCM decode */
  97
  98   <a href="ov_callbacks.html">ov_callbacks</a> callbacks;
  99
 100 } OggVorbis_File;</b></pre>
 101         </td>
 102 </tr>
 103 </table>
 104
 105 <h3>Relevant Struct Members</h3>
 106 <dl>
 107 <dt><i>datasource</i></dt>
 108
 109 <dd>Pointer to file or other ogg source.  When using stdio based
 110 file/stream access, this field contains a <tt>FILE</tt> pointer. When using
 111 custom IO via callbacks, libvorbisfile treats this void pointer as a
 112 black box only to be passed to the callback routines provided by the
 113 application.</dd>
 114
 115 <dt><i>seekable</i></dt>
 116 <dd>Read-only int indicating whether file is seekable. E.g., a physical file is seekable, a pipe isn't.</dd>
 117 <dt><i>links</i></dt>
 118 <dd>Read-only int indicating the number of logical bitstreams within the physical bitstream.</dd>
 119 <dt><i>ov_callbacks</i></dt>
 120 <dd>Collection of file manipulation routines to be used on this data source.  When using stdio/FILE access via <a href="ov_open.html">ov_open()</a>, the callbacks will be filled in with stdio calls or wrappers to stdio calls.</dd>
 121 </dl>
 122
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 125 <table border=0 width=100%>
 126 <tr valign=top>
 127 <td><p class=tiny>copyright &copy; 2000-2010 Xiph.Org</p></td>
 128 <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
 129 </tr><tr>
 130 <td><p class=tiny>Vorbisfile documentation</p></td>
 131 <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td>
 132 </tr>
 133 </table>
 134
 135 </body>
 136
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