Mercurial > hg > sv-dependency-builds
comparison src/libvorbis-1.3.3/doc/vorbisfile/ov_fopen.html @ 1:05aa0afa9217
Bring in flac, ogg, vorbis
| author | Chris Cannam |
|---|---|
| date | Tue, 19 Mar 2013 17:37:49 +0000 |
| parents | |
| children |
comparison
equal
deleted
inserted
replaced
| 0:c7265573341e | 1:05aa0afa9217 |
|---|---|
| 1 <html> | |
| 2 | |
| 3 <head> | |
| 4 <title>Vorbisfile - function - ov_fopen</title> | |
| 5 <link rel=stylesheet href="style.css" type="text/css"> | |
| 6 </head> | |
| 7 | |
| 8 <body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff"> | |
| 9 <table border=0 width=100%> | |
| 10 <tr> | |
| 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>ov_fopen</h1> | |
| 17 | |
| 18 <p><i>declared in "vorbis/vorbisfile.h";</i></p> | |
| 19 | |
| 20 <p>This is the simplest function used to open and initialize an OggVorbis_File | |
| 21 structure. It sets up all the related decoding structure. | |
| 22 <p>The first argument is a file path suitable | |
| 23 for passing to fopen(). <tt>vf</tt> should be a pointer to an empty | |
| 24 OggVorbis_File structure -- this is used for ALL the externally visible | |
| 25 libvorbisfile functions. Once this has been called, the same <a | |
| 26 href="OggVorbis_File.html">OggVorbis_File</a> struct should be passed | |
| 27 to all the libvorbisfile functions. | |
| 28 <p>The <tt>vf</tt> structure initialized using ov_fopen() must | |
| 29 eventually be cleaned using <a href="ov_clear.html">ov_clear()</a>. | |
| 30 | |
| 31 <p> | |
| 32 It is often useful to call <tt>ov_fopen()</tt> simply to determine | |
| 33 whether a given file is a Vorbis bitstream. If the <tt>ov_fopen()</tt> | |
| 34 call fails, then the file is either inaccessable (errno is set) or not | |
| 35 recognizable as Vorbis (errno unchanged). If the call succeeds but | |
| 36 the initialized <tt>vf</tt> structure will not be used, the | |
| 37 application is responsible for calling <a | |
| 38 href="ov_clear.html">ov_clear()</a> to clear the decoder's buffers and | |
| 39 close the file.<p> | |
| 40 | |
| 41 <br><br> | |
| 42 <table border=0 color=black cellspacing=0 cellpadding=7> | |
| 43 <tr bgcolor=#cccccc> | |
| 44 <td> | |
| 45 <pre><b> | |
| 46 int ov_fopen(char *path,<a href="OggVorbis_File.html">OggVorbis_File</a> *vf); | |
| 47 </b></pre> | |
| 48 </td> | |
| 49 </tr> | |
| 50 </table> | |
| 51 | |
| 52 <h3>Parameters</h3> | |
| 53 <dl> | |
| 54 <dt><i>path</i></dt> | |
| 55 <dd>Null terminated string containing a file path suitable for passing to <tt>fopen()</tt>. | |
| 56 </dd> | |
| 57 <dt><i>vf</i></dt> | |
| 58 <dd>A pointer to the OggVorbis_File structure--this is used for ALL the externally visible libvorbisfile | |
| 59 functions. Once this has been called, the same <tt>OggVorbis_File</tt> | |
| 60 struct should be passed to all the libvorbisfile functions.</dd> | |
| 61 </dl> | |
| 62 | |
| 63 | |
| 64 <h3>Return Values</h3> | |
| 65 <blockquote> | |
| 66 <li>0 indicates success</li> | |
| 67 | |
| 68 <li>less than zero for failure:</li> | |
| 69 <ul> | |
| 70 <li>OV_EREAD - A read from media returned an error.</li> | |
| 71 <li>OV_ENOTVORBIS - Bitstream does not contain any Vorbis data.</li> | |
| 72 <li>OV_EVERSION - Vorbis version mismatch.</li> | |
| 73 <li>OV_EBADHEADER - Invalid Vorbis bitstream header.</li> | |
| 74 <li>OV_EFAULT - Internal logic fault; indicates a bug or heap/stack corruption.</li> | |
| 75 </ul> | |
| 76 </blockquote> | |
| 77 <p> | |
| 78 | |
| 79 <h3>Notes</h3> | |
| 80 <dl> | |
| 81 | |
| 82 <dt><b>[a] Threaded decode</b><p> | |
| 83 <dd>If your decoder is threaded, it is recommended that you NOT call | |
| 84 <tt>ov_open_callbacks()</tt> | |
| 85 in the main control thread--instead, call <tt>ov_open_callbacks()</tt> in your decode/playback | |
| 86 thread. This is important because <tt>ov_open_callbacks()</tt> may be a fairly time-consuming | |
| 87 call, given that the full structure of the file is determined at this point, | |
| 88 which may require reading large parts of the file under certain circumstances | |
| 89 (determining all the logical bitstreams in one physical bitstream, for | |
| 90 example). See <a href="threads.html">Thread Safety</a> for other information on using libvorbisfile with threads. | |
| 91 <p> | |
| 92 | |
| 93 <dt><b>[b] Mixed media streams</b><p> | |
| 94 <dd> | |
| 95 As of Vorbisfile release 1.2.0, Vorbisfile is able to access the | |
| 96 Vorbis content in mixed-media Ogg streams, not just Vorbis-only | |
| 97 streams. For example, Vorbisfile may be used to open and access the | |
| 98 audio from an Ogg stream consisting of Theora video and Vorbis audio. | |
| 99 Vorbisfile 1.2.0 decodes the first logical audio stream of each | |
| 100 physical stream section.<p> | |
| 101 | |
| 102 <dt><b>[c] Faster testing for Vorbis files</b><p> | |
| 103 <dd><a href="ov_test.html">ov_test()</a> and <a | |
| 104 href="ov_test_callbacks.html">ov_test_callbacks()</a> provide less | |
| 105 computationally expensive ways to test a file for Vorbisness, but | |
| 106 require more setup code.<p> | |
| 107 | |
| 108 </dl> | |
| 109 | |
| 110 <br><br> | |
| 111 <hr noshade> | |
| 112 <table border=0 width=100%> | |
| 113 <tr valign=top> | |
| 114 <td><p class=tiny>copyright © 2000-2010 Xiph.Org</p></td> | |
| 115 <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td> | |
| 116 </tr><tr> | |
| 117 <td><p class=tiny>Vorbisfile documentation</p></td> | |
| 118 <td align=right><p class=tiny>vorbisfile version 1.3.2 - 20101101</p></td> | |
| 119 </tr> | |
| 120 </table> | |
| 121 | |
| 122 </body> | |
| 123 | |
| 124 </html> |