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vorbis_parser.h
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1 /*
2  * Copyright (c) 2012 Justin Ruggles
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * Vorbis audio parser
24  *
25  * Determines the duration for each packet.
26  */
27 
28 #ifndef AVCODEC_VORBIS_PARSER_H
29 #define AVCODEC_VORBIS_PARSER_H
30 
31 #include "avcodec.h"
32 
33 typedef struct VorbisParseContext {
34  AVCodecContext *avctx; ///< codec context
35  int extradata_parsed; ///< we have attempted to parse extradata
36  int valid_extradata; ///< extradata is valid, so we can calculate duration
37  int blocksize[2]; ///< short and long window sizes
38  int previous_blocksize; ///< previous window size
39  int mode_blocksize[64]; ///< window size mapping for each mode
40  int mode_count; ///< number of modes
41  int mode_mask; ///< bitmask used to get the mode in each packet
42  int prev_mask; ///< bitmask used to get the previous mode flag in each packet
44 
45 /**
46  * Initialize the Vorbis parser using headers in the extradata.
47  *
48  * @param avctx codec context
49  * @param s Vorbis parser context
50  */
52 
53 #define VORBIS_FLAG_HEADER 0x00000001
54 #define VORBIS_FLAG_COMMENT 0x00000002
55 
56 /**
57  * Get the duration for a Vorbis packet.
58  *
59  * avpriv_vorbis_parse_extradata() must have been successfully called prior to
60  * this in order for a correct duration to be returned. If @p flags is @c NULL,
61  * special frames are considered invalid.
62  *
63  * @param s Vorbis parser context
64  * @param buf buffer containing a Vorbis frame
65  * @param buf_size size of the buffer
66  * @param flags flags for special frames
67  */
69  int buf_size, int *flags);
70 
71 /**
72  * Get the duration for a Vorbis packet.
73  *
74  * avpriv_vorbis_parse_extradata() must have been successfully called prior to
75  * this in order for a correct duration to be returned.
76  *
77  * @param s Vorbis parser context
78  * @param buf buffer containing a Vorbis frame
79  * @param buf_size size of the buffer
80  */
82  int buf_size);
83 
85 
86 #endif /* AVCODEC_VORBIS_PARSER_H */