FFmpeg
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
flac.h
Go to the documentation of this file.
1 /*
2  * FLAC (Free Lossless Audio Codec) decoder/demuxer common functions
3  * Copyright (c) 2008 Justin Ruggles
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * FLAC (Free Lossless Audio Codec) decoder/demuxer common functions
25  */
26 
27 #ifndef AVCODEC_FLAC_H
28 #define AVCODEC_FLAC_H
29 
30 #include "avcodec.h"
31 #include "get_bits.h"
32 
33 #define FLAC_STREAMINFO_SIZE 34
34 #define FLAC_MAX_CHANNELS 8
35 #define FLAC_MIN_BLOCKSIZE 16
36 #define FLAC_MAX_BLOCKSIZE 65535
37 #define FLAC_MIN_FRAME_SIZE 11
38 
39 enum {
44 };
45 
46 enum {
55 };
56 
60 };
61 
62 #define FLACCOMMONINFO \
63  int samplerate; /**< sample rate */\
64  int channels; /**< number of channels */\
65  int bps; /**< bits-per-sample */\
66 
67 /**
68  * Data needed from the Streaminfo header for use by the raw FLAC demuxer
69  * and/or the FLAC decoder.
70  */
71 #define FLACSTREAMINFO \
72  FLACCOMMONINFO \
73  int max_blocksize; /**< maximum block size, in samples */\
74  int max_framesize; /**< maximum frame size, in bytes */\
75  int64_t samples; /**< total number of samples */\
76 
77 typedef struct FLACStreaminfo {
80 
81 typedef struct FLACFrameInfo {
83  int blocksize; /**< block size of the frame */
84  int ch_mode; /**< channel decorrelation mode */
85  int64_t frame_or_sample_num; /**< frame number or sample number */
86  int is_var_size; /**< specifies if the stream uses variable
87  block sizes or a fixed block size;
88  also determines the meaning of
89  frame_or_sample_num */
91 
92 /**
93  * Parse the Streaminfo metadata block
94  * @param[out] avctx codec context to set basic stream parameters
95  * @param[out] s where parsed information is stored
96  * @param[in] buffer pointer to start of 34-byte streaminfo data
97  */
99  const uint8_t *buffer);
100 
101 /**
102  * Validate the FLAC extradata.
103  * @param[in] avctx codec context containing the extradata.
104  * @param[out] format extradata format.
105  * @param[out] streaminfo_start pointer to start of 34-byte STREAMINFO data.
106  * @return 1 if valid, 0 if not valid.
107  */
109  enum FLACExtradataFormat *format,
110  uint8_t **streaminfo_start);
111 
112 /**
113  * Parse the metadata block parameters from the header.
114  * @param[in] block_header header data, at least 4 bytes
115  * @param[out] last indicator for last metadata block
116  * @param[out] type metadata block type
117  * @param[out] size metadata block size
118  */
119 void avpriv_flac_parse_block_header(const uint8_t *block_header,
120  int *last, int *type, int *size);
121 
122 /**
123  * Calculate an estimate for the maximum frame size based on verbatim mode.
124  * @param blocksize block size, in samples
125  * @param ch number of channels
126  * @param bps bits-per-sample
127  */
128 int ff_flac_get_max_frame_size(int blocksize, int ch, int bps);
129 
130 /**
131  * Validate and decode a frame header.
132  * @param avctx AVCodecContext to use as av_log() context
133  * @param gb GetBitContext from which to read frame header
134  * @param[out] fi frame information
135  * @param log_level_offset log level offset. can be used to silence error messages.
136  * @return non-zero on error, 0 if ok
137  */
139  FLACFrameInfo *fi, int log_level_offset);
140 
142 
143 #endif /* AVCODEC_FLAC_H */