xref: /third_party/ffmpeg/libavcodec/flac.h (revision cabdff1a) 
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 "bytestream.h"
32#include "get_bits.h"
33
34#define FLAC_STREAMINFO_SIZE   34
35#define FLAC_MAX_CHANNELS       8
36#define FLAC_MIN_BLOCKSIZE     16
37#define FLAC_MAX_BLOCKSIZE  65535
38#define FLAC_MIN_FRAME_SIZE    11
39
40enum {
41    FLAC_CHMODE_INDEPENDENT = 0,
42    FLAC_CHMODE_LEFT_SIDE   = 1,
43    FLAC_CHMODE_RIGHT_SIDE  = 2,
44    FLAC_CHMODE_MID_SIDE    = 3,
45};
46
47enum {
48    FLAC_METADATA_TYPE_STREAMINFO = 0,
49    FLAC_METADATA_TYPE_PADDING,
50    FLAC_METADATA_TYPE_APPLICATION,
51    FLAC_METADATA_TYPE_SEEKTABLE,
52    FLAC_METADATA_TYPE_VORBIS_COMMENT,
53    FLAC_METADATA_TYPE_CUESHEET,
54    FLAC_METADATA_TYPE_PICTURE,
55    FLAC_METADATA_TYPE_INVALID = 127
56};
57
58enum FLACExtradataFormat {
59    FLAC_EXTRADATA_FORMAT_STREAMINFO  = 0,
60    FLAC_EXTRADATA_FORMAT_FULL_HEADER = 1
61};
62
63#define FLACCOMMONINFO \
64    int samplerate;         /**< sample rate                             */\
65    int channels;           /**< number of channels                      */\
66    int bps;                /**< bits-per-sample                         */\
67
68/**
69 * Data needed from the Streaminfo header for use by the raw FLAC demuxer
70 * and/or the FLAC decoder.
71 */
72#define FLACSTREAMINFO \
73    FLACCOMMONINFO \
74    int max_blocksize;      /**< maximum block size, in samples          */\
75    int max_framesize;      /**< maximum frame size, in bytes            */\
76    int64_t samples;        /**< total number of samples                 */\
77
78typedef struct FLACStreaminfo {
79    FLACSTREAMINFO
80} FLACStreaminfo;
81
82typedef struct FLACFrameInfo {
83    FLACCOMMONINFO
84    int blocksize;          /**< block size of the frame                 */
85    int ch_mode;            /**< channel decorrelation mode              */
86    int64_t frame_or_sample_num;    /**< frame number or sample number   */
87    int is_var_size;                /**< specifies if the stream uses variable
88                                         block sizes or a fixed block size;
89                                         also determines the meaning of
90                                         frame_or_sample_num             */
91} FLACFrameInfo;
92
93/**
94 * Parse the Streaminfo metadata block
95 * @param[out] avctx   codec context to set basic stream parameters
96 * @param[out] s       where parsed information is stored
97 * @param[in]  buffer  pointer to start of 34-byte streaminfo data
98 *
99 * @return negative error code on faiure or >= 0 on success
100 */
101int ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
102                              const uint8_t *buffer);
103
104/**
105 * Validate the FLAC extradata.
106 * @param[in]  avctx codec context containing the extradata.
107 * @param[out] format extradata format.
108 * @param[out] streaminfo_start pointer to start of 34-byte STREAMINFO data.
109 * @return 1 if valid, 0 if not valid.
110 */
111int ff_flac_is_extradata_valid(AVCodecContext *avctx,
112                               enum FLACExtradataFormat *format,
113                               uint8_t **streaminfo_start);
114
115/**
116 * Calculate an estimate for the maximum frame size based on verbatim mode.
117 * @param blocksize block size, in samples
118 * @param ch number of channels
119 * @param bps bits-per-sample
120 */
121int ff_flac_get_max_frame_size(int blocksize, int ch, int bps);
122
123/**
124 * Validate and decode a frame header.
125 * @param      avctx AVCodecContext to use as av_log() context
126 * @param      gb    GetBitContext from which to read frame header
127 * @param[out] fi    frame information
128 * @param      log_level_offset  log level offset. can be used to silence error messages.
129 * @return non-zero on error, 0 if ok
130 */
131int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
132                                FLACFrameInfo *fi, int log_level_offset);
133
134void ff_flac_set_channel_layout(AVCodecContext *avctx, int channels);
135
136/**
137 * Parse the metadata block parameters from the header.
138 * @param[in]  block_header header data, at least 4 bytes
139 * @param[out] last indicator for last metadata block
140 * @param[out] type metadata block type
141 * @param[out] size metadata block size
142 */
143static av_always_inline void flac_parse_block_header(const uint8_t *block_header,
144                                                      int *last, int *type, int *size)
145{
146    int tmp = bytestream_get_byte(&block_header);
147    if (last)
148        *last = tmp & 0x80;
149    if (type)
150        *type = tmp & 0x7F;
151    if (size)
152        *size = bytestream_get_be24(&block_header);
153}
154
155#endif /* AVCODEC_FLAC_H */
156