ffmpeg/libavcodec/flac.h

   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
  40 enum {
  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
  47 enum {
  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
  58 enum 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
  78 typedef struct FLACStreaminfo {
  79     FLACSTREAMINFO
  80 } FLACStreaminfo;
  81
  82 typedef 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 void avpriv_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
 100                                   const uint8_t *buffer);
 101
 102 /**
 103  * Validate the FLAC extradata.
 104  * @param[in]  avctx codec context containing the extradata.
 105  * @param[out] format extradata format.
 106  * @param[out] streaminfo_start pointer to start of 34-byte STREAMINFO data.
 107  * @return 1 if valid, 0 if not valid.
 108  */
 109 int avpriv_flac_is_extradata_valid(AVCodecContext *avctx,
 110                                    enum FLACExtradataFormat *format,
 111                                    uint8_t **streaminfo_start);
 112
 113 /**
 114  * Calculate an estimate for the maximum frame size based on verbatim mode.
 115  * @param blocksize block size, in samples
 116  * @param ch number of channels
 117  * @param bps bits-per-sample
 118  */
 119 int ff_flac_get_max_frame_size(int blocksize, int ch, int bps);
 120
 121 /**
 122  * Validate and decode a frame header.
 123  * @param      avctx AVCodecContext to use as av_log() context
 124  * @param      gb    GetBitContext from which to read frame header
 125  * @param[out] fi    frame information
 126  * @param      log_level_offset  log level offset. can be used to silence error messages.
 127  * @return non-zero on error, 0 if ok
 128  */
 129 int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
 130                                 FLACFrameInfo *fi, int log_level_offset);
 131
 132 void ff_flac_set_channel_layout(AVCodecContext *avctx);
 133
 134 /**
 135  * Parse the metadata block parameters from the header.
 136  * @param[in]  block_header header data, at least 4 bytes
 137  * @param[out] last indicator for last metadata block
 138  * @param[out] type metadata block type
 139  * @param[out] size metadata block size
 140  */
 141 static av_always_inline void flac_parse_block_header(const uint8_t *block_header,
 142                                                       int *last, int *type, int *size)
 143 {
 144     int tmp = bytestream_get_byte(&block_header);
 145     if (last)
 146         *last = tmp & 0x80;
 147     if (type)
 148         *type = tmp & 0x7F;
 149     if (size)
 150         *size = bytestream_get_be24(&block_header);
 151 }
 152
 153 #endif /* AVCODEC_FLAC_H */