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  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 {
  40.     FLAC_CHMODE_INDEPENDENT = 0,
  41.     FLAC_CHMODE_LEFT_SIDE   = 1,
  42.     FLAC_CHMODE_RIGHT_SIDE  = 2,
  43.     FLAC_CHMODE_MID_SIDE    = 3,
  44. };
  45.  
  46. enum {
  47.     FLAC_METADATA_TYPE_STREAMINFO = 0,
  48.     FLAC_METADATA_TYPE_PADDING,
  49.     FLAC_METADATA_TYPE_APPLICATION,
  50.     FLAC_METADATA_TYPE_SEEKTABLE,
  51.     FLAC_METADATA_TYPE_VORBIS_COMMENT,
  52.     FLAC_METADATA_TYPE_CUESHEET,
  53.     FLAC_METADATA_TYPE_PICTURE,
  54.     FLAC_METADATA_TYPE_INVALID = 127
  55. };
  56.  
  57. enum FLACExtradataFormat {
  58.     FLAC_EXTRADATA_FORMAT_STREAMINFO  = 0,
  59.     FLAC_EXTRADATA_FORMAT_FULL_HEADER = 1
  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 {
  78.     FLACSTREAMINFO
  79. } FLACStreaminfo;
  80.  
  81. typedef struct FLACFrameInfo {
  82.     FLACCOMMONINFO
  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             */
  90. } FLACFrameInfo;
  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.  */
  98. void avpriv_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
  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.  */
  108. int avpriv_flac_is_extradata_valid(AVCodecContext *avctx,
  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.  */
  138. int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
  139.                                 FLACFrameInfo *fi, int log_level_offset);
  140.  
  141. void ff_flac_set_channel_layout(AVCodecContext *avctx);
  142.  
  143. #endif /* AVCODEC_FLAC_H */
  144.