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/* |
* FLAC common code |
* Copyright (c) 2009 Justin Ruggles |
* |
* This file is part of FFmpeg. |
* |
* FFmpeg is free software; you can redistribute it and/or |
* modify it under the terms of the GNU Lesser General Public |
* License as published by the Free Software Foundation; either |
* version 2.1 of the License, or (at your option) any later version. |
* |
* FFmpeg is distributed in the hope that it will be useful, |
* but WITHOUT ANY WARRANTY; without even the implied warranty of |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
* Lesser General Public License for more details. |
* |
* You should have received a copy of the GNU Lesser General Public |
* License along with FFmpeg; if not, write to the Free Software |
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
*/ |
|
#include "libavutil/channel_layout.h" |
#include "libavutil/crc.h" |
#include "libavutil/log.h" |
#include "bytestream.h" |
#include "get_bits.h" |
#include "flac.h" |
#include "flacdata.h" |
|
static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 }; |
|
static const uint64_t flac_channel_layouts[8] = { |
AV_CH_LAYOUT_MONO, |
AV_CH_LAYOUT_STEREO, |
AV_CH_LAYOUT_SURROUND, |
AV_CH_LAYOUT_QUAD, |
AV_CH_LAYOUT_5POINT0, |
AV_CH_LAYOUT_5POINT1, |
AV_CH_LAYOUT_6POINT1, |
AV_CH_LAYOUT_7POINT1 |
}; |
|
static int64_t get_utf8(GetBitContext *gb) |
{ |
int64_t val; |
GET_UTF8(val, get_bits(gb, 8), return -1;) |
return val; |
} |
|
int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb, |
FLACFrameInfo *fi, int log_level_offset) |
{ |
int bs_code, sr_code, bps_code; |
|
/* frame sync code */ |
if ((get_bits(gb, 15) & 0x7FFF) != 0x7FFC) { |
av_log(avctx, AV_LOG_ERROR + log_level_offset, "invalid sync code\n"); |
return AVERROR_INVALIDDATA; |
} |
|
/* variable block size stream code */ |
fi->is_var_size = get_bits1(gb); |
|
/* block size and sample rate codes */ |
bs_code = get_bits(gb, 4); |
sr_code = get_bits(gb, 4); |
|
/* channels and decorrelation */ |
fi->ch_mode = get_bits(gb, 4); |
if (fi->ch_mode < FLAC_MAX_CHANNELS) { |
fi->channels = fi->ch_mode + 1; |
fi->ch_mode = FLAC_CHMODE_INDEPENDENT; |
} else if (fi->ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) { |
fi->channels = 2; |
fi->ch_mode -= FLAC_MAX_CHANNELS - 1; |
} else { |
av_log(avctx, AV_LOG_ERROR + log_level_offset, |
"invalid channel mode: %d\n", fi->ch_mode); |
return AVERROR_INVALIDDATA; |
} |
|
/* bits per sample */ |
bps_code = get_bits(gb, 3); |
if (bps_code == 3 || bps_code == 7) { |
av_log(avctx, AV_LOG_ERROR + log_level_offset, |
"invalid sample size code (%d)\n", |
bps_code); |
return AVERROR_INVALIDDATA; |
} |
fi->bps = sample_size_table[bps_code]; |
|
/* reserved bit */ |
if (get_bits1(gb)) { |
av_log(avctx, AV_LOG_ERROR + log_level_offset, |
"broken stream, invalid padding\n"); |
return AVERROR_INVALIDDATA; |
} |
|
/* sample or frame count */ |
fi->frame_or_sample_num = get_utf8(gb); |
if (fi->frame_or_sample_num < 0) { |
av_log(avctx, AV_LOG_ERROR + log_level_offset, |
"sample/frame number invalid; utf8 fscked\n"); |
return AVERROR_INVALIDDATA; |
} |
|
/* blocksize */ |
if (bs_code == 0) { |
av_log(avctx, AV_LOG_ERROR + log_level_offset, |
"reserved blocksize code: 0\n"); |
return AVERROR_INVALIDDATA; |
} else if (bs_code == 6) { |
fi->blocksize = get_bits(gb, 8) + 1; |
} else if (bs_code == 7) { |
fi->blocksize = get_bits(gb, 16) + 1; |
} else { |
fi->blocksize = ff_flac_blocksize_table[bs_code]; |
} |
|
/* sample rate */ |
if (sr_code < 12) { |
fi->samplerate = ff_flac_sample_rate_table[sr_code]; |
} else if (sr_code == 12) { |
fi->samplerate = get_bits(gb, 8) * 1000; |
} else if (sr_code == 13) { |
fi->samplerate = get_bits(gb, 16); |
} else if (sr_code == 14) { |
fi->samplerate = get_bits(gb, 16) * 10; |
} else { |
av_log(avctx, AV_LOG_ERROR + log_level_offset, |
"illegal sample rate code %d\n", |
sr_code); |
return AVERROR_INVALIDDATA; |
} |
|
/* header CRC-8 check */ |
skip_bits(gb, 8); |
if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer, |
get_bits_count(gb)/8)) { |
av_log(avctx, AV_LOG_ERROR + log_level_offset, |
"header crc mismatch\n"); |
return AVERROR_INVALIDDATA; |
} |
|
return 0; |
} |
|
int ff_flac_get_max_frame_size(int blocksize, int ch, int bps) |
{ |
/* Technically, there is no limit to FLAC frame size, but an encoder |
should not write a frame that is larger than if verbatim encoding mode |
were to be used. */ |
|
int count; |
|
count = 16; /* frame header */ |
count += ch * ((7+bps+7)/8); /* subframe headers */ |
if (ch == 2) { |
/* for stereo, need to account for using decorrelation */ |
count += (( 2*bps+1) * blocksize + 7) / 8; |
} else { |
count += ( ch*bps * blocksize + 7) / 8; |
} |
count += 2; /* frame footer */ |
|
return count; |
} |
|
int avpriv_flac_is_extradata_valid(AVCodecContext *avctx, |
enum FLACExtradataFormat *format, |
uint8_t **streaminfo_start) |
{ |
if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) { |
av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n"); |
return 0; |
} |
if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) { |
/* extradata contains STREAMINFO only */ |
if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) { |
av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n", |
FLAC_STREAMINFO_SIZE-avctx->extradata_size); |
} |
*format = FLAC_EXTRADATA_FORMAT_STREAMINFO; |
*streaminfo_start = avctx->extradata; |
} else { |
if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) { |
av_log(avctx, AV_LOG_ERROR, "extradata too small.\n"); |
return 0; |
} |
*format = FLAC_EXTRADATA_FORMAT_FULL_HEADER; |
*streaminfo_start = &avctx->extradata[8]; |
} |
return 1; |
} |
|
void ff_flac_set_channel_layout(AVCodecContext *avctx) |
{ |
if (avctx->channels <= FF_ARRAY_ELEMS(flac_channel_layouts)) |
avctx->channel_layout = flac_channel_layouts[avctx->channels - 1]; |
else |
avctx->channel_layout = 0; |
} |
|
void avpriv_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s, |
const uint8_t *buffer) |
{ |
GetBitContext gb; |
init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8); |
|
skip_bits(&gb, 16); /* skip min blocksize */ |
s->max_blocksize = get_bits(&gb, 16); |
if (s->max_blocksize < FLAC_MIN_BLOCKSIZE) { |
av_log(avctx, AV_LOG_WARNING, "invalid max blocksize: %d\n", |
s->max_blocksize); |
s->max_blocksize = 16; |
} |
|
skip_bits(&gb, 24); /* skip min frame size */ |
s->max_framesize = get_bits_long(&gb, 24); |
|
s->samplerate = get_bits_long(&gb, 20); |
s->channels = get_bits(&gb, 3) + 1; |
s->bps = get_bits(&gb, 5) + 1; |
|
avctx->channels = s->channels; |
avctx->sample_rate = s->samplerate; |
avctx->bits_per_raw_sample = s->bps; |
ff_flac_set_channel_layout(avctx); |
|
s->samples = get_bits64(&gb, 36); |
|
skip_bits_long(&gb, 64); /* md5 sum */ |
skip_bits_long(&gb, 64); /* md5 sum */ |
} |
|
void avpriv_flac_parse_block_header(const uint8_t *block_header, |
int *last, int *type, int *size) |
{ |
int tmp = bytestream_get_byte(&block_header); |
if (last) |
*last = tmp & 0x80; |
if (type) |
*type = tmp & 0x7F; |
if (size) |
*size = bytestream_get_be24(&block_header); |
} |