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https://git.ffmpeg.org/ffmpeg.git
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254 lines
8.2 KiB
C
254 lines
8.2 KiB
C
/*
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* FLAC common code
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* Copyright (c) 2009 Justin Ruggles
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/channel_layout.h"
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#include "libavutil/crc.h"
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#include "libavutil/log.h"
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#include "bitstream.h"
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#include "bytestream.h"
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#include "flac.h"
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#include "flacdata.h"
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static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 };
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static const uint64_t flac_channel_layouts[8] = {
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AV_CH_LAYOUT_MONO,
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AV_CH_LAYOUT_STEREO,
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AV_CH_LAYOUT_SURROUND,
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AV_CH_LAYOUT_QUAD,
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AV_CH_LAYOUT_5POINT0,
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AV_CH_LAYOUT_5POINT1,
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AV_CH_LAYOUT_6POINT1,
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AV_CH_LAYOUT_7POINT1
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};
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static int64_t get_utf8(BitstreamContext *bc)
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{
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int64_t val;
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GET_UTF8(val, bitstream_read(bc, 8), return -1;)
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return val;
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}
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int ff_flac_decode_frame_header(AVCodecContext *avctx, BitstreamContext *bc,
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FLACFrameInfo *fi, int log_level_offset)
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{
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int bs_code, sr_code, bps_code;
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/* frame sync code */
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if ((bitstream_read(bc, 15) & 0x7FFF) != 0x7FFC) {
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av_log(avctx, AV_LOG_ERROR + log_level_offset, "invalid sync code\n");
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return AVERROR_INVALIDDATA;
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}
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/* variable block size stream code */
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fi->is_var_size = bitstream_read_bit(bc);
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/* block size and sample rate codes */
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bs_code = bitstream_read(bc, 4);
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sr_code = bitstream_read(bc, 4);
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/* channels and decorrelation */
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fi->ch_mode = bitstream_read(bc, 4);
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if (fi->ch_mode < FLAC_MAX_CHANNELS) {
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fi->channels = fi->ch_mode + 1;
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fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
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} else if (fi->ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) {
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fi->channels = 2;
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fi->ch_mode -= FLAC_MAX_CHANNELS - 1;
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} else {
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av_log(avctx, AV_LOG_ERROR + log_level_offset,
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"invalid channel mode: %d\n", fi->ch_mode);
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return AVERROR_INVALIDDATA;
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}
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/* bits per sample */
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bps_code = bitstream_read(bc, 3);
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if (bps_code == 3 || bps_code == 7) {
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av_log(avctx, AV_LOG_ERROR + log_level_offset,
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"invalid sample size code (%d)\n",
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bps_code);
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return AVERROR_INVALIDDATA;
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}
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fi->bps = sample_size_table[bps_code];
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/* reserved bit */
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if (bitstream_read_bit(bc)) {
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av_log(avctx, AV_LOG_ERROR + log_level_offset,
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"broken stream, invalid padding\n");
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return AVERROR_INVALIDDATA;
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}
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/* sample or frame count */
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fi->frame_or_sample_num = get_utf8(bc);
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if (fi->frame_or_sample_num < 0) {
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av_log(avctx, AV_LOG_ERROR + log_level_offset,
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"sample/frame number invalid; utf8 fscked\n");
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return AVERROR_INVALIDDATA;
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}
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/* blocksize */
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if (bs_code == 0) {
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av_log(avctx, AV_LOG_ERROR + log_level_offset,
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"reserved blocksize code: 0\n");
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return AVERROR_INVALIDDATA;
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} else if (bs_code == 6) {
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fi->blocksize = bitstream_read(bc, 8) + 1;
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} else if (bs_code == 7) {
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fi->blocksize = bitstream_read(bc, 16) + 1;
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} else {
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fi->blocksize = ff_flac_blocksize_table[bs_code];
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}
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/* sample rate */
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if (sr_code < 12) {
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fi->samplerate = ff_flac_sample_rate_table[sr_code];
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} else if (sr_code == 12) {
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fi->samplerate = bitstream_read(bc, 8) * 1000;
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} else if (sr_code == 13) {
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fi->samplerate = bitstream_read(bc, 16);
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} else if (sr_code == 14) {
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fi->samplerate = bitstream_read(bc, 16) * 10;
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} else {
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av_log(avctx, AV_LOG_ERROR + log_level_offset,
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"illegal sample rate code %d\n",
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sr_code);
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return AVERROR_INVALIDDATA;
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}
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/* header CRC-8 check */
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bitstream_skip(bc, 8);
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if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, bc->buffer,
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bitstream_tell(bc) / 8)) {
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av_log(avctx, AV_LOG_ERROR + log_level_offset,
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"header crc mismatch\n");
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return AVERROR_INVALIDDATA;
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}
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return 0;
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}
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int ff_flac_get_max_frame_size(int blocksize, int ch, int bps)
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{
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/* Technically, there is no limit to FLAC frame size, but an encoder
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should not write a frame that is larger than if verbatim encoding mode
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were to be used. */
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int count;
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count = 16; /* frame header */
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count += ch * ((7+bps+7)/8); /* subframe headers */
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if (ch == 2) {
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/* for stereo, need to account for using decorrelation */
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count += (( 2*bps+1) * blocksize + 7) / 8;
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} else {
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count += ( ch*bps * blocksize + 7) / 8;
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}
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count += 2; /* frame footer */
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return count;
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}
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int ff_flac_is_extradata_valid(AVCodecContext *avctx,
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enum FLACExtradataFormat *format,
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uint8_t **streaminfo_start)
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{
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if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n");
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return 0;
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}
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if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) {
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/* extradata contains STREAMINFO only */
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if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) {
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av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n",
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FLAC_STREAMINFO_SIZE-avctx->extradata_size);
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}
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*format = FLAC_EXTRADATA_FORMAT_STREAMINFO;
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*streaminfo_start = avctx->extradata;
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} else {
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if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "extradata too small.\n");
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return 0;
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}
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*format = FLAC_EXTRADATA_FORMAT_FULL_HEADER;
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*streaminfo_start = &avctx->extradata[8];
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}
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return 1;
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}
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void ff_flac_set_channel_layout(AVCodecContext *avctx)
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{
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if (avctx->channels <= FF_ARRAY_ELEMS(flac_channel_layouts))
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avctx->channel_layout = flac_channel_layouts[avctx->channels - 1];
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else
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avctx->channel_layout = 0;
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}
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void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
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const uint8_t *buffer)
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{
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BitstreamContext bc;
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bitstream_init8(&bc, buffer, FLAC_STREAMINFO_SIZE);
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bitstream_skip(&bc, 16); /* skip min blocksize */
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s->max_blocksize = bitstream_read(&bc, 16);
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if (s->max_blocksize < FLAC_MIN_BLOCKSIZE) {
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av_log(avctx, AV_LOG_WARNING, "invalid max blocksize: %d\n",
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s->max_blocksize);
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s->max_blocksize = 16;
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}
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bitstream_skip(&bc, 24); /* skip min frame size */
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s->max_framesize = bitstream_read(&bc, 24);
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s->samplerate = bitstream_read(&bc, 20);
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s->channels = bitstream_read(&bc, 3) + 1;
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s->bps = bitstream_read(&bc, 5) + 1;
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avctx->channels = s->channels;
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avctx->sample_rate = s->samplerate;
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avctx->bits_per_raw_sample = s->bps;
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if (!avctx->channel_layout ||
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av_get_channel_layout_nb_channels(avctx->channel_layout) != avctx->channels)
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ff_flac_set_channel_layout(avctx);
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s->samples = bitstream_read(&bc, 32) << 4;
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s->samples |= bitstream_read(&bc, 4);
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bitstream_skip(&bc, 64); /* md5 sum */
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bitstream_skip(&bc, 64); /* md5 sum */
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}
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#if LIBAVCODEC_VERSION_MAJOR < 57
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void avpriv_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
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const uint8_t *buffer)
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{
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ff_flac_parse_streaminfo(avctx, s, buffer);
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}
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int avpriv_flac_is_extradata_valid(AVCodecContext *avctx,
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enum FLACExtradataFormat *format,
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uint8_t **streaminfo_start)
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{
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return ff_flac_is_extradata_valid(avctx, format, streaminfo_start);
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}
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#endif
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