mirror of
https://git.videolan.org/git/ffmpeg.git
synced 2024-09-04 07:21:31 +02:00
166 lines
5.3 KiB
C
166 lines
5.3 KiB
C
/*
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* Copyright (c) 2007 Ian Caulfield
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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 <stdint.h>
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#include "libavutil/channel_layout.h"
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#include "get_bits.h"
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#include "mlp_parse.h"
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#include "mlp.h"
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static const uint8_t mlp_quants[16] = {
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16, 20, 24, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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};
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static const uint8_t mlp_channels[32] = {
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1, 2, 3, 4, 3, 4, 5, 3, 4, 5, 4, 5, 6, 4, 5, 4,
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5, 6, 5, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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};
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static const uint64_t mlp_layout[32] = {
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AV_CH_LAYOUT_MONO,
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AV_CH_LAYOUT_STEREO,
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AV_CH_LAYOUT_2_1,
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AV_CH_LAYOUT_QUAD,
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AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY,
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AV_CH_LAYOUT_2_1|AV_CH_LOW_FREQUENCY,
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AV_CH_LAYOUT_QUAD|AV_CH_LOW_FREQUENCY,
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AV_CH_LAYOUT_SURROUND,
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AV_CH_LAYOUT_4POINT0,
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AV_CH_LAYOUT_5POINT0_BACK,
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AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY,
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AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY,
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AV_CH_LAYOUT_5POINT1_BACK,
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AV_CH_LAYOUT_4POINT0,
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AV_CH_LAYOUT_5POINT0_BACK,
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AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY,
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AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY,
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AV_CH_LAYOUT_5POINT1_BACK,
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AV_CH_LAYOUT_QUAD|AV_CH_LOW_FREQUENCY,
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AV_CH_LAYOUT_5POINT0_BACK,
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AV_CH_LAYOUT_5POINT1_BACK,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
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};
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static int mlp_get_major_sync_size(const uint8_t * buf, int bufsize)
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{
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int has_extension, extensions = 0;
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int size = 28;
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if (bufsize < 28)
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return -1;
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if (AV_RB32(buf) == 0xf8726fba) {
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has_extension = buf[25] & 1;
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if (has_extension) {
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extensions = buf[26] >> 4;
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size += 2 + extensions * 2;
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}
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}
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return size;
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}
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/** Read a major sync info header - contains high level information about
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* the stream - sample rate, channel arrangement etc. Most of this
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* information is not actually necessary for decoding, only for playback.
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* gb must be a freshly initialized GetBitContext with no bits read.
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*/
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int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)
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{
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int ratebits, channel_arrangement, header_size;
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uint16_t checksum;
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av_assert1(get_bits_count(gb) == 0);
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header_size = mlp_get_major_sync_size(gb->buffer, gb->size_in_bits >> 3);
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if (header_size < 0 || gb->size_in_bits < header_size << 3) {
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av_log(log, AV_LOG_ERROR, "packet too short, unable to read major sync\n");
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return -1;
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}
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checksum = ff_mlp_checksum16(gb->buffer, header_size - 2);
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if (checksum != AV_RL16(gb->buffer+header_size-2)) {
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av_log(log, AV_LOG_ERROR, "major sync info header checksum error\n");
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return AVERROR_INVALIDDATA;
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}
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if (get_bits(gb, 24) != 0xf8726f) /* Sync words */
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return AVERROR_INVALIDDATA;
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mh->stream_type = get_bits(gb, 8);
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mh->header_size = header_size;
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if (mh->stream_type == 0xbb) {
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mh->group1_bits = mlp_quants[get_bits(gb, 4)];
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mh->group2_bits = mlp_quants[get_bits(gb, 4)];
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ratebits = get_bits(gb, 4);
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mh->group1_samplerate = mlp_samplerate(ratebits);
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mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4));
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skip_bits(gb, 11);
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mh->channel_arrangement=
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channel_arrangement = get_bits(gb, 5);
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mh->channels_mlp = mlp_channels[channel_arrangement];
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mh->channel_layout_mlp = mlp_layout[channel_arrangement];
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} else if (mh->stream_type == 0xba) {
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mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere?
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mh->group2_bits = 0;
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ratebits = get_bits(gb, 4);
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mh->group1_samplerate = mlp_samplerate(ratebits);
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mh->group2_samplerate = 0;
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skip_bits(gb, 4);
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mh->channel_modifier_thd_stream0 = get_bits(gb, 2);
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mh->channel_modifier_thd_stream1 = get_bits(gb, 2);
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mh->channel_arrangement=
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channel_arrangement = get_bits(gb, 5);
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mh->channels_thd_stream1 = truehd_channels(channel_arrangement);
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mh->channel_layout_thd_stream1 = truehd_layout(channel_arrangement);
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mh->channel_modifier_thd_stream2 = get_bits(gb, 2);
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channel_arrangement = get_bits(gb, 13);
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mh->channels_thd_stream2 = truehd_channels(channel_arrangement);
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mh->channel_layout_thd_stream2 = truehd_layout(channel_arrangement);
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} else
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return AVERROR_INVALIDDATA;
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mh->access_unit_size = 40 << (ratebits & 7);
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mh->access_unit_size_pow2 = 64 << (ratebits & 7);
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skip_bits_long(gb, 48);
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mh->is_vbr = get_bits1(gb);
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mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4;
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mh->num_substreams = get_bits(gb, 4);
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skip_bits_long(gb, 4 + (header_size - 17) * 8);
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return 0;
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}
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