357 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			357 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * MLP parser
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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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| 
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| /**
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|  * @file
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|  * MLP parser
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|  */
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| 
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| #include <stdint.h>
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| 
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| #include "libavutil/crc.h"
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| #include "libavutil/audioconvert.h"
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| #include "get_bits.h"
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| #include "parser.h"
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| #include "mlp_parser.h"
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| #include "mlp.h"
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| 
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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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| 
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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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| 
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| const uint64_t ff_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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| 
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| static const uint8_t thd_chancount[13] = {
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| //  LR    C   LFE  LRs LRvh  LRc LRrs  Cs   Ts  LRsd  LRw  Cvh  LFE2
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|      2,   1,   1,   2,   2,   2,   2,   1,   1,   2,   2,   1,   1
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| };
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| 
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| static const uint64_t thd_layout[13] = {
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|     AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT,                     // LR
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|     AV_CH_FRONT_CENTER,                                     // C
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|     AV_CH_LOW_FREQUENCY,                                    // LFE
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|     AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT,                       // LRs
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|     AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT,             // LRvh
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|     AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER, // LRc
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|     AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT,                       // LRrs
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|     AV_CH_BACK_CENTER,                                      // Cs
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|     AV_CH_TOP_CENTER,                                       // Ts
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|     AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT,                       // LRsd - TODO: Surround Direct
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|     AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER, // LRw  - TODO: Wide
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|     AV_CH_TOP_FRONT_CENTER,                                 // Cvh
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|     AV_CH_LOW_FREQUENCY                                     // LFE2
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| };
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| 
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| static int mlp_samplerate(int in)
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| {
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|     if (in == 0xF)
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|         return 0;
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| 
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|     return (in & 8 ? 44100 : 48000) << (in & 7) ;
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| }
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| 
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| static int truehd_channels(int chanmap)
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| {
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|     int channels = 0, i;
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| 
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|     for (i = 0; i < 13; i++)
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|         channels += thd_chancount[i] * ((chanmap >> i) & 1);
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| 
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|     return channels;
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| }
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| 
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| uint64_t ff_truehd_layout(int chanmap)
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| {
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|     int layout = 0, i;
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| 
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|     for (i = 0; i < 13; i++)
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|         layout |= thd_layout[i] * ((chanmap >> i) & 1);
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| 
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|     return layout;
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| }
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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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| 
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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;
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|     uint16_t checksum;
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| 
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|     assert(get_bits_count(gb) == 0);
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| 
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|     if (gb->size_in_bits < 28 << 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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| 
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|     checksum = ff_mlp_checksum16(gb->buffer, 26);
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|     if (checksum != AV_RL16(gb->buffer+26)) {
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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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| 
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|     if (get_bits_long(gb, 24) != 0xf8726f) /* Sync words */
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|         return AVERROR_INVALIDDATA;
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| 
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|     mh->stream_type = get_bits(gb, 8);
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| 
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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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| 
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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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| 
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|         skip_bits(gb, 11);
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| 
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|         mh->channels_mlp = get_bits(gb, 5);
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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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| 
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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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| 
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|         skip_bits(gb, 8);
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| 
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|         mh->channels_thd_stream1 = get_bits(gb, 5);
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| 
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|         skip_bits(gb, 2);
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| 
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|         mh->channels_thd_stream2 = get_bits(gb, 13);
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|     } else
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|         return AVERROR_INVALIDDATA;
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| 
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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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| 
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|     skip_bits_long(gb, 48);
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| 
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|     mh->is_vbr = get_bits1(gb);
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| 
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|     mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4;
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| 
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|     mh->num_substreams = get_bits(gb, 4);
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| 
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|     skip_bits_long(gb, 4 + 11 * 8);
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| 
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|     return 0;
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| }
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| 
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| typedef struct MLPParseContext
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| {
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|     ParseContext pc;
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| 
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|     int bytes_left;
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| 
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|     int in_sync;
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| 
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|     int num_substreams;
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| } MLPParseContext;
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| 
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| static av_cold int mlp_init(AVCodecParserContext *s)
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| {
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|     ff_mlp_init_crc();
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|     return 0;
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| }
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| 
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| static int mlp_parse(AVCodecParserContext *s,
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|                      AVCodecContext *avctx,
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|                      const uint8_t **poutbuf, int *poutbuf_size,
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|                      const uint8_t *buf, int buf_size)
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| {
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|     MLPParseContext *mp = s->priv_data;
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|     int sync_present;
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|     uint8_t parity_bits;
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|     int next;
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|     int i, p = 0;
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| 
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|     *poutbuf_size = 0;
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|     if (buf_size == 0)
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|         return 0;
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| 
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|     if (!mp->in_sync) {
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|         // Not in sync - find a major sync header
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| 
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|         for (i = 0; i < buf_size; i++) {
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|             mp->pc.state = (mp->pc.state << 8) | buf[i];
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|             if ((mp->pc.state & 0xfffffffe) == 0xf8726fba &&
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|                 // ignore if we do not have the data for the start of header
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|                 mp->pc.index + i >= 7) {
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|                 mp->in_sync = 1;
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|                 mp->bytes_left = 0;
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|                 break;
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|             }
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|         }
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| 
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|         if (!mp->in_sync) {
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|             ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size);
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|             return buf_size;
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|         }
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| 
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|         ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size);
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| 
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|         return i - 7;
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|     }
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| 
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|     if (mp->bytes_left == 0) {
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|         // Find length of this packet
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| 
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|         /* Copy overread bytes from last frame into buffer. */
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|         for(; mp->pc.overread>0; mp->pc.overread--) {
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|             mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];
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|         }
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| 
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|         if (mp->pc.index + buf_size < 2) {
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|             ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size);
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|             return buf_size;
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|         }
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| 
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|         mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)
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|                        |  (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);
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|         mp->bytes_left = (mp->bytes_left & 0xfff) * 2;
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|         if (mp->bytes_left <= 0) { // prevent infinite loop
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|             goto lost_sync;
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|         }
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|         mp->bytes_left -= mp->pc.index;
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|     }
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| 
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|     next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;
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| 
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|     if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {
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|         mp->bytes_left -= buf_size;
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|         return buf_size;
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|     }
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| 
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|     mp->bytes_left = 0;
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| 
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|     sync_present = (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;
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| 
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|     if (!sync_present) {
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|         /* The first nibble of a frame is a parity check of the 4-byte
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|          * access unit header and all the 2- or 4-byte substream headers. */
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|         // Only check when this isn't a sync frame - syncs have a checksum.
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| 
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|         parity_bits = 0;
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|         for (i = -1; i < mp->num_substreams; i++) {
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|             parity_bits ^= buf[p++];
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|             parity_bits ^= buf[p++];
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| 
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|             if (i < 0 || buf[p-2] & 0x80) {
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|                 parity_bits ^= buf[p++];
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|                 parity_bits ^= buf[p++];
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|             }
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|         }
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| 
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|         if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {
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|             av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");
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|             goto lost_sync;
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|         }
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|     } else {
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|         GetBitContext gb;
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|         MLPHeaderInfo mh;
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| 
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|         init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
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|         if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)
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|             goto lost_sync;
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| 
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|         avctx->bits_per_raw_sample = mh.group1_bits;
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|         if (avctx->bits_per_raw_sample > 16)
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|             avctx->sample_fmt = AV_SAMPLE_FMT_S32;
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|         else
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|             avctx->sample_fmt = AV_SAMPLE_FMT_S16;
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|         avctx->sample_rate = mh.group1_samplerate;
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|         avctx->frame_size = mh.access_unit_size;
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| 
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|         if (mh.stream_type == 0xbb) {
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|             /* MLP stream */
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|             avctx->channels = mlp_channels[mh.channels_mlp];
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|             avctx->channel_layout = ff_mlp_layout[mh.channels_mlp];
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|         } else { /* mh.stream_type == 0xba */
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|             /* TrueHD stream */
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|             if (mh.channels_thd_stream2) {
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|                 avctx->channels = truehd_channels(mh.channels_thd_stream2);
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|                 avctx->channel_layout = ff_truehd_layout(mh.channels_thd_stream2);
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|             } else {
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|                 avctx->channels = truehd_channels(mh.channels_thd_stream1);
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|                 avctx->channel_layout = ff_truehd_layout(mh.channels_thd_stream1);
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|             }
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|         }
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| 
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|         if (!mh.is_vbr) /* Stream is CBR */
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|             avctx->bit_rate = mh.peak_bitrate;
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| 
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|         mp->num_substreams = mh.num_substreams;
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|     }
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| 
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|     *poutbuf = buf;
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|     *poutbuf_size = buf_size;
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| 
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|     return next;
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| 
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| lost_sync:
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|     mp->in_sync = 0;
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|     return 1;
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| }
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| 
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| AVCodecParser ff_mlp_parser = {
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|     .codec_ids      = { CODEC_ID_MLP, CODEC_ID_TRUEHD },
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|     .priv_data_size = sizeof(MLPParseContext),
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|     .parser_init    = mlp_init,
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|     .parser_parse   = mlp_parse,
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|     .parser_close   = ff_parse_close,
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| };
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