Additionally, add comments regarding their definitions. Based on ARIB STD-B32, which bases on 14496-3:2009 and 14496-3:2009/AMD4.
		
			
				
	
	
		
			178 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			178 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * MPEG-4 Audio common header
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|  * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
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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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| #ifndef AVCODEC_MPEG4AUDIO_H
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| #define AVCODEC_MPEG4AUDIO_H
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| 
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| #include <stdint.h>
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| 
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| #include "libavutil/attributes.h"
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| 
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| #include "get_bits.h"
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| #include "internal.h"
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| #include "put_bits.h"
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| 
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| typedef struct MPEG4AudioConfig {
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|     int object_type;
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|     int sampling_index;
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|     int sample_rate;
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|     int chan_config;
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|     int sbr; ///< -1 implicit, 1 presence
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|     int ext_object_type;
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|     int ext_sampling_index;
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|     int ext_sample_rate;
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|     int ext_chan_config;
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|     int channels;
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|     int ps;  ///< -1 implicit, 1 presence
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|     int frame_length_short;
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| } MPEG4AudioConfig;
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| 
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| extern av_export_avcodec const int avpriv_mpeg4audio_sample_rates[16];
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| extern const uint8_t ff_mpeg4audio_channels[14];
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| 
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| /**
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|  * Parse MPEG-4 systems extradata from a potentially unaligned GetBitContext to retrieve audio configuration.
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|  * @param[in] c        MPEG4AudioConfig structure to fill.
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|  * @param[in] gb       Extradata from container.
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|  * @param[in] sync_extension look for a sync extension after config if true.
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|  * @param[in] logctx opaque struct starting with an AVClass element, used for logging.
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|  * @return negative AVERROR code on error, on success AudioSpecificConfig bit index in extradata.
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|  */
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| int ff_mpeg4audio_get_config_gb(MPEG4AudioConfig *c, GetBitContext *gb,
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|                                 int sync_extension, void *logctx);
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| 
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| #if LIBAVCODEC_VERSION_MAJOR < 59
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| /**
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|  * Parse MPEG-4 systems extradata from a raw buffer to retrieve audio configuration.
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|  * @param[in] c        MPEG4AudioConfig structure to fill.
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|  * @param[in] buf      Extradata from container.
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|  * @param[in] bit_size Extradata size in bits.
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|  * @param[in] sync_extension look for a sync extension after config if true.
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|  * @return negative AVERROR code on error, on success AudioSpecificConfig bit index in extradata.
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|  */
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| int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf,
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|                                  int bit_size, int sync_extension);
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| #endif
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| 
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| /**
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|  * Parse MPEG-4 systems extradata from a raw buffer to retrieve audio configuration.
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|  * @param[in] c        MPEG4AudioConfig structure to fill.
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|  * @param[in] buf      Extradata from container.
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|  * @param[in] size     Extradata size in bytes.
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|  * @param[in] sync_extension look for a sync extension after config if true.
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|  * @param[in] logctx opaque struct starting with an AVClass element, used for logging.
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|  * @return negative AVERROR code on error, AudioSpecificConfig bit index in extradata on success.
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|  */
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| int avpriv_mpeg4audio_get_config2(MPEG4AudioConfig *c, const uint8_t *buf,
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|                                   int size, int sync_extension, void *logctx);
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| 
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| enum AudioObjectType {
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|     AOT_NULL,
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|                                // Support?                Name
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|     AOT_AAC_MAIN,              ///< Y                       Main
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|     AOT_AAC_LC,                ///< Y                       Low Complexity
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|     AOT_AAC_SSR,               ///< N (code in SoC repo)    Scalable Sample Rate
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|     AOT_AAC_LTP,               ///< Y                       Long Term Prediction
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|     AOT_SBR,                   ///< Y                       Spectral Band Replication
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|     AOT_AAC_SCALABLE,          ///< N                       Scalable
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|     AOT_TWINVQ,                ///< N                       Twin Vector Quantizer
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|     AOT_CELP,                  ///< N                       Code Excited Linear Prediction
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|     AOT_HVXC,                  ///< N                       Harmonic Vector eXcitation Coding
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|     AOT_TTSI             = 12, ///< N                       Text-To-Speech Interface
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|     AOT_MAINSYNTH,             ///< N                       Main Synthesis
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|     AOT_WAVESYNTH,             ///< N                       Wavetable Synthesis
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|     AOT_MIDI,                  ///< N                       General MIDI
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|     AOT_SAFX,                  ///< N                       Algorithmic Synthesis and Audio Effects
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|     AOT_ER_AAC_LC,             ///< N                       Error Resilient Low Complexity
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|     AOT_ER_AAC_LTP       = 19, ///< N                       Error Resilient Long Term Prediction
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|     AOT_ER_AAC_SCALABLE,       ///< N                       Error Resilient Scalable
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|     AOT_ER_TWINVQ,             ///< N                       Error Resilient Twin Vector Quantizer
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|     AOT_ER_BSAC,               ///< N                       Error Resilient Bit-Sliced Arithmetic Coding
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|     AOT_ER_AAC_LD,             ///< N                       Error Resilient Low Delay
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|     AOT_ER_CELP,               ///< N                       Error Resilient Code Excited Linear Prediction
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|     AOT_ER_HVXC,               ///< N                       Error Resilient Harmonic Vector eXcitation Coding
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|     AOT_ER_HILN,               ///< N                       Error Resilient Harmonic and Individual Lines plus Noise
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|     AOT_ER_PARAM,              ///< N                       Error Resilient Parametric
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|     AOT_SSC,                   ///< N                       SinuSoidal Coding
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|     AOT_PS,                    ///< N                       Parametric Stereo
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|     AOT_SURROUND,              ///< N                       MPEG Surround
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|     AOT_ESCAPE,                ///< Y                       Escape Value
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|     AOT_L1,                    ///< Y                       Layer 1
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|     AOT_L2,                    ///< Y                       Layer 2
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|     AOT_L3,                    ///< Y                       Layer 3
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|     AOT_DST,                   ///< N                       Direct Stream Transfer
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|     AOT_ALS,                   ///< Y                       Audio LosslesS
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|     AOT_SLS,                   ///< N                       Scalable LosslesS
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|     AOT_SLS_NON_CORE,          ///< N                       Scalable LosslesS (non core)
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|     AOT_ER_AAC_ELD,            ///< N                       Error Resilient Enhanced Low Delay
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|     AOT_SMR_SIMPLE,            ///< N                       Symbolic Music Representation Simple
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|     AOT_SMR_MAIN,              ///< N                       Symbolic Music Representation Main
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|     AOT_USAC_NOSBR,            ///< N                       Unified Speech and Audio Coding (no SBR)
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|     AOT_SAOC,                  ///< N                       Spatial Audio Object Coding
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|     AOT_LD_SURROUND,           ///< N                       Low Delay MPEG Surround
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|     AOT_USAC,                  ///< N                       Unified Speech and Audio Coding
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| };
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| 
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| #define MAX_PCE_SIZE 320 ///<Maximum size of a PCE including the 3-bit ID_PCE
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|                          ///<marker and the comment
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| 
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| static av_always_inline unsigned int ff_pce_copy_bits(PutBitContext *pb,
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|                                                       GetBitContext *gb,
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|                                                       int bits)
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| {
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|     unsigned int el = get_bits(gb, bits);
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|     put_bits(pb, bits, el);
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|     return el;
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| }
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| 
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| static inline int ff_copy_pce_data(PutBitContext *pb, GetBitContext *gb)
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| {
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|     int five_bit_ch, four_bit_ch, comment_size, bits;
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|     int offset = put_bits_count(pb);
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| 
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|     ff_pce_copy_bits(pb, gb, 10);               // Tag, Object Type, Frequency
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|     five_bit_ch  = ff_pce_copy_bits(pb, gb, 4); // Front
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|     five_bit_ch += ff_pce_copy_bits(pb, gb, 4); // Side
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|     five_bit_ch += ff_pce_copy_bits(pb, gb, 4); // Back
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|     four_bit_ch  = ff_pce_copy_bits(pb, gb, 2); // LFE
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|     four_bit_ch += ff_pce_copy_bits(pb, gb, 3); // Data
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|     five_bit_ch += ff_pce_copy_bits(pb, gb, 4); // Coupling
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|     if (ff_pce_copy_bits(pb, gb, 1))            // Mono Mixdown
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|         ff_pce_copy_bits(pb, gb, 4);
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|     if (ff_pce_copy_bits(pb, gb, 1))            // Stereo Mixdown
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|         ff_pce_copy_bits(pb, gb, 4);
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|     if (ff_pce_copy_bits(pb, gb, 1))            // Matrix Mixdown
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|         ff_pce_copy_bits(pb, gb, 3);
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|     for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16)
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|         ff_pce_copy_bits(pb, gb, 16);
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|     if (bits)
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|         ff_pce_copy_bits(pb, gb, bits);
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|     avpriv_align_put_bits(pb);
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|     align_get_bits(gb);
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|     comment_size = ff_pce_copy_bits(pb, gb, 8);
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|     for (; comment_size > 0; comment_size--)
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|         ff_pce_copy_bits(pb, gb, 8);
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| 
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|     return put_bits_count(pb) - offset;
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| }
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| 
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| #endif /* AVCODEC_MPEG4AUDIO_H */
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