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/*
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 * Common code between the AC-3 and E-AC-3 decoders
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 * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
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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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 * @file
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 * Common code between the AC-3 and E-AC-3 decoders.
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 *
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 * Summary of MDCT Coefficient Grouping:
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 * The individual MDCT coefficient indices are often referred to in the
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 * (E-)AC-3 specification as frequency bins.  These bins are grouped together
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 * into subbands of 12 coefficients each.  The subbands are grouped together
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 * into bands as defined in the bitstream by the band structures, which
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 * determine the number of bands and the size of each band.  The full spectrum
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 * of 256 frequency bins is divided into 1 DC bin + 21 subbands = 253 bins.
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 * This system of grouping coefficients is used for channel bandwidth, stereo
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 * rematrixing, channel coupling, enhanced coupling, and spectral extension.
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 *
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 * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+
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 * |1|  |12|  |  [12|12|12|12]  |  |  |  |  |  |  |  |  |  |  |  |  |3|
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 * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+
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 * ~~~  ~~~~     ~~~~~~~~~~~~~                                      ~~~
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 *  |     |            |                                             |
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 *  |     |            |                    3 unused frequency bins--+
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 *  |     |            |
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 *  |     |            +--1 band containing 4 subbands
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 *  |     |
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 *  |     +--1 subband of 12 frequency bins
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 *  |
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 *  +--DC frequency bin
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 */
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#ifndef AVCODEC_AC3DEC_H
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#define AVCODEC_AC3DEC_H
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#include "libavutil/lfg.h"
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#include "ac3.h"
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#include "ac3dsp.h"
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#include "get_bits.h"
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#include "dsputil.h"
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#include "fft.h"
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#include "fmtconvert.h"
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/* override ac3.h to include coupling channel */
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#undef AC3_MAX_CHANNELS
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#define AC3_MAX_CHANNELS 7
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#define CPL_CH 0
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#define AC3_OUTPUT_LFEON  8
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#define SPX_MAX_BANDS    17
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/** Large enough for maximum possible frame size when the specification limit is ignored */
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#define AC3_FRAME_BUFFER_SIZE 32768
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typedef struct {
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    AVCodecContext *avctx;                  ///< parent context
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    GetBitContext gbc;                      ///< bitstream reader
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///@defgroup bsi bit stream information
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///@{
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    int frame_type;                         ///< frame type                             (strmtyp)
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    int substreamid;                        ///< substream identification
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    int frame_size;                         ///< current frame size, in bytes
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    int bit_rate;                           ///< stream bit rate, in bits-per-second
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    int sample_rate;                        ///< sample frequency, in Hz
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    int num_blocks;                         ///< number of audio blocks
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    int bitstream_mode;                     ///< bitstream mode                         (bsmod)
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    int channel_mode;                       ///< channel mode                           (acmod)
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    int channel_layout;                     ///< channel layout
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    int lfe_on;                             ///< lfe channel in use
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    int channel_map;                        ///< custom channel map
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    int center_mix_level;                   ///< Center mix level index
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    int surround_mix_level;                 ///< Surround mix level index
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    int eac3;                               ///< indicates if current frame is E-AC-3
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///@}
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///@defgroup audfrm frame syntax parameters
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    int snr_offset_strategy;                ///< SNR offset strategy                    (snroffststr)
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    int block_switch_syntax;                ///< block switch syntax enabled            (blkswe)
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    int dither_flag_syntax;                 ///< dither flag syntax enabled             (dithflage)
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    int bit_allocation_syntax;              ///< bit allocation model syntax enabled    (bamode)
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    int fast_gain_syntax;                   ///< fast gain codes enabled                (frmfgaincode)
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    int dba_syntax;                         ///< delta bit allocation syntax enabled    (dbaflde)
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    int skip_syntax;                        ///< skip field syntax enabled              (skipflde)
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 ///@}
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///@defgroup cpl standard coupling
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    int cpl_in_use[AC3_MAX_BLOCKS];         ///< coupling in use                        (cplinu)
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    int cpl_strategy_exists[AC3_MAX_BLOCKS];///< coupling strategy exists               (cplstre)
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    int channel_in_cpl[AC3_MAX_CHANNELS];   ///< channel in coupling                    (chincpl)
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    int phase_flags_in_use;                 ///< phase flags in use                     (phsflginu)
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    int phase_flags[AC3_MAX_CPL_BANDS];     ///< phase flags                            (phsflg)
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    int num_cpl_bands;                      ///< number of coupling bands               (ncplbnd)
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    uint8_t cpl_band_sizes[AC3_MAX_CPL_BANDS]; ///< number of coeffs in each coupling band
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    int firstchincpl;                       ///< first channel in coupling
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    int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states      (firstcplcos)
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    int cpl_coords[AC3_MAX_CHANNELS][AC3_MAX_CPL_BANDS]; ///< coupling coordinates      (cplco)
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///@}
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///@defgroup spx spectral extension
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///@{
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    int spx_in_use;                             ///< spectral extension in use              (spxinu)
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    uint8_t channel_uses_spx[AC3_MAX_CHANNELS]; ///< channel uses spectral extension        (chinspx)
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    int8_t spx_atten_code[AC3_MAX_CHANNELS];    ///< spx attenuation code                   (spxattencod)
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    int spx_src_start_freq;                     ///< spx start frequency bin
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    int spx_dst_end_freq;                       ///< spx end frequency bin
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    int spx_dst_start_freq;                     ///< spx starting frequency bin for copying (copystartmant)
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                                                ///< the copy region ends at the start of the spx region.
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    int num_spx_bands;                          ///< number of spx bands                    (nspxbnds)
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    uint8_t spx_band_sizes[SPX_MAX_BANDS];      ///< number of bins in each spx band
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    uint8_t first_spx_coords[AC3_MAX_CHANNELS]; ///< first spx coordinates states           (firstspxcos)
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    float spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor  (nblendfact)
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    float spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS];///< spx signal blending factor (sblendfact)
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///@}
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///@defgroup aht adaptive hybrid transform
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    int channel_uses_aht[AC3_MAX_CHANNELS];                         ///< channel AHT in use (chahtinu)
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    int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][AC3_MAX_BLOCKS];  ///< pre-IDCT mantissas
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///@}
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///@defgroup channel channel
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    int fbw_channels;                           ///< number of full-bandwidth channels
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    int channels;                               ///< number of total channels
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    int lfe_ch;                                 ///< index of LFE channel
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    float downmix_coeffs[AC3_MAX_CHANNELS][2];  ///< stereo downmix coefficients
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    int downmixed;                              ///< indicates if coeffs are currently downmixed
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    int output_mode;                            ///< output channel configuration
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    int out_channels;                           ///< number of output channels
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///@}
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///@defgroup dynrng dynamic range
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    float dynamic_range[2];                 ///< dynamic range
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///@}
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///@defgroup bandwidth bandwidth
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    int start_freq[AC3_MAX_CHANNELS];       ///< start frequency bin                    (strtmant)
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    int end_freq[AC3_MAX_CHANNELS];         ///< end frequency bin                      (endmant)
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///@}
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///@defgroup rematrixing rematrixing
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    int num_rematrixing_bands;              ///< number of rematrixing bands            (nrematbnd)
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    int rematrixing_flags[4];               ///< rematrixing flags                      (rematflg)
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///@}
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///@defgroup exponents exponents
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    int num_exp_groups[AC3_MAX_CHANNELS];           ///< Number of exponent groups      (nexpgrp)
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    int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS];  ///< decoded exponents
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    int exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies        (expstr)
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///@}
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///@defgroup bitalloc bit allocation
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    AC3BitAllocParameters bit_alloc_params;         ///< bit allocation parameters
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    int first_cpl_leak;                             ///< first coupling leak state      (firstcplleak)
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    int snr_offset[AC3_MAX_CHANNELS];               ///< signal-to-noise ratio offsets  (snroffst)
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    int fast_gain[AC3_MAX_CHANNELS];                ///< fast gain values/SMR's         (fgain)
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    uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< bit allocation pointers
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    int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< scaled exponents
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    int16_t band_psd[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< interpolated exponents
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    int16_t mask[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS];     ///< masking curve values
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    int dba_mode[AC3_MAX_CHANNELS];                 ///< delta bit allocation mode
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    int dba_nsegs[AC3_MAX_CHANNELS];                ///< number of delta segments
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    uint8_t dba_offsets[AC3_MAX_CHANNELS][8];       ///< delta segment offsets
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    uint8_t dba_lengths[AC3_MAX_CHANNELS][8];       ///< delta segment lengths
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    uint8_t dba_values[AC3_MAX_CHANNELS][8];        ///< delta values for each segment
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///@}
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///@defgroup dithering zero-mantissa dithering
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    int dither_flag[AC3_MAX_CHANNELS];      ///< dither flags                           (dithflg)
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    AVLFG dith_state;                       ///< for dither generation
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///@}
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///@defgroup imdct IMDCT
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    int block_switch[AC3_MAX_CHANNELS];     ///< block switch flags                     (blksw)
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    FFTContext imdct_512;                   ///< for 512 sample IMDCT
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    FFTContext imdct_256;                   ///< for 256 sample IMDCT
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///@}
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///@defgroup opt optimization
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    DSPContext dsp;                         ///< for optimization
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    AC3DSPContext ac3dsp;
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    FmtConvertContext fmt_conv;             ///< optimized conversion functions
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    float mul_bias;                         ///< scaling for float_to_int16 conversion
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///@}
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///@defgroup arrays aligned arrays
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    DECLARE_ALIGNED(16, int,   fixed_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];       ///< fixed-point transform coefficients
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    DECLARE_ALIGNED(16, float, transform_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< transform coefficients
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    DECLARE_ALIGNED(16, float, delay)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE];             ///< delay - added to the next block
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    DECLARE_ALIGNED(16, float, window)[AC3_BLOCK_SIZE];                              ///< window coefficients
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    DECLARE_ALIGNED(16, float, tmp_output)[AC3_BLOCK_SIZE];                          ///< temporary storage for output before windowing
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    DECLARE_ALIGNED(16, float, output)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE];            ///< output after imdct transform and windowing
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    DECLARE_ALIGNED(16, uint8_t, input_buffer)[AC3_FRAME_BUFFER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE]; ///< temp buffer to prevent overread
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///@}
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} AC3DecodeContext;
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/**
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 * Parse the E-AC-3 frame header.
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 * This parses both the bit stream info and audio frame header.
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 */
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int ff_eac3_parse_header(AC3DecodeContext *s);
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/**
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 * Decode mantissas in a single channel for the entire frame.
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 * This is used when AHT mode is enabled.
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 */
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void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch);
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void ff_ac3_downmix_c(float (*samples)[256], float (*matrix)[2],
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                      int out_ch, int in_ch, int len);
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/**
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 * Apply spectral extension to each channel by copying lower frequency
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 * coefficients to higher frequency bins and applying side information to
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 * approximate the original high frequency signal.
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 */
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void ff_eac3_apply_spectral_extension(AC3DecodeContext *s);
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#endif /* AVCODEC_AC3DEC_H */