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ffmpeg / libavcodec / ac3dec.h @ a42c8952

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/*
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 * Common code between AC3 and E-AC3 decoder
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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 ac3.h
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 * Common code between AC3 and E-AC3 decoder.
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 */
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#ifndef FFMPEG_AC3DEC_H
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#define FFMPEG_AC3DEC_H
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#include "libavutil/random.h"
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#include "ac3tab.h"
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#include "ac3.h"
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#include "bitstream.h"
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#include "dsputil.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 AC3_MAX_COEFS   256
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#define AC3_BLOCK_SIZE  256
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#define MAX_BLOCKS        6
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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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    uint8_t *input_buffer;                  ///< temp buffer to prevent overread
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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 channel_mode;                       ///< channel mode                           (acmod)
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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[MAX_BLOCKS];             ///< coupling in use                        (cplinu)
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    int cpl_strategy_exists[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[18];                    ///< phase flags                            (phsflg)
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    int num_cpl_subbands;                   ///< number of coupling sub bands           (ncplsubnd)
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    int num_cpl_bands;                      ///< number of coupling bands               (ncplbnd)
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    int cpl_band_struct[18];                ///< coupling band structure                (cplbndstrc)
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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][18];   ///< coupling coordinates                   (cplco)
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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][6];   ///< 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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    float downmix_coeff_adjust[2];              ///< adjustment needed for each output channel when downmixing
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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[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][50];         ///< interpolated exponents
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    int16_t mask[AC3_MAX_CHANNELS][50];             ///< 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_all;                         ///< true if all channels are dithered
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    int dither_flag[AC3_MAX_CHANNELS];      ///< dither flags                           (dithflg)
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    AVRandomState 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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    MDCTContext imdct_512;                  ///< for 512 sample IMDCT
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    MDCTContext 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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    float add_bias;                         ///< offset for float_to_int16 conversion
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    float mul_bias;                         ///< scaling for float_to_int16 conversion
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///@}
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    int fixed_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS];  ///> fixed-point transform coefficients
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///@defgroup arrays aligned arrays
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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*2]);                        ///< temporary storage for output before windowing
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    DECLARE_ALIGNED_16(float, tmp_imdct[AC3_BLOCK_SIZE]);                           ///< temporary storage for imdct transform
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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(short, int_output[AC3_MAX_CHANNELS-1][AC3_BLOCK_SIZE]);      ///< final 16-bit integer output
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///@}
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} AC3DecodeContext;
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#endif /* FFMPEG_AC3DEC_H */