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184 lines
9.1 KiB
C
184 lines
9.1 KiB
C
/*
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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 libavcodec/ac3.h
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* Common code between the AC-3 and E-AC-3 decoders.
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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/internal.h"
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#include "libavutil/lfg.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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uint8_t 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][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[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_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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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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DECLARE_ALIGNED_16(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]); ///< 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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///@}
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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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#endif /* AVCODEC_AC3DEC_H */
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