1/* 2 * Common code between the AC-3 and E-AC-3 decoders 3 * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22/** 23 * @file libavcodec/ac3.h 24 * Common code between the AC-3 and E-AC-3 decoders. 25 */ 26 27#ifndef AVCODEC_AC3DEC_H 28#define AVCODEC_AC3DEC_H 29 30#include "libavutil/internal.h" 31#include "libavutil/lfg.h" 32#include "ac3.h" 33#include "bitstream.h" 34#include "dsputil.h" 35 36/* override ac3.h to include coupling channel */ 37#undef AC3_MAX_CHANNELS 38#define AC3_MAX_CHANNELS 7 39#define CPL_CH 0 40 41#define AC3_OUTPUT_LFEON 8 42 43#define AC3_MAX_COEFS 256 44#define AC3_BLOCK_SIZE 256 45#define MAX_BLOCKS 6 46 47typedef struct { 48 AVCodecContext *avctx; ///< parent context 49 GetBitContext gbc; ///< bitstream reader 50 uint8_t *input_buffer; ///< temp buffer to prevent overread 51 52///@defgroup bsi bit stream information 53///@{ 54 int frame_type; ///< frame type (strmtyp) 55 int substreamid; ///< substream identification 56 int frame_size; ///< current frame size, in bytes 57 int bit_rate; ///< stream bit rate, in bits-per-second 58 int sample_rate; ///< sample frequency, in Hz 59 int num_blocks; ///< number of audio blocks 60 int channel_mode; ///< channel mode (acmod) 61 int lfe_on; ///< lfe channel in use 62 int channel_map; ///< custom channel map 63 int center_mix_level; ///< Center mix level index 64 int surround_mix_level; ///< Surround mix level index 65 int eac3; ///< indicates if current frame is E-AC-3 66///@} 67 68///@defgroup audfrm frame syntax parameters 69 int snr_offset_strategy; ///< SNR offset strategy (snroffststr) 70 int block_switch_syntax; ///< block switch syntax enabled (blkswe) 71 int dither_flag_syntax; ///< dither flag syntax enabled (dithflage) 72 int bit_allocation_syntax; ///< bit allocation model syntax enabled (bamode) 73 int fast_gain_syntax; ///< fast gain codes enabled (frmfgaincode) 74 int dba_syntax; ///< delta bit allocation syntax enabled (dbaflde) 75 int skip_syntax; ///< skip field syntax enabled (skipflde) 76 ///@} 77 78///@defgroup cpl standard coupling 79 int cpl_in_use[MAX_BLOCKS]; ///< coupling in use (cplinu) 80 int cpl_strategy_exists[MAX_BLOCKS]; ///< coupling strategy exists (cplstre) 81 int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling (chincpl) 82 int phase_flags_in_use; ///< phase flags in use (phsflginu) 83 int phase_flags[18]; ///< phase flags (phsflg) 84 int num_cpl_subbands; ///< number of coupling sub bands (ncplsubnd) 85 int num_cpl_bands; ///< number of coupling bands (ncplbnd) 86 uint8_t cpl_band_struct[18]; ///< coupling band structure (cplbndstrc) 87 int firstchincpl; ///< first channel in coupling 88 int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states (firstcplcos) 89 int cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates (cplco) 90///@} 91 92///@defgroup aht adaptive hybrid transform 93 int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu) 94 int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][MAX_BLOCKS]; ///< pre-IDCT mantissas 95///@} 96 97///@defgroup channel channel 98 int fbw_channels; ///< number of full-bandwidth channels 99 int channels; ///< number of total channels 100 int lfe_ch; ///< index of LFE channel 101 float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients 102 int downmixed; ///< indicates if coeffs are currently downmixed 103 int output_mode; ///< output channel configuration 104 int out_channels; ///< number of output channels 105///@} 106 107///@defgroup dynrng dynamic range 108 float dynamic_range[2]; ///< dynamic range 109///@} 110 111///@defgroup bandwidth bandwidth 112 int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin (strtmant) 113 int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin (endmant) 114///@} 115 116///@defgroup rematrixing rematrixing 117 int num_rematrixing_bands; ///< number of rematrixing bands (nrematbnd) 118 int rematrixing_flags[4]; ///< rematrixing flags (rematflg) 119///@} 120 121///@defgroup exponents exponents 122 int num_exp_groups[AC3_MAX_CHANNELS]; ///< Number of exponent groups (nexpgrp) 123 int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< decoded exponents 124 int exp_strategy[MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies (expstr) 125///@} 126 127///@defgroup bitalloc bit allocation 128 AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters 129 int first_cpl_leak; ///< first coupling leak state (firstcplleak) 130 int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets (snroffst) 131 int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values/SMR's (fgain) 132 uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< bit allocation pointers 133 int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< scaled exponents 134 int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents 135 int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values 136 int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode 137 int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments 138 uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets 139 uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths 140 uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment 141///@} 142 143///@defgroup dithering zero-mantissa dithering 144 int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags (dithflg) 145 AVLFG dith_state; ///< for dither generation 146///@} 147 148///@defgroup imdct IMDCT 149 int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags (blksw) 150 MDCTContext imdct_512; ///< for 512 sample IMDCT 151 MDCTContext imdct_256; ///< for 256 sample IMDCT 152///@} 153 154///@defgroup opt optimization 155 DSPContext dsp; ///< for optimization 156 float add_bias; ///< offset for float_to_int16 conversion 157 float mul_bias; ///< scaling for float_to_int16 conversion 158///@} 159 160 DECLARE_ALIGNED_16(int, fixed_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]); ///> fixed-point transform coefficients 161 162///@defgroup arrays aligned arrays 163 DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]); ///< transform coefficients 164 DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]); ///< delay - added to the next block 165 DECLARE_ALIGNED_16(float, window[AC3_BLOCK_SIZE]); ///< window coefficients 166 DECLARE_ALIGNED_16(float, tmp_output[AC3_BLOCK_SIZE]); ///< temporary storage for output before windowing 167 DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]); ///< output after imdct transform and windowing 168///@} 169} AC3DecodeContext; 170 171/** 172 * Parse the E-AC-3 frame header. 173 * This parses both the bit stream info and audio frame header. 174 */ 175int ff_eac3_parse_header(AC3DecodeContext *s); 176 177/** 178 * Decode mantissas in a single channel for the entire frame. 179 * This is used when AHT mode is enabled. 180 */ 181void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch); 182 183#endif /* AVCODEC_AC3DEC_H */ 184