/* * Common code between the AC-3 and E-AC-3 decoders * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Common code between the AC-3 and E-AC-3 decoders. * * Summary of MDCT Coefficient Grouping: * The individual MDCT coefficient indices are often referred to in the * (E-)AC-3 specification as frequency bins.  These bins are grouped together * into subbands of 12 coefficients each.  The subbands are grouped together * into bands as defined in the bitstream by the band structures, which * determine the number of bands and the size of each band.  The full spectrum * of 256 frequency bins is divided into 1 DC bin + 21 subbands = 253 bins. * This system of grouping coefficients is used for channel bandwidth, stereo * rematrixing, channel coupling, enhanced coupling, and spectral extension. * * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+ * |1|  |12|  |  [12|12|12|12]  |  |  |  |  |  |  |  |  |  |  |  |  |3| * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+ * ~~~  ~~~~     ~~~~~~~~~~~~~                                      ~~~ *  |     |            |                                             | *  |     |            |                    3 unused frequency bins--+ *  |     |            | *  |     |            +--1 band containing 4 subbands *  |     | *  |     +--1 subband of 12 frequency bins *  | *  +--DC frequency bin */ #ifndef AVCODEC_AC3DEC_H#define AVCODEC_AC3DEC_H #include "libavutil/tx.h"#include "libavutil/float_dsp.h"#include "libavutil/fixed_dsp.h"#include "libavutil/lfg.h"#include "libavutil/mem_internal.h" #include "ac3.h"#include "ac3dsp.h"#include "avcodec.h"#include "bswapdsp.h"#include "get_bits.h"#include "fmtconvert.h" #define AC3_OUTPUT_LFEON  8 #define SPX_MAX_BANDS    17 /** Large enough for maximum possible frame size when the specification limit is ignored */#define AC3_FRAME_BUFFER_SIZE 32768 typedef struct AC3DecodeContext {    AVClass        *class;                  ///< class for AVOptions    AVCodecContext *avctx;                  ///< parent context    GetBitContext gbc;                      ///< bitstream reader ///@name Bit stream information///@{    int frame_type;                         ///< frame type                             (strmtyp)    int substreamid;                        ///< substream identification    int superframe_size;                    ///< current superframe size, in bytes    int frame_size;                         ///< current frame size, in bytes    int bit_rate;                           ///< stream bit rate, in bits-per-second    int sample_rate;                        ///< sample frequency, in Hz    int num_blocks;                         ///< number of audio blocks    int bitstream_id;                       ///< bitstream id                           (bsid)    int bitstream_mode;                     ///< bitstream mode                         (bsmod)    int channel_mode;                       ///< channel mode                           (acmod)    int lfe_on;                             ///< lfe channel in use    int dialog_normalization[2];            ///< dialog level in dBFS                   (dialnorm)    int compression_exists[2];              ///< compression field is valid for frame   (compre)    int channel_map;                        ///< custom channel map                     (chanmap)    int preferred_downmix;                  ///< Preferred 2-channel downmix mode       (dmixmod)    int center_mix_level;                   ///< Center mix level index    int center_mix_level_ltrt;              ///< Center mix level index for Lt/Rt       (ltrtcmixlev)    int surround_mix_level;                 ///< Surround mix level index    int surround_mix_level_ltrt;            ///< Surround mix level index for Lt/Rt     (ltrtsurmixlev)    int lfe_mix_level_exists;               ///< indicates if lfemixlevcod is specified (lfemixlevcode)    int lfe_mix_level;                      ///< LFE mix level index                    (lfemixlevcod)    int eac3;                               ///< indicates if current frame is E-AC-3    int eac3_subsbtreamid_found;            ///< bitstream has E-AC-3 additional substream(s)    int eac3_extension_type_a;              ///< bitstream has E-AC-3 extension type A enabled frame(s)    int dolby_surround_mode;                ///< dolby surround mode                    (dsurmod)    int dolby_surround_ex_mode;             ///< dolby surround ex mode                 (dsurexmod)    int dolby_headphone_mode;               ///< dolby headphone mode                   (dheadphonmod)///@}     int preferred_stereo_downmix;    float ltrt_center_mix_level;    float ltrt_surround_mix_level;    float loro_center_mix_level;    float loro_surround_mix_level;    int target_level;                       ///< target level in dBFS    float level_gain[2]; ///@name Frame syntax parameters    int snr_offset_strategy;                ///< SNR offset strategy                    (snroffststr)    int block_switch_syntax;                ///< block switch syntax enabled            (blkswe)    int dither_flag_syntax;                 ///< dither flag syntax enabled             (dithflage)    int bit_allocation_syntax;              ///< bit allocation model syntax enabled    (bamode)    int fast_gain_syntax;                   ///< fast gain codes enabled                (frmfgaincode)    int dba_syntax;                         ///< delta bit allocation syntax enabled    (dbaflde)    int skip_syntax;                        ///< skip field syntax enabled              (skipflde) ///@} ///@name Standard coupling    int cpl_in_use[AC3_MAX_BLOCKS];         ///< coupling in use                        (cplinu)    int cpl_strategy_exists[AC3_MAX_BLOCKS];///< coupling strategy exists               (cplstre)    int channel_in_cpl[AC3_MAX_CHANNELS];   ///< channel in coupling                    (chincpl)    int phase_flags_in_use;                 ///< phase flags in use                     (phsflginu)    int phase_flags[AC3_MAX_CPL_BANDS];     ///< phase flags                            (phsflg)    int num_cpl_bands;                      ///< number of coupling bands               (ncplbnd)    uint8_t cpl_band_struct[AC3_MAX_CPL_BANDS];    uint8_t cpl_band_sizes[AC3_MAX_CPL_BANDS]; ///< number of coeffs in each coupling band    int firstchincpl;                       ///< first channel in coupling    int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states      (firstcplcos)    int cpl_coords[AC3_MAX_CHANNELS][AC3_MAX_CPL_BANDS]; ///< coupling coordinates      (cplco)///@} ///@name Spectral extension///@{    int spx_in_use;                             ///< spectral extension in use              (spxinu)    uint8_t channel_uses_spx[AC3_MAX_CHANNELS]; ///< channel uses spectral extension        (chinspx)    int8_t spx_atten_code[AC3_MAX_CHANNELS];    ///< spx attenuation code                   (spxattencod)    int spx_src_start_freq;                     ///< spx start frequency bin    int spx_dst_end_freq;                       ///< spx end frequency bin    int spx_dst_start_freq;                     ///< spx starting frequency bin for copying (copystartmant)                                                ///< the copy region ends at the start of the spx region.    int num_spx_bands;                          ///< number of spx bands                    (nspxbnds)    uint8_t spx_band_struct[SPX_MAX_BANDS];    uint8_t spx_band_sizes[SPX_MAX_BANDS];      ///< number of bins in each spx band    uint8_t first_spx_coords[AC3_MAX_CHANNELS]; ///< first spx coordinates states           (firstspxcos)    INTFLOAT spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor  (nblendfact)    INTFLOAT spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS];///< spx signal blending factor (sblendfact)///@} ///@name Adaptive hybrid transform    int channel_uses_aht[AC3_MAX_CHANNELS];                         ///< channel AHT in use (chahtinu)    int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][AC3_MAX_BLOCKS];  ///< pre-IDCT mantissas///@} ///@name Channel    int fbw_channels;                           ///< number of full-bandwidth channels    int channels;                               ///< number of total channels    int lfe_ch;                                 ///< index of LFE channel    SHORTFLOAT *downmix_coeffs[2];              ///< stereo downmix coefficients    int downmixed;                              ///< indicates if coeffs are currently downmixed    int output_mode;                            ///< output channel configuration    int prev_output_mode;                       ///< output channel configuration for previous frame    int out_channels;                           ///< number of output channels    int prev_bit_rate;                          ///< stream bit rate, in bits-per-second for previous frame///@} ///@name Dynamic range    INTFLOAT dynamic_range[2];                 ///< dynamic range    INTFLOAT drc_scale;                        ///< percentage of dynamic range compression to be applied    int heavy_compression;                     ///< apply heavy compression    INTFLOAT heavy_dynamic_range[2];           ///< heavy dynamic range compression///@} ///@name Bandwidth    int start_freq[AC3_MAX_CHANNELS];       ///< start frequency bin                    (strtmant)    int end_freq[AC3_MAX_CHANNELS];         ///< end frequency bin                      (endmant)///@} ///@name Consistent noise generation    int consistent_noise_generation;        ///< seed noise generation with AC-3 frame on decode///@} ///@name Rematrixing    int num_rematrixing_bands;              ///< number of rematrixing bands            (nrematbnd)    int rematrixing_flags[4];               ///< rematrixing flags                      (rematflg)///@} ///@name Exponents    int num_exp_groups[AC3_MAX_CHANNELS];           ///< Number of exponent groups      (nexpgrp)    int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS];  ///< decoded exponents    int exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies        (expstr)///@} ///@name Bit allocation    AC3BitAllocParameters bit_alloc_params;         ///< bit allocation parameters    int first_cpl_leak;                             ///< first coupling leak state      (firstcplleak)    int snr_offset[AC3_MAX_CHANNELS];               ///< signal-to-noise ratio offsets  (snroffst)    int fast_gain[AC3_MAX_CHANNELS];                ///< fast gain values/SMR's         (fgain)    uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< bit allocation pointers    int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< scaled exponents    int16_t band_psd[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< interpolated exponents    int16_t mask[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS];     ///< masking curve values    int dba_mode[AC3_MAX_CHANNELS];                 ///< delta bit allocation mode    int dba_nsegs[AC3_MAX_CHANNELS];                ///< number of delta segments    uint8_t dba_offsets[AC3_MAX_CHANNELS][8];       ///< delta segment offsets    uint8_t dba_lengths[AC3_MAX_CHANNELS][8];       ///< delta segment lengths    uint8_t dba_values[AC3_MAX_CHANNELS][8];        ///< delta values for each segment///@} ///@name Zero-mantissa dithering    int dither_flag[AC3_MAX_CHANNELS];      ///< dither flags                           (dithflg)    AVLFG dith_state;                       ///< for dither generation///@} ///@name IMDCT    int block_switch[AC3_MAX_CHANNELS];     ///< block switch flags                     (blksw)    AVTXContext *tx_128, *tx_256;    av_tx_fn tx_fn_128, tx_fn_256;///@} ///@name Optimization    BswapDSPContext bdsp;#if USE_FIXED    AVFixedDSPContext *fdsp;#else    AVFloatDSPContext *fdsp;#endif    AC3DSPContext ac3dsp;    FmtConvertContext fmt_conv;             ///< optimized conversion functions///@}     SHORTFLOAT *outptr[AC3_MAX_CHANNELS];    INTFLOAT *xcfptr[AC3_MAX_CHANNELS];    INTFLOAT *dlyptr[AC3_MAX_CHANNELS]; ///@name Aligned arrays    DECLARE_ALIGNED(16, int,   fixed_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];       ///< fixed-point transform coefficients    DECLARE_ALIGNED(32, INTFLOAT, transform_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< transform coefficients    DECLARE_ALIGNED(32, INTFLOAT, delay)[EAC3_MAX_CHANNELS][AC3_BLOCK_SIZE];         ///< delay - added to the next block    DECLARE_ALIGNED(32, INTFLOAT, window)[AC3_BLOCK_SIZE];                              ///< window coefficients    DECLARE_ALIGNED(32, INTFLOAT, tmp_output)[AC3_BLOCK_SIZE];                          ///< temporary storage for output before windowing    DECLARE_ALIGNED(32, SHORTFLOAT, output)[EAC3_MAX_CHANNELS][AC3_BLOCK_SIZE];            ///< output after imdct transform and windowing    DECLARE_ALIGNED(32, uint8_t, input_buffer)[AC3_FRAME_BUFFER_SIZE + AV_INPUT_BUFFER_PADDING_SIZE]; ///< temp buffer to prevent overread    DECLARE_ALIGNED(32, SHORTFLOAT, output_buffer)[EAC3_MAX_CHANNELS][AC3_BLOCK_SIZE * 6];  ///< final output buffer///@}     AVChannelLayout downmix_layout;} AC3DecodeContext; /** * Parse the E-AC-3 frame header. * This parses both the bit stream info and audio frame header. */static int ff_eac3_parse_header(AC3DecodeContext *s); /** * Decode mantissas in a single channel for the entire frame. * This is used when AHT mode is enabled. */static void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch); /** * Apply spectral extension to each channel by copying lower frequency * coefficients to higher frequency bins and applying side information to * approximate the original high frequency signal. */static void ff_eac3_apply_spectral_extension(AC3DecodeContext *s); #if (!USE_FIXED)extern float ff_ac3_heavy_dynamic_range_tab[256];#endif #endif /* AVCODEC_AC3DEC_H */