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   1 /*
   2  * Common code between AC3 and E-AC3 decoder
   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 ac3.h
  24  * Common code between AC3 and E-AC3 decoder.
  25  */
  26
  27 #ifndef FFMPEG_AC3DEC_H
  28 #define FFMPEG_AC3DEC_H
  29
  30 #include "libavutil/random.h"
  31 #include "ac3tab.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
  47 typedef 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 center_mix_level;                   ///< Center mix level index
  63     int surround_mix_level;                 ///< Surround mix level index
  64 ///@}
  65
  66 ///@defgroup cpl standard coupling
  67     int cpl_in_use[MAX_BLOCKS];             ///< coupling in use                        (cplinu)
  68     int channel_in_cpl[AC3_MAX_CHANNELS];   ///< channel in coupling                    (chincpl)
  69     int phase_flags_in_use;                 ///< phase flags in use                     (phsflginu)
  70     int phase_flags[18];                    ///< phase flags                            (phsflg)
  71     int num_cpl_subbands;                   ///< number of coupling sub bands           (ncplsubnd)
  72     int num_cpl_bands;                      ///< number of coupling bands               (ncplbnd)
  73     int cpl_band_struct[18];                ///< coupling band structure                (cplbndstrc)
  74     int cpl_coords[AC3_MAX_CHANNELS][18];   ///< coupling coordinates                   (cplco)
  75 ///@}
  76
  77 ///@defgroup channel channel
  78     int fbw_channels;                           ///< number of full-bandwidth channels
  79     int channels;                               ///< number of total channels
  80     int lfe_ch;                                 ///< index of LFE channel
  81     float downmix_coeffs[AC3_MAX_CHANNELS][2];  ///< stereo downmix coefficients
  82     float downmix_coeff_adjust[2];              ///< adjustment needed for each output channel when downmixing
  83     int downmixed;                              ///< indicates if coeffs are currently downmixed
  84     int output_mode;                            ///< output channel configuration
  85     int out_channels;                           ///< number of output channels
  86 ///@}
  87
  88 ///@defgroup dynrng dynamic range
  89     float dynamic_range[2];                 ///< dynamic range
  90 ///@}
  91
  92 ///@defgroup bandwidth bandwidth
  93     int start_freq[AC3_MAX_CHANNELS];       ///< start frequency bin                    (strtmant)
  94     int end_freq[AC3_MAX_CHANNELS];         ///< end frequency bin                      (endmant)
  95 ///@}
  96
  97 ///@defgroup rematrixing rematrixing
  98     int num_rematrixing_bands;              ///< number of rematrixing bands            (nrematbnd)
  99     int rematrixing_flags[4];               ///< rematrixing flags                      (rematflg)
 100 ///@}
 101
 102 ///@defgroup exponents exponents
 103     int num_exp_groups[AC3_MAX_CHANNELS];           ///< Number of exponent groups      (nexpgrp)
 104     int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS];  ///< decoded exponents
 105     int exp_strategy[MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies            (expstr)
 106 ///@}
 107
 108 ///@defgroup bitalloc bit allocation
 109     AC3BitAllocParameters bit_alloc_params;         ///< bit allocation parameters
 110     int snr_offset[AC3_MAX_CHANNELS];               ///< signal-to-noise ratio offsets  (snroffst)
 111     int fast_gain[AC3_MAX_CHANNELS];                ///< fast gain values/SMR's         (fgain)
 112     uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< bit allocation pointers
 113     int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< scaled exponents
 114     int16_t band_psd[AC3_MAX_CHANNELS][50];         ///< interpolated exponents
 115     int16_t mask[AC3_MAX_CHANNELS][50];             ///< masking curve values
 116     int dba_mode[AC3_MAX_CHANNELS];                 ///< delta bit allocation mode
 117     int dba_nsegs[AC3_MAX_CHANNELS];                ///< number of delta segments
 118     uint8_t dba_offsets[AC3_MAX_CHANNELS][8];       ///< delta segment offsets
 119     uint8_t dba_lengths[AC3_MAX_CHANNELS][8];       ///< delta segment lengths
 120     uint8_t dba_values[AC3_MAX_CHANNELS][8];        ///< delta values for each segment
 121 ///@}
 122
 123 ///@defgroup dithering zero-mantissa dithering
 124     int dither_all;                         ///< true if all channels are dithered
 125     int dither_flag[AC3_MAX_CHANNELS];      ///< dither flags                           (dithflg)
 126     AVRandomState dith_state;               ///< for dither generation
 127 ///@}
 128
 129 ///@defgroup imdct IMDCT
 130     int block_switch[AC3_MAX_CHANNELS];     ///< block switch flags                     (blksw)
 131     MDCTContext imdct_512;                  ///< for 512 sample IMDCT
 132     MDCTContext imdct_256;                  ///< for 256 sample IMDCT
 133 ///@}
 134
 135 ///@defgroup opt optimization
 136     DSPContext dsp;                         ///< for optimization
 137     float add_bias;                         ///< offset for float_to_int16 conversion
 138     float mul_bias;                         ///< scaling for float_to_int16 conversion
 139 ///@}
 140
 141     int fixed_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS];  ///> fixed-point transform coefficients
 142
 143 ///@defgroup arrays aligned arrays
 144     DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]);   ///< transform coefficients
 145     DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]);             ///< delay - added to the next block
 146     DECLARE_ALIGNED_16(float, window[AC3_BLOCK_SIZE]);                              ///< window coefficients
 147     DECLARE_ALIGNED_16(float, tmp_output[AC3_BLOCK_SIZE*2]);                        ///< temporary storage for output before windowing
 148     DECLARE_ALIGNED_16(float, tmp_imdct[AC3_BLOCK_SIZE]);                           ///< temporary storage for imdct transform
 149     DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]);            ///< output after imdct transform and windowing
 150     DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][AC3_BLOCK_SIZE]);      ///< final 16-bit integer output
 151 ///@}
 152 } AC3DecodeContext;
 153
 154 #endif /* FFMPEG_AC3DEC_H */