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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 typedef struct {
  44     AVCodecContext *avctx;                  ///< parent context
  45     GetBitContext gbc;                      ///< bitstream reader
  46     uint8_t *input_buffer;                  ///< temp buffer to prevent overread
  47
  48 ///@defgroup bsi bit stream information
  49 ///@{
  50     int frame_type;                         ///< frame type (strmtyp)
  51     int substreamid;                        ///< substream identification
  52     int frame_size;                         ///< current frame size, in bytes
  53     int bit_rate;                           ///< stream bit rate, in bits-per-second
  54     int sample_rate;                        ///< sample frequency, in Hz
  55     int num_blocks;                         ///< number of audio blocks
  56     int channel_mode;                       ///< channel mode (acmod)
  57     int lfe_on;                             ///< lfe channel in use
  58     int center_mix_level;                   ///< Center mix level index
  59     int surround_mix_level;                 ///< Surround mix level index
  60 ///@}
  61
  62 ///@defgroup cpl standard coupling
  63     int cpl_in_use;                         ///< coupling in use
  64     int channel_in_cpl[AC3_MAX_CHANNELS];   ///< channel in coupling
  65     int phase_flags_in_use;                 ///< phase flags in use
  66     int phase_flags[18];                    ///< phase flags
  67     int num_cpl_subbands;                   ///< number of coupling sub bands
  68     int num_cpl_bands;                      ///< number of coupling bands
  69     int cpl_band_struct[18];                ///< coupling band structure
  70     int cpl_coords[AC3_MAX_CHANNELS][18];   ///< coupling coordinates
  71 ///@}
  72
  73 ///@defgroup channel channel
  74     int fbw_channels;                           ///< number of full-bandwidth channels
  75     int channels;                               ///< number of total channels
  76     int lfe_ch;                                 ///< index of LFE channel
  77     float downmix_coeffs[AC3_MAX_CHANNELS][2];  ///< stereo downmix coefficients
  78     float downmix_coeff_adjust[2];              ///< adjustment needed for each output channel when downmixing
  79     int downmixed;                              ///< indicates if coeffs are currently downmixed
  80     int output_mode;                            ///< output channel configuration
  81     int out_channels;                           ///< number of output channels
  82 ///@}
  83
  84 ///@defgroup dynrng dynamic range
  85     float dynamic_range[2];                 ///< dynamic range
  86 ///@}
  87
  88 ///@defgroup bandwidth bandwidth
  89     int start_freq[AC3_MAX_CHANNELS];       ///< start frequency bin
  90     int end_freq[AC3_MAX_CHANNELS];         ///< end frequency bin
  91 ///@}
  92
  93 ///@defgroup rematrixing rematrixing
  94     int num_rematrixing_bands;              ///< number of rematrixing bands
  95     int rematrixing_flags[4];               ///< rematrixing flags
  96 ///@}
  97
  98 ///@defgroup exponents exponents
  99     int num_exp_groups[AC3_MAX_CHANNELS];   ///< Number of exponent groups
 100     int8_t dexps[AC3_MAX_CHANNELS][256];    ///< decoded exponents
 101     int exp_strategy[AC3_MAX_CHANNELS];     ///< exponent strategies
 102 ///@}
 103
 104 ///@defgroup bitalloc bit allocation
 105     AC3BitAllocParameters bit_alloc_params;     ///< bit allocation parameters
 106     int snr_offset[AC3_MAX_CHANNELS];           ///< signal-to-noise ratio offsets
 107     int fast_gain[AC3_MAX_CHANNELS];            ///< fast gain values (signal-to-mask ratio)
 108     uint8_t bap[AC3_MAX_CHANNELS][256];         ///< bit allocation pointers
 109     int16_t psd[AC3_MAX_CHANNELS][256];         ///< scaled exponents
 110     int16_t band_psd[AC3_MAX_CHANNELS][50];     ///< interpolated exponents
 111     int16_t mask[AC3_MAX_CHANNELS][50];         ///< masking curve values
 112     int dba_mode[AC3_MAX_CHANNELS];             ///< delta bit allocation mode
 113     int dba_nsegs[AC3_MAX_CHANNELS];            ///< number of delta segments
 114     uint8_t dba_offsets[AC3_MAX_CHANNELS][8];   ///< delta segment offsets
 115     uint8_t dba_lengths[AC3_MAX_CHANNELS][8];   ///< delta segment lengths
 116     uint8_t dba_values[AC3_MAX_CHANNELS][8];    ///< delta values for each segment
 117 ///@}
 118
 119 ///@defgroup dithering zero-mantissa dithering
 120     int dither_all;                         ///< true if all channels are dithered
 121     int dither_flag[AC3_MAX_CHANNELS];      ///< dither flags
 122     AVRandomState dith_state;               ///< for dither generation
 123 ///@}
 124
 125 ///@defgroup imdct IMDCT
 126     int block_switch[AC3_MAX_CHANNELS];     ///< block switch flags
 127     MDCTContext imdct_512;                  ///< for 512 sample IMDCT
 128     MDCTContext imdct_256;                  ///< for 256 sample IMDCT
 129 ///@}
 130
 131 ///@defgroup opt optimization
 132     DSPContext dsp;                         ///< for optimization
 133     float add_bias;                         ///< offset for float_to_int16 conversion
 134     float mul_bias;                         ///< scaling for float_to_int16 conversion
 135 ///@}
 136
 137     int fixed_coeffs[AC3_MAX_CHANNELS][256];    ///> fixed-point transform coefficients
 138
 139 ///@defgroup arrays aligned arrays
 140     DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); ///< transform coefficients
 141     DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS][256]);            ///< delay - added to the next block
 142     DECLARE_ALIGNED_16(float, window[256]);                             ///< window coefficients
 143     DECLARE_ALIGNED_16(float, tmp_output[512]);                         ///< temporary storage for output before windowing
 144     DECLARE_ALIGNED_16(float, tmp_imdct[256]);                          ///< temporary storage for imdct transform
 145     DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS][256]);           ///< output after imdct transform and windowing
 146     DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]);     ///< final 16-bit integer output
 147 ///@}
 148 } AC3DecodeContext;
 149
 150 #endif /* FFMPEG_AC3DEC_H */