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/*
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 * AC-3 Audio Decoder
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 * This code is developed as part of Google Summer of Code 2006 Program.
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 *
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 * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com).
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 * Copyright (c) 2007 Justin Ruggles
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 *
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 * Portions of this code are derived from liba52
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 * http://liba52.sourceforge.net
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 * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
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 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
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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 General Public
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 * License as published by the Free Software Foundation; either
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 * version 2 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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 * General Public License for more details.
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 *
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 * You should have received a copy of the GNU 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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#include <stdio.h>
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#include <stddef.h>
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#include <math.h>
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#include <string.h>
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#include "avcodec.h"
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#include "ac3_parser.h"
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#include "bitstream.h"
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#include "dsputil.h"
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#include "random.h"
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/**
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 * Table of bin locations for rematrixing bands
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 * reference: Section 7.5.2 Rematrixing : Frequency Band Definitions
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 */
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static const uint8_t rematrix_band_tbl[5] = { 13, 25, 37, 61, 253 };
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/* table for exponent to scale_factor mapping
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 * scale_factor[i] = 2 ^ -(i + 15)
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 */
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static float scale_factors[25];
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/** table for grouping exponents */
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static uint8_t exp_ungroup_tbl[128][3];
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/** tables for ungrouping mantissas */
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static float b1_mantissas[32][3];
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static float b2_mantissas[128][3];
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static float b3_mantissas[8];
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static float b4_mantissas[128][2];
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static float b5_mantissas[16];
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/**
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 * Quantization table: levels for symmetric. bits for asymmetric.
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 * reference: Table 7.18 Mapping of bap to Quantizer
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 */
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static const uint8_t qntztab[16] = {
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    0, 3, 5, 7, 11, 15,
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    5, 6, 7, 8, 9, 10, 11, 12, 14, 16
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};
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/** dynamic range table. converts codes to scale factors. */
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static float dynrng_tbl[256];
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/** dialogue normalization table */
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static float dialnorm_tbl[32];
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/* Adjustmens in dB gain */
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#define LEVEL_MINUS_3DB         0.7071067811865476
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#define LEVEL_MINUS_4POINT5DB   0.5946035575013605
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#define LEVEL_MINUS_6DB         0.5000000000000000
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#define LEVEL_MINUS_9DB         0.3535533905932738
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#define LEVEL_ZERO              0.0000000000000000
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#define LEVEL_ONE               1.0000000000000000
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static const float gain_levels[6] = {
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    LEVEL_ZERO,
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    LEVEL_ONE,
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    LEVEL_MINUS_3DB,
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    LEVEL_MINUS_4POINT5DB,
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    LEVEL_MINUS_6DB,
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    LEVEL_MINUS_9DB
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};
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/**
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 * Table for center mix levels
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 * reference: Section 5.4.2.4 cmixlev
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 */
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static const uint8_t clevs[4] = { 2, 3, 4, 3 };
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/**
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 * Table for surround mix levels
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 * reference: Section 5.4.2.5 surmixlev
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 */
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static const uint8_t slevs[4] = { 2, 4, 0, 4 };
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/**
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 * Table for default stereo downmixing coefficients
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 * reference: Section 7.8.2 Downmixing Into Two Channels
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 */
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static const uint8_t ac3_default_coeffs[8][5][2] = {
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    { { 1, 0 }, { 0, 1 },                               },
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    { { 2, 2 },                                         },
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    { { 1, 0 }, { 0, 1 },                               },
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    { { 1, 0 }, { 3, 3 }, { 0, 1 },                     },
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    { { 1, 0 }, { 0, 1 }, { 4, 4 },                     },
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    { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 5, 5 },           },
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    { { 1, 0 }, { 0, 1 }, { 4, 0 }, { 0, 4 },           },
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    { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
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};
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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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typedef struct {
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    int acmod;
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    int dsurmod;
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    int blksw[AC3_MAX_CHANNELS];
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    int dithflag[AC3_MAX_CHANNELS];
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    int dither_all;
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    int cplinu;
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    int chincpl[AC3_MAX_CHANNELS];
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    int phsflginu;
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    int cplbndstrc[18];
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    int rematstr;
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    int nrematbnd;
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    int rematflg[4];
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    int expstr[AC3_MAX_CHANNELS];
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    int snroffst[AC3_MAX_CHANNELS];
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    int fgain[AC3_MAX_CHANNELS];
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    int deltbae[AC3_MAX_CHANNELS];
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    int deltnseg[AC3_MAX_CHANNELS];
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    uint8_t  deltoffst[AC3_MAX_CHANNELS][8];
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    uint8_t  deltlen[AC3_MAX_CHANNELS][8];
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    uint8_t  deltba[AC3_MAX_CHANNELS][8];
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    /* Derived Attributes. */
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    int      sampling_rate;
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    int      bit_rate;
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    int      frame_size;
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    int      nchans;            //number of total channels
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    int      nfchans;           //number of full-bandwidth channels
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    int      lfeon;             //lfe channel in use
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    int      lfe_ch;            ///< index of LFE channel
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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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    float    downmix_coeffs[AC3_MAX_CHANNELS][2];   ///< stereo downmix coefficients
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    float    dialnorm[2];                       ///< dialogue normalization
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    float    dynrng;            //dynamic range gain
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    float    dynrng2;           //dynamic range gain for 1+1 mode
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    float    cplco[AC3_MAX_CHANNELS][18];   //coupling coordinates
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    int      ncplbnd;           //number of coupling bands
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    int      ncplsubnd;         //number of coupling sub bands
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    int      startmant[AC3_MAX_CHANNELS];   ///< start frequency bin
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    int      endmant[AC3_MAX_CHANNELS];     //channel end mantissas
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    AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
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    int8_t   dexps[AC3_MAX_CHANNELS][256];  ///< decoded exponents
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    uint8_t  bap[AC3_MAX_CHANNELS][256];    ///< bit allocation pointers
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    int16_t  psd[AC3_MAX_CHANNELS][256];    ///< scaled exponents
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    int16_t  bndpsd[AC3_MAX_CHANNELS][50];  ///< interpolated exponents
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    int16_t  mask[AC3_MAX_CHANNELS][50];    ///< masking curve values
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    DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]);  //transform coefficients
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    /* For IMDCT. */
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    MDCTContext imdct_512;  //for 512 sample imdct transform
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    MDCTContext imdct_256;  //for 256 sample imdct transform
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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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    DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS-1][256]); //output after imdct transform and windowing
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    DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]); ///< final 16-bit integer output
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    DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS-1][256]);  //delay - added to the next block
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    DECLARE_ALIGNED_16(float, tmp_imdct[256]);                  //temporary storage for imdct transform
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    DECLARE_ALIGNED_16(float, tmp_output[512]);                 //temporary storage for output before windowing
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    DECLARE_ALIGNED_16(float, window[256]);                     //window coefficients
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    /* Miscellaneous. */
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    GetBitContext gb;
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    AVRandomState dith_state;   //for dither generation
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} AC3DecodeContext;
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/*********** BEGIN INIT HELPER FUNCTIONS ***********/
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/**
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 * Generate a Kaiser-Bessel Derived Window.
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 */
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static void ac3_window_init(float *window)
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{
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   int i, j;
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   double sum = 0.0, bessel, tmp;
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   double local_window[256];
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   double alpha2 = (5.0 * M_PI / 256.0) * (5.0 * M_PI / 256.0);
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   for (i = 0; i < 256; i++) {
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       tmp = i * (256 - i) * alpha2;
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       bessel = 1.0;
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       for (j = 100; j > 0; j--) /* defaul to 100 iterations */
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           bessel = bessel * tmp / (j * j) + 1;
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       sum += bessel;
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       local_window[i] = sum;
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   }
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   sum++;
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   for (i = 0; i < 256; i++)
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       window[i] = sqrt(local_window[i] / sum);
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}
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static inline float
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symmetric_dequant(int code, int levels)
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{
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    return (code - (levels >> 1)) * (2.0f / levels);
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}
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/*
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 * Initialize tables at runtime.
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 */
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static void ac3_tables_init(void)
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{
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    int i;
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    /* generate grouped mantissa tables
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       reference: Section 7.3.5 Ungrouping of Mantissas */
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    for(i=0; i<32; i++) {
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        /* bap=1 mantissas */
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        b1_mantissas[i][0] = symmetric_dequant( i / 9     , 3);
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        b1_mantissas[i][1] = symmetric_dequant((i % 9) / 3, 3);
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        b1_mantissas[i][2] = symmetric_dequant((i % 9) % 3, 3);
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    }
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    for(i=0; i<128; i++) {
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        /* bap=2 mantissas */
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        b2_mantissas[i][0] = symmetric_dequant( i / 25     , 5);
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        b2_mantissas[i][1] = symmetric_dequant((i % 25) / 5, 5);
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        b2_mantissas[i][2] = symmetric_dequant((i % 25) % 5, 5);
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        /* bap=4 mantissas */
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        b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
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        b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
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    }
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    /* generate ungrouped mantissa tables
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       reference: Tables 7.21 and 7.23 */
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    for(i=0; i<7; i++) {
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        /* bap=3 mantissas */
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        b3_mantissas[i] = symmetric_dequant(i, 7);
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    }
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    for(i=0; i<15; i++) {
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        /* bap=5 mantissas */
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        b5_mantissas[i] = symmetric_dequant(i, 15);
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    }
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    /* generate dynamic range table
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       reference: Section 7.7.1 Dynamic Range Control */
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    for(i=0; i<256; i++) {
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        int v = (i >> 5) - ((i >> 7) << 3) - 5;
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        dynrng_tbl[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
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    }
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    /* generate dialogue normalization table
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       references: Section 5.4.2.8 dialnorm
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                   Section 7.6 Dialogue Normalization */
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    for(i=1; i<32; i++) {
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        dialnorm_tbl[i] = expf((i-31) * M_LN10 / 20.0f);
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    }
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    dialnorm_tbl[0] = dialnorm_tbl[31];
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    //generate scale factors
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    for (i = 0; i < 25; i++)
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        scale_factors[i] = pow(2.0, -i);
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    /* generate exponent tables
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       reference: Section 7.1.3 Exponent Decoding */
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    for(i=0; i<128; i++) {
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        exp_ungroup_tbl[i][0] =  i / 25;
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        exp_ungroup_tbl[i][1] = (i % 25) / 5;
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        exp_ungroup_tbl[i][2] = (i % 25) % 5;
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    }
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}
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static int ac3_decode_init(AVCodecContext *avctx)
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{
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    AC3DecodeContext *ctx = avctx->priv_data;
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    ac3_common_init();
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    ac3_tables_init();
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    ff_mdct_init(&ctx->imdct_256, 8, 1);
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    ff_mdct_init(&ctx->imdct_512, 9, 1);
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    ac3_window_init(ctx->window);
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    dsputil_init(&ctx->dsp, avctx);
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    av_init_random(0, &ctx->dith_state);
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    if(ctx->dsp.float_to_int16 == ff_float_to_int16_c) {
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        ctx->add_bias = 385.0f;
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        ctx->mul_bias = 1.0f;
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    } else {
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        ctx->add_bias = 0.0f;
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        ctx->mul_bias = 32767.0f;
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    }
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    return 0;
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}
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/*********** END INIT FUNCTIONS ***********/
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/**
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 * Parses the 'sync info' and 'bit stream info' from the AC-3 bitstream.
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 * GetBitContext within AC3DecodeContext must point to
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 * start of the synchronized ac3 bitstream.
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 */
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static int ac3_parse_header(AC3DecodeContext *ctx)
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{
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    AC3HeaderInfo hdr;
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    GetBitContext *gb = &ctx->gb;
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    float cmixlev, surmixlev;
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    int err, i;
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    err = ff_ac3_parse_header(gb->buffer, &hdr);
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    if(err)
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        return err;
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    /* get decoding parameters from header info */
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    ctx->bit_alloc_params.fscod       = hdr.fscod;
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    ctx->acmod                        = hdr.acmod;
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    cmixlev                           = gain_levels[clevs[hdr.cmixlev]];
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    surmixlev                         = gain_levels[slevs[hdr.surmixlev]];
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    ctx->dsurmod                      = hdr.dsurmod;
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    ctx->lfeon                        = hdr.lfeon;
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    ctx->bit_alloc_params.halfratecod = hdr.halfratecod;
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    ctx->sampling_rate                = hdr.sample_rate;
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    ctx->bit_rate                     = hdr.bit_rate;
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    ctx->nchans                       = hdr.channels;
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    ctx->nfchans                      = ctx->nchans - ctx->lfeon;
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    ctx->lfe_ch                       = ctx->nfchans + 1;
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    ctx->frame_size                   = hdr.frame_size;
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    /* set default output to all source channels */
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    ctx->out_channels = ctx->nchans;
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    ctx->output_mode = ctx->acmod;
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    if(ctx->lfeon)
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        ctx->output_mode |= AC3_OUTPUT_LFEON;
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    /* skip over portion of header which has already been read */
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    skip_bits(gb, 16); //skip the sync_word, sync_info->sync_word = get_bits(gb, 16);
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    skip_bits(gb, 16); // skip crc1
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    skip_bits(gb, 8);  // skip fscod and frmsizecod
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    skip_bits(gb, 11); // skip bsid, bsmod, and acmod
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    if(ctx->acmod == AC3_ACMOD_STEREO) {
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        skip_bits(gb, 2); // skip dsurmod
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    } else {
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        if((ctx->acmod & 1) && ctx->acmod != AC3_ACMOD_MONO)
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            skip_bits(gb, 2); // skip cmixlev
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        if(ctx->acmod & 4)
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            skip_bits(gb, 2); // skip surmixlev
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    }
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    skip_bits1(gb); // skip lfeon
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    /* read the rest of the bsi. read twice for dual mono mode. */
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    i = !(ctx->acmod);
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    do {
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        ctx->dialnorm[i] = dialnorm_tbl[get_bits(gb, 5)]; // dialogue normalization
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        if (get_bits1(gb))
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            skip_bits(gb, 8); //skip compression
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        if (get_bits1(gb))
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            skip_bits(gb, 8); //skip language code
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        if (get_bits1(gb))
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            skip_bits(gb, 7); //skip audio production information
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    } while (i--);
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    skip_bits(gb, 2); //skip copyright bit and original bitstream bit
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    /* FIXME: read & use the xbsi1 downmix levels */
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    if (get_bits1(gb))
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        skip_bits(gb, 14); //skip timecode1
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    if (get_bits1(gb))
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        skip_bits(gb, 14); //skip timecode2
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    if (get_bits1(gb)) {
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        i = get_bits(gb, 6); //additional bsi length
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        do {
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            skip_bits(gb, 8);
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        } while(i--);
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    }
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    /* set stereo downmixing coefficients
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       reference: Section 7.8.2 Downmixing Into Two Channels */
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    for(i=0; i<ctx->nfchans; i++) {
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        ctx->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[ctx->acmod][i][0]];
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        ctx->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[ctx->acmod][i][1]];
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    }
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    if(ctx->acmod > 1 && ctx->acmod & 1) {
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        ctx->downmix_coeffs[1][0] = ctx->downmix_coeffs[1][1] = cmixlev;
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    }
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    if(ctx->acmod == AC3_ACMOD_2F1R || ctx->acmod == AC3_ACMOD_3F1R) {
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        int nf = ctx->acmod - 2;
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        ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf][1] = surmixlev * LEVEL_MINUS_3DB;
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    }
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    if(ctx->acmod == AC3_ACMOD_2F2R || ctx->acmod == AC3_ACMOD_3F2R) {
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        int nf = ctx->acmod - 4;
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        ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf+1][1] = surmixlev;
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    }
418
419 9fc1ab72 Justin Ruggles
    return 0;
420 2aa2c5c4 Justin Ruggles
}
421
422 3bb004fc Justin Ruggles
/**
423
 * Decodes the grouped exponents.
424 c7cfc48f Justin Ruggles
 * This function decodes the coded exponents according to exponent strategy
425
 * and stores them in the decoded exponents buffer.
426
 *
427 3bb004fc Justin Ruggles
 * @param[in]  gb      GetBitContext which points to start of coded exponents
428
 * @param[in]  expstr  Exponent coding strategy
429
 * @param[in]  ngrps   Number of grouped exponents
430
 * @param[in]  absexp  Absolute exponent or DC exponent
431
 * @param[out] dexps   Decoded exponents are stored in dexps
432 2aa2c5c4 Justin Ruggles
 */
433 4415076f Justin Ruggles
static void decode_exponents(GetBitContext *gb, int expstr, int ngrps,
434 bc8edb7e Justin Ruggles
                             uint8_t absexp, int8_t *dexps)
435 2aa2c5c4 Justin Ruggles
{
436 4415076f Justin Ruggles
    int i, j, grp, grpsize;
437
    int dexp[256];
438
    int expacc, prevexp;
439
440
    /* unpack groups */
441
    grpsize = expstr + (expstr == EXP_D45);
442
    for(grp=0,i=0; grp<ngrps; grp++) {
443
        expacc = get_bits(gb, 7);
444
        dexp[i++] = exp_ungroup_tbl[expacc][0];
445
        dexp[i++] = exp_ungroup_tbl[expacc][1];
446
        dexp[i++] = exp_ungroup_tbl[expacc][2];
447
    }
448 2aa2c5c4 Justin Ruggles
449 4415076f Justin Ruggles
    /* convert to absolute exps and expand groups */
450
    prevexp = absexp;
451
    for(i=0; i<ngrps*3; i++) {
452
        prevexp = av_clip(prevexp + dexp[i]-2, 0, 24);
453
        for(j=0; j<grpsize; j++) {
454
            dexps[(i*grpsize)+j] = prevexp;
455 1b293437 Justin Ruggles
        }
456 2aa2c5c4 Justin Ruggles
    }
457
}
458
459 d7dc7ad0 Justin Ruggles
/**
460
 * Generates transform coefficients for each coupled channel in the coupling
461
 * range using the coupling coefficients and coupling coordinates.
462
 * reference: Section 7.4.3 Coupling Coordinate Format
463
 */
464
static void uncouple_channels(AC3DecodeContext *ctx)
465
{
466
    int i, j, ch, bnd, subbnd;
467
468
    subbnd = -1;
469 7b4076a7 Justin Ruggles
    i = ctx->startmant[CPL_CH];
470 d7dc7ad0 Justin Ruggles
    for(bnd=0; bnd<ctx->ncplbnd; bnd++) {
471
        do {
472
            subbnd++;
473
            for(j=0; j<12; j++) {
474
                for(ch=1; ch<=ctx->nfchans; ch++) {
475 7b4076a7 Justin Ruggles
                    if(ctx->chincpl[ch])
476
                        ctx->transform_coeffs[ch][i] = ctx->transform_coeffs[CPL_CH][i] * ctx->cplco[ch][bnd] * 8.0f;
477 d7dc7ad0 Justin Ruggles
                }
478
                i++;
479
            }
480 6d96d626 Justin Ruggles
        } while(ctx->cplbndstrc[subbnd]);
481 d7dc7ad0 Justin Ruggles
    }
482
}
483
484 486637af Justin Ruggles
typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantization */
485 5aefe3eb Justin Ruggles
    float b1_mant[3];
486
    float b2_mant[3];
487
    float b4_mant[2];
488
    int b1ptr;
489
    int b2ptr;
490
    int b4ptr;
491 486637af Justin Ruggles
} mant_groups;
492
493 1b293437 Justin Ruggles
/* Get the transform coefficients for particular channel */
494 2fbbd087 Justin Ruggles
static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_groups *m)
495 1b293437 Justin Ruggles
{
496 2fbbd087 Justin Ruggles
    GetBitContext *gb = &ctx->gb;
497 60f07fad Justin Ruggles
    int i, gcode, tbap, start, end;
498 2fbbd087 Justin Ruggles
    uint8_t *exps;
499
    uint8_t *bap;
500
    float *coeffs;
501
502 775369e0 Justin Ruggles
    exps = ctx->dexps[ch_index];
503
    bap = ctx->bap[ch_index];
504
    coeffs = ctx->transform_coeffs[ch_index];
505
    start = ctx->startmant[ch_index];
506
    end = ctx->endmant[ch_index];
507 1b293437 Justin Ruggles
508 2fbbd087 Justin Ruggles
509 285bf28c Justin Ruggles
    for (i = start; i < end; i++) {
510 98a27a8a Justin Ruggles
        tbap = bap[i];
511
        switch (tbap) {
512 1b293437 Justin Ruggles
            case 0:
513 5aefe3eb Justin Ruggles
                coeffs[i] = ((av_random(&ctx->dith_state) & 0xFFFF) * LEVEL_MINUS_3DB) / 32768.0f;
514 d63f6fea Justin Ruggles
                break;
515 1b293437 Justin Ruggles
516
            case 1:
517 5aefe3eb Justin Ruggles
                if(m->b1ptr > 2) {
518 00585845 Justin Ruggles
                    gcode = get_bits(gb, 5);
519 5aefe3eb Justin Ruggles
                    m->b1_mant[0] = b1_mantissas[gcode][0];
520
                    m->b1_mant[1] = b1_mantissas[gcode][1];
521
                    m->b1_mant[2] = b1_mantissas[gcode][2];
522
                    m->b1ptr = 0;
523 1b293437 Justin Ruggles
                }
524 5aefe3eb Justin Ruggles
                coeffs[i] = m->b1_mant[m->b1ptr++];
525 d63f6fea Justin Ruggles
                break;
526 1b293437 Justin Ruggles
527
            case 2:
528 5aefe3eb Justin Ruggles
                if(m->b2ptr > 2) {
529 00585845 Justin Ruggles
                    gcode = get_bits(gb, 7);
530 5aefe3eb Justin Ruggles
                    m->b2_mant[0] = b2_mantissas[gcode][0];
531
                    m->b2_mant[1] = b2_mantissas[gcode][1];
532
                    m->b2_mant[2] = b2_mantissas[gcode][2];
533
                    m->b2ptr = 0;
534 1b293437 Justin Ruggles
                }
535 5aefe3eb Justin Ruggles
                coeffs[i] = m->b2_mant[m->b2ptr++];
536 d63f6fea Justin Ruggles
                break;
537 1b293437 Justin Ruggles
538
            case 3:
539 5aefe3eb Justin Ruggles
                coeffs[i] = b3_mantissas[get_bits(gb, 3)];
540 d63f6fea Justin Ruggles
                break;
541 1b293437 Justin Ruggles
542
            case 4:
543 5aefe3eb Justin Ruggles
                if(m->b4ptr > 1) {
544 00585845 Justin Ruggles
                    gcode = get_bits(gb, 7);
545 5aefe3eb Justin Ruggles
                    m->b4_mant[0] = b4_mantissas[gcode][0];
546
                    m->b4_mant[1] = b4_mantissas[gcode][1];
547
                    m->b4ptr = 0;
548 1b293437 Justin Ruggles
                }
549 5aefe3eb Justin Ruggles
                coeffs[i] = m->b4_mant[m->b4ptr++];
550 d63f6fea Justin Ruggles
                break;
551 1b293437 Justin Ruggles
552
            case 5:
553 5aefe3eb Justin Ruggles
                coeffs[i] = b5_mantissas[get_bits(gb, 4)];
554 d63f6fea Justin Ruggles
                break;
555 1b293437 Justin Ruggles
556
            default:
557 5aefe3eb Justin Ruggles
                coeffs[i] = get_sbits(gb, qntztab[tbap]) * scale_factors[qntztab[tbap]-1];
558 d63f6fea Justin Ruggles
                break;
559 1b293437 Justin Ruggles
        }
560 d63f6fea Justin Ruggles
        coeffs[i] *= scale_factors[exps[i]];
561 1b293437 Justin Ruggles
    }
562
563
    return 0;
564
}
565
566 60f07fad Justin Ruggles
/**
567
 * Removes random dithering from coefficients with zero-bit mantissas
568
 * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
569
 */
570
static void remove_dithering(AC3DecodeContext *ctx) {
571
    int ch, i;
572
    int end=0;
573
    float *coeffs;
574
    uint8_t *bap;
575
576
    for(ch=1; ch<=ctx->nfchans; ch++) {
577 7b4076a7 Justin Ruggles
        if(!ctx->dithflag[ch]) {
578 60f07fad Justin Ruggles
            coeffs = ctx->transform_coeffs[ch];
579 7b4076a7 Justin Ruggles
            bap = ctx->bap[ch];
580
            if(ctx->chincpl[ch])
581
                end = ctx->startmant[CPL_CH];
582 60f07fad Justin Ruggles
            else
583 7b4076a7 Justin Ruggles
                end = ctx->endmant[ch];
584 60f07fad Justin Ruggles
            for(i=0; i<end; i++) {
585
                if(bap[i] == 0)
586
                    coeffs[i] = 0.0f;
587
            }
588 7b4076a7 Justin Ruggles
            if(ctx->chincpl[ch]) {
589
                bap = ctx->bap[CPL_CH];
590
                for(; i<ctx->endmant[CPL_CH]; i++) {
591 60f07fad Justin Ruggles
                    if(bap[i] == 0)
592
                        coeffs[i] = 0.0f;
593
                }
594
            }
595
        }
596
    }
597
}
598
599 c7cfc48f Justin Ruggles
/* Get the transform coefficients.
600
 * This function extracts the tranform coefficients form the ac3 bitstream.
601
 * This function is called after bit allocation is performed.
602
 */
603 1b293437 Justin Ruggles
static int get_transform_coeffs(AC3DecodeContext * ctx)
604
{
605 7b4076a7 Justin Ruggles
    int ch, end;
606 1b293437 Justin Ruggles
    int got_cplchan = 0;
607 486637af Justin Ruggles
    mant_groups m;
608
609 5aefe3eb Justin Ruggles
    m.b1ptr = m.b2ptr = m.b4ptr = 3;
610 1b293437 Justin Ruggles
611 7b4076a7 Justin Ruggles
    for (ch = 1; ch <= ctx->nchans; ch++) {
612 1b293437 Justin Ruggles
        /* transform coefficients for individual channel */
613 75b9b036 Justin Ruggles
        if (get_transform_coeffs_ch(ctx, ch, &m))
614 1b293437 Justin Ruggles
            return -1;
615
        /* tranform coefficients for coupling channels */
616 75b9b036 Justin Ruggles
        if (ctx->chincpl[ch])  {
617 486637af Justin Ruggles
            if (!got_cplchan) {
618 7b4076a7 Justin Ruggles
                if (get_transform_coeffs_ch(ctx, CPL_CH, &m)) {
619 98a27a8a Justin Ruggles
                    av_log(NULL, AV_LOG_ERROR, "error in decoupling channels\n");
620 486637af Justin Ruggles
                    return -1;
621 98a27a8a Justin Ruggles
                }
622 d7dc7ad0 Justin Ruggles
                uncouple_channels(ctx);
623 486637af Justin Ruggles
                got_cplchan = 1;
624
            }
625 7b4076a7 Justin Ruggles
            end = ctx->endmant[CPL_CH];
626 eaf84d97 Justin Ruggles
        } else {
627 75b9b036 Justin Ruggles
            end = ctx->endmant[ch];
628 eaf84d97 Justin Ruggles
        }
629 486637af Justin Ruggles
        do
630 7b4076a7 Justin Ruggles
            ctx->transform_coeffs[ch][end] = 0;
631 486637af Justin Ruggles
        while(++end < 256);
632
    }
633 1b293437 Justin Ruggles
634 60f07fad Justin Ruggles
    /* if any channel doesn't use dithering, zero appropriate coefficients */
635
    if(!ctx->dither_all)
636
        remove_dithering(ctx);
637
638 1b293437 Justin Ruggles
    return 0;
639 2aa2c5c4 Justin Ruggles
}
640
641 8b60bbbf Justin Ruggles
/**
642
 * Performs stereo rematrixing.
643
 * reference: Section 7.5.4 Rematrixing : Decoding Technique
644
 */
645 1b293437 Justin Ruggles
static void do_rematrixing(AC3DecodeContext *ctx)
646
{
647 8b60bbbf Justin Ruggles
    int bnd, i;
648 2fbbd087 Justin Ruggles
    int end, bndend;
649 8b60bbbf Justin Ruggles
    float tmp0, tmp1;
650 2fbbd087 Justin Ruggles
651 7b4076a7 Justin Ruggles
    end = FFMIN(ctx->endmant[1], ctx->endmant[2]);
652 1b293437 Justin Ruggles
653 8b60bbbf Justin Ruggles
    for(bnd=0; bnd<ctx->nrematbnd; bnd++) {
654
        if(ctx->rematflg[bnd]) {
655
            bndend = FFMIN(end, rematrix_band_tbl[bnd+1]);
656
            for(i=rematrix_band_tbl[bnd]; i<bndend; i++) {
657
                tmp0 = ctx->transform_coeffs[1][i];
658
                tmp1 = ctx->transform_coeffs[2][i];
659
                ctx->transform_coeffs[1][i] = tmp0 + tmp1;
660
                ctx->transform_coeffs[2][i] = tmp0 - tmp1;
661
            }
662
        }
663 1b293437 Justin Ruggles
    }
664
}
665 2aa2c5c4 Justin Ruggles
666 c7cfc48f Justin Ruggles
/* This function performs the imdct on 256 sample transform
667
 * coefficients.
668
 */
669 45b0ed13 Justin Ruggles
static void do_imdct_256(AC3DecodeContext *ctx, int chindex)
670 486637af Justin Ruggles
{
671 0de73a46 Justin Ruggles
    int i, k;
672 dfd57c36 Justin Ruggles
    DECLARE_ALIGNED_16(float, x[128]);
673 0de73a46 Justin Ruggles
    FFTComplex z[2][64];
674
    float *o_ptr = ctx->tmp_output;
675
676
    for(i=0; i<2; i++) {
677
        /* de-interleave coefficients */
678
        for(k=0; k<128; k++) {
679
            x[k] = ctx->transform_coeffs[chindex][2*k+i];
680
        }
681 98a27a8a Justin Ruggles
682 0de73a46 Justin Ruggles
        /* run standard IMDCT */
683
        ctx->imdct_256.fft.imdct_calc(&ctx->imdct_256, o_ptr, x, ctx->tmp_imdct);
684
685
        /* reverse the post-rotation & reordering from standard IMDCT */
686
        for(k=0; k<32; k++) {
687
            z[i][32+k].re = -o_ptr[128+2*k];
688
            z[i][32+k].im = -o_ptr[2*k];
689
            z[i][31-k].re =  o_ptr[2*k+1];
690
            z[i][31-k].im =  o_ptr[128+2*k+1];
691
        }
692 1ea76064 Justin Ruggles
    }
693 486637af Justin Ruggles
694 0de73a46 Justin Ruggles
    /* apply AC-3 post-rotation & reordering */
695
    for(k=0; k<64; k++) {
696
        o_ptr[    2*k  ] = -z[0][   k].im;
697
        o_ptr[    2*k+1] =  z[0][63-k].re;
698
        o_ptr[128+2*k  ] = -z[0][   k].re;
699
        o_ptr[128+2*k+1] =  z[0][63-k].im;
700
        o_ptr[256+2*k  ] = -z[1][   k].re;
701
        o_ptr[256+2*k+1] =  z[1][63-k].im;
702
        o_ptr[384+2*k  ] =  z[1][   k].im;
703
        o_ptr[384+2*k+1] = -z[1][63-k].re;
704
    }
705 98a27a8a Justin Ruggles
}
706 486637af Justin Ruggles
707 c7cfc48f Justin Ruggles
/* IMDCT Transform. */
708 486637af Justin Ruggles
static inline void do_imdct(AC3DecodeContext *ctx)
709
{
710 0de73a46 Justin Ruggles
    int ch;
711 7b4076a7 Justin Ruggles
    int nchans;
712 486637af Justin Ruggles
713 7b4076a7 Justin Ruggles
    nchans = ctx->nfchans;
714
    if(ctx->output_mode & AC3_OUTPUT_LFEON)
715
        nchans++;
716
717
    for (ch=1; ch<=nchans; ch++) {
718
        if (ctx->blksw[ch]) {
719 0de73a46 Justin Ruggles
            do_imdct_256(ctx, ch);
720 eaf84d97 Justin Ruggles
        } else {
721 0de73a46 Justin Ruggles
            ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output,
722
                                          ctx->transform_coeffs[ch],
723
                                          ctx->tmp_imdct);
724 eaf84d97 Justin Ruggles
        }
725 7b4076a7 Justin Ruggles
        ctx->dsp.vector_fmul_add_add(ctx->output[ch-1], ctx->tmp_output,
726 3bbb0bf8 Justin Ruggles
                                     ctx->window, ctx->delay[ch-1], 0, 256, 1);
727 7b4076a7 Justin Ruggles
        ctx->dsp.vector_fmul_reverse(ctx->delay[ch-1], ctx->tmp_output+256,
728 0de73a46 Justin Ruggles
                                     ctx->window, 256);
729 486637af Justin Ruggles
    }
730
}
731
732 3bbb0bf8 Justin Ruggles
/**
733
 * Downmixes the output to stereo.
734
 */
735
static void ac3_downmix(float samples[AC3_MAX_CHANNELS][256], int nfchans,
736
                        int output_mode, float coef[AC3_MAX_CHANNELS][2])
737
{
738
    int i, j;
739
    float v0, v1, s0, s1;
740
741
    for(i=0; i<256; i++) {
742
        v0 = v1 = s0 = s1 = 0.0f;
743
        for(j=0; j<nfchans; j++) {
744
            v0 += samples[j][i] * coef[j][0];
745
            v1 += samples[j][i] * coef[j][1];
746
            s0 += coef[j][0];
747
            s1 += coef[j][1];
748
        }
749
        v0 /= s0;
750
        v1 /= s1;
751
        if(output_mode == AC3_ACMOD_MONO) {
752
            samples[0][i] = (v0 + v1) * LEVEL_MINUS_3DB;
753
        } else if(output_mode == AC3_ACMOD_STEREO) {
754
            samples[0][i] = v0;
755
            samples[1][i] = v1;
756
        }
757
    }
758
}
759
760 c7cfc48f Justin Ruggles
/* Parse the audio block from ac3 bitstream.
761
 * This function extract the audio block from the ac3 bitstream
762
 * and produces the output for the block. This function must
763
 * be called for each of the six audio block in the ac3 bitstream.
764
 */
765 9fc1ab72 Justin Ruggles
static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
766 2aa2c5c4 Justin Ruggles
{
767 98a27a8a Justin Ruggles
    int nfchans = ctx->nfchans;
768
    int acmod = ctx->acmod;
769 0bff58a5 Justin Ruggles
    int i, bnd, seg, ch;
770 1b293437 Justin Ruggles
    GetBitContext *gb = &ctx->gb;
771 7b4076a7 Justin Ruggles
    uint8_t bit_alloc_stages[AC3_MAX_CHANNELS];
772 1b293437 Justin Ruggles
773 7b4076a7 Justin Ruggles
    memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
774
775
    for (ch = 1; ch <= nfchans; ch++) /*block switch flag */
776 75b9b036 Justin Ruggles
        ctx->blksw[ch] = get_bits1(gb);
777 98a27a8a Justin Ruggles
778 60f07fad Justin Ruggles
    ctx->dither_all = 1;
779 7b4076a7 Justin Ruggles
    for (ch = 1; ch <= nfchans; ch++) { /* dithering flag */
780 75b9b036 Justin Ruggles
        ctx->dithflag[ch] = get_bits1(gb);
781
        if(!ctx->dithflag[ch])
782 60f07fad Justin Ruggles
            ctx->dither_all = 0;
783
    }
784 98a27a8a Justin Ruggles
785 00585845 Justin Ruggles
    if (get_bits1(gb)) { /* dynamic range */
786 3357ff33 Justin Ruggles
        ctx->dynrng = dynrng_tbl[get_bits(gb, 8)];
787 9fc1ab72 Justin Ruggles
    } else if(blk == 0) {
788
        ctx->dynrng = 1.0;
789 1b293437 Justin Ruggles
    }
790 98a27a8a Justin Ruggles
791 9fc1ab72 Justin Ruggles
    if(acmod == AC3_ACMOD_DUALMONO) { /* dynamic range 1+1 mode */
792
        if(get_bits1(gb)) {
793 3357ff33 Justin Ruggles
            ctx->dynrng2 = dynrng_tbl[get_bits(gb, 8)];
794 9fc1ab72 Justin Ruggles
        } else if(blk == 0) {
795
            ctx->dynrng2 = 1.0;
796
        }
797 98a27a8a Justin Ruggles
    }
798
799 00585845 Justin Ruggles
    if (get_bits1(gb)) { /* coupling strategy */
800 7b4076a7 Justin Ruggles
        memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
801 98a27a8a Justin Ruggles
        ctx->cplinu = get_bits1(gb);
802
        if (ctx->cplinu) { /* coupling in use */
803 b6acc57f Justin Ruggles
            int cplbegf, cplendf;
804
805 7b4076a7 Justin Ruggles
            for (ch = 1; ch <= nfchans; ch++)
806 75b9b036 Justin Ruggles
                ctx->chincpl[ch] = get_bits1(gb);
807 98a27a8a Justin Ruggles
808 e2cd6686 Justin Ruggles
            if (acmod == AC3_ACMOD_STEREO)
809 98a27a8a Justin Ruggles
                ctx->phsflginu = get_bits1(gb); //phase flag in use
810
811 b6acc57f Justin Ruggles
            cplbegf = get_bits(gb, 4);
812
            cplendf = get_bits(gb, 4);
813 98a27a8a Justin Ruggles
814 b6acc57f Justin Ruggles
            if (3 + cplendf - cplbegf < 0) {
815
                av_log(NULL, AV_LOG_ERROR, "cplendf = %d < cplbegf = %d\n", cplendf, cplbegf);
816 00585845 Justin Ruggles
                return -1;
817 98a27a8a Justin Ruggles
            }
818
819 b6acc57f Justin Ruggles
            ctx->ncplbnd = ctx->ncplsubnd = 3 + cplendf - cplbegf;
820 7b4076a7 Justin Ruggles
            ctx->startmant[CPL_CH] = cplbegf * 12 + 37;
821
            ctx->endmant[CPL_CH] = cplendf * 12 + 73;
822 75b9b036 Justin Ruggles
            for (bnd = 0; bnd < ctx->ncplsubnd - 1; bnd++) { /* coupling band structure */
823 00585845 Justin Ruggles
                if (get_bits1(gb)) {
824 75b9b036 Justin Ruggles
                    ctx->cplbndstrc[bnd] = 1;
825 98a27a8a Justin Ruggles
                    ctx->ncplbnd--;
826 1b293437 Justin Ruggles
                }
827 eaf84d97 Justin Ruggles
            }
828 878c40a1 Justin Ruggles
        } else {
829 7b4076a7 Justin Ruggles
            for (ch = 1; ch <= nfchans; ch++)
830 75b9b036 Justin Ruggles
                ctx->chincpl[ch] = 0;
831 1b293437 Justin Ruggles
        }
832
    }
833 98a27a8a Justin Ruggles
834
    if (ctx->cplinu) {
835 fc59010b Justin Ruggles
        int cplcoe = 0;
836 98a27a8a Justin Ruggles
837 7b4076a7 Justin Ruggles
        for (ch = 1; ch <= nfchans; ch++) {
838 75b9b036 Justin Ruggles
            if (ctx->chincpl[ch]) {
839 00585845 Justin Ruggles
                if (get_bits1(gb)) { /* coupling co-ordinates */
840 8e2eb3b6 Justin Ruggles
                    int mstrcplco, cplcoexp, cplcomant;
841 fc59010b Justin Ruggles
                    cplcoe = 1;
842 486637af Justin Ruggles
                    mstrcplco = 3 * get_bits(gb, 2);
843 98a27a8a Justin Ruggles
                    for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
844 486637af Justin Ruggles
                        cplcoexp = get_bits(gb, 4);
845
                        cplcomant = get_bits(gb, 4);
846
                        if (cplcoexp == 15)
847 75b9b036 Justin Ruggles
                            ctx->cplco[ch][bnd] = cplcomant / 16.0f;
848 486637af Justin Ruggles
                        else
849 75b9b036 Justin Ruggles
                            ctx->cplco[ch][bnd] = (cplcomant + 16.0f) / 32.0f;
850
                        ctx->cplco[ch][bnd] *= scale_factors[cplcoexp + mstrcplco];
851 486637af Justin Ruggles
                    }
852
                }
853 eaf84d97 Justin Ruggles
            }
854
        }
855 98a27a8a Justin Ruggles
856 eaf84d97 Justin Ruggles
        if (acmod == AC3_ACMOD_STEREO && ctx->phsflginu && cplcoe) {
857
            for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
858 98a27a8a Justin Ruggles
                if (get_bits1(gb))
859 7b4076a7 Justin Ruggles
                    ctx->cplco[2][bnd] = -ctx->cplco[2][bnd];
860 eaf84d97 Justin Ruggles
            }
861
        }
862 2aa2c5c4 Justin Ruggles
    }
863 98a27a8a Justin Ruggles
864 e2cd6686 Justin Ruggles
    if (acmod == AC3_ACMOD_STEREO) {/* rematrixing */
865 98a27a8a Justin Ruggles
        ctx->rematstr = get_bits1(gb);
866
        if (ctx->rematstr) {
867 8b60bbbf Justin Ruggles
            ctx->nrematbnd = 4;
868 7b4076a7 Justin Ruggles
            if(ctx->cplinu && ctx->startmant[CPL_CH] <= 61)
869
                ctx->nrematbnd -= 1 + (ctx->startmant[CPL_CH] == 37);
870 8b60bbbf Justin Ruggles
            for(bnd=0; bnd<ctx->nrematbnd; bnd++)
871
                ctx->rematflg[bnd] = get_bits1(gb);
872 1b293437 Justin Ruggles
        }
873 98a27a8a Justin Ruggles
    }
874
875 7b4076a7 Justin Ruggles
    ctx->expstr[CPL_CH] = EXP_REUSE;
876
    ctx->expstr[ctx->lfe_ch] = EXP_REUSE;
877
    for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) {
878
        if(ch == ctx->lfe_ch)
879
            ctx->expstr[ch] = get_bits(gb, 1);
880
        else
881
            ctx->expstr[ch] = get_bits(gb, 2);
882
        if(ctx->expstr[ch] != EXP_REUSE)
883
            bit_alloc_stages[ch] = 3;
884
    }
885
886
    for (ch = 1; ch <= nfchans; ch++) { /* channel bandwidth code */
887
        ctx->startmant[ch] = 0;
888
        if (ctx->expstr[ch] != EXP_REUSE) {
889
            int prev = ctx->endmant[ch];
890 75b9b036 Justin Ruggles
            if (ctx->chincpl[ch])
891 7b4076a7 Justin Ruggles
                ctx->endmant[ch] = ctx->startmant[CPL_CH];
892 00585845 Justin Ruggles
            else {
893 8e2eb3b6 Justin Ruggles
                int chbwcod = get_bits(gb, 6);
894 98a27a8a Justin Ruggles
                if (chbwcod > 60) {
895
                    av_log(NULL, AV_LOG_ERROR, "chbwcod = %d > 60", chbwcod);
896 00585845 Justin Ruggles
                    return -1;
897
                }
898 75b9b036 Justin Ruggles
                ctx->endmant[ch] = chbwcod * 3 + 73;
899 1b293437 Justin Ruggles
            }
900 7b4076a7 Justin Ruggles
            if(blk > 0 && ctx->endmant[ch] != prev)
901
                memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
902 00585845 Justin Ruggles
        }
903 eaf84d97 Justin Ruggles
    }
904 7b4076a7 Justin Ruggles
    ctx->startmant[ctx->lfe_ch] = 0;
905
    ctx->endmant[ctx->lfe_ch] = 7;
906
907
    for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) {
908
        if (ctx->expstr[ch] != EXP_REUSE) {
909
            int grpsize, ngrps;
910
            grpsize = 3 << (ctx->expstr[ch] - 1);
911
            if(ch == CPL_CH)
912
                ngrps = (ctx->endmant[ch] - ctx->startmant[ch]) / grpsize;
913
            else if(ch == ctx->lfe_ch)
914
                ngrps = 2;
915
            else
916 775369e0 Justin Ruggles
                ngrps = (ctx->endmant[ch] + grpsize - 4) / grpsize;
917 7b4076a7 Justin Ruggles
            ctx->dexps[ch][0] = get_bits(gb, 4) << !ch;
918
            decode_exponents(gb, ctx->expstr[ch], ngrps, ctx->dexps[ch][0],
919
                             &ctx->dexps[ch][ctx->startmant[ch]+!!ch]);
920
            if(ch != CPL_CH && ch != ctx->lfe_ch)
921 775369e0 Justin Ruggles
                skip_bits(gb, 2); /* skip gainrng */
922 1b293437 Justin Ruggles
        }
923 eaf84d97 Justin Ruggles
    }
924 98a27a8a Justin Ruggles
925 00585845 Justin Ruggles
    if (get_bits1(gb)) { /* bit allocation information */
926 8f58a4c9 Justin Ruggles
        ctx->bit_alloc_params.sdecay = ff_sdecaytab[get_bits(gb, 2)];
927
        ctx->bit_alloc_params.fdecay = ff_fdecaytab[get_bits(gb, 2)];
928
        ctx->bit_alloc_params.sgain  = ff_sgaintab[get_bits(gb, 2)];
929
        ctx->bit_alloc_params.dbknee = ff_dbkneetab[get_bits(gb, 2)];
930
        ctx->bit_alloc_params.floor  = ff_floortab[get_bits(gb, 3)];
931 7b4076a7 Justin Ruggles
        for(ch=!ctx->cplinu; ch<=ctx->nchans; ch++) {
932
            bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
933
        }
934 1b293437 Justin Ruggles
    }
935 98a27a8a Justin Ruggles
936 00585845 Justin Ruggles
    if (get_bits1(gb)) { /* snroffset */
937 4611b64e Justin Ruggles
        int csnr;
938
        csnr = (get_bits(gb, 6) - 15) << 4;
939 7b4076a7 Justin Ruggles
        for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) { /* snr offset and fast gain */
940 75b9b036 Justin Ruggles
            ctx->snroffst[ch] = (csnr + get_bits(gb, 4)) << 2;
941
            ctx->fgain[ch] = ff_fgaintab[get_bits(gb, 3)];
942 1b293437 Justin Ruggles
        }
943 7b4076a7 Justin Ruggles
        memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
944 1b293437 Justin Ruggles
    }
945 98a27a8a Justin Ruggles
946
    if (ctx->cplinu && get_bits1(gb)) { /* coupling leak information */
947 8f58a4c9 Justin Ruggles
        ctx->bit_alloc_params.cplfleak = get_bits(gb, 3);
948
        ctx->bit_alloc_params.cplsleak = get_bits(gb, 3);
949 7b4076a7 Justin Ruggles
        bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
950 98a27a8a Justin Ruggles
    }
951
952 00585845 Justin Ruggles
    if (get_bits1(gb)) { /* delta bit allocation information */
953 7b4076a7 Justin Ruggles
        for (ch = !ctx->cplinu; ch <= nfchans; ch++) {
954 75b9b036 Justin Ruggles
            ctx->deltbae[ch] = get_bits(gb, 2);
955
            if (ctx->deltbae[ch] == DBA_RESERVED) {
956 1b293437 Justin Ruggles
                av_log(NULL, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
957
                return -1;
958
            }
959 7b4076a7 Justin Ruggles
            bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
960 1b293437 Justin Ruggles
        }
961 98a27a8a Justin Ruggles
962 7b4076a7 Justin Ruggles
        for (ch = !ctx->cplinu; ch <= nfchans; ch++) {
963 75b9b036 Justin Ruggles
            if (ctx->deltbae[ch] == DBA_NEW) {/*channel delta offset, len and bit allocation */
964
                ctx->deltnseg[ch] = get_bits(gb, 3);
965
                for (seg = 0; seg <= ctx->deltnseg[ch]; seg++) {
966
                    ctx->deltoffst[ch][seg] = get_bits(gb, 5);
967
                    ctx->deltlen[ch][seg] = get_bits(gb, 4);
968
                    ctx->deltba[ch][seg] = get_bits(gb, 3);
969 1b293437 Justin Ruggles
                }
970
            }
971 eaf84d97 Justin Ruggles
        }
972 9fc1ab72 Justin Ruggles
    } else if(blk == 0) {
973 7b4076a7 Justin Ruggles
        for(ch=0; ch<=ctx->nchans; ch++) {
974 75b9b036 Justin Ruggles
            ctx->deltbae[ch] = DBA_NONE;
975 9fc1ab72 Justin Ruggles
        }
976 1b293437 Justin Ruggles
    }
977 00585845 Justin Ruggles
978 7b4076a7 Justin Ruggles
    for(ch=!ctx->cplinu; ch<=ctx->nchans; ch++) {
979
        if(bit_alloc_stages[ch] > 2) {
980
            /* Exponent mapping into PSD and PSD integration */
981
            ff_ac3_bit_alloc_calc_psd(ctx->dexps[ch],
982
                                      ctx->startmant[ch], ctx->endmant[ch],
983
                                      ctx->psd[ch], ctx->bndpsd[ch]);
984 eaf84d97 Justin Ruggles
        }
985 7b4076a7 Justin Ruggles
        if(bit_alloc_stages[ch] > 1) {
986
            /* Compute excitation function, Compute masking curve, and
987
               Apply delta bit allocation */
988
            ff_ac3_bit_alloc_calc_mask(&ctx->bit_alloc_params, ctx->bndpsd[ch],
989
                                       ctx->startmant[ch], ctx->endmant[ch],
990
                                       ctx->fgain[ch], (ch == ctx->lfe_ch),
991
                                       ctx->deltbae[ch], ctx->deltnseg[ch],
992
                                       ctx->deltoffst[ch], ctx->deltlen[ch],
993
                                       ctx->deltba[ch], ctx->mask[ch]);
994 eaf84d97 Justin Ruggles
        }
995 7b4076a7 Justin Ruggles
        if(bit_alloc_stages[ch] > 0) {
996
            /* Compute bit allocation */
997
            ff_ac3_bit_alloc_calc_bap(ctx->mask[ch], ctx->psd[ch],
998
                                      ctx->startmant[ch], ctx->endmant[ch],
999
                                      ctx->snroffst[ch],
1000
                                      ctx->bit_alloc_params.floor,
1001
                                      ctx->bap[ch]);
1002 eaf84d97 Justin Ruggles
        }
1003 2fbbd087 Justin Ruggles
    }
1004 98a27a8a Justin Ruggles
1005 00585845 Justin Ruggles
    if (get_bits1(gb)) { /* unused dummy data */
1006 8e2eb3b6 Justin Ruggles
        int skipl = get_bits(gb, 9);
1007 98a27a8a Justin Ruggles
        while(skipl--)
1008 00585845 Justin Ruggles
            skip_bits(gb, 8);
1009 1b293437 Justin Ruggles
    }
1010
    /* unpack the transform coefficients
1011
     * * this also uncouples channels if coupling is in use.
1012
     */
1013
    if (get_transform_coeffs(ctx)) {
1014
        av_log(NULL, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
1015
        return -1;
1016
    }
1017 486637af Justin Ruggles
1018 1b293437 Justin Ruggles
    /* recover coefficients if rematrixing is in use */
1019 878c40a1 Justin Ruggles
    if(ctx->acmod == AC3_ACMOD_STEREO)
1020 1b293437 Justin Ruggles
        do_rematrixing(ctx);
1021
1022 01f35453 Justin Ruggles
    /* apply scaling to coefficients (headroom, dialnorm, dynrng) */
1023 7b4076a7 Justin Ruggles
    for(ch=1; ch<=ctx->nchans; ch++) {
1024 4e092320 Justin Ruggles
        float gain = 2.0f * ctx->mul_bias;
1025 7bfd22f2 Justin Ruggles
        if(ctx->acmod == AC3_ACMOD_DUALMONO && ch == 2) {
1026 01f35453 Justin Ruggles
            gain *= ctx->dialnorm[ch-1] * ctx->dynrng2;
1027 7bfd22f2 Justin Ruggles
        } else {
1028 01f35453 Justin Ruggles
            gain *= ctx->dialnorm[0] * ctx->dynrng;
1029 7bfd22f2 Justin Ruggles
        }
1030 7b4076a7 Justin Ruggles
        for(i=0; i<ctx->endmant[ch]; i++) {
1031 7bfd22f2 Justin Ruggles
            ctx->transform_coeffs[ch][i] *= gain;
1032
        }
1033
    }
1034 d7bcc4ad Justin Ruggles
1035 486637af Justin Ruggles
    do_imdct(ctx);
1036
1037 3bbb0bf8 Justin Ruggles
    /* downmix output if needed */
1038
    if(ctx->nchans != ctx->out_channels && !((ctx->output_mode & AC3_OUTPUT_LFEON) &&
1039
            ctx->nfchans == ctx->out_channels)) {
1040
        ac3_downmix(ctx->output, ctx->nfchans, ctx->output_mode,
1041
                    ctx->downmix_coeffs);
1042
    }
1043
1044 4e092320 Justin Ruggles
    /* convert float to 16-bit integer */
1045
    for(ch=0; ch<ctx->out_channels; ch++) {
1046 3bbb0bf8 Justin Ruggles
        for(i=0; i<256; i++) {
1047
            ctx->output[ch][i] += ctx->add_bias;
1048
        }
1049 4e092320 Justin Ruggles
        ctx->dsp.float_to_int16(ctx->int_output[ch], ctx->output[ch], 256);
1050
    }
1051 1b293437 Justin Ruggles
1052 4e092320 Justin Ruggles
    return 0;
1053 486637af Justin Ruggles
}
1054
1055 c7cfc48f Justin Ruggles
/* Decode ac3 frame.
1056
 *
1057
 * @param avctx Pointer to AVCodecContext
1058
 * @param data Pointer to pcm smaples
1059
 * @param data_size Set to number of pcm samples produced by decoding
1060
 * @param buf Data to be decoded
1061
 * @param buf_size Size of the buffer
1062
 */
1063 00585845 Justin Ruggles
static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
1064 1b293437 Justin Ruggles
{
1065 00585845 Justin Ruggles
    AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
1066
    int16_t *out_samples = (int16_t *)data;
1067 7b4076a7 Justin Ruggles
    int i, blk, ch;
1068 d7bcc4ad Justin Ruggles
1069 1b293437 Justin Ruggles
    //Initialize the GetBitContext with the start of valid AC3 Frame.
1070 9ef60390 Justin Ruggles
    init_get_bits(&ctx->gb, buf, buf_size * 8);
1071 00585845 Justin Ruggles
1072 1b293437 Justin Ruggles
    //Parse the syncinfo.
1073 9fc1ab72 Justin Ruggles
    if (ac3_parse_header(ctx)) {
1074 00585845 Justin Ruggles
        av_log(avctx, AV_LOG_ERROR, "\n");
1075 1b293437 Justin Ruggles
        *data_size = 0;
1076 486637af Justin Ruggles
        return buf_size;
1077 1b293437 Justin Ruggles
    }
1078 2aa2c5c4 Justin Ruggles
1079 98a27a8a Justin Ruggles
    avctx->sample_rate = ctx->sampling_rate;
1080
    avctx->bit_rate = ctx->bit_rate;
1081 45b0ed13 Justin Ruggles
1082 7bfd22f2 Justin Ruggles
    /* channel config */
1083 3bbb0bf8 Justin Ruggles
    ctx->out_channels = ctx->nchans;
1084 1b293437 Justin Ruggles
    if (avctx->channels == 0) {
1085 7bfd22f2 Justin Ruggles
        avctx->channels = ctx->out_channels;
1086 3bbb0bf8 Justin Ruggles
    } else if(ctx->out_channels < avctx->channels) {
1087
        av_log(avctx, AV_LOG_ERROR, "Cannot upmix AC3 from %d to %d channels.\n",
1088
               ctx->out_channels, avctx->channels);
1089
        return -1;
1090 45b0ed13 Justin Ruggles
    }
1091 3bbb0bf8 Justin Ruggles
    if(avctx->channels == 2) {
1092
        ctx->output_mode = AC3_ACMOD_STEREO;
1093
    } else if(avctx->channels == 1) {
1094
        ctx->output_mode = AC3_ACMOD_MONO;
1095
    } else if(avctx->channels != ctx->out_channels) {
1096
        av_log(avctx, AV_LOG_ERROR, "Cannot downmix AC3 from %d to %d channels.\n",
1097
               ctx->out_channels, avctx->channels);
1098 7bfd22f2 Justin Ruggles
        return -1;
1099 1b293437 Justin Ruggles
    }
1100 3bbb0bf8 Justin Ruggles
    ctx->out_channels = avctx->channels;
1101 1b293437 Justin Ruggles
1102 d7bcc4ad Justin Ruggles
    //av_log(avctx, AV_LOG_INFO, "channels = %d \t bit rate = %d \t sampling rate = %d \n", avctx->channels, avctx->bit_rate * 1000, avctx->sample_rate);
1103 1b293437 Justin Ruggles
1104
    //Parse the Audio Blocks.
1105 75b9b036 Justin Ruggles
    for (blk = 0; blk < NB_BLOCKS; blk++) {
1106
        if (ac3_parse_audio_block(ctx, blk)) {
1107 1b293437 Justin Ruggles
            av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
1108
            *data_size = 0;
1109 98a27a8a Justin Ruggles
            return ctx->frame_size;
1110 1b293437 Justin Ruggles
        }
1111 75b9b036 Justin Ruggles
        for (i = 0; i < 256; i++)
1112 7b4076a7 Justin Ruggles
            for (ch = 0; ch < ctx->out_channels; ch++)
1113 4e092320 Justin Ruggles
                *(out_samples++) = ctx->int_output[ch][i];
1114 1b293437 Justin Ruggles
    }
1115 8fbb368d Justin Ruggles
    *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t);
1116 98a27a8a Justin Ruggles
    return ctx->frame_size;
1117 2aa2c5c4 Justin Ruggles
}
1118 1b293437 Justin Ruggles
1119 c7cfc48f Justin Ruggles
/* Uninitialize ac3 decoder.
1120
 */
1121
static int ac3_decode_end(AVCodecContext *avctx)
1122 1b293437 Justin Ruggles
{
1123 c7cfc48f Justin Ruggles
    AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
1124
    ff_mdct_end(&ctx->imdct_512);
1125
    ff_mdct_end(&ctx->imdct_256);
1126
1127 1b293437 Justin Ruggles
    return 0;
1128
}
1129
1130 fa67992d Justin Ruggles
AVCodec ac3_decoder = {
1131 e6bca37c Justin Ruggles
    .name = "ac3",
1132
    .type = CODEC_TYPE_AUDIO,
1133
    .id = CODEC_ID_AC3,
1134
    .priv_data_size = sizeof (AC3DecodeContext),
1135
    .init = ac3_decode_init,
1136
    .close = ac3_decode_end,
1137
    .decode = ac3_decode_frame,
1138 1b293437 Justin Ruggles
};