00001 /* 00002 * Common code between AC3 and E-AC3 decoder 00003 * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com> 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00022 /** 00023 * @file ac3.h 00024 * Common code between AC3 and E-AC3 decoder. 00025 */ 00026 00027 #ifndef FFMPEG_AC3DEC_H 00028 #define FFMPEG_AC3DEC_H 00029 00030 #include "libavutil/random.h" 00031 #include "ac3tab.h" 00032 #include "ac3.h" 00033 #include "bitstream.h" 00034 #include "dsputil.h" 00035 00036 /* override ac3.h to include coupling channel */ 00037 #undef AC3_MAX_CHANNELS 00038 #define AC3_MAX_CHANNELS 7 00039 #define CPL_CH 0 00040 00041 #define AC3_OUTPUT_LFEON 8 00042 00043 #define AC3_MAX_COEFS 256 00044 #define AC3_BLOCK_SIZE 256 00045 #define MAX_BLOCKS 6 00046 00047 typedef struct { 00048 AVCodecContext *avctx; ///< parent context 00049 GetBitContext gbc; ///< bitstream reader 00050 uint8_t *input_buffer; ///< temp buffer to prevent overread 00051 00052 ///@defgroup bsi bit stream information 00053 ///@{ 00054 int frame_type; ///< frame type (strmtyp) 00055 int substreamid; ///< substream identification 00056 int frame_size; ///< current frame size, in bytes 00057 int bit_rate; ///< stream bit rate, in bits-per-second 00058 int sample_rate; ///< sample frequency, in Hz 00059 int num_blocks; ///< number of audio blocks 00060 int channel_mode; ///< channel mode (acmod) 00061 int lfe_on; ///< lfe channel in use 00062 int channel_map; ///< custom channel map 00063 int center_mix_level; ///< Center mix level index 00064 int surround_mix_level; ///< Surround mix level index 00065 int eac3; ///< indicates if current frame is E-AC-3 00066 ///@} 00067 00068 ///@defgroup audfrm frame syntax parameters 00069 int snr_offset_strategy; ///< SNR offset strategy (snroffststr) 00070 int block_switch_syntax; ///< block switch syntax enabled (blkswe) 00071 int dither_flag_syntax; ///< dither flag syntax enabled (dithflage) 00072 int bit_allocation_syntax; ///< bit allocation model syntax enabled (bamode) 00073 int fast_gain_syntax; ///< fast gain codes enabled (frmfgaincode) 00074 int dba_syntax; ///< delta bit allocation syntax enabled (dbaflde) 00075 int skip_syntax; ///< skip field syntax enabled (skipflde) 00076 ///@} 00077 00078 ///@defgroup cpl standard coupling 00079 int cpl_in_use[MAX_BLOCKS]; ///< coupling in use (cplinu) 00080 int cpl_strategy_exists[MAX_BLOCKS]; ///< coupling strategy exists (cplstre) 00081 int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling (chincpl) 00082 int phase_flags_in_use; ///< phase flags in use (phsflginu) 00083 int phase_flags[18]; ///< phase flags (phsflg) 00084 int num_cpl_subbands; ///< number of coupling sub bands (ncplsubnd) 00085 int num_cpl_bands; ///< number of coupling bands (ncplbnd) 00086 int cpl_band_struct[18]; ///< coupling band structure (cplbndstrc) 00087 int firstchincpl; ///< first channel in coupling 00088 int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states (firstcplcos) 00089 int cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates (cplco) 00090 ///@} 00091 00092 ///@defgroup aht adaptive hybrid transform 00093 int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu) 00094 int pre_mantissa[6][AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< pre-IDCT mantissas 00095 ///@} 00096 00097 ///@defgroup channel channel 00098 int fbw_channels; ///< number of full-bandwidth channels 00099 int channels; ///< number of total channels 00100 int lfe_ch; ///< index of LFE channel 00101 float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients 00102 float downmix_coeff_adjust[2]; ///< adjustment needed for each output channel when downmixing 00103 int downmixed; ///< indicates if coeffs are currently downmixed 00104 int output_mode; ///< output channel configuration 00105 int out_channels; ///< number of output channels 00106 ///@} 00107 00108 ///@defgroup dynrng dynamic range 00109 float dynamic_range[2]; ///< dynamic range 00110 ///@} 00111 00112 ///@defgroup bandwidth bandwidth 00113 int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin (strtmant) 00114 int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin (endmant) 00115 ///@} 00116 00117 ///@defgroup rematrixing rematrixing 00118 int num_rematrixing_bands; ///< number of rematrixing bands (nrematbnd) 00119 int rematrixing_flags[4]; ///< rematrixing flags (rematflg) 00120 ///@} 00121 00122 ///@defgroup exponents exponents 00123 int num_exp_groups[AC3_MAX_CHANNELS]; ///< Number of exponent groups (nexpgrp) 00124 int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< decoded exponents 00125 int exp_strategy[MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies (expstr) 00126 ///@} 00127 00128 ///@defgroup bitalloc bit allocation 00129 AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters 00130 int first_cpl_leak; ///< first coupling leak state (firstcplleak) 00131 int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets (snroffst) 00132 int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values/SMR's (fgain) 00133 uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< bit allocation pointers 00134 int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< scaled exponents 00135 int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents 00136 int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values 00137 int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode 00138 int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments 00139 uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets 00140 uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths 00141 uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment 00142 ///@} 00143 00144 ///@defgroup dithering zero-mantissa dithering 00145 int dither_all; ///< true if all channels are dithered 00146 int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags (dithflg) 00147 AVRandomState dith_state; ///< for dither generation 00148 ///@} 00149 00150 ///@defgroup imdct IMDCT 00151 int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags (blksw) 00152 MDCTContext imdct_512; ///< for 512 sample IMDCT 00153 MDCTContext imdct_256; ///< for 256 sample IMDCT 00154 ///@} 00155 00156 ///@defgroup opt optimization 00157 DSPContext dsp; ///< for optimization 00158 float add_bias; ///< offset for float_to_int16 conversion 00159 float mul_bias; ///< scaling for float_to_int16 conversion 00160 ///@} 00161 00162 int fixed_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///> fixed-point transform coefficients 00163 00164 ///@defgroup arrays aligned arrays 00165 DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]); ///< transform coefficients 00166 DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]); ///< delay - added to the next block 00167 DECLARE_ALIGNED_16(float, window[AC3_BLOCK_SIZE]); ///< window coefficients 00168 DECLARE_ALIGNED_16(float, tmp_output[AC3_BLOCK_SIZE*2]); ///< temporary storage for output before windowing 00169 DECLARE_ALIGNED_16(float, tmp_imdct[AC3_BLOCK_SIZE]); ///< temporary storage for imdct transform 00170 DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]); ///< output after imdct transform and windowing 00171 DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][AC3_BLOCK_SIZE]); ///< final 16-bit integer output 00172 ///@} 00173 } AC3DecodeContext; 00174 00175 #endif /* FFMPEG_AC3DEC_H */
1.5.1