yading@10: /* yading@10: * Common code between the AC-3 and E-AC-3 decoders yading@10: * Copyright (c) 2007 Bartlomiej Wolowiec yading@10: * yading@10: * This file is part of FFmpeg. yading@10: * yading@10: * FFmpeg is free software; you can redistribute it and/or yading@10: * modify it under the terms of the GNU Lesser General Public yading@10: * License as published by the Free Software Foundation; either yading@10: * version 2.1 of the License, or (at your option) any later version. yading@10: * yading@10: * FFmpeg is distributed in the hope that it will be useful, yading@10: * but WITHOUT ANY WARRANTY; without even the implied warranty of yading@10: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU yading@10: * Lesser General Public License for more details. yading@10: * yading@10: * You should have received a copy of the GNU Lesser General Public yading@10: * License along with FFmpeg; if not, write to the Free Software yading@10: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA yading@10: */ yading@10: yading@10: /** yading@10: * @file yading@10: * Common code between the AC-3 and E-AC-3 decoders. yading@10: * yading@10: * Summary of MDCT Coefficient Grouping: yading@10: * The individual MDCT coefficient indices are often referred to in the yading@10: * (E-)AC-3 specification as frequency bins. These bins are grouped together yading@10: * into subbands of 12 coefficients each. The subbands are grouped together yading@10: * into bands as defined in the bitstream by the band structures, which yading@10: * determine the number of bands and the size of each band. The full spectrum yading@10: * of 256 frequency bins is divided into 1 DC bin + 21 subbands = 253 bins. yading@10: * This system of grouping coefficients is used for channel bandwidth, stereo yading@10: * rematrixing, channel coupling, enhanced coupling, and spectral extension. yading@10: * yading@10: * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+ yading@10: * |1| |12| | [12|12|12|12] | | | | | | | | | | | | |3| yading@10: * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+ yading@10: * ~~~ ~~~~ ~~~~~~~~~~~~~ ~~~ yading@10: * | | | | yading@10: * | | | 3 unused frequency bins--+ yading@10: * | | | yading@10: * | | +--1 band containing 4 subbands yading@10: * | | yading@10: * | +--1 subband of 12 frequency bins yading@10: * | yading@10: * +--DC frequency bin yading@10: */ yading@10: yading@10: #ifndef AVCODEC_AC3DEC_H yading@10: #define AVCODEC_AC3DEC_H yading@10: yading@10: #include "libavutil/float_dsp.h" yading@10: #include "libavutil/lfg.h" yading@10: #include "ac3.h" yading@10: #include "ac3dsp.h" yading@10: #include "get_bits.h" yading@10: #include "dsputil.h" yading@10: #include "fft.h" yading@10: #include "fmtconvert.h" yading@10: yading@10: #define AC3_OUTPUT_LFEON 8 yading@10: yading@10: #define SPX_MAX_BANDS 17 yading@10: yading@10: /** Large enough for maximum possible frame size when the specification limit is ignored */ yading@10: #define AC3_FRAME_BUFFER_SIZE 32768 yading@10: yading@10: typedef struct AC3DecodeContext { yading@10: AVClass *class; ///< class for AVOptions yading@10: AVCodecContext *avctx; ///< parent context yading@10: GetBitContext gbc; ///< bitstream reader yading@10: yading@10: ///@name Bit stream information yading@10: ///@{ yading@10: int frame_type; ///< frame type (strmtyp) yading@10: int substreamid; ///< substream identification yading@10: int frame_size; ///< current frame size, in bytes yading@10: int bit_rate; ///< stream bit rate, in bits-per-second yading@10: int sample_rate; ///< sample frequency, in Hz yading@10: int num_blocks; ///< number of audio blocks yading@10: int bitstream_mode; ///< bitstream mode (bsmod) yading@10: int channel_mode; ///< channel mode (acmod) yading@10: int channel_layout; ///< channel layout yading@10: int lfe_on; ///< lfe channel in use yading@10: int channel_map; ///< custom channel map yading@10: int center_mix_level; ///< Center mix level index yading@10: int surround_mix_level; ///< Surround mix level index yading@10: int eac3; ///< indicates if current frame is E-AC-3 yading@10: ///@} yading@10: yading@10: int preferred_stereo_downmix; yading@10: float ltrt_center_mix_level; yading@10: float ltrt_surround_mix_level; yading@10: float loro_center_mix_level; yading@10: float loro_surround_mix_level; yading@10: yading@10: ///@name Frame syntax parameters yading@10: int snr_offset_strategy; ///< SNR offset strategy (snroffststr) yading@10: int block_switch_syntax; ///< block switch syntax enabled (blkswe) yading@10: int dither_flag_syntax; ///< dither flag syntax enabled (dithflage) yading@10: int bit_allocation_syntax; ///< bit allocation model syntax enabled (bamode) yading@10: int fast_gain_syntax; ///< fast gain codes enabled (frmfgaincode) yading@10: int dba_syntax; ///< delta bit allocation syntax enabled (dbaflde) yading@10: int skip_syntax; ///< skip field syntax enabled (skipflde) yading@10: ///@} yading@10: yading@10: ///@name Standard coupling yading@10: int cpl_in_use[AC3_MAX_BLOCKS]; ///< coupling in use (cplinu) yading@10: int cpl_strategy_exists[AC3_MAX_BLOCKS];///< coupling strategy exists (cplstre) yading@10: int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling (chincpl) yading@10: int phase_flags_in_use; ///< phase flags in use (phsflginu) yading@10: int phase_flags[AC3_MAX_CPL_BANDS]; ///< phase flags (phsflg) yading@10: int num_cpl_bands; ///< number of coupling bands (ncplbnd) yading@10: uint8_t cpl_band_sizes[AC3_MAX_CPL_BANDS]; ///< number of coeffs in each coupling band yading@10: int firstchincpl; ///< first channel in coupling yading@10: int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states (firstcplcos) yading@10: int cpl_coords[AC3_MAX_CHANNELS][AC3_MAX_CPL_BANDS]; ///< coupling coordinates (cplco) yading@10: ///@} yading@10: yading@10: ///@name Spectral extension yading@10: ///@{ yading@10: int spx_in_use; ///< spectral extension in use (spxinu) yading@10: uint8_t channel_uses_spx[AC3_MAX_CHANNELS]; ///< channel uses spectral extension (chinspx) yading@10: int8_t spx_atten_code[AC3_MAX_CHANNELS]; ///< spx attenuation code (spxattencod) yading@10: int spx_src_start_freq; ///< spx start frequency bin yading@10: int spx_dst_end_freq; ///< spx end frequency bin yading@10: int spx_dst_start_freq; ///< spx starting frequency bin for copying (copystartmant) yading@10: ///< the copy region ends at the start of the spx region. yading@10: int num_spx_bands; ///< number of spx bands (nspxbnds) yading@10: uint8_t spx_band_sizes[SPX_MAX_BANDS]; ///< number of bins in each spx band yading@10: uint8_t first_spx_coords[AC3_MAX_CHANNELS]; ///< first spx coordinates states (firstspxcos) yading@10: float spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor (nblendfact) yading@10: float spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS];///< spx signal blending factor (sblendfact) yading@10: ///@} yading@10: yading@10: ///@name Adaptive hybrid transform yading@10: int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu) yading@10: int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][AC3_MAX_BLOCKS]; ///< pre-IDCT mantissas yading@10: ///@} yading@10: yading@10: ///@name Channel yading@10: int fbw_channels; ///< number of full-bandwidth channels yading@10: int channels; ///< number of total channels yading@10: int lfe_ch; ///< index of LFE channel yading@10: float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients yading@10: int downmixed; ///< indicates if coeffs are currently downmixed yading@10: int output_mode; ///< output channel configuration yading@10: int out_channels; ///< number of output channels yading@10: ///@} yading@10: yading@10: ///@name Dynamic range yading@10: float dynamic_range[2]; ///< dynamic range yading@10: float drc_scale; ///< percentage of dynamic range compression to be applied yading@10: ///@} yading@10: yading@10: ///@name Bandwidth yading@10: int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin (strtmant) yading@10: int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin (endmant) yading@10: ///@} yading@10: yading@10: ///@name Rematrixing yading@10: int num_rematrixing_bands; ///< number of rematrixing bands (nrematbnd) yading@10: int rematrixing_flags[4]; ///< rematrixing flags (rematflg) yading@10: ///@} yading@10: yading@10: ///@name Exponents yading@10: int num_exp_groups[AC3_MAX_CHANNELS]; ///< Number of exponent groups (nexpgrp) yading@10: int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< decoded exponents yading@10: int exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies (expstr) yading@10: ///@} yading@10: yading@10: ///@name Bit allocation yading@10: AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters yading@10: int first_cpl_leak; ///< first coupling leak state (firstcplleak) yading@10: int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets (snroffst) yading@10: int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values/SMR's (fgain) yading@10: uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< bit allocation pointers yading@10: int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< scaled exponents yading@10: int16_t band_psd[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< interpolated exponents yading@10: int16_t mask[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< masking curve values yading@10: int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode yading@10: int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments yading@10: uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets yading@10: uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths yading@10: uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment yading@10: ///@} yading@10: yading@10: ///@name Zero-mantissa dithering yading@10: int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags (dithflg) yading@10: AVLFG dith_state; ///< for dither generation yading@10: ///@} yading@10: yading@10: ///@name IMDCT yading@10: int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags (blksw) yading@10: FFTContext imdct_512; ///< for 512 sample IMDCT yading@10: FFTContext imdct_256; ///< for 256 sample IMDCT yading@10: ///@} yading@10: yading@10: ///@name Optimization yading@10: DSPContext dsp; ///< for optimization yading@10: AVFloatDSPContext fdsp; yading@10: AC3DSPContext ac3dsp; yading@10: FmtConvertContext fmt_conv; ///< optimized conversion functions yading@10: ///@} yading@10: yading@10: float *outptr[AC3_MAX_CHANNELS]; yading@10: float *xcfptr[AC3_MAX_CHANNELS]; yading@10: float *dlyptr[AC3_MAX_CHANNELS]; yading@10: yading@10: ///@name Aligned arrays yading@10: DECLARE_ALIGNED(16, int, fixed_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< fixed-point transform coefficients yading@10: DECLARE_ALIGNED(32, float, transform_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< transform coefficients yading@10: DECLARE_ALIGNED(32, float, delay)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]; ///< delay - added to the next block yading@10: DECLARE_ALIGNED(32, float, window)[AC3_BLOCK_SIZE]; ///< window coefficients yading@10: DECLARE_ALIGNED(32, float, tmp_output)[AC3_BLOCK_SIZE]; ///< temporary storage for output before windowing yading@10: DECLARE_ALIGNED(32, float, output)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]; ///< output after imdct transform and windowing yading@10: DECLARE_ALIGNED(32, uint8_t, input_buffer)[AC3_FRAME_BUFFER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE]; ///< temp buffer to prevent overread yading@10: ///@} yading@10: } AC3DecodeContext; yading@10: yading@10: /** yading@10: * Parse the E-AC-3 frame header. yading@10: * This parses both the bit stream info and audio frame header. yading@10: */ yading@10: int ff_eac3_parse_header(AC3DecodeContext *s); yading@10: yading@10: /** yading@10: * Decode mantissas in a single channel for the entire frame. yading@10: * This is used when AHT mode is enabled. yading@10: */ yading@10: void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch); yading@10: yading@10: /** yading@10: * Apply spectral extension to each channel by copying lower frequency yading@10: * coefficients to higher frequency bins and applying side information to yading@10: * approximate the original high frequency signal. yading@10: */ yading@10: void ff_eac3_apply_spectral_extension(AC3DecodeContext *s); yading@10: yading@10: #endif /* AVCODEC_AC3DEC_H */