2 * Common code between the AC-3 and E-AC-3 decoders
3 * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
5 * This file is part of FFmpeg.
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.
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.
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
24 * Common code between the AC-3 and E-AC-3 decoders.
27 #ifndef AVCODEC_AC3DEC_H
28 #define AVCODEC_AC3DEC_H
30 #include "libavutil/lfg.h"
32 #include "bitstream.h"
35 /* override ac3.h to include coupling channel */
36 #undef AC3_MAX_CHANNELS
37 #define AC3_MAX_CHANNELS 7
40 #define AC3_OUTPUT_LFEON 8
42 #define AC3_MAX_COEFS 256
43 #define AC3_BLOCK_SIZE 256
45 #define SPX_MAX_BANDS 17
47 #define INT24_MIN -8388608
48 #define INT24_MAX 8388607
49 #define M_SQRT_POW2_15 181
52 AVCodecContext *avctx; ///< parent context
53 GetBitContext gbc; ///< bitstream reader
54 uint8_t *input_buffer; ///< temp buffer to prevent overread
56 ///@defgroup bsi bit stream information
58 int frame_type; ///< frame type (strmtyp)
59 int substreamid; ///< substream identification
60 int frame_size; ///< current frame size, in bytes
61 int bit_rate; ///< stream bit rate, in bits-per-second
62 int sample_rate; ///< sample frequency, in Hz
63 int num_blocks; ///< number of audio blocks
64 int channel_mode; ///< channel mode (acmod)
65 int lfe_on; ///< lfe channel in use
66 int channel_map; ///< custom channel map
67 int center_mix_level; ///< Center mix level index
68 int surround_mix_level; ///< Surround mix level index
69 int eac3; ///< indicates if current frame is E-AC-3
72 ///@defgroup audfrm frame syntax parameters
73 int snr_offset_strategy; ///< SNR offset strategy (snroffststr)
74 int block_switch_syntax; ///< block switch syntax enabled (blkswe)
75 int dither_flag_syntax; ///< dither flag syntax enabled (dithflage)
76 int bit_allocation_syntax; ///< bit allocation model syntax enabled (bamode)
77 int fast_gain_syntax; ///< fast gain codes enabled (frmfgaincode)
78 int dba_syntax; ///< delta bit allocation syntax enabled (dbaflde)
79 int skip_syntax; ///< skip field syntax enabled (skipflde)
82 ///@defgroup cpl standard coupling
83 int cpl_in_use[MAX_BLOCKS]; ///< coupling in use (cplinu)
84 int cpl_strategy_exists[MAX_BLOCKS]; ///< coupling strategy exists (cplstre)
85 int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling (chincpl)
86 int phase_flags_in_use; ///< phase flags in use (phsflginu)
87 int phase_flags[18]; ///< phase flags (phsflg)
88 int num_cpl_subbands; ///< number of coupling sub bands (ncplsubnd)
89 int num_cpl_bands; ///< number of coupling bands (ncplbnd)
90 uint8_t cpl_band_struct[18]; ///< coupling band structure (cplbndstrc)
91 int firstchincpl; ///< first channel in coupling
92 int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states (firstcplcos)
93 int cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates (cplco)
96 ///@defgroup spx spectral extension
98 int spx_in_use[MAX_BLOCKS]; ///< spectral extension in use (spxinu)
99 int channel_in_spx[AC3_MAX_CHANNELS]; ///< channel in spectral extension (chinspx)
100 int spx_atten_code[AC3_MAX_CHANNELS]; ///< spx attenuation code (spxattencod)
101 int spx_coords_exist[AC3_MAX_CHANNELS]; ///< indicates if a channel has spx coords (spxcoe)
102 int spx_start_subband; ///< spx beginning frequency band (spxbegf)
103 int spx_start_freq; ///< spx start frequency bin
104 int spx_end_freq; ///< spx end frequency bin
105 int spx_copy_start_freq; ///< spx starting frequency for copying (copystartmant)
106 int num_spx_subbands; ///< number of spectral extension subbands
107 int num_spx_bands; ///< number of spectral extension bands (nspxbnds)
108 uint8_t spx_band_struct[SPX_MAX_BANDS]; ///< spectral extension band structure (spxbndstrc)
109 int spx_band_sizes[SPX_MAX_BANDS]; ///< number of bins in each band (spxbndsztab)
110 int first_spx_coords[AC3_MAX_CHANNELS]; ///< first spx coordinates states (firstspxcos)
111 int spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor (nblendfact)
112 int spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx signal blending factor (sblendfact)
113 int spx_coords[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spectral extension coordinates (spxco)
116 ///@defgroup aht adaptive hybrid transform
117 int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu)
118 int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][MAX_BLOCKS]; ///< pre-IDCT mantissas
121 ///@defgroup channel channel
122 int fbw_channels; ///< number of full-bandwidth channels
123 int channels; ///< number of total channels
124 int lfe_ch; ///< index of LFE channel
125 float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients
126 int downmixed; ///< indicates if coeffs are currently downmixed
127 int output_mode; ///< output channel configuration
128 int out_channels; ///< number of output channels
131 ///@defgroup dynrng dynamic range
132 float dynamic_range[2]; ///< dynamic range
135 ///@defgroup bandwidth bandwidth
136 int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin (strtmant)
137 int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin (endmant)
140 ///@defgroup rematrixing rematrixing
141 int num_rematrixing_bands; ///< number of rematrixing bands (nrematbnd)
142 int rematrixing_flags[4]; ///< rematrixing flags (rematflg)
145 ///@defgroup exponents exponents
146 int num_exp_groups[AC3_MAX_CHANNELS]; ///< Number of exponent groups (nexpgrp)
147 int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< decoded exponents
148 int exp_strategy[MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies (expstr)
151 ///@defgroup bitalloc bit allocation
152 AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
153 int first_cpl_leak; ///< first coupling leak state (firstcplleak)
154 int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets (snroffst)
155 int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values/SMR's (fgain)
156 uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< bit allocation pointers
157 int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< scaled exponents
158 int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
159 int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
160 int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
161 int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments
162 uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets
163 uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths
164 uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment
167 ///@defgroup dithering zero-mantissa dithering
168 int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags (dithflg)
169 AVLFG dith_state; ///< for dither generation
172 ///@defgroup imdct IMDCT
173 int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags (blksw)
174 MDCTContext imdct_512; ///< for 512 sample IMDCT
175 MDCTContext imdct_256; ///< for 256 sample IMDCT
178 ///@defgroup opt optimization
179 DSPContext dsp; ///< for optimization
180 float add_bias; ///< offset for float_to_int16 conversion
181 float mul_bias; ///< scaling for float_to_int16 conversion
184 DECLARE_ALIGNED_16(int, fixed_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]); ///> fixed-point transform coefficients
186 ///@defgroup arrays aligned arrays
187 DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]); ///< transform coefficients
188 DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]); ///< delay - added to the next block
189 DECLARE_ALIGNED_16(float, window[AC3_BLOCK_SIZE]); ///< window coefficients
190 DECLARE_ALIGNED_16(float, tmp_output[AC3_BLOCK_SIZE]); ///< temporary storage for output before windowing
191 DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]); ///< output after imdct transform and windowing
196 * Parse the E-AC-3 frame header.
197 * This parses both the bit stream info and audio frame header.
199 int ff_eac3_parse_header(AC3DecodeContext *s);
202 * Decode mantissas in a single channel for the entire frame.
203 * This is used when AHT mode is enabled.
205 void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch);
207 void ff_eac3_apply_spectral_extension(AC3DecodeContext *s);
209 #endif /* AVCODEC_AC3DEC_H */