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
23 * @file libavcodec/ac3.h
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/internal.h"
31 #include "libavutil/lfg.h"
36 /* override ac3.h to include coupling channel */
37 #undef AC3_MAX_CHANNELS
38 #define AC3_MAX_CHANNELS 7
41 #define AC3_OUTPUT_LFEON 8
43 #define AC3_MAX_COEFS 256
44 #define AC3_BLOCK_SIZE 256
48 AVCodecContext *avctx; ///< parent context
49 GetBitContext gbc; ///< bitstream reader
50 uint8_t *input_buffer; ///< temp buffer to prevent overread
52 ///@defgroup bsi bit stream information
54 int frame_type; ///< frame type (strmtyp)
55 int substreamid; ///< substream identification
56 int frame_size; ///< current frame size, in bytes
57 int bit_rate; ///< stream bit rate, in bits-per-second
58 int sample_rate; ///< sample frequency, in Hz
59 int num_blocks; ///< number of audio blocks
60 int channel_mode; ///< channel mode (acmod)
61 int channel_layout; ///< channel layout
62 int lfe_on; ///< lfe channel in use
63 int channel_map; ///< custom channel map
64 int center_mix_level; ///< Center mix level index
65 int surround_mix_level; ///< Surround mix level index
66 int eac3; ///< indicates if current frame is E-AC-3
69 ///@defgroup audfrm frame syntax parameters
70 int snr_offset_strategy; ///< SNR offset strategy (snroffststr)
71 int block_switch_syntax; ///< block switch syntax enabled (blkswe)
72 int dither_flag_syntax; ///< dither flag syntax enabled (dithflage)
73 int bit_allocation_syntax; ///< bit allocation model syntax enabled (bamode)
74 int fast_gain_syntax; ///< fast gain codes enabled (frmfgaincode)
75 int dba_syntax; ///< delta bit allocation syntax enabled (dbaflde)
76 int skip_syntax; ///< skip field syntax enabled (skipflde)
79 ///@defgroup cpl standard coupling
80 int cpl_in_use[MAX_BLOCKS]; ///< coupling in use (cplinu)
81 int cpl_strategy_exists[MAX_BLOCKS]; ///< coupling strategy exists (cplstre)
82 int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling (chincpl)
83 int phase_flags_in_use; ///< phase flags in use (phsflginu)
84 int phase_flags[18]; ///< phase flags (phsflg)
85 int num_cpl_subbands; ///< number of coupling sub bands (ncplsubnd)
86 int num_cpl_bands; ///< number of coupling bands (ncplbnd)
87 uint8_t cpl_band_struct[18]; ///< coupling band structure (cplbndstrc)
88 int firstchincpl; ///< first channel in coupling
89 int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states (firstcplcos)
90 int cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates (cplco)
93 ///@defgroup aht adaptive hybrid transform
94 int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu)
95 int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][MAX_BLOCKS]; ///< pre-IDCT mantissas
98 ///@defgroup channel channel
99 int fbw_channels; ///< number of full-bandwidth channels
100 int channels; ///< number of total channels
101 int lfe_ch; ///< index of LFE channel
102 float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients
103 int downmixed; ///< indicates if coeffs are currently downmixed
104 int output_mode; ///< output channel configuration
105 int out_channels; ///< number of output channels
108 ///@defgroup dynrng dynamic range
109 float dynamic_range[2]; ///< dynamic range
112 ///@defgroup bandwidth bandwidth
113 int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin (strtmant)
114 int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin (endmant)
117 ///@defgroup rematrixing rematrixing
118 int num_rematrixing_bands; ///< number of rematrixing bands (nrematbnd)
119 int rematrixing_flags[4]; ///< rematrixing flags (rematflg)
122 ///@defgroup exponents exponents
123 int num_exp_groups[AC3_MAX_CHANNELS]; ///< Number of exponent groups (nexpgrp)
124 int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< decoded exponents
125 int exp_strategy[MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies (expstr)
128 ///@defgroup bitalloc bit allocation
129 AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
130 int first_cpl_leak; ///< first coupling leak state (firstcplleak)
131 int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets (snroffst)
132 int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values/SMR's (fgain)
133 uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< bit allocation pointers
134 int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< scaled exponents
135 int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
136 int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
137 int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
138 int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments
139 uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets
140 uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths
141 uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment
144 ///@defgroup dithering zero-mantissa dithering
145 int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags (dithflg)
146 AVLFG dith_state; ///< for dither generation
149 ///@defgroup imdct IMDCT
150 int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags (blksw)
151 MDCTContext imdct_512; ///< for 512 sample IMDCT
152 MDCTContext imdct_256; ///< for 256 sample IMDCT
155 ///@defgroup opt optimization
156 DSPContext dsp; ///< for optimization
157 float add_bias; ///< offset for float_to_int16 conversion
158 float mul_bias; ///< scaling for float_to_int16 conversion
161 DECLARE_ALIGNED_16(int, fixed_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]); ///> fixed-point transform coefficients
163 ///@defgroup arrays aligned arrays
164 DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]); ///< transform coefficients
165 DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]); ///< delay - added to the next block
166 DECLARE_ALIGNED_16(float, window[AC3_BLOCK_SIZE]); ///< window coefficients
167 DECLARE_ALIGNED_16(float, tmp_output[AC3_BLOCK_SIZE]); ///< temporary storage for output before windowing
168 DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]); ///< output after imdct transform and windowing
173 * Parse the E-AC-3 frame header.
174 * This parses both the bit stream info and audio frame header.
176 int ff_eac3_parse_header(AC3DecodeContext *s);
179 * Decode mantissas in a single channel for the entire frame.
180 * This is used when AHT mode is enabled.
182 void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch);
184 #endif /* AVCODEC_AC3DEC_H */