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1 /*
2  * Common code between the AC-3 and E-AC-3 decoders
3  * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
4  *
5  * This file is part of FFmpeg.
6  *
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.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * Lesser General Public License for more details.
16  *
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
20  */
22 /**
23  * @file
24  * Common code between the AC-3 and E-AC-3 decoders.
25  *
26  * Summary of MDCT Coefficient Grouping:
27  * The individual MDCT coefficient indices are often referred to in the
28  * (E-)AC-3 specification as frequency bins. These bins are grouped together
29  * into subbands of 12 coefficients each. The subbands are grouped together
30  * into bands as defined in the bitstream by the band structures, which
31  * determine the number of bands and the size of each band. The full spectrum
32  * of 256 frequency bins is divided into 1 DC bin + 21 subbands = 253 bins.
33  * This system of grouping coefficients is used for channel bandwidth, stereo
34  * rematrixing, channel coupling, enhanced coupling, and spectral extension.
35  *
36  * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+
37  * |1| |12| | [12|12|12|12] | | | | | | | | | | | | |3|
38  * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+
39  * ~~~ ~~~~ ~~~~~~~~~~~~~ ~~~
40  * | | | |
41  * | | | 3 unused frequency bins--+
42  * | | |
43  * | | +--1 band containing 4 subbands
44  * | |
45  * | +--1 subband of 12 frequency bins
46  * |
47  * +--DC frequency bin
48  */
50 #ifndef AVCODEC_AC3DEC_H
51 #define AVCODEC_AC3DEC_H
53 #include "libavutil/float_dsp.h"
54 #include "libavutil/fixed_dsp.h"
55 #include "libavutil/lfg.h"
56 #include "ac3.h"
57 #include "ac3dsp.h"
58 #include "bswapdsp.h"
59 #include "get_bits.h"
60 #include "fft.h"
61 #include "fmtconvert.h"
63 #define AC3_OUTPUT_LFEON 8
65 #define SPX_MAX_BANDS 17
67 /** Large enough for maximum possible frame size when the specification limit is ignored */
68 #define AC3_FRAME_BUFFER_SIZE 32768
70 typedef struct AC3DecodeContext {
71  AVClass *class; ///< class for AVOptions
72  AVCodecContext *avctx; ///< parent context
73  GetBitContext gbc; ///< bitstream reader
75 ///@name Bit stream information
76 ///@{
77  int frame_type; ///< frame type (strmtyp)
78  int substreamid; ///< substream identification
79  int frame_size; ///< current frame size, in bytes
80  int bit_rate; ///< stream bit rate, in bits-per-second
81  int sample_rate; ///< sample frequency, in Hz
82  int num_blocks; ///< number of audio blocks
83  int bitstream_id; ///< bitstream id (bsid)
84  int bitstream_mode; ///< bitstream mode (bsmod)
85  int channel_mode; ///< channel mode (acmod)
86  int lfe_on; ///< lfe channel in use
87  int dialog_normalization[2]; ///< dialog level in dBFS (dialnorm)
88  int compression_exists[2]; ///< compression field is valid for frame (compre)
89  int compression_gain[2]; ///< gain to apply for heavy compression (compr)
90  int channel_map; ///< custom channel map
91  int preferred_downmix; ///< Preferred 2-channel downmix mode (dmixmod)
92  int center_mix_level; ///< Center mix level index
93  int center_mix_level_ltrt; ///< Center mix level index for Lt/Rt (ltrtcmixlev)
94  int surround_mix_level; ///< Surround mix level index
95  int surround_mix_level_ltrt; ///< Surround mix level index for Lt/Rt (ltrtsurmixlev)
96  int lfe_mix_level_exists; ///< indicates if lfemixlevcod is specified (lfemixlevcode)
97  int lfe_mix_level; ///< LFE mix level index (lfemixlevcod)
98  int eac3; ///< indicates if current frame is E-AC-3
99  int dolby_surround_mode; ///< dolby surround mode (dsurmod)
100  int dolby_surround_ex_mode; ///< dolby surround ex mode (dsurexmod)
101  int dolby_headphone_mode; ///< dolby headphone mode (dheadphonmod)
102 ///@}
109  int target_level; ///< target level in dBFS
110  float level_gain[2];
112 ///@name Frame syntax parameters
113  int snr_offset_strategy; ///< SNR offset strategy (snroffststr)
114  int block_switch_syntax; ///< block switch syntax enabled (blkswe)
115  int dither_flag_syntax; ///< dither flag syntax enabled (dithflage)
116  int bit_allocation_syntax; ///< bit allocation model syntax enabled (bamode)
117  int fast_gain_syntax; ///< fast gain codes enabled (frmfgaincode)
118  int dba_syntax; ///< delta bit allocation syntax enabled (dbaflde)
119  int skip_syntax; ///< skip field syntax enabled (skipflde)
120  ///@}
122 ///@name Standard coupling
123  int cpl_in_use[AC3_MAX_BLOCKS]; ///< coupling in use (cplinu)
124  int cpl_strategy_exists[AC3_MAX_BLOCKS];///< coupling strategy exists (cplstre)
125  int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling (chincpl)
126  int phase_flags_in_use; ///< phase flags in use (phsflginu)
127  int phase_flags[AC3_MAX_CPL_BANDS]; ///< phase flags (phsflg)
128  int num_cpl_bands; ///< number of coupling bands (ncplbnd)
129  uint8_t cpl_band_sizes[AC3_MAX_CPL_BANDS]; ///< number of coeffs in each coupling band
130  int firstchincpl; ///< first channel in coupling
131  int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states (firstcplcos)
132  int cpl_coords[AC3_MAX_CHANNELS][AC3_MAX_CPL_BANDS]; ///< coupling coordinates (cplco)
133 ///@}
135 ///@name Spectral extension
136 ///@{
137  int spx_in_use; ///< spectral extension in use (spxinu)
138  uint8_t channel_uses_spx[AC3_MAX_CHANNELS]; ///< channel uses spectral extension (chinspx)
139  int8_t spx_atten_code[AC3_MAX_CHANNELS]; ///< spx attenuation code (spxattencod)
140  int spx_src_start_freq; ///< spx start frequency bin
141  int spx_dst_end_freq; ///< spx end frequency bin
142  int spx_dst_start_freq; ///< spx starting frequency bin for copying (copystartmant)
143  ///< the copy region ends at the start of the spx region.
144  int num_spx_bands; ///< number of spx bands (nspxbnds)
145  uint8_t spx_band_sizes[SPX_MAX_BANDS]; ///< number of bins in each spx band
146  uint8_t first_spx_coords[AC3_MAX_CHANNELS]; ///< first spx coordinates states (firstspxcos)
147  INTFLOAT spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor (nblendfact)
148  INTFLOAT spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS];///< spx signal blending factor (sblendfact)
149 ///@}
151 ///@name Adaptive hybrid transform
152  int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu)
154 ///@}
156 ///@name Channel
157  int fbw_channels; ///< number of full-bandwidth channels
158  int channels; ///< number of total channels
159  int lfe_ch; ///< index of LFE channel
160  SHORTFLOAT downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients
161  int downmixed; ///< indicates if coeffs are currently downmixed
162  int output_mode; ///< output channel configuration
163  int out_channels; ///< number of output channels
164 ///@}
166 ///@name Dynamic range
167  INTFLOAT dynamic_range[2]; ///< dynamic range
168  INTFLOAT drc_scale; ///< percentage of dynamic range compression to be applied
169  int heavy_compression; ///< apply heavy compression
170  INTFLOAT heavy_dynamic_range[2]; ///< heavy dynamic range compression
171 ///@}
173 ///@name Bandwidth
174  int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin (strtmant)
175  int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin (endmant)
176 ///@}
178 ///@name Rematrixing
179  int num_rematrixing_bands; ///< number of rematrixing bands (nrematbnd)
180  int rematrixing_flags[4]; ///< rematrixing flags (rematflg)
181 ///@}
183 ///@name Exponents
184  int num_exp_groups[AC3_MAX_CHANNELS]; ///< Number of exponent groups (nexpgrp)
185  int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< decoded exponents
186  int exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies (expstr)
187 ///@}
189 ///@name Bit allocation
190  AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
191  int first_cpl_leak; ///< first coupling leak state (firstcplleak)
192  int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets (snroffst)
193  int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values/SMR's (fgain)
194  uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< bit allocation pointers
195  int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< scaled exponents
196  int16_t band_psd[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< interpolated exponents
197  int16_t mask[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< masking curve values
198  int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
199  int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments
200  uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets
201  uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths
202  uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment
203 ///@}
205 ///@name Zero-mantissa dithering
206  int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags (dithflg)
207  AVLFG dith_state; ///< for dither generation
208 ///@}
210 ///@name IMDCT
211  int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags (blksw)
212  FFTContext imdct_512; ///< for 512 sample IMDCT
213  FFTContext imdct_256; ///< for 256 sample IMDCT
214 ///@}
216 ///@name Optimization
218 #if USE_FIXED
220 #else
222 #endif
224  FmtConvertContext fmt_conv; ///< optimized conversion functions
225 ///@}
231 ///@name Aligned arrays
232  DECLARE_ALIGNED(16, int, fixed_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< fixed-point transform coefficients
234  DECLARE_ALIGNED(32, INTFLOAT, delay)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]; ///< delay - added to the next block
235  DECLARE_ALIGNED(32, INTFLOAT, window)[AC3_BLOCK_SIZE]; ///< window coefficients
236  DECLARE_ALIGNED(32, INTFLOAT, tmp_output)[AC3_BLOCK_SIZE]; ///< temporary storage for output before windowing
237  DECLARE_ALIGNED(32, SHORTFLOAT, output)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]; ///< output after imdct transform and windowing
239 ///@}
242 /**
243  * Parse the E-AC-3 frame header.
244  * This parses both the bit stream info and audio frame header.
245  */
248 /**
249  * Decode mantissas in a single channel for the entire frame.
250  * This is used when AHT mode is enabled.
251  */
254 /**
255  * Apply spectral extension to each channel by copying lower frequency
256  * coefficients to higher frequency bins and applying side information to
257  * approximate the original high frequency signal.
258  */
261 #endif /* AVCODEC_AC3DEC_H */
Definition: lfg.h:25
INTFLOAT drc_scale
percentage of dynamic range compression to be applied
Definition: ac3dec.h:168
int dba_nsegs[AC3_MAX_CHANNELS]
number of delta segments
Definition: ac3dec.h:199
const char * s
Definition: avisynth_c.h:631
temp buffer to prevent overread
Definition: ac3dec.h:238
scaled exponents
Definition: ac3dec.h:195
int spx_in_use
spectral extension in use (spxinu)
Definition: ac3dec.h:137
uint8_t dba_offsets[AC3_MAX_CHANNELS][8]
delta segment offsets
Definition: ac3dec.h:200
int dither_flag[AC3_MAX_CHANNELS]
dither flags (dithflg)
Definition: ac3dec.h:206
masking curve values
Definition: ac3dec.h:197
int preferred_downmix
Preferred 2-channel downmix mode (dmixmod)
Definition: ac3dec.h:91
#define AC3_MAX_COEFS
Definition: ac3.h:34
Definition: aac_defines.h:87
int channels
number of total channels
Definition: ac3dec.h:158
#define DECLARE_ALIGNED(n, t, v)
Definition: mem.h:53
AVFloatDSPContext * fdsp
Definition: ac3dec.h:221
int spx_dst_end_freq
spx end frequency bin
Definition: ac3dec.h:141
int exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS]
exponent strategies (expstr)
Definition: ac3dec.h:186
int lfe_on
lfe channel in use
Definition: ac3dec.h:86
int block_switch[AC3_MAX_CHANNELS]
block switch flags (blksw)
Definition: ac3dec.h:211
int dba_syntax
delta bit allocation syntax enabled (dbaflde)
Definition: ac3dec.h:118
int preferred_stereo_downmix
Definition: ac3dec.h:104
int dialog_normalization[2]
dialog level in dBFS (dialnorm)
Definition: ac3dec.h:87
int spx_src_start_freq
spx start frequency bin
Definition: ac3dec.h:140
int heavy_compression
apply heavy compression
Definition: ac3dec.h:169
uint8_t cpl_band_sizes[AC3_MAX_CPL_BANDS]
number of coeffs in each coupling band
Definition: ac3dec.h:129
Large enough for maximum possible frame size when the specification limit is ignored.
Definition: ac3dec.h:68
int lfe_mix_level_exists
indicates if lfemixlevcod is specified (lfemixlevcode)
Definition: ac3dec.h:96
float ltrt_center_mix_level
Definition: ac3dec.h:105
int first_cpl_coords[AC3_MAX_CHANNELS]
first coupling coordinates states (firstcplcos)
Definition: ac3dec.h:131
#define INTFLOAT
Definition: aac_defines.h:85
spx noise blending factor (nblendfact)
Definition: ac3dec.h:147
int compression_gain[2]
gain to apply for heavy compression (compr)
Definition: ac3dec.h:89
static void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch)
Decode mantissas in a single channel for the entire frame.
output after imdct transform and windowing
Definition: ac3dec.h:237
int num_rematrixing_bands
number of rematrixing bands (nrematbnd)
Definition: ac3dec.h:179
int fast_gain[AC3_MAX_CHANNELS]
fast gain values/SMR's (fgain)
Definition: ac3dec.h:193
float ltrt_surround_mix_level
Definition: ac3dec.h:106
coupling coordinates (cplco)
Definition: ac3dec.h:132
int num_exp_groups[AC3_MAX_CHANNELS]
Number of exponent groups (nexpgrp)
Definition: ac3dec.h:184
bitstream reader API header.
static int ff_eac3_parse_header(AC3DecodeContext *s)
Parse the E-AC-3 frame header.
delay - added to the next block
Definition: ac3dec.h:234
int bit_allocation_syntax
bit allocation model syntax enabled (bamode)
Definition: ac3dec.h:116
int phase_flags_in_use
phase flags in use (phsflginu)
Definition: ac3dec.h:126
int phase_flags[AC3_MAX_CPL_BANDS]
phase flags (phsflg)
Definition: ac3dec.h:127
int out_channels
number of output channels
Definition: ac3dec.h:163
int channel_map
custom channel map
Definition: ac3dec.h:90
int substreamid
substream identification
Definition: ac3dec.h:78
FFTContext imdct_256
for 256 sample IMDCT
Definition: ac3dec.h:213
int bit_rate
stream bit rate, in bits-per-second
Definition: ac3dec.h:80
int lfe_ch
index of LFE channel
Definition: ac3dec.h:159
uint8_t first_spx_coords[AC3_MAX_CHANNELS]
first spx coordinates states (firstspxcos)
Definition: ac3dec.h:146
AC3BitAllocParameters bit_alloc_params
bit allocation parameters
Definition: ac3dec.h:190
int dolby_surround_mode
dolby surround mode (dsurmod)
Definition: ac3dec.h:99
GetBitContext gbc
bitstream reader
Definition: ac3dec.h:73
AC3DSPContext ac3dsp
Definition: ac3dec.h:223
maximum number of channels, including coupling channel
Definition: ac3.h:31
int dolby_headphone_mode
dolby headphone mode (dheadphonmod)
Definition: ac3dec.h:101
float loro_center_mix_level
Definition: ac3dec.h:107
int compression_exists[2]
compression field is valid for frame (compre)
Definition: ac3dec.h:88
int block_switch_syntax
block switch syntax enabled (blkswe)
Definition: ac3dec.h:114
float level_gain[2]
Definition: ac3dec.h:110
int fast_gain_syntax
fast gain codes enabled (frmfgaincode)
Definition: ac3dec.h:117
interpolated exponents
Definition: ac3dec.h:196
uint8_t channel_uses_spx[AC3_MAX_CHANNELS]
channel uses spectral extension (chinspx)
Definition: ac3dec.h:138
#define AC3_BLOCK_SIZE
Definition: ac3.h:35
INTFLOAT dynamic_range[2]
dynamic range
Definition: ac3dec.h:167
Definition: ac3dec.h:227
Definition: fft.h:88
BswapDSPContext bdsp
Definition: ac3dec.h:217
int surround_mix_level_ltrt
Surround mix level index for Lt/Rt (ltrtsurmixlev)
Definition: ac3dec.h:95
float loro_surround_mix_level
Definition: ac3dec.h:108
int dither_flag_syntax
dither flag syntax enabled (dithflage)
Definition: ac3dec.h:115
int end_freq[AC3_MAX_CHANNELS]
end frequency bin (endmant)
Definition: ac3dec.h:175
INTFLOAT heavy_dynamic_range[2]
heavy dynamic range compression
Definition: ac3dec.h:170
uint8_t dba_values[AC3_MAX_CHANNELS][8]
delta values for each segment
Definition: ac3dec.h:202
FFTContext imdct_512
for 512 sample IMDCT
Definition: ac3dec.h:212
AVCodecContext * avctx
parent context
Definition: ac3dec.h:72
int channel_in_cpl[AC3_MAX_CHANNELS]
channel in coupling (chincpl)
Definition: ac3dec.h:125
int fbw_channels
number of full-bandwidth channels
Definition: ac3dec.h:157
int8_t spx_atten_code[AC3_MAX_CHANNELS]
spx attenuation code (spxattencod)
Definition: ac3dec.h:139
Definition: ac3dec.h:228
bit allocation pointers
Definition: ac3dec.h:194
main external API structure.
Definition: avcodec.h:1502
Definition: ac3.h:39
int num_cpl_bands
number of coupling bands (ncplbnd)
Definition: ac3dec.h:128
int num_spx_bands
number of spx bands (nspxbnds)
Definition: ac3dec.h:144
static void ff_eac3_apply_spectral_extension(AC3DecodeContext *s)
Apply spectral extension to each channel by copying lower frequency coefficients to higher frequency ...
float tmp_output[AC3_BLOCK_SIZE]
temporary storage for output before windowing
Definition: ac3dec.h:236
spx signal blending factor (sblendfact)
Definition: ac3dec.h:148
Describe the class of an AVClass context structure.
Definition: log.h:67
int bitstream_mode
bitstream mode (bsmod)
Definition: ac3dec.h:84
int center_mix_level_ltrt
Center mix level index for Lt/Rt (ltrtcmixlev)
Definition: ac3dec.h:93
int frame_type
frame type (strmtyp)
Definition: ac3dec.h:77
#define AC3_MAX_BLOCKS
Definition: ac3.h:36
int eac3
indicates if current frame is E-AC-3
Definition: ac3dec.h:98
int channel_uses_aht[AC3_MAX_CHANNELS]
channel AHT in use (chahtinu)
Definition: ac3dec.h:152
uint8_t dba_lengths[AC3_MAX_CHANNELS][8]
delta segment lengths
Definition: ac3dec.h:201
int cpl_in_use[AC3_MAX_BLOCKS]
coupling in use (cplinu)
Definition: ac3dec.h:123
int firstchincpl
first channel in coupling
Definition: ac3dec.h:130
int dba_mode[AC3_MAX_CHANNELS]
delta bit allocation mode
Definition: ac3dec.h:198
int first_cpl_leak
first coupling leak state (firstcplleak)
Definition: ac3dec.h:191
int surround_mix_level
Surround mix level index.
Definition: ac3dec.h:94
int snr_offset[AC3_MAX_CHANNELS]
signal-to-noise ratio offsets (snroffst)
Definition: ac3dec.h:192
int downmixed
indicates if coeffs are currently downmixed
Definition: ac3dec.h:161
float window[AC3_BLOCK_SIZE]
window coefficients
Definition: ac3dec.h:235
Definition: ac3.h:40
Definition: ac3dec.h:229
SHORTFLOAT downmix_coeffs[AC3_MAX_CHANNELS][2]
stereo downmix coefficients
Definition: ac3dec.h:160
int num_blocks
number of audio blocks
Definition: ac3dec.h:82
FmtConvertContext fmt_conv
optimized conversion functions
Definition: ac3dec.h:224
float transform_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]
transform coefficients
Definition: ac3dec.h:233
Definition: ac3dec.h:65
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:636
int target_level
target level in dBFS
Definition: ac3dec.h:109
pre-IDCT mantissas
Definition: ac3dec.h:153
int rematrixing_flags[4]
rematrixing flags (rematflg)
Definition: ac3dec.h:180
int fixed_coeffs[AC3_MAX_CHANNELS][AC3_MAX_COEFS]
fixed-point transform coefficients
Definition: ac3dec.h:232
uint8_t spx_band_sizes[SPX_MAX_BANDS]
number of bins in each spx band
Definition: ac3dec.h:145
int lfe_mix_level
LFE mix level index (lfemixlevcod)
Definition: ac3dec.h:97
int snr_offset_strategy
SNR offset strategy (snroffststr)
Definition: ac3dec.h:113
int start_freq[AC3_MAX_CHANNELS]
start frequency bin (strtmant)
Definition: ac3dec.h:174
int sample_rate
sample frequency, in Hz
Definition: ac3dec.h:81
int center_mix_level
Center mix level index.
Definition: ac3dec.h:92
int output_mode
output channel configuration
Definition: ac3dec.h:162
int frame_size
current frame size, in bytes
Definition: ac3dec.h:79
int dolby_surround_ex_mode
dolby surround ex mode (dsurexmod)
Definition: ac3dec.h:100
AVLFG dith_state
for dither generation
Definition: ac3dec.h:207
int cpl_strategy_exists[AC3_MAX_BLOCKS]
coupling strategy exists (cplstre)
Definition: ac3dec.h:124
int bitstream_id
bitstream id (bsid)
Definition: ac3dec.h:83
Common code between the AC-3 encoder and decoder.
int channel_mode
channel mode (acmod)
Definition: ac3dec.h:85
int spx_dst_start_freq
spx starting frequency bin for copying (copystartmant) the copy region ends at the start of the spx r...
Definition: ac3dec.h:142
int skip_syntax
skip field syntax enabled (skipflde)
Definition: ac3dec.h:119
decoded exponents
Definition: ac3dec.h:185