Commit | Line | Data |
---|---|---|
2ba45a60 DM |
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 | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
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 | */ | |
21 | ||
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 | */ | |
49 | ||
50 | #ifndef AVCODEC_AC3DEC_H | |
51 | #define AVCODEC_AC3DEC_H | |
52 | ||
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" | |
62 | ||
63 | #define AC3_OUTPUT_LFEON 8 | |
64 | ||
65 | #define SPX_MAX_BANDS 17 | |
66 | ||
67 | /** Large enough for maximum possible frame size when the specification limit is ignored */ | |
68 | #define AC3_FRAME_BUFFER_SIZE 32768 | |
69 | ||
70 | typedef struct AC3DecodeContext { | |
71 | AVClass *class; ///< class for AVOptions | |
72 | AVCodecContext *avctx; ///< parent context | |
73 | GetBitContext gbc; ///< bitstream reader | |
74 | ||
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 | ///@} | |
103 | ||
104 | int preferred_stereo_downmix; | |
105 | float ltrt_center_mix_level; | |
106 | float ltrt_surround_mix_level; | |
107 | float loro_center_mix_level; | |
108 | float loro_surround_mix_level; | |
109 | int target_level; ///< target level in dBFS | |
110 | float level_gain[2]; | |
111 | ||
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 | ///@} | |
121 | ||
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 | ///@} | |
134 | ||
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 | ///@} | |
150 | ||
151 | ///@name Adaptive hybrid transform | |
152 | int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu) | |
153 | int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][AC3_MAX_BLOCKS]; ///< pre-IDCT mantissas | |
154 | ///@} | |
155 | ||
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 | ///@} | |
165 | ||
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 | ///@} | |
172 | ||
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 | ///@} | |
177 | ||
178 | ///@name Rematrixing | |
179 | int num_rematrixing_bands; ///< number of rematrixing bands (nrematbnd) | |
180 | int rematrixing_flags[4]; ///< rematrixing flags (rematflg) | |
181 | ///@} | |
182 | ||
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 | ///@} | |
188 | ||
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 | ///@} | |
204 | ||
205 | ///@name Zero-mantissa dithering | |
206 | int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags (dithflg) | |
207 | AVLFG dith_state; ///< for dither generation | |
208 | ///@} | |
209 | ||
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 | ///@} | |
215 | ||
216 | ///@name Optimization | |
217 | BswapDSPContext bdsp; | |
218 | #if USE_FIXED | |
219 | AVFixedDSPContext *fdsp; | |
220 | #else | |
f6fa7814 | 221 | AVFloatDSPContext *fdsp; |
2ba45a60 DM |
222 | #endif |
223 | AC3DSPContext ac3dsp; | |
224 | FmtConvertContext fmt_conv; ///< optimized conversion functions | |
225 | ///@} | |
226 | ||
227 | SHORTFLOAT *outptr[AC3_MAX_CHANNELS]; | |
228 | INTFLOAT *xcfptr[AC3_MAX_CHANNELS]; | |
229 | INTFLOAT *dlyptr[AC3_MAX_CHANNELS]; | |
230 | ||
231 | ///@name Aligned arrays | |
232 | DECLARE_ALIGNED(16, int, fixed_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< fixed-point transform coefficients | |
233 | DECLARE_ALIGNED(32, INTFLOAT, transform_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< 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 | |
238 | DECLARE_ALIGNED(32, uint8_t, input_buffer)[AC3_FRAME_BUFFER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE]; ///< temp buffer to prevent overread | |
239 | ///@} | |
240 | } AC3DecodeContext; | |
241 | ||
242 | /** | |
243 | * Parse the E-AC-3 frame header. | |
244 | * This parses both the bit stream info and audio frame header. | |
245 | */ | |
246 | int ff_eac3_parse_header(AC3DecodeContext *s); | |
247 | ||
248 | /** | |
249 | * Decode mantissas in a single channel for the entire frame. | |
250 | * This is used when AHT mode is enabled. | |
251 | */ | |
252 | void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch); | |
253 | ||
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 | */ | |
259 | void ff_eac3_apply_spectral_extension(AC3DecodeContext *s); | |
260 | ||
261 | #endif /* AVCODEC_AC3DEC_H */ |