cosmetics: rename GetBitContext gb to gbc
[libav.git] / libavcodec / ac3dec.c
CommitLineData
0ec2cc35
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1/*
2 * AC-3 Audio Decoder
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3 * This code is developed as part of Google Summer of Code 2006 Program.
4 *
0ec2cc35 5 * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com).
36266421 6 * Copyright (c) 2007 Justin Ruggles
032732d4 7 *
36266421 8 * Portions of this code are derived from liba52
032732d4 9 * http://liba52.sourceforge.net
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10 * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
11 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
032732d4 12 *
0ec2cc35 13 * This file is part of FFmpeg.
2aa2c5c4 14 *
0ec2cc35 15 * FFmpeg is free software; you can redistribute it and/or
9d109601 16 * modify it under the terms of the GNU General Public
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17 * License as published by the Free Software Foundation; either
18 * version 2 of the License, or (at your option) any later version.
19 *
0ec2cc35 20 * FFmpeg is distributed in the hope that it will be useful,
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21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
283614b5 23 * General Public License for more details.
2aa2c5c4 24 *
283614b5 25 * You should have received a copy of the GNU General Public
0ec2cc35 26 * License along with FFmpeg; if not, write to the Free Software
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27 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 */
29
30#include <stdio.h>
31#include <stddef.h>
32#include <math.h>
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33#include <string.h>
34
e6bca37c 35#include "avcodec.h"
9fc1ab72 36#include "ac3_parser.h"
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37#include "bitstream.h"
38#include "dsputil.h"
cb503702 39#include "random.h"
98a27a8a 40
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41/**
42 * Table of bin locations for rematrixing bands
43 * reference: Section 7.5.2 Rematrixing : Frequency Band Definitions
44 */
bfcf690c 45static const uint8_t rematrix_band_tab[5] = { 13, 25, 37, 61, 253 };
8b60bbbf 46
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47/**
48 * table for exponent to scale_factor mapping
49 * scale_factors[i] = 2 ^ -i
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50 */
51static float scale_factors[25];
52
4415076f 53/** table for grouping exponents */
bfcf690c 54static uint8_t exp_ungroup_tab[128][3];
967d397a 55
967d397a 56
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57/** tables for ungrouping mantissas */
58static float b1_mantissas[32][3];
59static float b2_mantissas[128][3];
60static float b3_mantissas[8];
61static float b4_mantissas[128][2];
62static float b5_mantissas[16];
967d397a 63
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64/**
65 * Quantization table: levels for symmetric. bits for asymmetric.
66 * reference: Table 7.18 Mapping of bap to Quantizer
67 */
e2270b4e 68static const uint8_t quantization_tab[16] = {
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69 0, 3, 5, 7, 11, 15,
70 5, 6, 7, 8, 9, 10, 11, 12, 14, 16
71};
967d397a 72
3357ff33 73/** dynamic range table. converts codes to scale factors. */
e2270b4e 74static float dynamic_range_tab[256];
3357ff33 75
5066f515 76/** Adjustments in dB gain */
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77#define LEVEL_MINUS_3DB 0.7071067811865476
78#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
79#define LEVEL_MINUS_6DB 0.5000000000000000
3bbb0bf8 80#define LEVEL_MINUS_9DB 0.3535533905932738
967d397a 81#define LEVEL_ZERO 0.0000000000000000
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82#define LEVEL_ONE 1.0000000000000000
83
84static const float gain_levels[6] = {
85 LEVEL_ZERO,
86 LEVEL_ONE,
87 LEVEL_MINUS_3DB,
88 LEVEL_MINUS_4POINT5DB,
89 LEVEL_MINUS_6DB,
90 LEVEL_MINUS_9DB
91};
967d397a 92
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93/**
94 * Table for center mix levels
95 * reference: Section 5.4.2.4 cmixlev
96 */
e59cc205 97static const uint8_t center_levels[4] = { 2, 3, 4, 3 };
967d397a 98
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99/**
100 * Table for surround mix levels
101 * reference: Section 5.4.2.5 surmixlev
102 */
e59cc205 103static const uint8_t surround_levels[4] = { 2, 4, 0, 4 };
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104
105/**
106 * Table for default stereo downmixing coefficients
107 * reference: Section 7.8.2 Downmixing Into Two Channels
108 */
109static const uint8_t ac3_default_coeffs[8][5][2] = {
110 { { 1, 0 }, { 0, 1 }, },
111 { { 2, 2 }, },
112 { { 1, 0 }, { 0, 1 }, },
113 { { 1, 0 }, { 3, 3 }, { 0, 1 }, },
114 { { 1, 0 }, { 0, 1 }, { 4, 4 }, },
115 { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 5, 5 }, },
116 { { 1, 0 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
117 { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
118};
967d397a 119
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120/* override ac3.h to include coupling channel */
121#undef AC3_MAX_CHANNELS
122#define AC3_MAX_CHANNELS 7
123#define CPL_CH 0
124
7bfd22f2 125#define AC3_OUTPUT_LFEON 8
1b293437 126
98a27a8a 127typedef struct {
e59cc205 128 int channel_mode; ///< channel mode (acmod)
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129 int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags
130 int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags
5066f515 131 int dither_all; ///< true if all channels are dithered
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132 int cpl_in_use; ///< coupling in use
133 int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling
134 int phase_flags_in_use; ///< phase flags in use
135 int cpl_band_struct[18]; ///< coupling band structure
136 int rematrixing_strategy; ///< rematrixing strategy
137 int num_rematrixing_bands; ///< number of rematrixing bands
138 int rematrixing_flags[4]; ///< rematrixing flags
139 int exp_strategy[AC3_MAX_CHANNELS]; ///< exponent strategies
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140 int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets
141 int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values (signal-to-mask ratio)
142 int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
143 int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments
144 uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets
145 uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths
146 uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment
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147
148 int sampling_rate; ///< sample frequency, in Hz
149 int bit_rate; ///< stream bit rate, in bits-per-second
150 int frame_size; ///< current frame size, in bytes
151
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152 int channels; ///< number of total channels
153 int fbw_channels; ///< number of full-bandwidth channels
e59cc205 154 int lfe_on; ///< lfe channel in use
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155 int lfe_ch; ///< index of LFE channel
156 int output_mode; ///< output channel configuration
157 int out_channels; ///< number of output channels
c7cfc48f 158
222ae64c 159 float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients
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160 float dynamic_range[2]; ///< dynamic range
161 float cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates
162 int num_cpl_bands; ///< number of coupling bands
163 int num_cpl_subbands; ///< number of coupling sub bands
164 int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin
165 int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin
623b7943 166 AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
c7cfc48f 167
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168 int8_t dexps[AC3_MAX_CHANNELS][256]; ///< decoded exponents
169 uint8_t bap[AC3_MAX_CHANNELS][256]; ///< bit allocation pointers
170 int16_t psd[AC3_MAX_CHANNELS][256]; ///< scaled exponents
5ce21342 171 int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
222ae64c 172 int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
c7cfc48f 173
5066f515 174 DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); ///< transform coefficients
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175
176 /* For IMDCT. */
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177 MDCTContext imdct_512; ///< for 512 sample IMDCT
178 MDCTContext imdct_256; ///< for 256 sample IMDCT
179 DSPContext dsp; ///< for optimization
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180 float add_bias; ///< offset for float_to_int16 conversion
181 float mul_bias; ///< scaling for float_to_int16 conversion
c7cfc48f 182
5066f515 183 DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS-1][256]); ///< output after imdct transform and windowing
4e092320 184 DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]); ///< final 16-bit integer output
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185 DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS-1][256]); ///< delay - added to the next block
186 DECLARE_ALIGNED_16(float, tmp_imdct[256]); ///< temporary storage for imdct transform
187 DECLARE_ALIGNED_16(float, tmp_output[512]); ///< temporary storage for output before windowing
188 DECLARE_ALIGNED_16(float, window[256]); ///< window coefficients
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189
190 /* Miscellaneous. */
23c8cb89 191 GetBitContext gbc; ///< bitstream reader
5066f515 192 AVRandomState dith_state; ///< for dither generation
222ae64c 193 AVCodecContext *avctx; ///< parent context
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194} AC3DecodeContext;
195
2fbbd087 196/**
2fbbd087 197 * Generate a Kaiser-Bessel Derived Window.
2fbbd087 198 */
860fe8c9 199static void ac3_window_init(float *window)
2fbbd087 200{
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201 int i, j;
202 double sum = 0.0, bessel, tmp;
203 double local_window[256];
204 double alpha2 = (5.0 * M_PI / 256.0) * (5.0 * M_PI / 256.0);
205
206 for (i = 0; i < 256; i++) {
207 tmp = i * (256 - i) * alpha2;
208 bessel = 1.0;
5066f515 209 for (j = 100; j > 0; j--) /* default to 100 iterations */
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210 bessel = bessel * tmp / (j * j) + 1;
211 sum += bessel;
212 local_window[i] = sum;
213 }
214
215 sum++;
216 for (i = 0; i < 256; i++)
217 window[i] = sqrt(local_window[i] / sum);
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218}
219
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220/**
221 * Symmetrical Dequantization
222 * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
223 * Tables 7.19 to 7.23
224 */
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225static inline float
226symmetric_dequant(int code, int levels)
98a27a8a 227{
5aefe3eb 228 return (code - (levels >> 1)) * (2.0f / levels);
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229}
230
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231/*
232 * Initialize tables at runtime.
233 */
98a27a8a 234static void ac3_tables_init(void)
00585845 235{
4415076f 236 int i;
98a27a8a 237
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238 /* generate grouped mantissa tables
239 reference: Section 7.3.5 Ungrouping of Mantissas */
240 for(i=0; i<32; i++) {
241 /* bap=1 mantissas */
242 b1_mantissas[i][0] = symmetric_dequant( i / 9 , 3);
243 b1_mantissas[i][1] = symmetric_dequant((i % 9) / 3, 3);
244 b1_mantissas[i][2] = symmetric_dequant((i % 9) % 3, 3);
245 }
246 for(i=0; i<128; i++) {
247 /* bap=2 mantissas */
248 b2_mantissas[i][0] = symmetric_dequant( i / 25 , 5);
249 b2_mantissas[i][1] = symmetric_dequant((i % 25) / 5, 5);
250 b2_mantissas[i][2] = symmetric_dequant((i % 25) % 5, 5);
251
252 /* bap=4 mantissas */
253 b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
254 b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
255 }
256 /* generate ungrouped mantissa tables
257 reference: Tables 7.21 and 7.23 */
258 for(i=0; i<7; i++) {
259 /* bap=3 mantissas */
260 b3_mantissas[i] = symmetric_dequant(i, 7);
261 }
262 for(i=0; i<15; i++) {
263 /* bap=5 mantissas */
264 b5_mantissas[i] = symmetric_dequant(i, 15);
265 }
c7cfc48f 266
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267 /* generate dynamic range table
268 reference: Section 7.7.1 Dynamic Range Control */
269 for(i=0; i<256; i++) {
270 int v = (i >> 5) - ((i >> 7) << 3) - 5;
e2270b4e 271 dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
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272 }
273
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274 /* generate scale factors for exponents and asymmetrical dequantization
275 reference: Section 7.3.2 Expansion of Mantissas for Asymmetric Quantization */
c7cfc48f 276 for (i = 0; i < 25; i++)
5aefe3eb 277 scale_factors[i] = pow(2.0, -i);
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278
279 /* generate exponent tables
280 reference: Section 7.1.3 Exponent Decoding */
281 for(i=0; i<128; i++) {
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282 exp_ungroup_tab[i][0] = i / 25;
283 exp_ungroup_tab[i][1] = (i % 25) / 5;
284 exp_ungroup_tab[i][2] = (i % 25) % 5;
4415076f 285 }
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286}
287
1b293437 288
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289/**
290 * AVCodec initialization
291 */
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292static int ac3_decode_init(AVCodecContext *avctx)
293{
294 AC3DecodeContext *ctx = avctx->priv_data;
82758fd6 295 ctx->avctx = avctx;
1b293437 296
cc2a8443 297 ac3_common_init();
98a27a8a 298 ac3_tables_init();
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299 ff_mdct_init(&ctx->imdct_256, 8, 1);
300 ff_mdct_init(&ctx->imdct_512, 9, 1);
6dc5d71f 301 ac3_window_init(ctx->window);
1d0a6f52 302 dsputil_init(&ctx->dsp, avctx);
cb503702 303 av_init_random(0, &ctx->dith_state);
2aa2c5c4 304
5066f515 305 /* set bias values for float to int16 conversion */
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306 if(ctx->dsp.float_to_int16 == ff_float_to_int16_c) {
307 ctx->add_bias = 385.0f;
308 ctx->mul_bias = 1.0f;
309 } else {
310 ctx->add_bias = 0.0f;
311 ctx->mul_bias = 32767.0f;
312 }
313
1b293437 314 return 0;
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315}
316
9fc1ab72 317/**
5066f515 318 * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
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319 * GetBitContext within AC3DecodeContext must point to
320 * start of the synchronized ac3 bitstream.
c7cfc48f 321 */
9fc1ab72 322static int ac3_parse_header(AC3DecodeContext *ctx)
2aa2c5c4 323{
9fc1ab72 324 AC3HeaderInfo hdr;
23c8cb89 325 GetBitContext *gbc = &ctx->gbc;
e59cc205 326 float center_mix_level, surround_mix_level;
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327 int err, i;
328
23c8cb89 329 err = ff_ac3_parse_header(gbc->buffer, &hdr);
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330 if(err)
331 return err;
332
333 /* get decoding parameters from header info */
5ce21342 334 ctx->bit_alloc_params.sr_code = hdr.sr_code;
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335 ctx->channel_mode = hdr.channel_mode;
336 center_mix_level = gain_levels[center_levels[hdr.center_mix_level]];
337 surround_mix_level = gain_levels[surround_levels[hdr.surround_mix_level]];
e59cc205 338 ctx->lfe_on = hdr.lfe_on;
5ce21342 339 ctx->bit_alloc_params.sr_shift = hdr.sr_shift;
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340 ctx->sampling_rate = hdr.sample_rate;
341 ctx->bit_rate = hdr.bit_rate;
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342 ctx->channels = hdr.channels;
343 ctx->fbw_channels = ctx->channels - ctx->lfe_on;
344 ctx->lfe_ch = ctx->fbw_channels + 1;
9fc1ab72 345 ctx->frame_size = hdr.frame_size;
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346
347 /* set default output to all source channels */
e2270b4e 348 ctx->out_channels = ctx->channels;
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349 ctx->output_mode = ctx->channel_mode;
350 if(ctx->lfe_on)
7bfd22f2 351 ctx->output_mode |= AC3_OUTPUT_LFEON;
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352
353 /* skip over portion of header which has already been read */
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354 skip_bits(gbc, 16); // skip the sync_word
355 skip_bits(gbc, 16); // skip crc1
356 skip_bits(gbc, 8); // skip fscod and frmsizecod
357 skip_bits(gbc, 11); // skip bsid, bsmod, and acmod
e59cc205 358 if(ctx->channel_mode == AC3_CHMODE_STEREO) {
23c8cb89 359 skip_bits(gbc, 2); // skip dsurmod
9fc1ab72 360 } else {
e59cc205 361 if((ctx->channel_mode & 1) && ctx->channel_mode != AC3_CHMODE_MONO)
23c8cb89 362 skip_bits(gbc, 2); // skip cmixlev
e59cc205 363 if(ctx->channel_mode & 4)
23c8cb89 364 skip_bits(gbc, 2); // skip surmixlev
00585845 365 }
23c8cb89 366 skip_bits1(gbc); // skip lfeon
98a27a8a 367
9fc1ab72 368 /* read the rest of the bsi. read twice for dual mono mode. */
e59cc205 369 i = !(ctx->channel_mode);
98a27a8a 370 do {
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371 skip_bits(gbc, 5); // skip dialog normalization
372 if (get_bits1(gbc))
373 skip_bits(gbc, 8); //skip compression
374 if (get_bits1(gbc))
375 skip_bits(gbc, 8); //skip language code
376 if (get_bits1(gbc))
377 skip_bits(gbc, 7); //skip audio production information
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378 } while (i--);
379
23c8cb89 380 skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
98a27a8a 381
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382 /* skip the timecodes (or extra bitstream information for Alternate Syntax)
383 TODO: read & use the xbsi1 downmix levels */
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384 if (get_bits1(gbc))
385 skip_bits(gbc, 14); //skip timecode1 / xbsi1
386 if (get_bits1(gbc))
387 skip_bits(gbc, 14); //skip timecode2 / xbsi2
98a27a8a 388
5066f515 389 /* skip additional bitstream info */
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390 if (get_bits1(gbc)) {
391 i = get_bits(gbc, 6);
486637af 392 do {
23c8cb89 393 skip_bits(gbc, 8);
98a27a8a 394 } while(i--);
1b293437 395 }
9fc1ab72 396
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397 /* set stereo downmixing coefficients
398 reference: Section 7.8.2 Downmixing Into Two Channels */
e2270b4e 399 for(i=0; i<ctx->fbw_channels; i++) {
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400 ctx->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[ctx->channel_mode][i][0]];
401 ctx->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[ctx->channel_mode][i][1]];
3bbb0bf8 402 }
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403 if(ctx->channel_mode > 1 && ctx->channel_mode & 1) {
404 ctx->downmix_coeffs[1][0] = ctx->downmix_coeffs[1][1] = center_mix_level;
3bbb0bf8 405 }
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406 if(ctx->channel_mode == AC3_CHMODE_2F1R || ctx->channel_mode == AC3_CHMODE_3F1R) {
407 int nf = ctx->channel_mode - 2;
408 ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf][1] = surround_mix_level * LEVEL_MINUS_3DB;
3bbb0bf8 409 }
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410 if(ctx->channel_mode == AC3_CHMODE_2F2R || ctx->channel_mode == AC3_CHMODE_3F2R) {
411 int nf = ctx->channel_mode - 4;
412 ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf+1][1] = surround_mix_level;
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413 }
414
9fc1ab72 415 return 0;
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416}
417
3bb004fc 418/**
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419 * Decode the grouped exponents according to exponent strategy.
420 * reference: Section 7.1.3 Exponent Decoding
2aa2c5c4 421 */
23c8cb89 422static void decode_exponents(GetBitContext *gbc, int exp_strategy, int ngrps,
bc8edb7e 423 uint8_t absexp, int8_t *dexps)
2aa2c5c4 424{
e2270b4e 425 int i, j, grp, group_size;
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426 int dexp[256];
427 int expacc, prevexp;
428
429 /* unpack groups */
e2270b4e 430 group_size = exp_strategy + (exp_strategy == EXP_D45);
4415076f 431 for(grp=0,i=0; grp<ngrps; grp++) {
23c8cb89 432 expacc = get_bits(gbc, 7);
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433 dexp[i++] = exp_ungroup_tab[expacc][0];
434 dexp[i++] = exp_ungroup_tab[expacc][1];
435 dexp[i++] = exp_ungroup_tab[expacc][2];
4415076f 436 }
2aa2c5c4 437
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438 /* convert to absolute exps and expand groups */
439 prevexp = absexp;
440 for(i=0; i<ngrps*3; i++) {
441 prevexp = av_clip(prevexp + dexp[i]-2, 0, 24);
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442 for(j=0; j<group_size; j++) {
443 dexps[(i*group_size)+j] = prevexp;
1b293437 444 }
2aa2c5c4 445 }
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446}
447
d7dc7ad0 448/**
5066f515 449 * Generate transform coefficients for each coupled channel in the coupling
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450 * range using the coupling coefficients and coupling coordinates.
451 * reference: Section 7.4.3 Coupling Coordinate Format
452 */
453static void uncouple_channels(AC3DecodeContext *ctx)
454{
455 int i, j, ch, bnd, subbnd;
456
457 subbnd = -1;
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458 i = ctx->start_freq[CPL_CH];
459 for(bnd=0; bnd<ctx->num_cpl_bands; bnd++) {
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460 do {
461 subbnd++;
462 for(j=0; j<12; j++) {
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463 for(ch=1; ch<=ctx->fbw_channels; ch++) {
464 if(ctx->channel_in_cpl[ch])
465 ctx->transform_coeffs[ch][i] = ctx->transform_coeffs[CPL_CH][i] * ctx->cpl_coords[ch][bnd] * 8.0f;
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466 }
467 i++;
468 }
e2270b4e 469 } while(ctx->cpl_band_struct[subbnd]);
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470 }
471}
472
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473/**
474 * Grouped mantissas for 3-level 5-level and 11-level quantization
475 */
476typedef struct {
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477 float b1_mant[3];
478 float b2_mant[3];
479 float b4_mant[2];
480 int b1ptr;
481 int b2ptr;
482 int b4ptr;
486637af
JR
483} mant_groups;
484
5066f515
JR
485/**
486 * Get the transform coefficients for a particular channel
487 * reference: Section 7.3 Quantization and Decoding of Mantissas
488 */
2fbbd087 489static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_groups *m)
1b293437 490{
23c8cb89 491 GetBitContext *gbc = &ctx->gbc;
60f07fad 492 int i, gcode, tbap, start, end;
2fbbd087
JR
493 uint8_t *exps;
494 uint8_t *bap;
495 float *coeffs;
2fbbd087 496
775369e0
JR
497 exps = ctx->dexps[ch_index];
498 bap = ctx->bap[ch_index];
499 coeffs = ctx->transform_coeffs[ch_index];
e2270b4e
JR
500 start = ctx->start_freq[ch_index];
501 end = ctx->end_freq[ch_index];
1b293437 502
285bf28c 503 for (i = start; i < end; i++) {
98a27a8a
JR
504 tbap = bap[i];
505 switch (tbap) {
1b293437 506 case 0:
d5b7144e 507 coeffs[i] = ((av_random(&ctx->dith_state) & 0xFFFF) / 65535.0f) - 0.5f;
d63f6fea 508 break;
1b293437
JR
509
510 case 1:
5aefe3eb 511 if(m->b1ptr > 2) {
23c8cb89 512 gcode = get_bits(gbc, 5);
5aefe3eb
JR
513 m->b1_mant[0] = b1_mantissas[gcode][0];
514 m->b1_mant[1] = b1_mantissas[gcode][1];
515 m->b1_mant[2] = b1_mantissas[gcode][2];
516 m->b1ptr = 0;
1b293437 517 }
5aefe3eb 518 coeffs[i] = m->b1_mant[m->b1ptr++];
d63f6fea 519 break;
1b293437
JR
520
521 case 2:
5aefe3eb 522 if(m->b2ptr > 2) {
23c8cb89 523 gcode = get_bits(gbc, 7);
5aefe3eb
JR
524 m->b2_mant[0] = b2_mantissas[gcode][0];
525 m->b2_mant[1] = b2_mantissas[gcode][1];
526 m->b2_mant[2] = b2_mantissas[gcode][2];
527 m->b2ptr = 0;
1b293437 528 }
5aefe3eb 529 coeffs[i] = m->b2_mant[m->b2ptr++];
d63f6fea 530 break;
1b293437
JR
531
532 case 3:
23c8cb89 533 coeffs[i] = b3_mantissas[get_bits(gbc, 3)];
d63f6fea 534 break;
1b293437
JR
535
536 case 4:
5aefe3eb 537 if(m->b4ptr > 1) {
23c8cb89 538 gcode = get_bits(gbc, 7);
5aefe3eb
JR
539 m->b4_mant[0] = b4_mantissas[gcode][0];
540 m->b4_mant[1] = b4_mantissas[gcode][1];
541 m->b4ptr = 0;
1b293437 542 }
5aefe3eb 543 coeffs[i] = m->b4_mant[m->b4ptr++];
d63f6fea 544 break;
1b293437
JR
545
546 case 5:
23c8cb89 547 coeffs[i] = b5_mantissas[get_bits(gbc, 4)];
d63f6fea 548 break;
1b293437
JR
549
550 default:
5066f515 551 /* asymmetric dequantization */
23c8cb89 552 coeffs[i] = get_sbits(gbc, quantization_tab[tbap]) * scale_factors[quantization_tab[tbap]-1];
d63f6fea 553 break;
1b293437 554 }
d63f6fea 555 coeffs[i] *= scale_factors[exps[i]];
1b293437
JR
556 }
557
1b293437
JR
558 return 0;
559}
560
60f07fad 561/**
5066f515 562 * Remove random dithering from coefficients with zero-bit mantissas
60f07fad
JR
563 * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
564 */
565static void remove_dithering(AC3DecodeContext *ctx) {
566 int ch, i;
567 int end=0;
568 float *coeffs;
569 uint8_t *bap;
570
e2270b4e
JR
571 for(ch=1; ch<=ctx->fbw_channels; ch++) {
572 if(!ctx->dither_flag[ch]) {
60f07fad 573 coeffs = ctx->transform_coeffs[ch];
7b4076a7 574 bap = ctx->bap[ch];
e2270b4e
JR
575 if(ctx->channel_in_cpl[ch])
576 end = ctx->start_freq[CPL_CH];
60f07fad 577 else
e2270b4e 578 end = ctx->end_freq[ch];
60f07fad
JR
579 for(i=0; i<end; i++) {
580 if(bap[i] == 0)
581 coeffs[i] = 0.0f;
582 }
e2270b4e 583 if(ctx->channel_in_cpl[ch]) {
7b4076a7 584 bap = ctx->bap[CPL_CH];
e2270b4e 585 for(; i<ctx->end_freq[CPL_CH]; i++) {
60f07fad
JR
586 if(bap[i] == 0)
587 coeffs[i] = 0.0f;
588 }
589 }
590 }
591 }
592}
593
5066f515
JR
594/**
595 * Get the transform coefficients.
c7cfc48f 596 */
1b293437
JR
597static int get_transform_coeffs(AC3DecodeContext * ctx)
598{
7b4076a7 599 int ch, end;
1b293437 600 int got_cplchan = 0;
486637af
JR
601 mant_groups m;
602
5aefe3eb 603 m.b1ptr = m.b2ptr = m.b4ptr = 3;
1b293437 604
e2270b4e 605 for (ch = 1; ch <= ctx->channels; ch++) {
5066f515 606 /* transform coefficients for full-bandwidth channel */
75b9b036 607 if (get_transform_coeffs_ch(ctx, ch, &m))
1b293437 608 return -1;
5066f515
JR
609 /* tranform coefficients for coupling channel come right after the
610 coefficients for the first coupled channel*/
e2270b4e 611 if (ctx->channel_in_cpl[ch]) {
486637af 612 if (!got_cplchan) {
7b4076a7 613 if (get_transform_coeffs_ch(ctx, CPL_CH, &m)) {
82758fd6 614 av_log(ctx->avctx, AV_LOG_ERROR, "error in decoupling channels\n");
486637af 615 return -1;
98a27a8a 616 }
d7dc7ad0 617 uncouple_channels(ctx);
486637af
JR
618 got_cplchan = 1;
619 }
e2270b4e 620 end = ctx->end_freq[CPL_CH];
eaf84d97 621 } else {
e2270b4e 622 end = ctx->end_freq[ch];
eaf84d97 623 }
486637af 624 do
7b4076a7 625 ctx->transform_coeffs[ch][end] = 0;
486637af
JR
626 while(++end < 256);
627 }
1b293437 628
60f07fad
JR
629 /* if any channel doesn't use dithering, zero appropriate coefficients */
630 if(!ctx->dither_all)
631 remove_dithering(ctx);
632
1b293437 633 return 0;
2aa2c5c4
JR
634}
635
8b60bbbf 636/**
5066f515 637 * Stereo rematrixing.
8b60bbbf
JR
638 * reference: Section 7.5.4 Rematrixing : Decoding Technique
639 */
1b293437
JR
640static void do_rematrixing(AC3DecodeContext *ctx)
641{
8b60bbbf 642 int bnd, i;
2fbbd087 643 int end, bndend;
8b60bbbf 644 float tmp0, tmp1;
2fbbd087 645
e2270b4e 646 end = FFMIN(ctx->end_freq[1], ctx->end_freq[2]);
1b293437 647
e2270b4e
JR
648 for(bnd=0; bnd<ctx->num_rematrixing_bands; bnd++) {
649 if(ctx->rematrixing_flags[bnd]) {
bfcf690c
JR
650 bndend = FFMIN(end, rematrix_band_tab[bnd+1]);
651 for(i=rematrix_band_tab[bnd]; i<bndend; i++) {
8b60bbbf
JR
652 tmp0 = ctx->transform_coeffs[1][i];
653 tmp1 = ctx->transform_coeffs[2][i];
654 ctx->transform_coeffs[1][i] = tmp0 + tmp1;
655 ctx->transform_coeffs[2][i] = tmp0 - tmp1;
656 }
657 }
1b293437
JR
658 }
659}
2aa2c5c4 660
5066f515
JR
661/**
662 * Perform the 256-point IMDCT
c7cfc48f 663 */
45b0ed13 664static void do_imdct_256(AC3DecodeContext *ctx, int chindex)
486637af 665{
0de73a46 666 int i, k;
dfd57c36 667 DECLARE_ALIGNED_16(float, x[128]);
0de73a46
JR
668 FFTComplex z[2][64];
669 float *o_ptr = ctx->tmp_output;
670
671 for(i=0; i<2; i++) {
672 /* de-interleave coefficients */
673 for(k=0; k<128; k++) {
674 x[k] = ctx->transform_coeffs[chindex][2*k+i];
675 }
98a27a8a 676
0de73a46
JR
677 /* run standard IMDCT */
678 ctx->imdct_256.fft.imdct_calc(&ctx->imdct_256, o_ptr, x, ctx->tmp_imdct);
679
680 /* reverse the post-rotation & reordering from standard IMDCT */
681 for(k=0; k<32; k++) {
682 z[i][32+k].re = -o_ptr[128+2*k];
683 z[i][32+k].im = -o_ptr[2*k];
684 z[i][31-k].re = o_ptr[2*k+1];
685 z[i][31-k].im = o_ptr[128+2*k+1];
686 }
1ea76064 687 }
486637af 688
0de73a46
JR
689 /* apply AC-3 post-rotation & reordering */
690 for(k=0; k<64; k++) {
691 o_ptr[ 2*k ] = -z[0][ k].im;
692 o_ptr[ 2*k+1] = z[0][63-k].re;
693 o_ptr[128+2*k ] = -z[0][ k].re;
694 o_ptr[128+2*k+1] = z[0][63-k].im;
695 o_ptr[256+2*k ] = -z[1][ k].re;
696 o_ptr[256+2*k+1] = z[1][63-k].im;
697 o_ptr[384+2*k ] = z[1][ k].im;
698 o_ptr[384+2*k+1] = -z[1][63-k].re;
699 }
98a27a8a 700}
486637af 701
5066f515
JR
702/**
703 * Inverse MDCT Transform.
704 * Convert frequency domain coefficients to time-domain audio samples.
705 * reference: Section 7.9.4 Transformation Equations
706 */
486637af
JR
707static inline void do_imdct(AC3DecodeContext *ctx)
708{
0de73a46 709 int ch;
e2270b4e 710 int channels;
486637af 711
5066f515 712 /* Don't perform the IMDCT on the LFE channel unless it's used in the output */
e2270b4e 713 channels = ctx->fbw_channels;
7b4076a7 714 if(ctx->output_mode & AC3_OUTPUT_LFEON)
e2270b4e 715 channels++;
7b4076a7 716
e2270b4e
JR
717 for (ch=1; ch<=channels; ch++) {
718 if (ctx->block_switch[ch]) {
0de73a46 719 do_imdct_256(ctx, ch);
eaf84d97 720 } else {
0de73a46
JR
721 ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output,
722 ctx->transform_coeffs[ch],
723 ctx->tmp_imdct);
eaf84d97 724 }
5066f515
JR
725 /* For the first half of the block, apply the window, add the delay
726 from the previous block, and send to output */
7b4076a7 727 ctx->dsp.vector_fmul_add_add(ctx->output[ch-1], ctx->tmp_output,
3bbb0bf8 728 ctx->window, ctx->delay[ch-1], 0, 256, 1);
5066f515
JR
729 /* For the second half of the block, apply the window and store the
730 samples to delay, to be combined with the next block */
7b4076a7 731 ctx->dsp.vector_fmul_reverse(ctx->delay[ch-1], ctx->tmp_output+256,
0de73a46 732 ctx->window, 256);
486637af
JR
733 }
734}
735
3bbb0bf8 736/**
5066f515 737 * Downmix the output to mono or stereo.
3bbb0bf8 738 */
224bc440
JR
739static void ac3_downmix(float samples[AC3_MAX_CHANNELS][256], int fbw_channels,
740 int output_mode, float coef[AC3_MAX_CHANNELS][2])
3bbb0bf8
JR
741{
742 int i, j;
743 float v0, v1, s0, s1;
744
745 for(i=0; i<256; i++) {
746 v0 = v1 = s0 = s1 = 0.0f;
224bc440
JR
747 for(j=0; j<fbw_channels; j++) {
748 v0 += samples[j][i] * coef[j][0];
749 v1 += samples[j][i] * coef[j][1];
750 s0 += coef[j][0];
751 s1 += coef[j][1];
3bbb0bf8
JR
752 }
753 v0 /= s0;
754 v1 /= s1;
e59cc205 755 if(output_mode == AC3_CHMODE_MONO) {
224bc440 756 samples[0][i] = (v0 + v1) * LEVEL_MINUS_3DB;
e59cc205 757 } else if(output_mode == AC3_CHMODE_STEREO) {
224bc440
JR
758 samples[0][i] = v0;
759 samples[1][i] = v1;
3bbb0bf8
JR
760 }
761 }
762}
763
5066f515
JR
764/**
765 * Parse an audio block from AC-3 bitstream.
c7cfc48f 766 */
9fc1ab72 767static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
2aa2c5c4 768{
e2270b4e 769 int fbw_channels = ctx->fbw_channels;
e59cc205 770 int channel_mode = ctx->channel_mode;
0bff58a5 771 int i, bnd, seg, ch;
23c8cb89 772 GetBitContext *gbc = &ctx->gbc;
7b4076a7 773 uint8_t bit_alloc_stages[AC3_MAX_CHANNELS];
1b293437 774
7b4076a7
JR
775 memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
776
5066f515 777 /* block switch flags */
224bc440 778 for (ch = 1; ch <= fbw_channels; ch++)
23c8cb89 779 ctx->block_switch[ch] = get_bits1(gbc);
98a27a8a 780
5066f515 781 /* dithering flags */
60f07fad 782 ctx->dither_all = 1;
e2270b4e 783 for (ch = 1; ch <= fbw_channels; ch++) {
23c8cb89 784 ctx->dither_flag[ch] = get_bits1(gbc);
e2270b4e 785 if(!ctx->dither_flag[ch])
60f07fad
JR
786 ctx->dither_all = 0;
787 }
98a27a8a 788
77416325 789 /* dynamic range */
e59cc205 790 i = !(ctx->channel_mode);
77416325 791 do {
23c8cb89
JR
792 if(get_bits1(gbc)) {
793 ctx->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)]-1.0) *
1408352a 794 ctx->avctx->drc_scale)+1.0;
9fc1ab72 795 } else if(blk == 0) {
e2270b4e 796 ctx->dynamic_range[i] = 1.0f;
9fc1ab72 797 }
77416325 798 } while(i--);
98a27a8a 799
5066f515 800 /* coupling strategy */
23c8cb89 801 if (get_bits1(gbc)) {
7b4076a7 802 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
23c8cb89 803 ctx->cpl_in_use = get_bits1(gbc);
e2270b4e 804 if (ctx->cpl_in_use) {
5066f515 805 /* coupling in use */
e2270b4e 806 int cpl_begin_freq, cpl_end_freq;
b6acc57f 807
5066f515 808 /* determine which channels are coupled */
e2270b4e 809 for (ch = 1; ch <= fbw_channels; ch++)
23c8cb89 810 ctx->channel_in_cpl[ch] = get_bits1(gbc);
98a27a8a 811
5066f515 812 /* phase flags in use */
e59cc205 813 if (channel_mode == AC3_CHMODE_STEREO)
23c8cb89 814 ctx->phase_flags_in_use = get_bits1(gbc);
98a27a8a 815
5066f515 816 /* coupling frequency range and band structure */
23c8cb89
JR
817 cpl_begin_freq = get_bits(gbc, 4);
818 cpl_end_freq = get_bits(gbc, 4);
e2270b4e
JR
819 if (3 + cpl_end_freq - cpl_begin_freq < 0) {
820 av_log(ctx->avctx, AV_LOG_ERROR, "3+cplendf = %d < cplbegf = %d\n", 3+cpl_end_freq, cpl_begin_freq);
00585845 821 return -1;
98a27a8a 822 }
e2270b4e
JR
823 ctx->num_cpl_bands = ctx->num_cpl_subbands = 3 + cpl_end_freq - cpl_begin_freq;
824 ctx->start_freq[CPL_CH] = cpl_begin_freq * 12 + 37;
825 ctx->end_freq[CPL_CH] = cpl_end_freq * 12 + 73;
826 for (bnd = 0; bnd < ctx->num_cpl_subbands - 1; bnd++) {
23c8cb89 827 if (get_bits1(gbc)) {
e2270b4e
JR
828 ctx->cpl_band_struct[bnd] = 1;
829 ctx->num_cpl_bands--;
1b293437 830 }
eaf84d97 831 }
878c40a1 832 } else {
5066f515 833 /* coupling not in use */
e2270b4e
JR
834 for (ch = 1; ch <= fbw_channels; ch++)
835 ctx->channel_in_cpl[ch] = 0;
1b293437
JR
836 }
837 }
98a27a8a 838
5066f515 839 /* coupling coordinates */
e2270b4e
JR
840 if (ctx->cpl_in_use) {
841 int cpl_coords_exist = 0;
98a27a8a 842
e2270b4e
JR
843 for (ch = 1; ch <= fbw_channels; ch++) {
844 if (ctx->channel_in_cpl[ch]) {
23c8cb89 845 if (get_bits1(gbc)) {
e2270b4e
JR
846 int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
847 cpl_coords_exist = 1;
23c8cb89 848 master_cpl_coord = 3 * get_bits(gbc, 2);
e2270b4e 849 for (bnd = 0; bnd < ctx->num_cpl_bands; bnd++) {
23c8cb89
JR
850 cpl_coord_exp = get_bits(gbc, 4);
851 cpl_coord_mant = get_bits(gbc, 4);
e2270b4e
JR
852 if (cpl_coord_exp == 15)
853 ctx->cpl_coords[ch][bnd] = cpl_coord_mant / 16.0f;
486637af 854 else
e2270b4e
JR
855 ctx->cpl_coords[ch][bnd] = (cpl_coord_mant + 16.0f) / 32.0f;
856 ctx->cpl_coords[ch][bnd] *= scale_factors[cpl_coord_exp + master_cpl_coord];
486637af 857 }
486637af 858 }
eaf84d97
JR
859 }
860 }
5066f515 861 /* phase flags */
e2270b4e
JR
862 if (channel_mode == AC3_CHMODE_STEREO && ctx->phase_flags_in_use && cpl_coords_exist) {
863 for (bnd = 0; bnd < ctx->num_cpl_bands; bnd++) {
23c8cb89 864 if (get_bits1(gbc))
e2270b4e 865 ctx->cpl_coords[2][bnd] = -ctx->cpl_coords[2][bnd];
eaf84d97
JR
866 }
867 }
2aa2c5c4 868 }
98a27a8a 869
5066f515 870 /* stereo rematrixing strategy and band structure */
e59cc205 871 if (channel_mode == AC3_CHMODE_STEREO) {
23c8cb89 872 ctx->rematrixing_strategy = get_bits1(gbc);
e2270b4e
JR
873 if (ctx->rematrixing_strategy) {
874 ctx->num_rematrixing_bands = 4;
875 if(ctx->cpl_in_use && ctx->start_freq[CPL_CH] <= 61)
876 ctx->num_rematrixing_bands -= 1 + (ctx->start_freq[CPL_CH] == 37);
877 for(bnd=0; bnd<ctx->num_rematrixing_bands; bnd++)
23c8cb89 878 ctx->rematrixing_flags[bnd] = get_bits1(gbc);
1b293437 879 }
98a27a8a
JR
880 }
881
5066f515 882 /* exponent strategies for each channel */
e2270b4e
JR
883 ctx->exp_strategy[CPL_CH] = EXP_REUSE;
884 ctx->exp_strategy[ctx->lfe_ch] = EXP_REUSE;
885 for (ch = !ctx->cpl_in_use; ch <= ctx->channels; ch++) {
7b4076a7 886 if(ch == ctx->lfe_ch)
23c8cb89 887 ctx->exp_strategy[ch] = get_bits(gbc, 1);
7b4076a7 888 else
23c8cb89 889 ctx->exp_strategy[ch] = get_bits(gbc, 2);
e2270b4e 890 if(ctx->exp_strategy[ch] != EXP_REUSE)
7b4076a7
JR
891 bit_alloc_stages[ch] = 3;
892 }
893
5066f515 894 /* channel bandwidth */
e2270b4e
JR
895 for (ch = 1; ch <= fbw_channels; ch++) {
896 ctx->start_freq[ch] = 0;
897 if (ctx->exp_strategy[ch] != EXP_REUSE) {
898 int prev = ctx->end_freq[ch];
899 if (ctx->channel_in_cpl[ch])
900 ctx->end_freq[ch] = ctx->start_freq[CPL_CH];
00585845 901 else {
23c8cb89 902 int bandwidth_code = get_bits(gbc, 6);
e2270b4e
JR
903 if (bandwidth_code > 60) {
904 av_log(ctx->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60", bandwidth_code);
00585845
JR
905 return -1;
906 }
e2270b4e 907 ctx->end_freq[ch] = bandwidth_code * 3 + 73;
1b293437 908 }
e2270b4e 909 if(blk > 0 && ctx->end_freq[ch] != prev)
7b4076a7 910 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
00585845 911 }
eaf84d97 912 }
e2270b4e
JR
913 ctx->start_freq[ctx->lfe_ch] = 0;
914 ctx->end_freq[ctx->lfe_ch] = 7;
7b4076a7 915
5066f515 916 /* decode exponents for each channel */
e2270b4e
JR
917 for (ch = !ctx->cpl_in_use; ch <= ctx->channels; ch++) {
918 if (ctx->exp_strategy[ch] != EXP_REUSE) {
919 int group_size, num_groups;
920 group_size = 3 << (ctx->exp_strategy[ch] - 1);
7b4076a7 921 if(ch == CPL_CH)
e2270b4e 922 num_groups = (ctx->end_freq[ch] - ctx->start_freq[ch]) / group_size;
7b4076a7 923 else if(ch == ctx->lfe_ch)
e2270b4e 924 num_groups = 2;
7b4076a7 925 else
e2270b4e 926 num_groups = (ctx->end_freq[ch] + group_size - 4) / group_size;
23c8cb89
JR
927 ctx->dexps[ch][0] = get_bits(gbc, 4) << !ch;
928 decode_exponents(gbc, ctx->exp_strategy[ch], num_groups, ctx->dexps[ch][0],
e2270b4e 929 &ctx->dexps[ch][ctx->start_freq[ch]+!!ch]);
7b4076a7 930 if(ch != CPL_CH && ch != ctx->lfe_ch)
23c8cb89 931 skip_bits(gbc, 2); /* skip gainrng */
1b293437 932 }
eaf84d97 933 }
98a27a8a 934
5066f515 935 /* bit allocation information */
23c8cb89
JR
936 if (get_bits1(gbc)) {
937 ctx->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> ctx->bit_alloc_params.sr_shift;
938 ctx->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> ctx->bit_alloc_params.sr_shift;
939 ctx->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
940 ctx->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
941 ctx->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
e2270b4e 942 for(ch=!ctx->cpl_in_use; ch<=ctx->channels; ch++) {
7b4076a7
JR
943 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
944 }
1b293437 945 }
98a27a8a 946
5066f515 947 /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
23c8cb89 948 if (get_bits1(gbc)) {
4611b64e 949 int csnr;
23c8cb89 950 csnr = (get_bits(gbc, 6) - 15) << 4;
e2270b4e 951 for (ch = !ctx->cpl_in_use; ch <= ctx->channels; ch++) { /* snr offset and fast gain */
23c8cb89
JR
952 ctx->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2;
953 ctx->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
1b293437 954 }
7b4076a7 955 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
1b293437 956 }
98a27a8a 957
5066f515 958 /* coupling leak information */
23c8cb89
JR
959 if (ctx->cpl_in_use && get_bits1(gbc)) {
960 ctx->bit_alloc_params.cpl_fast_leak = get_bits(gbc, 3);
961 ctx->bit_alloc_params.cpl_slow_leak = get_bits(gbc, 3);
7b4076a7 962 bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
98a27a8a
JR
963 }
964
5066f515 965 /* delta bit allocation information */
23c8cb89 966 if (get_bits1(gbc)) {
5066f515 967 /* delta bit allocation exists (strategy) */
e2270b4e 968 for (ch = !ctx->cpl_in_use; ch <= fbw_channels; ch++) {
23c8cb89 969 ctx->dba_mode[ch] = get_bits(gbc, 2);
5ce21342 970 if (ctx->dba_mode[ch] == DBA_RESERVED) {
82758fd6 971 av_log(ctx->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
1b293437
JR
972 return -1;
973 }
7b4076a7 974 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1b293437 975 }
5066f515 976 /* channel delta offset, len and bit allocation */
e2270b4e 977 for (ch = !ctx->cpl_in_use; ch <= fbw_channels; ch++) {
5ce21342 978 if (ctx->dba_mode[ch] == DBA_NEW) {
23c8cb89 979 ctx->dba_nsegs[ch] = get_bits(gbc, 3);
5ce21342 980 for (seg = 0; seg <= ctx->dba_nsegs[ch]; seg++) {
23c8cb89
JR
981 ctx->dba_offsets[ch][seg] = get_bits(gbc, 5);
982 ctx->dba_lengths[ch][seg] = get_bits(gbc, 4);
983 ctx->dba_values[ch][seg] = get_bits(gbc, 3);
1b293437
JR
984 }
985 }
eaf84d97 986 }
9fc1ab72 987 } else if(blk == 0) {
e2270b4e 988 for(ch=0; ch<=ctx->channels; ch++) {
5ce21342 989 ctx->dba_mode[ch] = DBA_NONE;
9fc1ab72 990 }
1b293437 991 }
00585845 992
5066f515 993 /* Bit allocation */
e2270b4e 994 for(ch=!ctx->cpl_in_use; ch<=ctx->channels; ch++) {
7b4076a7
JR
995 if(bit_alloc_stages[ch] > 2) {
996 /* Exponent mapping into PSD and PSD integration */
997 ff_ac3_bit_alloc_calc_psd(ctx->dexps[ch],
e2270b4e 998 ctx->start_freq[ch], ctx->end_freq[ch],
5ce21342 999 ctx->psd[ch], ctx->band_psd[ch]);
eaf84d97 1000 }
7b4076a7
JR
1001 if(bit_alloc_stages[ch] > 1) {
1002 /* Compute excitation function, Compute masking curve, and
1003 Apply delta bit allocation */
5ce21342 1004 ff_ac3_bit_alloc_calc_mask(&ctx->bit_alloc_params, ctx->band_psd[ch],
e2270b4e 1005 ctx->start_freq[ch], ctx->end_freq[ch],
5ce21342
JR
1006 ctx->fast_gain[ch], (ch == ctx->lfe_ch),
1007 ctx->dba_mode[ch], ctx->dba_nsegs[ch],
1008 ctx->dba_offsets[ch], ctx->dba_lengths[ch],
1009 ctx->dba_values[ch], ctx->mask[ch]);
eaf84d97 1010 }
7b4076a7
JR
1011 if(bit_alloc_stages[ch] > 0) {
1012 /* Compute bit allocation */
1013 ff_ac3_bit_alloc_calc_bap(ctx->mask[ch], ctx->psd[ch],
e2270b4e 1014 ctx->start_freq[ch], ctx->end_freq[ch],
5ce21342 1015 ctx->snr_offset[ch],
7b4076a7
JR
1016 ctx->bit_alloc_params.floor,
1017 ctx->bap[ch]);
eaf84d97 1018 }
2fbbd087 1019 }
98a27a8a 1020
5066f515 1021 /* unused dummy data */
23c8cb89
JR
1022 if (get_bits1(gbc)) {
1023 int skipl = get_bits(gbc, 9);
98a27a8a 1024 while(skipl--)
23c8cb89 1025 skip_bits(gbc, 8);
1b293437 1026 }
f5cefb21 1027
1b293437 1028 /* unpack the transform coefficients
5066f515 1029 this also uncouples channels if coupling is in use. */
1b293437 1030 if (get_transform_coeffs(ctx)) {
82758fd6 1031 av_log(ctx->avctx, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
1b293437
JR
1032 return -1;
1033 }
486637af 1034
1b293437 1035 /* recover coefficients if rematrixing is in use */
e59cc205 1036 if(ctx->channel_mode == AC3_CHMODE_STEREO)
1b293437
JR
1037 do_rematrixing(ctx);
1038
03726b70 1039 /* apply scaling to coefficients (headroom, dynrng) */
e2270b4e 1040 for(ch=1; ch<=ctx->channels; ch++) {
4e092320 1041 float gain = 2.0f * ctx->mul_bias;
e59cc205 1042 if(ctx->channel_mode == AC3_CHMODE_DUALMONO) {
03726b70 1043 gain *= ctx->dynamic_range[ch-1];
7bfd22f2 1044 } else {
03726b70 1045 gain *= ctx->dynamic_range[0];
7bfd22f2 1046 }
e2270b4e 1047 for(i=0; i<ctx->end_freq[ch]; i++) {
7bfd22f2
JR
1048 ctx->transform_coeffs[ch][i] *= gain;
1049 }
1050 }
d7bcc4ad 1051
486637af 1052 do_imdct(ctx);
486637af 1053
224bc440 1054 /* downmix output if needed */
e2270b4e
JR
1055 if(ctx->channels != ctx->out_channels && !((ctx->output_mode & AC3_OUTPUT_LFEON) &&
1056 ctx->fbw_channels == ctx->out_channels)) {
1057 ac3_downmix(ctx->output, ctx->fbw_channels, ctx->output_mode,
224bc440 1058 ctx->downmix_coeffs);
3bbb0bf8
JR
1059 }
1060
4e092320
JR
1061 /* convert float to 16-bit integer */
1062 for(ch=0; ch<ctx->out_channels; ch++) {
3bbb0bf8
JR
1063 for(i=0; i<256; i++) {
1064 ctx->output[ch][i] += ctx->add_bias;
1065 }
4e092320
JR
1066 ctx->dsp.float_to_int16(ctx->int_output[ch], ctx->output[ch], 256);
1067 }
1b293437 1068
4e092320 1069 return 0;
486637af
JR
1070}
1071
5066f515
JR
1072/**
1073 * Decode a single AC-3 frame.
c7cfc48f 1074 */
00585845 1075static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
1b293437 1076{
00585845 1077 AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
00585845 1078 int16_t *out_samples = (int16_t *)data;
3df88093 1079 int i, blk, ch, err;
d7bcc4ad 1080
5066f515 1081 /* initialize the GetBitContext with the start of valid AC-3 Frame */
23c8cb89 1082 init_get_bits(&ctx->gbc, buf, buf_size * 8);
00585845 1083
5066f515 1084 /* parse the syncinfo */
3df88093
JR
1085 err = ac3_parse_header(ctx);
1086 if(err) {
1087 switch(err) {
1088 case AC3_PARSE_ERROR_SYNC:
1089 av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
1090 break;
1091 case AC3_PARSE_ERROR_BSID:
1092 av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
1093 break;
1094 case AC3_PARSE_ERROR_SAMPLE_RATE:
1095 av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
1096 break;
1097 case AC3_PARSE_ERROR_FRAME_SIZE:
1098 av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
1099 break;
1100 default:
1101 av_log(avctx, AV_LOG_ERROR, "invalid header\n");
1102 break;
1103 }
1104 return -1;
1b293437 1105 }
2aa2c5c4 1106
98a27a8a
JR
1107 avctx->sample_rate = ctx->sampling_rate;
1108 avctx->bit_rate = ctx->bit_rate;
45b0ed13 1109
a135bea5
JR
1110 /* check that reported frame size fits in input buffer */
1111 if(ctx->frame_size > buf_size) {
1112 av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
1113 return -1;
1114 }
1115
7bfd22f2 1116 /* channel config */
e2270b4e 1117 ctx->out_channels = ctx->channels;
6708eefe
1118 if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&
1119 avctx->request_channels < ctx->channels) {
1120 ctx->out_channels = avctx->request_channels;
1121 ctx->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
1b293437 1122 }
6708eefe 1123 avctx->channels = ctx->out_channels;
1b293437 1124
5066f515 1125 /* parse the audio blocks */
75b9b036
JR
1126 for (blk = 0; blk < NB_BLOCKS; blk++) {
1127 if (ac3_parse_audio_block(ctx, blk)) {
1b293437
JR
1128 av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
1129 *data_size = 0;
98a27a8a 1130 return ctx->frame_size;
1b293437 1131 }
75b9b036 1132 for (i = 0; i < 256; i++)
7b4076a7 1133 for (ch = 0; ch < ctx->out_channels; ch++)
4e092320 1134 *(out_samples++) = ctx->int_output[ch][i];
1b293437 1135 }
8fbb368d 1136 *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t);
98a27a8a 1137 return ctx->frame_size;
2aa2c5c4 1138}
1b293437 1139
5066f515
JR
1140/**
1141 * Uninitialize the AC-3 decoder.
c7cfc48f
JR
1142 */
1143static int ac3_decode_end(AVCodecContext *avctx)
1b293437 1144{
c7cfc48f
JR
1145 AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
1146 ff_mdct_end(&ctx->imdct_512);
1147 ff_mdct_end(&ctx->imdct_256);
1148
1b293437
JR
1149 return 0;
1150}
1151
fa67992d 1152AVCodec ac3_decoder = {
e6bca37c
JR
1153 .name = "ac3",
1154 .type = CODEC_TYPE_AUDIO,
1155 .id = CODEC_ID_AC3,
1156 .priv_data_size = sizeof (AC3DecodeContext),
1157 .init = ac3_decode_init,
1158 .close = ac3_decode_end,
1159 .decode = ac3_decode_frame,
1b293437 1160};