use reget_buffer and remove internal copying of buffer - codec works again
[libav.git] / libavcodec / ac3dec.c
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0ec2cc35
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1/*
2 * AC-3 Audio Decoder
032732d4
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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 */
45static const uint8_t rematrix_band_tbl[5] = { 13, 25, 37, 61, 253 };
46
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47/* table for exponent to scale_factor mapping
48 * scale_factor[i] = 2 ^ -(i + 15)
49 */
50static float scale_factors[25];
51
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52/** table for grouping exponents */
53static uint8_t exp_ungroup_tbl[128][3];
967d397a 54
967d397a 55
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56/** tables for ungrouping mantissas */
57static float b1_mantissas[32][3];
58static float b2_mantissas[128][3];
59static float b3_mantissas[8];
60static float b4_mantissas[128][2];
61static float b5_mantissas[16];
967d397a 62
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63/**
64 * Quantization table: levels for symmetric. bits for asymmetric.
65 * reference: Table 7.18 Mapping of bap to Quantizer
66 */
67static const uint8_t qntztab[16] = {
68 0, 3, 5, 7, 11, 15,
69 5, 6, 7, 8, 9, 10, 11, 12, 14, 16
70};
967d397a 71
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72/** dynamic range table. converts codes to scale factors. */
73static float dynrng_tbl[256];
74
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75/** dialogue normalization table */
76static float dialnorm_tbl[32];
77
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78/* Adjustmens in dB gain */
79#define LEVEL_MINUS_3DB 0.7071067811865476
80#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
81#define LEVEL_MINUS_6DB 0.5000000000000000
3bbb0bf8 82#define LEVEL_MINUS_9DB 0.3535533905932738
967d397a 83#define LEVEL_ZERO 0.0000000000000000
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84#define LEVEL_ONE 1.0000000000000000
85
86static const float gain_levels[6] = {
87 LEVEL_ZERO,
88 LEVEL_ONE,
89 LEVEL_MINUS_3DB,
90 LEVEL_MINUS_4POINT5DB,
91 LEVEL_MINUS_6DB,
92 LEVEL_MINUS_9DB
93};
967d397a 94
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95/**
96 * Table for center mix levels
97 * reference: Section 5.4.2.4 cmixlev
98 */
99static const uint8_t clevs[4] = { 2, 3, 4, 3 };
967d397a 100
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101/**
102 * Table for surround mix levels
103 * reference: Section 5.4.2.5 surmixlev
104 */
105static const uint8_t slevs[4] = { 2, 4, 0, 4 };
106
107/**
108 * Table for default stereo downmixing coefficients
109 * reference: Section 7.8.2 Downmixing Into Two Channels
110 */
111static const uint8_t ac3_default_coeffs[8][5][2] = {
112 { { 1, 0 }, { 0, 1 }, },
113 { { 2, 2 }, },
114 { { 1, 0 }, { 0, 1 }, },
115 { { 1, 0 }, { 3, 3 }, { 0, 1 }, },
116 { { 1, 0 }, { 0, 1 }, { 4, 4 }, },
117 { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 5, 5 }, },
118 { { 1, 0 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
119 { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
120};
967d397a 121
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122/* override ac3.h to include coupling channel */
123#undef AC3_MAX_CHANNELS
124#define AC3_MAX_CHANNELS 7
125#define CPL_CH 0
126
7bfd22f2 127#define AC3_OUTPUT_LFEON 8
1b293437 128
98a27a8a 129typedef struct {
e9a38248 130 int acmod;
e9a38248 131 int dsurmod;
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132 int blksw[AC3_MAX_CHANNELS];
133 int dithflag[AC3_MAX_CHANNELS];
60f07fad 134 int dither_all;
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135 int cplinu;
136 int chincpl[AC3_MAX_CHANNELS];
137 int phsflginu;
6d96d626 138 int cplbndstrc[18];
e9a38248 139 int rematstr;
8b60bbbf 140 int nrematbnd;
5e61de0c 141 int rematflg[4];
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142 int expstr[AC3_MAX_CHANNELS];
143 int snroffst[AC3_MAX_CHANNELS];
144 int fgain[AC3_MAX_CHANNELS];
145 int deltbae[AC3_MAX_CHANNELS];
146 int deltnseg[AC3_MAX_CHANNELS];
147 uint8_t deltoffst[AC3_MAX_CHANNELS][8];
148 uint8_t deltlen[AC3_MAX_CHANNELS][8];
149 uint8_t deltba[AC3_MAX_CHANNELS][8];
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150
151 /* Derived Attributes. */
152 int sampling_rate;
153 int bit_rate;
154 int frame_size;
155
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156 int nchans; //number of total channels
157 int nfchans; //number of full-bandwidth channels
c7cfc48f 158 int lfeon; //lfe channel in use
7b4076a7 159 int lfe_ch; ///< index of LFE channel
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160 int output_mode; ///< output channel configuration
161 int out_channels; ///< number of output channels
c7cfc48f 162
3bbb0bf8 163 float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients
01f35453 164 float dialnorm[2]; ///< dialogue normalization
77416325 165 float dynrng[2]; ///< dynamic range
7b4076a7 166 float cplco[AC3_MAX_CHANNELS][18]; //coupling coordinates
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167 int ncplbnd; //number of coupling bands
168 int ncplsubnd; //number of coupling sub bands
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169 int startmant[AC3_MAX_CHANNELS]; ///< start frequency bin
170 int endmant[AC3_MAX_CHANNELS]; //channel end mantissas
623b7943 171 AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
c7cfc48f 172
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173 int8_t dexps[AC3_MAX_CHANNELS][256]; ///< decoded exponents
174 uint8_t bap[AC3_MAX_CHANNELS][256]; ///< bit allocation pointers
175 int16_t psd[AC3_MAX_CHANNELS][256]; ///< scaled exponents
176 int16_t bndpsd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
177 int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
c7cfc48f 178
8fbb368d 179 DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); //transform coefficients
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180
181 /* For IMDCT. */
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182 MDCTContext imdct_512; //for 512 sample imdct transform
183 MDCTContext imdct_256; //for 256 sample imdct transform
1d0a6f52 184 DSPContext dsp; //for optimization
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185 float add_bias; ///< offset for float_to_int16 conversion
186 float mul_bias; ///< scaling for float_to_int16 conversion
c7cfc48f 187
7b4076a7 188 DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS-1][256]); //output after imdct transform and windowing
4e092320 189 DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]); ///< final 16-bit integer output
7b4076a7 190 DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS-1][256]); //delay - added to the next block
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191 DECLARE_ALIGNED_16(float, tmp_imdct[256]); //temporary storage for imdct transform
192 DECLARE_ALIGNED_16(float, tmp_output[512]); //temporary storage for output before windowing
193 DECLARE_ALIGNED_16(float, window[256]); //window coefficients
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194
195 /* Miscellaneous. */
196 GetBitContext gb;
cb503702 197 AVRandomState dith_state; //for dither generation
82758fd6 198 AVCodecContext *avctx; ///< parent context
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199} AC3DecodeContext;
200
2fbbd087 201/**
2fbbd087 202 * Generate a Kaiser-Bessel Derived Window.
2fbbd087 203 */
860fe8c9 204static void ac3_window_init(float *window)
2fbbd087 205{
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206 int i, j;
207 double sum = 0.0, bessel, tmp;
208 double local_window[256];
209 double alpha2 = (5.0 * M_PI / 256.0) * (5.0 * M_PI / 256.0);
210
211 for (i = 0; i < 256; i++) {
212 tmp = i * (256 - i) * alpha2;
213 bessel = 1.0;
214 for (j = 100; j > 0; j--) /* defaul to 100 iterations */
215 bessel = bessel * tmp / (j * j) + 1;
216 sum += bessel;
217 local_window[i] = sum;
218 }
219
220 sum++;
221 for (i = 0; i < 256; i++)
222 window[i] = sqrt(local_window[i] / sum);
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223}
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;
271 dynrng_tbl[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
272 }
273
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274 /* generate dialogue normalization table
275 references: Section 5.4.2.8 dialnorm
276 Section 7.6 Dialogue Normalization */
277 for(i=1; i<32; i++) {
278 dialnorm_tbl[i] = expf((i-31) * M_LN10 / 20.0f);
279 }
280 dialnorm_tbl[0] = dialnorm_tbl[31];
281
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282 //generate scale factors
283 for (i = 0; i < 25; i++)
5aefe3eb 284 scale_factors[i] = pow(2.0, -i);
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285
286 /* generate exponent tables
287 reference: Section 7.1.3 Exponent Decoding */
288 for(i=0; i<128; i++) {
289 exp_ungroup_tbl[i][0] = i / 25;
290 exp_ungroup_tbl[i][1] = (i % 25) / 5;
291 exp_ungroup_tbl[i][2] = (i % 25) % 5;
292 }
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293}
294
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295
296static int ac3_decode_init(AVCodecContext *avctx)
297{
298 AC3DecodeContext *ctx = avctx->priv_data;
82758fd6 299 ctx->avctx = avctx;
1b293437 300
cc2a8443 301 ac3_common_init();
98a27a8a 302 ac3_tables_init();
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303 ff_mdct_init(&ctx->imdct_256, 8, 1);
304 ff_mdct_init(&ctx->imdct_512, 9, 1);
6dc5d71f 305 ac3_window_init(ctx->window);
1d0a6f52 306 dsputil_init(&ctx->dsp, avctx);
cb503702 307 av_init_random(0, &ctx->dith_state);
2aa2c5c4 308
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309 if(ctx->dsp.float_to_int16 == ff_float_to_int16_c) {
310 ctx->add_bias = 385.0f;
311 ctx->mul_bias = 1.0f;
312 } else {
313 ctx->add_bias = 0.0f;
314 ctx->mul_bias = 32767.0f;
315 }
316
1b293437 317 return 0;
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318}
319
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320/**
321 * Parses the 'sync info' and 'bit stream info' from the AC-3 bitstream.
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322 * GetBitContext within AC3DecodeContext must point to
323 * start of the synchronized ac3 bitstream.
c7cfc48f 324 */
9fc1ab72 325static int ac3_parse_header(AC3DecodeContext *ctx)
2aa2c5c4 326{
9fc1ab72 327 AC3HeaderInfo hdr;
1b293437 328 GetBitContext *gb = &ctx->gb;
3bbb0bf8 329 float cmixlev, surmixlev;
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330 int err, i;
331
332 err = ff_ac3_parse_header(gb->buffer, &hdr);
333 if(err)
334 return err;
335
336 /* get decoding parameters from header info */
337 ctx->bit_alloc_params.fscod = hdr.fscod;
338 ctx->acmod = hdr.acmod;
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339 cmixlev = gain_levels[clevs[hdr.cmixlev]];
340 surmixlev = gain_levels[slevs[hdr.surmixlev]];
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341 ctx->dsurmod = hdr.dsurmod;
342 ctx->lfeon = hdr.lfeon;
343 ctx->bit_alloc_params.halfratecod = hdr.halfratecod;
344 ctx->sampling_rate = hdr.sample_rate;
345 ctx->bit_rate = hdr.bit_rate;
346 ctx->nchans = hdr.channels;
347 ctx->nfchans = ctx->nchans - ctx->lfeon;
7b4076a7 348 ctx->lfe_ch = ctx->nfchans + 1;
9fc1ab72 349 ctx->frame_size = hdr.frame_size;
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350
351 /* set default output to all source channels */
352 ctx->out_channels = ctx->nchans;
353 ctx->output_mode = ctx->acmod;
9fc1ab72 354 if(ctx->lfeon)
7bfd22f2 355 ctx->output_mode |= AC3_OUTPUT_LFEON;
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356
357 /* skip over portion of header which has already been read */
98a27a8a 358 skip_bits(gb, 16); //skip the sync_word, sync_info->sync_word = get_bits(gb, 16);
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359 skip_bits(gb, 16); // skip crc1
360 skip_bits(gb, 8); // skip fscod and frmsizecod
361 skip_bits(gb, 11); // skip bsid, bsmod, and acmod
362 if(ctx->acmod == AC3_ACMOD_STEREO) {
363 skip_bits(gb, 2); // skip dsurmod
364 } else {
365 if((ctx->acmod & 1) && ctx->acmod != AC3_ACMOD_MONO)
366 skip_bits(gb, 2); // skip cmixlev
367 if(ctx->acmod & 4)
368 skip_bits(gb, 2); // skip surmixlev
00585845 369 }
9fc1ab72 370 skip_bits1(gb); // skip lfeon
98a27a8a 371
9fc1ab72 372 /* read the rest of the bsi. read twice for dual mono mode. */
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373 i = !(ctx->acmod);
374 do {
01f35453 375 ctx->dialnorm[i] = dialnorm_tbl[get_bits(gb, 5)]; // dialogue normalization
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376 if (get_bits1(gb))
377 skip_bits(gb, 8); //skip compression
378 if (get_bits1(gb))
379 skip_bits(gb, 8); //skip language code
380 if (get_bits1(gb))
381 skip_bits(gb, 7); //skip audio production information
382 } while (i--);
383
384 skip_bits(gb, 2); //skip copyright bit and original bitstream bit
385
9fc1ab72 386 /* FIXME: read & use the xbsi1 downmix levels */
00585845 387 if (get_bits1(gb))
98a27a8a 388 skip_bits(gb, 14); //skip timecode1
00585845 389 if (get_bits1(gb))
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390 skip_bits(gb, 14); //skip timecode2
391
00585845 392 if (get_bits1(gb)) {
98a27a8a 393 i = get_bits(gb, 6); //additional bsi length
486637af 394 do {
00585845 395 skip_bits(gb, 8);
98a27a8a 396 } while(i--);
1b293437 397 }
9fc1ab72 398
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399 /* set stereo downmixing coefficients
400 reference: Section 7.8.2 Downmixing Into Two Channels */
401 for(i=0; i<ctx->nfchans; i++) {
402 ctx->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[ctx->acmod][i][0]];
403 ctx->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[ctx->acmod][i][1]];
404 }
405 if(ctx->acmod > 1 && ctx->acmod & 1) {
406 ctx->downmix_coeffs[1][0] = ctx->downmix_coeffs[1][1] = cmixlev;
407 }
408 if(ctx->acmod == AC3_ACMOD_2F1R || ctx->acmod == AC3_ACMOD_3F1R) {
409 int nf = ctx->acmod - 2;
410 ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf][1] = surmixlev * LEVEL_MINUS_3DB;
411 }
412 if(ctx->acmod == AC3_ACMOD_2F2R || ctx->acmod == AC3_ACMOD_3F2R) {
413 int nf = ctx->acmod - 4;
414 ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf+1][1] = surmixlev;
415 }
416
9fc1ab72 417 return 0;
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418}
419
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420/**
421 * Decodes the grouped exponents.
c7cfc48f
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422 * This function decodes the coded exponents according to exponent strategy
423 * and stores them in the decoded exponents buffer.
424 *
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425 * @param[in] gb GetBitContext which points to start of coded exponents
426 * @param[in] expstr Exponent coding strategy
427 * @param[in] ngrps Number of grouped exponents
428 * @param[in] absexp Absolute exponent or DC exponent
429 * @param[out] dexps Decoded exponents are stored in dexps
2aa2c5c4 430 */
4415076f 431static void decode_exponents(GetBitContext *gb, int expstr, int ngrps,
bc8edb7e 432 uint8_t absexp, int8_t *dexps)
2aa2c5c4 433{
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434 int i, j, grp, grpsize;
435 int dexp[256];
436 int expacc, prevexp;
437
438 /* unpack groups */
439 grpsize = expstr + (expstr == EXP_D45);
440 for(grp=0,i=0; grp<ngrps; grp++) {
441 expacc = get_bits(gb, 7);
442 dexp[i++] = exp_ungroup_tbl[expacc][0];
443 dexp[i++] = exp_ungroup_tbl[expacc][1];
444 dexp[i++] = exp_ungroup_tbl[expacc][2];
445 }
2aa2c5c4 446
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447 /* convert to absolute exps and expand groups */
448 prevexp = absexp;
449 for(i=0; i<ngrps*3; i++) {
450 prevexp = av_clip(prevexp + dexp[i]-2, 0, 24);
451 for(j=0; j<grpsize; j++) {
452 dexps[(i*grpsize)+j] = prevexp;
1b293437 453 }
2aa2c5c4 454 }
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455}
456
d7dc7ad0
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457/**
458 * Generates transform coefficients for each coupled channel in the coupling
459 * range using the coupling coefficients and coupling coordinates.
460 * reference: Section 7.4.3 Coupling Coordinate Format
461 */
462static void uncouple_channels(AC3DecodeContext *ctx)
463{
464 int i, j, ch, bnd, subbnd;
465
466 subbnd = -1;
7b4076a7 467 i = ctx->startmant[CPL_CH];
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468 for(bnd=0; bnd<ctx->ncplbnd; bnd++) {
469 do {
470 subbnd++;
471 for(j=0; j<12; j++) {
472 for(ch=1; ch<=ctx->nfchans; ch++) {
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473 if(ctx->chincpl[ch])
474 ctx->transform_coeffs[ch][i] = ctx->transform_coeffs[CPL_CH][i] * ctx->cplco[ch][bnd] * 8.0f;
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475 }
476 i++;
477 }
6d96d626 478 } while(ctx->cplbndstrc[subbnd]);
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479 }
480}
481
486637af 482typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantization */
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483 float b1_mant[3];
484 float b2_mant[3];
485 float b4_mant[2];
486 int b1ptr;
487 int b2ptr;
488 int b4ptr;
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489} mant_groups;
490
1b293437 491/* Get the transform coefficients for particular channel */
2fbbd087 492static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_groups *m)
1b293437 493{
2fbbd087 494 GetBitContext *gb = &ctx->gb;
60f07fad 495 int i, gcode, tbap, start, end;
2fbbd087
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496 uint8_t *exps;
497 uint8_t *bap;
498 float *coeffs;
2fbbd087 499
775369e0
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500 exps = ctx->dexps[ch_index];
501 bap = ctx->bap[ch_index];
502 coeffs = ctx->transform_coeffs[ch_index];
503 start = ctx->startmant[ch_index];
504 end = ctx->endmant[ch_index];
1b293437 505
285bf28c 506 for (i = start; i < end; i++) {
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507 tbap = bap[i];
508 switch (tbap) {
1b293437 509 case 0:
5aefe3eb 510 coeffs[i] = ((av_random(&ctx->dith_state) & 0xFFFF) * LEVEL_MINUS_3DB) / 32768.0f;
d63f6fea 511 break;
1b293437
JR
512
513 case 1:
5aefe3eb 514 if(m->b1ptr > 2) {
00585845 515 gcode = get_bits(gb, 5);
5aefe3eb
JR
516 m->b1_mant[0] = b1_mantissas[gcode][0];
517 m->b1_mant[1] = b1_mantissas[gcode][1];
518 m->b1_mant[2] = b1_mantissas[gcode][2];
519 m->b1ptr = 0;
1b293437 520 }
5aefe3eb 521 coeffs[i] = m->b1_mant[m->b1ptr++];
d63f6fea 522 break;
1b293437
JR
523
524 case 2:
5aefe3eb 525 if(m->b2ptr > 2) {
00585845 526 gcode = get_bits(gb, 7);
5aefe3eb
JR
527 m->b2_mant[0] = b2_mantissas[gcode][0];
528 m->b2_mant[1] = b2_mantissas[gcode][1];
529 m->b2_mant[2] = b2_mantissas[gcode][2];
530 m->b2ptr = 0;
1b293437 531 }
5aefe3eb 532 coeffs[i] = m->b2_mant[m->b2ptr++];
d63f6fea 533 break;
1b293437
JR
534
535 case 3:
5aefe3eb 536 coeffs[i] = b3_mantissas[get_bits(gb, 3)];
d63f6fea 537 break;
1b293437
JR
538
539 case 4:
5aefe3eb 540 if(m->b4ptr > 1) {
00585845 541 gcode = get_bits(gb, 7);
5aefe3eb
JR
542 m->b4_mant[0] = b4_mantissas[gcode][0];
543 m->b4_mant[1] = b4_mantissas[gcode][1];
544 m->b4ptr = 0;
1b293437 545 }
5aefe3eb 546 coeffs[i] = m->b4_mant[m->b4ptr++];
d63f6fea 547 break;
1b293437
JR
548
549 case 5:
5aefe3eb 550 coeffs[i] = b5_mantissas[get_bits(gb, 4)];
d63f6fea 551 break;
1b293437
JR
552
553 default:
5aefe3eb 554 coeffs[i] = get_sbits(gb, qntztab[tbap]) * scale_factors[qntztab[tbap]-1];
d63f6fea 555 break;
1b293437 556 }
d63f6fea 557 coeffs[i] *= scale_factors[exps[i]];
1b293437
JR
558 }
559
1b293437
JR
560 return 0;
561}
562
60f07fad
JR
563/**
564 * Removes random dithering from coefficients with zero-bit mantissas
565 * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
566 */
567static void remove_dithering(AC3DecodeContext *ctx) {
568 int ch, i;
569 int end=0;
570 float *coeffs;
571 uint8_t *bap;
572
573 for(ch=1; ch<=ctx->nfchans; ch++) {
7b4076a7 574 if(!ctx->dithflag[ch]) {
60f07fad 575 coeffs = ctx->transform_coeffs[ch];
7b4076a7
JR
576 bap = ctx->bap[ch];
577 if(ctx->chincpl[ch])
578 end = ctx->startmant[CPL_CH];
60f07fad 579 else
7b4076a7 580 end = ctx->endmant[ch];
60f07fad
JR
581 for(i=0; i<end; i++) {
582 if(bap[i] == 0)
583 coeffs[i] = 0.0f;
584 }
7b4076a7
JR
585 if(ctx->chincpl[ch]) {
586 bap = ctx->bap[CPL_CH];
587 for(; i<ctx->endmant[CPL_CH]; i++) {
60f07fad
JR
588 if(bap[i] == 0)
589 coeffs[i] = 0.0f;
590 }
591 }
592 }
593 }
594}
595
c7cfc48f
JR
596/* Get the transform coefficients.
597 * This function extracts the tranform coefficients form the ac3 bitstream.
598 * This function is called after bit allocation is performed.
599 */
1b293437
JR
600static int get_transform_coeffs(AC3DecodeContext * ctx)
601{
7b4076a7 602 int ch, end;
1b293437 603 int got_cplchan = 0;
486637af
JR
604 mant_groups m;
605
5aefe3eb 606 m.b1ptr = m.b2ptr = m.b4ptr = 3;
1b293437 607
7b4076a7 608 for (ch = 1; ch <= ctx->nchans; ch++) {
1b293437 609 /* transform coefficients for individual channel */
75b9b036 610 if (get_transform_coeffs_ch(ctx, ch, &m))
1b293437
JR
611 return -1;
612 /* tranform coefficients for coupling channels */
75b9b036 613 if (ctx->chincpl[ch]) {
486637af 614 if (!got_cplchan) {
7b4076a7 615 if (get_transform_coeffs_ch(ctx, CPL_CH, &m)) {
82758fd6 616 av_log(ctx->avctx, AV_LOG_ERROR, "error in decoupling channels\n");
486637af 617 return -1;
98a27a8a 618 }
d7dc7ad0 619 uncouple_channels(ctx);
486637af
JR
620 got_cplchan = 1;
621 }
7b4076a7 622 end = ctx->endmant[CPL_CH];
eaf84d97 623 } else {
75b9b036 624 end = ctx->endmant[ch];
eaf84d97 625 }
486637af 626 do
7b4076a7 627 ctx->transform_coeffs[ch][end] = 0;
486637af
JR
628 while(++end < 256);
629 }
1b293437 630
60f07fad
JR
631 /* if any channel doesn't use dithering, zero appropriate coefficients */
632 if(!ctx->dither_all)
633 remove_dithering(ctx);
634
1b293437 635 return 0;
2aa2c5c4
JR
636}
637
8b60bbbf
JR
638/**
639 * Performs stereo rematrixing.
640 * reference: Section 7.5.4 Rematrixing : Decoding Technique
641 */
1b293437
JR
642static void do_rematrixing(AC3DecodeContext *ctx)
643{
8b60bbbf 644 int bnd, i;
2fbbd087 645 int end, bndend;
8b60bbbf 646 float tmp0, tmp1;
2fbbd087 647
7b4076a7 648 end = FFMIN(ctx->endmant[1], ctx->endmant[2]);
1b293437 649
8b60bbbf
JR
650 for(bnd=0; bnd<ctx->nrematbnd; bnd++) {
651 if(ctx->rematflg[bnd]) {
652 bndend = FFMIN(end, rematrix_band_tbl[bnd+1]);
653 for(i=rematrix_band_tbl[bnd]; i<bndend; i++) {
654 tmp0 = ctx->transform_coeffs[1][i];
655 tmp1 = ctx->transform_coeffs[2][i];
656 ctx->transform_coeffs[1][i] = tmp0 + tmp1;
657 ctx->transform_coeffs[2][i] = tmp0 - tmp1;
658 }
659 }
1b293437
JR
660 }
661}
2aa2c5c4 662
c7cfc48f
JR
663/* This function performs the imdct on 256 sample transform
664 * coefficients.
665 */
45b0ed13 666static void do_imdct_256(AC3DecodeContext *ctx, int chindex)
486637af 667{
0de73a46 668 int i, k;
dfd57c36 669 DECLARE_ALIGNED_16(float, x[128]);
0de73a46
JR
670 FFTComplex z[2][64];
671 float *o_ptr = ctx->tmp_output;
672
673 for(i=0; i<2; i++) {
674 /* de-interleave coefficients */
675 for(k=0; k<128; k++) {
676 x[k] = ctx->transform_coeffs[chindex][2*k+i];
677 }
98a27a8a 678
0de73a46
JR
679 /* run standard IMDCT */
680 ctx->imdct_256.fft.imdct_calc(&ctx->imdct_256, o_ptr, x, ctx->tmp_imdct);
681
682 /* reverse the post-rotation & reordering from standard IMDCT */
683 for(k=0; k<32; k++) {
684 z[i][32+k].re = -o_ptr[128+2*k];
685 z[i][32+k].im = -o_ptr[2*k];
686 z[i][31-k].re = o_ptr[2*k+1];
687 z[i][31-k].im = o_ptr[128+2*k+1];
688 }
1ea76064 689 }
486637af 690
0de73a46
JR
691 /* apply AC-3 post-rotation & reordering */
692 for(k=0; k<64; k++) {
693 o_ptr[ 2*k ] = -z[0][ k].im;
694 o_ptr[ 2*k+1] = z[0][63-k].re;
695 o_ptr[128+2*k ] = -z[0][ k].re;
696 o_ptr[128+2*k+1] = z[0][63-k].im;
697 o_ptr[256+2*k ] = -z[1][ k].re;
698 o_ptr[256+2*k+1] = z[1][63-k].im;
699 o_ptr[384+2*k ] = z[1][ k].im;
700 o_ptr[384+2*k+1] = -z[1][63-k].re;
701 }
98a27a8a 702}
486637af 703
c7cfc48f 704/* IMDCT Transform. */
486637af
JR
705static inline void do_imdct(AC3DecodeContext *ctx)
706{
0de73a46 707 int ch;
7b4076a7 708 int nchans;
486637af 709
7b4076a7
JR
710 nchans = ctx->nfchans;
711 if(ctx->output_mode & AC3_OUTPUT_LFEON)
712 nchans++;
713
714 for (ch=1; ch<=nchans; ch++) {
715 if (ctx->blksw[ch]) {
0de73a46 716 do_imdct_256(ctx, ch);
eaf84d97 717 } else {
0de73a46
JR
718 ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output,
719 ctx->transform_coeffs[ch],
720 ctx->tmp_imdct);
eaf84d97 721 }
7b4076a7 722 ctx->dsp.vector_fmul_add_add(ctx->output[ch-1], ctx->tmp_output,
3bbb0bf8 723 ctx->window, ctx->delay[ch-1], 0, 256, 1);
7b4076a7 724 ctx->dsp.vector_fmul_reverse(ctx->delay[ch-1], ctx->tmp_output+256,
0de73a46 725 ctx->window, 256);
486637af
JR
726 }
727}
728
3bbb0bf8
JR
729/**
730 * Downmixes the output to stereo.
731 */
732static void ac3_downmix(float samples[AC3_MAX_CHANNELS][256], int nfchans,
733 int output_mode, float coef[AC3_MAX_CHANNELS][2])
734{
735 int i, j;
736 float v0, v1, s0, s1;
737
738 for(i=0; i<256; i++) {
739 v0 = v1 = s0 = s1 = 0.0f;
740 for(j=0; j<nfchans; j++) {
741 v0 += samples[j][i] * coef[j][0];
742 v1 += samples[j][i] * coef[j][1];
743 s0 += coef[j][0];
744 s1 += coef[j][1];
745 }
746 v0 /= s0;
747 v1 /= s1;
748 if(output_mode == AC3_ACMOD_MONO) {
749 samples[0][i] = (v0 + v1) * LEVEL_MINUS_3DB;
750 } else if(output_mode == AC3_ACMOD_STEREO) {
751 samples[0][i] = v0;
752 samples[1][i] = v1;
753 }
754 }
755}
756
c7cfc48f
JR
757/* Parse the audio block from ac3 bitstream.
758 * This function extract the audio block from the ac3 bitstream
759 * and produces the output for the block. This function must
760 * be called for each of the six audio block in the ac3 bitstream.
761 */
9fc1ab72 762static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
2aa2c5c4 763{
98a27a8a
JR
764 int nfchans = ctx->nfchans;
765 int acmod = ctx->acmod;
0bff58a5 766 int i, bnd, seg, ch;
1b293437 767 GetBitContext *gb = &ctx->gb;
7b4076a7 768 uint8_t bit_alloc_stages[AC3_MAX_CHANNELS];
1b293437 769
7b4076a7
JR
770 memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
771
772 for (ch = 1; ch <= nfchans; ch++) /*block switch flag */
75b9b036 773 ctx->blksw[ch] = get_bits1(gb);
98a27a8a 774
60f07fad 775 ctx->dither_all = 1;
7b4076a7 776 for (ch = 1; ch <= nfchans; ch++) { /* dithering flag */
75b9b036
JR
777 ctx->dithflag[ch] = get_bits1(gb);
778 if(!ctx->dithflag[ch])
60f07fad
JR
779 ctx->dither_all = 0;
780 }
98a27a8a 781
77416325
JR
782 /* dynamic range */
783 i = !(ctx->acmod);
784 do {
9fc1ab72 785 if(get_bits1(gb)) {
77416325 786 ctx->dynrng[i] = dynrng_tbl[get_bits(gb, 8)];
9fc1ab72 787 } else if(blk == 0) {
77416325 788 ctx->dynrng[i] = 1.0f;
9fc1ab72 789 }
77416325 790 } while(i--);
98a27a8a 791
00585845 792 if (get_bits1(gb)) { /* coupling strategy */
7b4076a7 793 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
98a27a8a
JR
794 ctx->cplinu = get_bits1(gb);
795 if (ctx->cplinu) { /* coupling in use */
b6acc57f
JR
796 int cplbegf, cplendf;
797
7b4076a7 798 for (ch = 1; ch <= nfchans; ch++)
75b9b036 799 ctx->chincpl[ch] = get_bits1(gb);
98a27a8a 800
e2cd6686 801 if (acmod == AC3_ACMOD_STEREO)
98a27a8a
JR
802 ctx->phsflginu = get_bits1(gb); //phase flag in use
803
b6acc57f
JR
804 cplbegf = get_bits(gb, 4);
805 cplendf = get_bits(gb, 4);
98a27a8a 806
b6acc57f 807 if (3 + cplendf - cplbegf < 0) {
82758fd6 808 av_log(ctx->avctx, AV_LOG_ERROR, "cplendf = %d < cplbegf = %d\n", cplendf, cplbegf);
00585845 809 return -1;
98a27a8a
JR
810 }
811
b6acc57f 812 ctx->ncplbnd = ctx->ncplsubnd = 3 + cplendf - cplbegf;
7b4076a7
JR
813 ctx->startmant[CPL_CH] = cplbegf * 12 + 37;
814 ctx->endmant[CPL_CH] = cplendf * 12 + 73;
75b9b036 815 for (bnd = 0; bnd < ctx->ncplsubnd - 1; bnd++) { /* coupling band structure */
00585845 816 if (get_bits1(gb)) {
75b9b036 817 ctx->cplbndstrc[bnd] = 1;
98a27a8a 818 ctx->ncplbnd--;
1b293437 819 }
eaf84d97 820 }
878c40a1 821 } else {
7b4076a7 822 for (ch = 1; ch <= nfchans; ch++)
75b9b036 823 ctx->chincpl[ch] = 0;
1b293437
JR
824 }
825 }
98a27a8a
JR
826
827 if (ctx->cplinu) {
fc59010b 828 int cplcoe = 0;
98a27a8a 829
7b4076a7 830 for (ch = 1; ch <= nfchans; ch++) {
75b9b036 831 if (ctx->chincpl[ch]) {
00585845 832 if (get_bits1(gb)) { /* coupling co-ordinates */
8e2eb3b6 833 int mstrcplco, cplcoexp, cplcomant;
fc59010b 834 cplcoe = 1;
486637af 835 mstrcplco = 3 * get_bits(gb, 2);
98a27a8a 836 for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
486637af
JR
837 cplcoexp = get_bits(gb, 4);
838 cplcomant = get_bits(gb, 4);
839 if (cplcoexp == 15)
75b9b036 840 ctx->cplco[ch][bnd] = cplcomant / 16.0f;
486637af 841 else
75b9b036
JR
842 ctx->cplco[ch][bnd] = (cplcomant + 16.0f) / 32.0f;
843 ctx->cplco[ch][bnd] *= scale_factors[cplcoexp + mstrcplco];
486637af 844 }
486637af 845 }
eaf84d97
JR
846 }
847 }
98a27a8a 848
eaf84d97
JR
849 if (acmod == AC3_ACMOD_STEREO && ctx->phsflginu && cplcoe) {
850 for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
98a27a8a 851 if (get_bits1(gb))
7b4076a7 852 ctx->cplco[2][bnd] = -ctx->cplco[2][bnd];
eaf84d97
JR
853 }
854 }
2aa2c5c4 855 }
98a27a8a 856
e2cd6686 857 if (acmod == AC3_ACMOD_STEREO) {/* rematrixing */
98a27a8a
JR
858 ctx->rematstr = get_bits1(gb);
859 if (ctx->rematstr) {
8b60bbbf 860 ctx->nrematbnd = 4;
7b4076a7
JR
861 if(ctx->cplinu && ctx->startmant[CPL_CH] <= 61)
862 ctx->nrematbnd -= 1 + (ctx->startmant[CPL_CH] == 37);
8b60bbbf
JR
863 for(bnd=0; bnd<ctx->nrematbnd; bnd++)
864 ctx->rematflg[bnd] = get_bits1(gb);
1b293437 865 }
98a27a8a
JR
866 }
867
7b4076a7
JR
868 ctx->expstr[CPL_CH] = EXP_REUSE;
869 ctx->expstr[ctx->lfe_ch] = EXP_REUSE;
870 for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) {
871 if(ch == ctx->lfe_ch)
872 ctx->expstr[ch] = get_bits(gb, 1);
873 else
874 ctx->expstr[ch] = get_bits(gb, 2);
875 if(ctx->expstr[ch] != EXP_REUSE)
876 bit_alloc_stages[ch] = 3;
877 }
878
879 for (ch = 1; ch <= nfchans; ch++) { /* channel bandwidth code */
880 ctx->startmant[ch] = 0;
881 if (ctx->expstr[ch] != EXP_REUSE) {
882 int prev = ctx->endmant[ch];
75b9b036 883 if (ctx->chincpl[ch])
7b4076a7 884 ctx->endmant[ch] = ctx->startmant[CPL_CH];
00585845 885 else {
8e2eb3b6 886 int chbwcod = get_bits(gb, 6);
98a27a8a 887 if (chbwcod > 60) {
82758fd6 888 av_log(ctx->avctx, AV_LOG_ERROR, "chbwcod = %d > 60", chbwcod);
00585845
JR
889 return -1;
890 }
75b9b036 891 ctx->endmant[ch] = chbwcod * 3 + 73;
1b293437 892 }
7b4076a7
JR
893 if(blk > 0 && ctx->endmant[ch] != prev)
894 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
00585845 895 }
eaf84d97 896 }
7b4076a7
JR
897 ctx->startmant[ctx->lfe_ch] = 0;
898 ctx->endmant[ctx->lfe_ch] = 7;
899
900 for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) {
901 if (ctx->expstr[ch] != EXP_REUSE) {
902 int grpsize, ngrps;
903 grpsize = 3 << (ctx->expstr[ch] - 1);
904 if(ch == CPL_CH)
905 ngrps = (ctx->endmant[ch] - ctx->startmant[ch]) / grpsize;
906 else if(ch == ctx->lfe_ch)
907 ngrps = 2;
908 else
775369e0 909 ngrps = (ctx->endmant[ch] + grpsize - 4) / grpsize;
7b4076a7
JR
910 ctx->dexps[ch][0] = get_bits(gb, 4) << !ch;
911 decode_exponents(gb, ctx->expstr[ch], ngrps, ctx->dexps[ch][0],
912 &ctx->dexps[ch][ctx->startmant[ch]+!!ch]);
913 if(ch != CPL_CH && ch != ctx->lfe_ch)
775369e0 914 skip_bits(gb, 2); /* skip gainrng */
1b293437 915 }
eaf84d97 916 }
98a27a8a 917
00585845 918 if (get_bits1(gb)) { /* bit allocation information */
8f58a4c9
JR
919 ctx->bit_alloc_params.sdecay = ff_sdecaytab[get_bits(gb, 2)];
920 ctx->bit_alloc_params.fdecay = ff_fdecaytab[get_bits(gb, 2)];
921 ctx->bit_alloc_params.sgain = ff_sgaintab[get_bits(gb, 2)];
922 ctx->bit_alloc_params.dbknee = ff_dbkneetab[get_bits(gb, 2)];
923 ctx->bit_alloc_params.floor = ff_floortab[get_bits(gb, 3)];
7b4076a7
JR
924 for(ch=!ctx->cplinu; ch<=ctx->nchans; ch++) {
925 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
926 }
1b293437 927 }
98a27a8a 928
00585845 929 if (get_bits1(gb)) { /* snroffset */
4611b64e 930 int csnr;
4611b64e 931 csnr = (get_bits(gb, 6) - 15) << 4;
7b4076a7 932 for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) { /* snr offset and fast gain */
75b9b036
JR
933 ctx->snroffst[ch] = (csnr + get_bits(gb, 4)) << 2;
934 ctx->fgain[ch] = ff_fgaintab[get_bits(gb, 3)];
1b293437 935 }
7b4076a7 936 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
1b293437 937 }
98a27a8a 938
98a27a8a 939 if (ctx->cplinu && get_bits1(gb)) { /* coupling leak information */
8f58a4c9
JR
940 ctx->bit_alloc_params.cplfleak = get_bits(gb, 3);
941 ctx->bit_alloc_params.cplsleak = get_bits(gb, 3);
7b4076a7 942 bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
98a27a8a
JR
943 }
944
00585845 945 if (get_bits1(gb)) { /* delta bit allocation information */
7b4076a7 946 for (ch = !ctx->cplinu; ch <= nfchans; ch++) {
75b9b036
JR
947 ctx->deltbae[ch] = get_bits(gb, 2);
948 if (ctx->deltbae[ch] == DBA_RESERVED) {
82758fd6 949 av_log(ctx->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
1b293437
JR
950 return -1;
951 }
7b4076a7 952 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1b293437 953 }
7b4076a7 954 for (ch = !ctx->cplinu; ch <= nfchans; ch++) {
75b9b036
JR
955 if (ctx->deltbae[ch] == DBA_NEW) {/*channel delta offset, len and bit allocation */
956 ctx->deltnseg[ch] = get_bits(gb, 3);
957 for (seg = 0; seg <= ctx->deltnseg[ch]; seg++) {
958 ctx->deltoffst[ch][seg] = get_bits(gb, 5);
959 ctx->deltlen[ch][seg] = get_bits(gb, 4);
960 ctx->deltba[ch][seg] = get_bits(gb, 3);
1b293437
JR
961 }
962 }
eaf84d97 963 }
9fc1ab72 964 } else if(blk == 0) {
7b4076a7 965 for(ch=0; ch<=ctx->nchans; ch++) {
75b9b036 966 ctx->deltbae[ch] = DBA_NONE;
9fc1ab72 967 }
1b293437 968 }
00585845 969
7b4076a7
JR
970 for(ch=!ctx->cplinu; ch<=ctx->nchans; ch++) {
971 if(bit_alloc_stages[ch] > 2) {
972 /* Exponent mapping into PSD and PSD integration */
973 ff_ac3_bit_alloc_calc_psd(ctx->dexps[ch],
974 ctx->startmant[ch], ctx->endmant[ch],
975 ctx->psd[ch], ctx->bndpsd[ch]);
eaf84d97 976 }
7b4076a7
JR
977 if(bit_alloc_stages[ch] > 1) {
978 /* Compute excitation function, Compute masking curve, and
979 Apply delta bit allocation */
980 ff_ac3_bit_alloc_calc_mask(&ctx->bit_alloc_params, ctx->bndpsd[ch],
981 ctx->startmant[ch], ctx->endmant[ch],
982 ctx->fgain[ch], (ch == ctx->lfe_ch),
983 ctx->deltbae[ch], ctx->deltnseg[ch],
984 ctx->deltoffst[ch], ctx->deltlen[ch],
985 ctx->deltba[ch], ctx->mask[ch]);
eaf84d97 986 }
7b4076a7
JR
987 if(bit_alloc_stages[ch] > 0) {
988 /* Compute bit allocation */
989 ff_ac3_bit_alloc_calc_bap(ctx->mask[ch], ctx->psd[ch],
990 ctx->startmant[ch], ctx->endmant[ch],
991 ctx->snroffst[ch],
992 ctx->bit_alloc_params.floor,
993 ctx->bap[ch]);
eaf84d97 994 }
2fbbd087 995 }
98a27a8a 996
00585845 997 if (get_bits1(gb)) { /* unused dummy data */
8e2eb3b6 998 int skipl = get_bits(gb, 9);
98a27a8a 999 while(skipl--)
00585845 1000 skip_bits(gb, 8);
1b293437 1001 }
f5cefb21 1002
1b293437
JR
1003 /* unpack the transform coefficients
1004 * * this also uncouples channels if coupling is in use.
1005 */
1006 if (get_transform_coeffs(ctx)) {
82758fd6 1007 av_log(ctx->avctx, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
1b293437
JR
1008 return -1;
1009 }
486637af 1010
1b293437 1011 /* recover coefficients if rematrixing is in use */
878c40a1 1012 if(ctx->acmod == AC3_ACMOD_STEREO)
1b293437
JR
1013 do_rematrixing(ctx);
1014
01f35453 1015 /* apply scaling to coefficients (headroom, dialnorm, dynrng) */
7b4076a7 1016 for(ch=1; ch<=ctx->nchans; ch++) {
4e092320 1017 float gain = 2.0f * ctx->mul_bias;
77416325
JR
1018 if(ctx->acmod == AC3_ACMOD_DUALMONO) {
1019 gain *= ctx->dialnorm[ch-1] * ctx->dynrng[ch-1];
7bfd22f2 1020 } else {
77416325 1021 gain *= ctx->dialnorm[0] * ctx->dynrng[0];
7bfd22f2 1022 }
7b4076a7 1023 for(i=0; i<ctx->endmant[ch]; i++) {
7bfd22f2
JR
1024 ctx->transform_coeffs[ch][i] *= gain;
1025 }
1026 }
d7bcc4ad 1027
486637af 1028 do_imdct(ctx);
486637af 1029
3bbb0bf8
JR
1030 /* downmix output if needed */
1031 if(ctx->nchans != ctx->out_channels && !((ctx->output_mode & AC3_OUTPUT_LFEON) &&
1032 ctx->nfchans == ctx->out_channels)) {
1033 ac3_downmix(ctx->output, ctx->nfchans, ctx->output_mode,
1034 ctx->downmix_coeffs);
1035 }
1036
4e092320
JR
1037 /* convert float to 16-bit integer */
1038 for(ch=0; ch<ctx->out_channels; ch++) {
3bbb0bf8
JR
1039 for(i=0; i<256; i++) {
1040 ctx->output[ch][i] += ctx->add_bias;
1041 }
4e092320
JR
1042 ctx->dsp.float_to_int16(ctx->int_output[ch], ctx->output[ch], 256);
1043 }
1b293437 1044
4e092320 1045 return 0;
486637af
JR
1046}
1047
c7cfc48f
JR
1048/* Decode ac3 frame.
1049 *
1050 * @param avctx Pointer to AVCodecContext
1051 * @param data Pointer to pcm smaples
1052 * @param data_size Set to number of pcm samples produced by decoding
1053 * @param buf Data to be decoded
1054 * @param buf_size Size of the buffer
1055 */
00585845 1056static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
1b293437 1057{
00585845 1058 AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
00585845 1059 int16_t *out_samples = (int16_t *)data;
7b4076a7 1060 int i, blk, ch;
d7bcc4ad 1061
1b293437 1062 //Initialize the GetBitContext with the start of valid AC3 Frame.
9ef60390 1063 init_get_bits(&ctx->gb, buf, buf_size * 8);
00585845 1064
1b293437 1065 //Parse the syncinfo.
9fc1ab72 1066 if (ac3_parse_header(ctx)) {
00585845 1067 av_log(avctx, AV_LOG_ERROR, "\n");
1b293437 1068 *data_size = 0;
486637af 1069 return buf_size;
1b293437 1070 }
2aa2c5c4 1071
98a27a8a
JR
1072 avctx->sample_rate = ctx->sampling_rate;
1073 avctx->bit_rate = ctx->bit_rate;
45b0ed13 1074
7bfd22f2 1075 /* channel config */
3bbb0bf8 1076 ctx->out_channels = ctx->nchans;
1b293437 1077 if (avctx->channels == 0) {
7bfd22f2 1078 avctx->channels = ctx->out_channels;
3bbb0bf8
JR
1079 } else if(ctx->out_channels < avctx->channels) {
1080 av_log(avctx, AV_LOG_ERROR, "Cannot upmix AC3 from %d to %d channels.\n",
1081 ctx->out_channels, avctx->channels);
1082 return -1;
45b0ed13 1083 }
3bbb0bf8
JR
1084 if(avctx->channels == 2) {
1085 ctx->output_mode = AC3_ACMOD_STEREO;
1086 } else if(avctx->channels == 1) {
1087 ctx->output_mode = AC3_ACMOD_MONO;
1088 } else if(avctx->channels != ctx->out_channels) {
1089 av_log(avctx, AV_LOG_ERROR, "Cannot downmix AC3 from %d to %d channels.\n",
1090 ctx->out_channels, avctx->channels);
7bfd22f2 1091 return -1;
1b293437 1092 }
3bbb0bf8 1093 ctx->out_channels = avctx->channels;
1b293437 1094
1b293437 1095 //Parse the Audio Blocks.
75b9b036
JR
1096 for (blk = 0; blk < NB_BLOCKS; blk++) {
1097 if (ac3_parse_audio_block(ctx, blk)) {
1b293437
JR
1098 av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
1099 *data_size = 0;
98a27a8a 1100 return ctx->frame_size;
1b293437 1101 }
75b9b036 1102 for (i = 0; i < 256; i++)
7b4076a7 1103 for (ch = 0; ch < ctx->out_channels; ch++)
4e092320 1104 *(out_samples++) = ctx->int_output[ch][i];
1b293437 1105 }
8fbb368d 1106 *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t);
98a27a8a 1107 return ctx->frame_size;
2aa2c5c4 1108}
1b293437 1109
c7cfc48f
JR
1110/* Uninitialize ac3 decoder.
1111 */
1112static int ac3_decode_end(AVCodecContext *avctx)
1b293437 1113{
c7cfc48f
JR
1114 AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
1115 ff_mdct_end(&ctx->imdct_512);
1116 ff_mdct_end(&ctx->imdct_256);
1117
1b293437
JR
1118 return 0;
1119}
1120
fa67992d 1121AVCodec ac3_decoder = {
e6bca37c
JR
1122 .name = "ac3",
1123 .type = CODEC_TYPE_AUDIO,
1124 .id = CODEC_ID_AC3,
1125 .priv_data_size = sizeof (AC3DecodeContext),
1126 .init = ac3_decode_init,
1127 .close = ac3_decode_end,
1128 .decode = ac3_decode_frame,
1b293437 1129};