Clarify the intended meaning of wont_fix.
[libav.git] / libavcodec / ac3dec.c
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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"
2aa2c5c4 37#include "bitstream.h"
d6939960 38#include "crc.h"
2aa2c5c4 39#include "dsputil.h"
cb503702 40#include "random.h"
98a27a8a 41
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42/**
43 * Table of bin locations for rematrixing bands
44 * reference: Section 7.5.2 Rematrixing : Frequency Band Definitions
45 */
bfcf690c 46static const uint8_t rematrix_band_tab[5] = { 13, 25, 37, 61, 253 };
8b60bbbf 47
4415076f 48/** table for grouping exponents */
bfcf690c 49static uint8_t exp_ungroup_tab[128][3];
967d397a 50
967d397a 51
5aefe3eb 52/** tables for ungrouping mantissas */
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53static int b1_mantissas[32][3];
54static int b2_mantissas[128][3];
55static int b3_mantissas[8];
56static int b4_mantissas[128][2];
57static int b5_mantissas[16];
967d397a 58
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59/**
60 * Quantization table: levels for symmetric. bits for asymmetric.
61 * reference: Table 7.18 Mapping of bap to Quantizer
62 */
e2270b4e 63static const uint8_t quantization_tab[16] = {
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64 0, 3, 5, 7, 11, 15,
65 5, 6, 7, 8, 9, 10, 11, 12, 14, 16
66};
967d397a 67
3357ff33 68/** dynamic range table. converts codes to scale factors. */
e2270b4e 69static float dynamic_range_tab[256];
3357ff33 70
5066f515 71/** Adjustments in dB gain */
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72#define LEVEL_MINUS_3DB 0.7071067811865476
73#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
74#define LEVEL_MINUS_6DB 0.5000000000000000
3bbb0bf8 75#define LEVEL_MINUS_9DB 0.3535533905932738
967d397a 76#define LEVEL_ZERO 0.0000000000000000
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77#define LEVEL_ONE 1.0000000000000000
78
79static const float gain_levels[6] = {
80 LEVEL_ZERO,
81 LEVEL_ONE,
82 LEVEL_MINUS_3DB,
83 LEVEL_MINUS_4POINT5DB,
84 LEVEL_MINUS_6DB,
85 LEVEL_MINUS_9DB
86};
967d397a 87
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88/**
89 * Table for center mix levels
90 * reference: Section 5.4.2.4 cmixlev
91 */
e59cc205 92static const uint8_t center_levels[4] = { 2, 3, 4, 3 };
967d397a 93
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94/**
95 * Table for surround mix levels
96 * reference: Section 5.4.2.5 surmixlev
97 */
e59cc205 98static const uint8_t surround_levels[4] = { 2, 4, 0, 4 };
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99
100/**
101 * Table for default stereo downmixing coefficients
102 * reference: Section 7.8.2 Downmixing Into Two Channels
103 */
104static const uint8_t ac3_default_coeffs[8][5][2] = {
105 { { 1, 0 }, { 0, 1 }, },
106 { { 2, 2 }, },
107 { { 1, 0 }, { 0, 1 }, },
108 { { 1, 0 }, { 3, 3 }, { 0, 1 }, },
109 { { 1, 0 }, { 0, 1 }, { 4, 4 }, },
110 { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 5, 5 }, },
111 { { 1, 0 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
112 { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
113};
967d397a 114
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115/* override ac3.h to include coupling channel */
116#undef AC3_MAX_CHANNELS
117#define AC3_MAX_CHANNELS 7
118#define CPL_CH 0
119
7bfd22f2 120#define AC3_OUTPUT_LFEON 8
1b293437 121
98a27a8a 122typedef struct {
e59cc205 123 int channel_mode; ///< channel mode (acmod)
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124 int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags
125 int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags
5066f515 126 int dither_all; ///< true if all channels are dithered
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127 int cpl_in_use; ///< coupling in use
128 int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling
129 int phase_flags_in_use; ///< phase flags in use
b02fbf75 130 int phase_flags[18]; ///< phase flags
e2270b4e 131 int cpl_band_struct[18]; ///< coupling band structure
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132 int num_rematrixing_bands; ///< number of rematrixing bands
133 int rematrixing_flags[4]; ///< rematrixing flags
134 int exp_strategy[AC3_MAX_CHANNELS]; ///< exponent strategies
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135 int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets
136 int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values (signal-to-mask ratio)
137 int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
138 int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments
139 uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets
140 uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths
141 uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment
5066f515 142
866181e5 143 int sample_rate; ///< sample frequency, in Hz
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144 int bit_rate; ///< stream bit rate, in bits-per-second
145 int frame_size; ///< current frame size, in bytes
146
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147 int channels; ///< number of total channels
148 int fbw_channels; ///< number of full-bandwidth channels
e59cc205 149 int lfe_on; ///< lfe channel in use
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150 int lfe_ch; ///< index of LFE channel
151 int output_mode; ///< output channel configuration
152 int out_channels; ///< number of output channels
c7cfc48f 153
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154 int center_mix_level; ///< Center mix level index
155 int surround_mix_level; ///< Surround mix level index
222ae64c 156 float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients
d8870f12 157 float downmix_coeff_adjust[2]; ///< adjustment needed for each output channel when downmixing
e2270b4e 158 float dynamic_range[2]; ///< dynamic range
a4de6dd2 159 int cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates
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160 int num_cpl_bands; ///< number of coupling bands
161 int num_cpl_subbands; ///< number of coupling sub bands
162 int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin
163 int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin
623b7943 164 AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
c7cfc48f 165
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166 int8_t dexps[AC3_MAX_CHANNELS][256]; ///< decoded exponents
167 uint8_t bap[AC3_MAX_CHANNELS][256]; ///< bit allocation pointers
168 int16_t psd[AC3_MAX_CHANNELS][256]; ///< scaled exponents
5ce21342 169 int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
222ae64c 170 int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
c7cfc48f 171
a4de6dd2 172 int fixed_coeffs[AC3_MAX_CHANNELS][256]; ///> fixed-point transform coefficients
5066f515 173 DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); ///< transform coefficients
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174
175 /* For IMDCT. */
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176 MDCTContext imdct_512; ///< for 512 sample IMDCT
177 MDCTContext imdct_256; ///< for 256 sample IMDCT
178 DSPContext dsp; ///< for optimization
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179 float add_bias; ///< offset for float_to_int16 conversion
180 float mul_bias; ///< scaling for float_to_int16 conversion
c7cfc48f 181
5066f515 182 DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS-1][256]); ///< output after imdct transform and windowing
4e092320 183 DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]); ///< final 16-bit integer output
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184 DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS-1][256]); ///< delay - added to the next block
185 DECLARE_ALIGNED_16(float, tmp_imdct[256]); ///< temporary storage for imdct transform
186 DECLARE_ALIGNED_16(float, tmp_output[512]); ///< temporary storage for output before windowing
187 DECLARE_ALIGNED_16(float, window[256]); ///< window coefficients
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188
189 /* Miscellaneous. */
23c8cb89 190 GetBitContext gbc; ///< bitstream reader
5066f515 191 AVRandomState dith_state; ///< for dither generation
222ae64c 192 AVCodecContext *avctx; ///< parent context
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193} AC3DecodeContext;
194
2fbbd087 195/**
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196 * Symmetrical Dequantization
197 * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
198 * Tables 7.19 to 7.23
199 */
a4de6dd2 200static inline int
5aefe3eb 201symmetric_dequant(int code, int levels)
98a27a8a 202{
a4de6dd2 203 return ((code - (levels >> 1)) << 24) / levels;
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204}
205
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206/*
207 * Initialize tables at runtime.
208 */
98a27a8a 209static void ac3_tables_init(void)
00585845 210{
4415076f 211 int i;
98a27a8a 212
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213 /* generate grouped mantissa tables
214 reference: Section 7.3.5 Ungrouping of Mantissas */
215 for(i=0; i<32; i++) {
216 /* bap=1 mantissas */
217 b1_mantissas[i][0] = symmetric_dequant( i / 9 , 3);
218 b1_mantissas[i][1] = symmetric_dequant((i % 9) / 3, 3);
219 b1_mantissas[i][2] = symmetric_dequant((i % 9) % 3, 3);
220 }
221 for(i=0; i<128; i++) {
222 /* bap=2 mantissas */
223 b2_mantissas[i][0] = symmetric_dequant( i / 25 , 5);
224 b2_mantissas[i][1] = symmetric_dequant((i % 25) / 5, 5);
225 b2_mantissas[i][2] = symmetric_dequant((i % 25) % 5, 5);
226
227 /* bap=4 mantissas */
228 b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
229 b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
230 }
231 /* generate ungrouped mantissa tables
232 reference: Tables 7.21 and 7.23 */
233 for(i=0; i<7; i++) {
234 /* bap=3 mantissas */
235 b3_mantissas[i] = symmetric_dequant(i, 7);
236 }
237 for(i=0; i<15; i++) {
238 /* bap=5 mantissas */
239 b5_mantissas[i] = symmetric_dequant(i, 15);
240 }
c7cfc48f 241
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242 /* generate dynamic range table
243 reference: Section 7.7.1 Dynamic Range Control */
244 for(i=0; i<256; i++) {
245 int v = (i >> 5) - ((i >> 7) << 3) - 5;
e2270b4e 246 dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
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247 }
248
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249 /* generate exponent tables
250 reference: Section 7.1.3 Exponent Decoding */
251 for(i=0; i<128; i++) {
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252 exp_ungroup_tab[i][0] = i / 25;
253 exp_ungroup_tab[i][1] = (i % 25) / 5;
254 exp_ungroup_tab[i][2] = (i % 25) % 5;
4415076f 255 }
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256}
257
1b293437 258
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259/**
260 * AVCodec initialization
261 */
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262static int ac3_decode_init(AVCodecContext *avctx)
263{
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264 AC3DecodeContext *s = avctx->priv_data;
265 s->avctx = avctx;
1b293437 266
cc2a8443 267 ac3_common_init();
98a27a8a 268 ac3_tables_init();
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269 ff_mdct_init(&s->imdct_256, 8, 1);
270 ff_mdct_init(&s->imdct_512, 9, 1);
3ed546fe 271 ff_kbd_window_init(s->window, 5.0, 256);
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272 dsputil_init(&s->dsp, avctx);
273 av_init_random(0, &s->dith_state);
2aa2c5c4 274
5066f515 275 /* set bias values for float to int16 conversion */
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276 if(s->dsp.float_to_int16 == ff_float_to_int16_c) {
277 s->add_bias = 385.0f;
278 s->mul_bias = 1.0f;
4e092320 279 } else {
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280 s->add_bias = 0.0f;
281 s->mul_bias = 32767.0f;
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282 }
283
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284 /* allow downmixing to stereo or mono */
285 if (avctx->channels > 0 && avctx->request_channels > 0 &&
286 avctx->request_channels < avctx->channels &&
287 avctx->request_channels <= 2) {
288 avctx->channels = avctx->request_channels;
289 }
290
1b293437 291 return 0;
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292}
293
9fc1ab72 294/**
5066f515 295 * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
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296 * GetBitContext within AC3DecodeContext must point to
297 * start of the synchronized ac3 bitstream.
c7cfc48f 298 */
d802d7ca 299static int ac3_parse_header(AC3DecodeContext *s)
2aa2c5c4 300{
9fc1ab72 301 AC3HeaderInfo hdr;
d802d7ca 302 GetBitContext *gbc = &s->gbc;
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303 int err, i;
304
23c8cb89 305 err = ff_ac3_parse_header(gbc->buffer, &hdr);
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306 if(err)
307 return err;
308
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309 if(hdr.bitstream_id > 10)
310 return AC3_PARSE_ERROR_BSID;
311
9fc1ab72 312 /* get decoding parameters from header info */
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313 s->bit_alloc_params.sr_code = hdr.sr_code;
314 s->channel_mode = hdr.channel_mode;
1b70d88b 315 s->lfe_on = hdr.lfe_on;
d802d7ca 316 s->bit_alloc_params.sr_shift = hdr.sr_shift;
866181e5 317 s->sample_rate = hdr.sample_rate;
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318 s->bit_rate = hdr.bit_rate;
319 s->channels = hdr.channels;
320 s->fbw_channels = s->channels - s->lfe_on;
321 s->lfe_ch = s->fbw_channels + 1;
322 s->frame_size = hdr.frame_size;
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323
324 /* set default output to all source channels */
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325 s->out_channels = s->channels;
326 s->output_mode = s->channel_mode;
327 if(s->lfe_on)
328 s->output_mode |= AC3_OUTPUT_LFEON;
9fc1ab72 329
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330 /* set default mix levels */
331 s->center_mix_level = 3; // -4.5dB
332 s->surround_mix_level = 4; // -6.0dB
333
9fc1ab72 334 /* skip over portion of header which has already been read */
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335 skip_bits(gbc, 16); // skip the sync_word
336 skip_bits(gbc, 16); // skip crc1
337 skip_bits(gbc, 8); // skip fscod and frmsizecod
338 skip_bits(gbc, 11); // skip bsid, bsmod, and acmod
d802d7ca 339 if(s->channel_mode == AC3_CHMODE_STEREO) {
23c8cb89 340 skip_bits(gbc, 2); // skip dsurmod
9fc1ab72 341 } else {
d802d7ca 342 if((s->channel_mode & 1) && s->channel_mode != AC3_CHMODE_MONO)
f0b3a7ba 343 s->center_mix_level = center_levels[get_bits(gbc, 2)];
d802d7ca 344 if(s->channel_mode & 4)
f0b3a7ba 345 s->surround_mix_level = surround_levels[get_bits(gbc, 2)];
00585845 346 }
23c8cb89 347 skip_bits1(gbc); // skip lfeon
98a27a8a 348
9fc1ab72 349 /* read the rest of the bsi. read twice for dual mono mode. */
d802d7ca 350 i = !(s->channel_mode);
98a27a8a 351 do {
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352 skip_bits(gbc, 5); // skip dialog normalization
353 if (get_bits1(gbc))
354 skip_bits(gbc, 8); //skip compression
355 if (get_bits1(gbc))
356 skip_bits(gbc, 8); //skip language code
357 if (get_bits1(gbc))
358 skip_bits(gbc, 7); //skip audio production information
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359 } while (i--);
360
23c8cb89 361 skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
98a27a8a 362
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363 /* skip the timecodes (or extra bitstream information for Alternate Syntax)
364 TODO: read & use the xbsi1 downmix levels */
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365 if (get_bits1(gbc))
366 skip_bits(gbc, 14); //skip timecode1 / xbsi1
367 if (get_bits1(gbc))
368 skip_bits(gbc, 14); //skip timecode2 / xbsi2
98a27a8a 369
5066f515 370 /* skip additional bitstream info */
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371 if (get_bits1(gbc)) {
372 i = get_bits(gbc, 6);
486637af 373 do {
23c8cb89 374 skip_bits(gbc, 8);
98a27a8a 375 } while(i--);
1b293437 376 }
9fc1ab72 377
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378 return 0;
379}
380
381/**
382 * Set stereo downmixing coefficients based on frame header info.
383 * reference: Section 7.8.2 Downmixing Into Two Channels
384 */
385static void set_downmix_coeffs(AC3DecodeContext *s)
386{
387 int i;
388 float cmix = gain_levels[s->center_mix_level];
389 float smix = gain_levels[s->surround_mix_level];
390
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391 for(i=0; i<s->fbw_channels; i++) {
392 s->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]];
393 s->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]];
3bbb0bf8 394 }
d802d7ca 395 if(s->channel_mode > 1 && s->channel_mode & 1) {
f0b3a7ba 396 s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = cmix;
3bbb0bf8 397 }
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398 if(s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
399 int nf = s->channel_mode - 2;
f0b3a7ba 400 s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB;
3bbb0bf8 401 }
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402 if(s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
403 int nf = s->channel_mode - 4;
f0b3a7ba 404 s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf+1][1] = smix;
3bbb0bf8 405 }
9d10e6e6 406
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407 /* calculate adjustment needed for each channel to avoid clipping */
408 s->downmix_coeff_adjust[0] = s->downmix_coeff_adjust[1] = 0.0f;
9d10e6e6 409 for(i=0; i<s->fbw_channels; i++) {
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410 s->downmix_coeff_adjust[0] += s->downmix_coeffs[i][0];
411 s->downmix_coeff_adjust[1] += s->downmix_coeffs[i][1];
9d10e6e6 412 }
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413 s->downmix_coeff_adjust[0] = 1.0f / s->downmix_coeff_adjust[0];
414 s->downmix_coeff_adjust[1] = 1.0f / s->downmix_coeff_adjust[1];
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415}
416
3bb004fc 417/**
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418 * Decode the grouped exponents according to exponent strategy.
419 * reference: Section 7.1.3 Exponent Decoding
2aa2c5c4 420 */
23c8cb89 421static void decode_exponents(GetBitContext *gbc, int exp_strategy, int ngrps,
bc8edb7e 422 uint8_t absexp, int8_t *dexps)
2aa2c5c4 423{
e2270b4e 424 int i, j, grp, group_size;
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425 int dexp[256];
426 int expacc, prevexp;
427
428 /* unpack groups */
e2270b4e 429 group_size = exp_strategy + (exp_strategy == EXP_D45);
4415076f 430 for(grp=0,i=0; grp<ngrps; grp++) {
23c8cb89 431 expacc = get_bits(gbc, 7);
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432 dexp[i++] = exp_ungroup_tab[expacc][0];
433 dexp[i++] = exp_ungroup_tab[expacc][1];
434 dexp[i++] = exp_ungroup_tab[expacc][2];
4415076f 435 }
2aa2c5c4 436
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437 /* convert to absolute exps and expand groups */
438 prevexp = absexp;
439 for(i=0; i<ngrps*3; i++) {
440 prevexp = av_clip(prevexp + dexp[i]-2, 0, 24);
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441 for(j=0; j<group_size; j++) {
442 dexps[(i*group_size)+j] = prevexp;
1b293437 443 }
2aa2c5c4 444 }
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445}
446
d7dc7ad0 447/**
5066f515 448 * Generate transform coefficients for each coupled channel in the coupling
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449 * range using the coupling coefficients and coupling coordinates.
450 * reference: Section 7.4.3 Coupling Coordinate Format
451 */
d802d7ca 452static void uncouple_channels(AC3DecodeContext *s)
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453{
454 int i, j, ch, bnd, subbnd;
455
456 subbnd = -1;
d802d7ca
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457 i = s->start_freq[CPL_CH];
458 for(bnd=0; bnd<s->num_cpl_bands; bnd++) {
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459 do {
460 subbnd++;
461 for(j=0; j<12; j++) {
d802d7ca 462 for(ch=1; ch<=s->fbw_channels; ch++) {
b02fbf75 463 if(s->channel_in_cpl[ch]) {
a4de6dd2 464 s->fixed_coeffs[ch][i] = ((int64_t)s->fixed_coeffs[CPL_CH][i] * (int64_t)s->cpl_coords[ch][bnd]) >> 23;
b02fbf75 465 if (ch == 2 && s->phase_flags[bnd])
a4de6dd2 466 s->fixed_coeffs[ch][i] = -s->fixed_coeffs[ch][i];
b02fbf75 467 }
d7dc7ad0
JR
468 }
469 i++;
470 }
d802d7ca 471 } while(s->cpl_band_struct[subbnd]);
d7dc7ad0
JR
472 }
473}
474
5066f515
JR
475/**
476 * Grouped mantissas for 3-level 5-level and 11-level quantization
477 */
478typedef struct {
a4de6dd2
JR
479 int b1_mant[3];
480 int b2_mant[3];
481 int b4_mant[2];
5aefe3eb
JR
482 int b1ptr;
483 int b2ptr;
484 int b4ptr;
486637af
JR
485} mant_groups;
486
5066f515
JR
487/**
488 * Get the transform coefficients for a particular channel
489 * reference: Section 7.3 Quantization and Decoding of Mantissas
490 */
d802d7ca 491static int get_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
1b293437 492{
d802d7ca 493 GetBitContext *gbc = &s->gbc;
60f07fad 494 int i, gcode, tbap, start, end;
2fbbd087
JR
495 uint8_t *exps;
496 uint8_t *bap;
a4de6dd2 497 int *coeffs;
2fbbd087 498
d802d7ca
JR
499 exps = s->dexps[ch_index];
500 bap = s->bap[ch_index];
a4de6dd2 501 coeffs = s->fixed_coeffs[ch_index];
d802d7ca
JR
502 start = s->start_freq[ch_index];
503 end = s->end_freq[ch_index];
1b293437 504
285bf28c 505 for (i = start; i < end; i++) {
98a27a8a
JR
506 tbap = bap[i];
507 switch (tbap) {
1b293437 508 case 0:
a4de6dd2 509 coeffs[i] = (av_random(&s->dith_state) & 0x7FFFFF) - 4194304;
d63f6fea 510 break;
1b293437
JR
511
512 case 1:
5aefe3eb 513 if(m->b1ptr > 2) {
23c8cb89 514 gcode = get_bits(gbc, 5);
5aefe3eb
JR
515 m->b1_mant[0] = b1_mantissas[gcode][0];
516 m->b1_mant[1] = b1_mantissas[gcode][1];
517 m->b1_mant[2] = b1_mantissas[gcode][2];
518 m->b1ptr = 0;
1b293437 519 }
5aefe3eb 520 coeffs[i] = m->b1_mant[m->b1ptr++];
d63f6fea 521 break;
1b293437
JR
522
523 case 2:
5aefe3eb 524 if(m->b2ptr > 2) {
23c8cb89 525 gcode = get_bits(gbc, 7);
5aefe3eb
JR
526 m->b2_mant[0] = b2_mantissas[gcode][0];
527 m->b2_mant[1] = b2_mantissas[gcode][1];
528 m->b2_mant[2] = b2_mantissas[gcode][2];
529 m->b2ptr = 0;
1b293437 530 }
5aefe3eb 531 coeffs[i] = m->b2_mant[m->b2ptr++];
d63f6fea 532 break;
1b293437
JR
533
534 case 3:
23c8cb89 535 coeffs[i] = b3_mantissas[get_bits(gbc, 3)];
d63f6fea 536 break;
1b293437
JR
537
538 case 4:
5aefe3eb 539 if(m->b4ptr > 1) {
23c8cb89 540 gcode = get_bits(gbc, 7);
5aefe3eb
JR
541 m->b4_mant[0] = b4_mantissas[gcode][0];
542 m->b4_mant[1] = b4_mantissas[gcode][1];
543 m->b4ptr = 0;
1b293437 544 }
5aefe3eb 545 coeffs[i] = m->b4_mant[m->b4ptr++];
d63f6fea 546 break;
1b293437
JR
547
548 case 5:
23c8cb89 549 coeffs[i] = b5_mantissas[get_bits(gbc, 4)];
d63f6fea 550 break;
1b293437 551
a4de6dd2 552 default: {
5066f515 553 /* asymmetric dequantization */
a4de6dd2
JR
554 int qlevel = quantization_tab[tbap];
555 coeffs[i] = get_sbits(gbc, qlevel) << (24 - qlevel);
d63f6fea 556 break;
a4de6dd2 557 }
1b293437 558 }
a4de6dd2 559 coeffs[i] >>= exps[i];
1b293437
JR
560 }
561
1b293437
JR
562 return 0;
563}
564
60f07fad 565/**
5066f515 566 * Remove random dithering from coefficients with zero-bit mantissas
60f07fad
JR
567 * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
568 */
d802d7ca 569static void remove_dithering(AC3DecodeContext *s) {
60f07fad
JR
570 int ch, i;
571 int end=0;
a4de6dd2 572 int *coeffs;
60f07fad
JR
573 uint8_t *bap;
574
d802d7ca
JR
575 for(ch=1; ch<=s->fbw_channels; ch++) {
576 if(!s->dither_flag[ch]) {
a4de6dd2 577 coeffs = s->fixed_coeffs[ch];
d802d7ca
JR
578 bap = s->bap[ch];
579 if(s->channel_in_cpl[ch])
580 end = s->start_freq[CPL_CH];
60f07fad 581 else
d802d7ca 582 end = s->end_freq[ch];
60f07fad 583 for(i=0; i<end; i++) {
12eaa3b7 584 if(!bap[i])
a4de6dd2 585 coeffs[i] = 0;
60f07fad 586 }
d802d7ca
JR
587 if(s->channel_in_cpl[ch]) {
588 bap = s->bap[CPL_CH];
589 for(; i<s->end_freq[CPL_CH]; i++) {
12eaa3b7 590 if(!bap[i])
a4de6dd2 591 coeffs[i] = 0;
60f07fad
JR
592 }
593 }
594 }
595 }
596}
597
5066f515
JR
598/**
599 * Get the transform coefficients.
c7cfc48f 600 */
d802d7ca 601static int get_transform_coeffs(AC3DecodeContext *s)
1b293437 602{
7b4076a7 603 int ch, end;
1b293437 604 int got_cplchan = 0;
486637af
JR
605 mant_groups m;
606
5aefe3eb 607 m.b1ptr = m.b2ptr = m.b4ptr = 3;
1b293437 608
d802d7ca 609 for (ch = 1; ch <= s->channels; ch++) {
5066f515 610 /* transform coefficients for full-bandwidth channel */
d802d7ca 611 if (get_transform_coeffs_ch(s, ch, &m))
1b293437 612 return -1;
5066f515
JR
613 /* tranform coefficients for coupling channel come right after the
614 coefficients for the first coupled channel*/
d802d7ca 615 if (s->channel_in_cpl[ch]) {
486637af 616 if (!got_cplchan) {
d802d7ca
JR
617 if (get_transform_coeffs_ch(s, CPL_CH, &m)) {
618 av_log(s->avctx, AV_LOG_ERROR, "error in decoupling channels\n");
486637af 619 return -1;
98a27a8a 620 }
d802d7ca 621 uncouple_channels(s);
486637af
JR
622 got_cplchan = 1;
623 }
d802d7ca 624 end = s->end_freq[CPL_CH];
eaf84d97 625 } else {
d802d7ca 626 end = s->end_freq[ch];
eaf84d97 627 }
486637af 628 do
d802d7ca 629 s->transform_coeffs[ch][end] = 0;
486637af
JR
630 while(++end < 256);
631 }
1b293437 632
60f07fad 633 /* if any channel doesn't use dithering, zero appropriate coefficients */
d802d7ca
JR
634 if(!s->dither_all)
635 remove_dithering(s);
60f07fad 636
1b293437 637 return 0;
2aa2c5c4
JR
638}
639
8b60bbbf 640/**
5066f515 641 * Stereo rematrixing.
8b60bbbf
JR
642 * reference: Section 7.5.4 Rematrixing : Decoding Technique
643 */
d802d7ca 644static void do_rematrixing(AC3DecodeContext *s)
1b293437 645{
8b60bbbf 646 int bnd, i;
2fbbd087 647 int end, bndend;
a4de6dd2 648 int tmp0, tmp1;
2fbbd087 649
d802d7ca 650 end = FFMIN(s->end_freq[1], s->end_freq[2]);
1b293437 651
d802d7ca
JR
652 for(bnd=0; bnd<s->num_rematrixing_bands; bnd++) {
653 if(s->rematrixing_flags[bnd]) {
bfcf690c
JR
654 bndend = FFMIN(end, rematrix_band_tab[bnd+1]);
655 for(i=rematrix_band_tab[bnd]; i<bndend; i++) {
a4de6dd2
JR
656 tmp0 = s->fixed_coeffs[1][i];
657 tmp1 = s->fixed_coeffs[2][i];
658 s->fixed_coeffs[1][i] = tmp0 + tmp1;
659 s->fixed_coeffs[2][i] = tmp0 - tmp1;
8b60bbbf
JR
660 }
661 }
1b293437
JR
662 }
663}
2aa2c5c4 664
5066f515
JR
665/**
666 * Perform the 256-point IMDCT
c7cfc48f 667 */
d802d7ca 668static void do_imdct_256(AC3DecodeContext *s, int chindex)
486637af 669{
0de73a46 670 int i, k;
dfd57c36 671 DECLARE_ALIGNED_16(float, x[128]);
0de73a46 672 FFTComplex z[2][64];
d802d7ca 673 float *o_ptr = s->tmp_output;
0de73a46
JR
674
675 for(i=0; i<2; i++) {
676 /* de-interleave coefficients */
677 for(k=0; k<128; k++) {
d802d7ca 678 x[k] = s->transform_coeffs[chindex][2*k+i];
0de73a46 679 }
98a27a8a 680
0de73a46 681 /* run standard IMDCT */
d802d7ca 682 s->imdct_256.fft.imdct_calc(&s->imdct_256, o_ptr, x, s->tmp_imdct);
0de73a46
JR
683
684 /* reverse the post-rotation & reordering from standard IMDCT */
685 for(k=0; k<32; k++) {
686 z[i][32+k].re = -o_ptr[128+2*k];
687 z[i][32+k].im = -o_ptr[2*k];
688 z[i][31-k].re = o_ptr[2*k+1];
689 z[i][31-k].im = o_ptr[128+2*k+1];
690 }
1ea76064 691 }
486637af 692
0de73a46
JR
693 /* apply AC-3 post-rotation & reordering */
694 for(k=0; k<64; k++) {
695 o_ptr[ 2*k ] = -z[0][ k].im;
696 o_ptr[ 2*k+1] = z[0][63-k].re;
697 o_ptr[128+2*k ] = -z[0][ k].re;
698 o_ptr[128+2*k+1] = z[0][63-k].im;
699 o_ptr[256+2*k ] = -z[1][ k].re;
700 o_ptr[256+2*k+1] = z[1][63-k].im;
701 o_ptr[384+2*k ] = z[1][ k].im;
702 o_ptr[384+2*k+1] = -z[1][63-k].re;
703 }
98a27a8a 704}
486637af 705
5066f515
JR
706/**
707 * Inverse MDCT Transform.
708 * Convert frequency domain coefficients to time-domain audio samples.
709 * reference: Section 7.9.4 Transformation Equations
710 */
d802d7ca 711static inline void do_imdct(AC3DecodeContext *s)
486637af 712{
0de73a46 713 int ch;
e2270b4e 714 int channels;
486637af 715
5066f515 716 /* Don't perform the IMDCT on the LFE channel unless it's used in the output */
d802d7ca
JR
717 channels = s->fbw_channels;
718 if(s->output_mode & AC3_OUTPUT_LFEON)
e2270b4e 719 channels++;
7b4076a7 720
e2270b4e 721 for (ch=1; ch<=channels; ch++) {
d802d7ca
JR
722 if (s->block_switch[ch]) {
723 do_imdct_256(s, ch);
eaf84d97 724 } else {
d802d7ca 725 s->imdct_512.fft.imdct_calc(&s->imdct_512, s->tmp_output,
1b70d88b 726 s->transform_coeffs[ch], s->tmp_imdct);
eaf84d97 727 }
5066f515
JR
728 /* For the first half of the block, apply the window, add the delay
729 from the previous block, and send to output */
d802d7ca
JR
730 s->dsp.vector_fmul_add_add(s->output[ch-1], s->tmp_output,
731 s->window, s->delay[ch-1], 0, 256, 1);
5066f515
JR
732 /* For the second half of the block, apply the window and store the
733 samples to delay, to be combined with the next block */
d802d7ca 734 s->dsp.vector_fmul_reverse(s->delay[ch-1], s->tmp_output+256,
1b70d88b 735 s->window, 256);
486637af
JR
736 }
737}
738
3bbb0bf8 739/**
5066f515 740 * Downmix the output to mono or stereo.
3bbb0bf8 741 */
b35c67e5 742static void ac3_downmix(AC3DecodeContext *s)
3bbb0bf8
JR
743{
744 int i, j;
9d10e6e6 745 float v0, v1;
3bbb0bf8
JR
746
747 for(i=0; i<256; i++) {
9d10e6e6 748 v0 = v1 = 0.0f;
b35c67e5
JR
749 for(j=0; j<s->fbw_channels; j++) {
750 v0 += s->output[j][i] * s->downmix_coeffs[j][0];
751 v1 += s->output[j][i] * s->downmix_coeffs[j][1];
3bbb0bf8 752 }
d8870f12
JR
753 v0 *= s->downmix_coeff_adjust[0];
754 v1 *= s->downmix_coeff_adjust[1];
b35c67e5
JR
755 if(s->output_mode == AC3_CHMODE_MONO) {
756 s->output[0][i] = (v0 + v1) * LEVEL_MINUS_3DB;
757 } else if(s->output_mode == AC3_CHMODE_STEREO) {
758 s->output[0][i] = v0;
759 s->output[1][i] = v1;
3bbb0bf8
JR
760 }
761 }
762}
763
5066f515
JR
764/**
765 * Parse an audio block from AC-3 bitstream.
c7cfc48f 766 */
d802d7ca 767static int ac3_parse_audio_block(AC3DecodeContext *s, int blk)
2aa2c5c4 768{
d802d7ca
JR
769 int fbw_channels = s->fbw_channels;
770 int channel_mode = s->channel_mode;
0bff58a5 771 int i, bnd, seg, ch;
d802d7ca 772 GetBitContext *gbc = &s->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++)
d802d7ca 779 s->block_switch[ch] = get_bits1(gbc);
98a27a8a 780
5066f515 781 /* dithering flags */
d802d7ca 782 s->dither_all = 1;
e2270b4e 783 for (ch = 1; ch <= fbw_channels; ch++) {
d802d7ca
JR
784 s->dither_flag[ch] = get_bits1(gbc);
785 if(!s->dither_flag[ch])
786 s->dither_all = 0;
60f07fad 787 }
98a27a8a 788
77416325 789 /* dynamic range */
d802d7ca 790 i = !(s->channel_mode);
77416325 791 do {
23c8cb89 792 if(get_bits1(gbc)) {
d802d7ca 793 s->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)]-1.0) *
1b70d88b 794 s->avctx->drc_scale)+1.0;
9fc1ab72 795 } else if(blk == 0) {
d802d7ca 796 s->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);
d802d7ca
JR
803 s->cpl_in_use = get_bits1(gbc);
804 if (s->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++)
d802d7ca 810 s->channel_in_cpl[ch] = get_bits1(gbc);
98a27a8a 811
5066f515 812 /* phase flags in use */
e59cc205 813 if (channel_mode == AC3_CHMODE_STEREO)
d802d7ca 814 s->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 819 if (3 + cpl_end_freq - cpl_begin_freq < 0) {
d802d7ca 820 av_log(s->avctx, AV_LOG_ERROR, "3+cplendf = %d < cplbegf = %d\n", 3+cpl_end_freq, cpl_begin_freq);
00585845 821 return -1;
98a27a8a 822 }
d802d7ca
JR
823 s->num_cpl_bands = s->num_cpl_subbands = 3 + cpl_end_freq - cpl_begin_freq;
824 s->start_freq[CPL_CH] = cpl_begin_freq * 12 + 37;
825 s->end_freq[CPL_CH] = cpl_end_freq * 12 + 73;
826 for (bnd = 0; bnd < s->num_cpl_subbands - 1; bnd++) {
23c8cb89 827 if (get_bits1(gbc)) {
d802d7ca
JR
828 s->cpl_band_struct[bnd] = 1;
829 s->num_cpl_bands--;
1b293437 830 }
eaf84d97 831 }
4bc829bb 832 s->cpl_band_struct[s->num_cpl_subbands-1] = 0;
878c40a1 833 } else {
5066f515 834 /* coupling not in use */
e2270b4e 835 for (ch = 1; ch <= fbw_channels; ch++)
d802d7ca 836 s->channel_in_cpl[ch] = 0;
1b293437
JR
837 }
838 }
98a27a8a 839
5066f515 840 /* coupling coordinates */
d802d7ca 841 if (s->cpl_in_use) {
e2270b4e 842 int cpl_coords_exist = 0;
98a27a8a 843
e2270b4e 844 for (ch = 1; ch <= fbw_channels; ch++) {
d802d7ca 845 if (s->channel_in_cpl[ch]) {
23c8cb89 846 if (get_bits1(gbc)) {
e2270b4e
JR
847 int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
848 cpl_coords_exist = 1;
23c8cb89 849 master_cpl_coord = 3 * get_bits(gbc, 2);
d802d7ca 850 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
23c8cb89
JR
851 cpl_coord_exp = get_bits(gbc, 4);
852 cpl_coord_mant = get_bits(gbc, 4);
e2270b4e 853 if (cpl_coord_exp == 15)
a4de6dd2 854 s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
486637af 855 else
a4de6dd2
JR
856 s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21;
857 s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord);
486637af 858 }
486637af 859 }
eaf84d97
JR
860 }
861 }
5066f515 862 /* phase flags */
b02fbf75 863 if (channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) {
d802d7ca 864 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
b02fbf75 865 s->phase_flags[bnd] = s->phase_flags_in_use? get_bits1(gbc) : 0;
eaf84d97
JR
866 }
867 }
2aa2c5c4 868 }
98a27a8a 869
5066f515 870 /* stereo rematrixing strategy and band structure */
e59cc205 871 if (channel_mode == AC3_CHMODE_STEREO) {
82a6c481 872 if (get_bits1(gbc)) {
d802d7ca
JR
873 s->num_rematrixing_bands = 4;
874 if(s->cpl_in_use && s->start_freq[CPL_CH] <= 61)
875 s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
876 for(bnd=0; bnd<s->num_rematrixing_bands; bnd++)
877 s->rematrixing_flags[bnd] = get_bits1(gbc);
1b293437 878 }
98a27a8a
JR
879 }
880
5066f515 881 /* exponent strategies for each channel */
d802d7ca
JR
882 s->exp_strategy[CPL_CH] = EXP_REUSE;
883 s->exp_strategy[s->lfe_ch] = EXP_REUSE;
884 for (ch = !s->cpl_in_use; ch <= s->channels; ch++) {
885 if(ch == s->lfe_ch)
886 s->exp_strategy[ch] = get_bits(gbc, 1);
7b4076a7 887 else
d802d7ca
JR
888 s->exp_strategy[ch] = get_bits(gbc, 2);
889 if(s->exp_strategy[ch] != EXP_REUSE)
7b4076a7
JR
890 bit_alloc_stages[ch] = 3;
891 }
892
5066f515 893 /* channel bandwidth */
e2270b4e 894 for (ch = 1; ch <= fbw_channels; ch++) {
d802d7ca
JR
895 s->start_freq[ch] = 0;
896 if (s->exp_strategy[ch] != EXP_REUSE) {
897 int prev = s->end_freq[ch];
898 if (s->channel_in_cpl[ch])
899 s->end_freq[ch] = s->start_freq[CPL_CH];
00585845 900 else {
23c8cb89 901 int bandwidth_code = get_bits(gbc, 6);
e2270b4e 902 if (bandwidth_code > 60) {
d802d7ca 903 av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60", bandwidth_code);
00585845
JR
904 return -1;
905 }
d802d7ca 906 s->end_freq[ch] = bandwidth_code * 3 + 73;
1b293437 907 }
d802d7ca 908 if(blk > 0 && s->end_freq[ch] != prev)
7b4076a7 909 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
00585845 910 }
eaf84d97 911 }
d802d7ca
JR
912 s->start_freq[s->lfe_ch] = 0;
913 s->end_freq[s->lfe_ch] = 7;
7b4076a7 914
5066f515 915 /* decode exponents for each channel */
d802d7ca
JR
916 for (ch = !s->cpl_in_use; ch <= s->channels; ch++) {
917 if (s->exp_strategy[ch] != EXP_REUSE) {
e2270b4e 918 int group_size, num_groups;
d802d7ca 919 group_size = 3 << (s->exp_strategy[ch] - 1);
7b4076a7 920 if(ch == CPL_CH)
d802d7ca
JR
921 num_groups = (s->end_freq[ch] - s->start_freq[ch]) / group_size;
922 else if(ch == s->lfe_ch)
e2270b4e 923 num_groups = 2;
7b4076a7 924 else
d802d7ca
JR
925 num_groups = (s->end_freq[ch] + group_size - 4) / group_size;
926 s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
927 decode_exponents(gbc, s->exp_strategy[ch], num_groups, s->dexps[ch][0],
928 &s->dexps[ch][s->start_freq[ch]+!!ch]);
929 if(ch != CPL_CH && ch != s->lfe_ch)
23c8cb89 930 skip_bits(gbc, 2); /* skip gainrng */
1b293437 931 }
eaf84d97 932 }
98a27a8a 933
5066f515 934 /* bit allocation information */
23c8cb89 935 if (get_bits1(gbc)) {
d802d7ca
JR
936 s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
937 s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
938 s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
939 s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
940 s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
941 for(ch=!s->cpl_in_use; ch<=s->channels; ch++) {
7b4076a7
JR
942 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
943 }
1b293437 944 }
98a27a8a 945
5066f515 946 /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
23c8cb89 947 if (get_bits1(gbc)) {
4611b64e 948 int csnr;
23c8cb89 949 csnr = (get_bits(gbc, 6) - 15) << 4;
d802d7ca
JR
950 for (ch = !s->cpl_in_use; ch <= s->channels; ch++) { /* snr offset and fast gain */
951 s->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2;
952 s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
1b293437 953 }
7b4076a7 954 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
1b293437 955 }
98a27a8a 956
5066f515 957 /* coupling leak information */
d802d7ca
JR
958 if (s->cpl_in_use && get_bits1(gbc)) {
959 s->bit_alloc_params.cpl_fast_leak = get_bits(gbc, 3);
960 s->bit_alloc_params.cpl_slow_leak = get_bits(gbc, 3);
7b4076a7 961 bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
98a27a8a
JR
962 }
963
5066f515 964 /* delta bit allocation information */
23c8cb89 965 if (get_bits1(gbc)) {
5066f515 966 /* delta bit allocation exists (strategy) */
d802d7ca
JR
967 for (ch = !s->cpl_in_use; ch <= fbw_channels; ch++) {
968 s->dba_mode[ch] = get_bits(gbc, 2);
969 if (s->dba_mode[ch] == DBA_RESERVED) {
970 av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
1b293437
JR
971 return -1;
972 }
7b4076a7 973 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1b293437 974 }
5066f515 975 /* channel delta offset, len and bit allocation */
d802d7ca
JR
976 for (ch = !s->cpl_in_use; ch <= fbw_channels; ch++) {
977 if (s->dba_mode[ch] == DBA_NEW) {
978 s->dba_nsegs[ch] = get_bits(gbc, 3);
979 for (seg = 0; seg <= s->dba_nsegs[ch]; seg++) {
980 s->dba_offsets[ch][seg] = get_bits(gbc, 5);
981 s->dba_lengths[ch][seg] = get_bits(gbc, 4);
982 s->dba_values[ch][seg] = get_bits(gbc, 3);
1b293437
JR
983 }
984 }
eaf84d97 985 }
9fc1ab72 986 } else if(blk == 0) {
d802d7ca
JR
987 for(ch=0; ch<=s->channels; ch++) {
988 s->dba_mode[ch] = DBA_NONE;
9fc1ab72 989 }
1b293437 990 }
00585845 991
5066f515 992 /* Bit allocation */
d802d7ca 993 for(ch=!s->cpl_in_use; ch<=s->channels; ch++) {
7b4076a7
JR
994 if(bit_alloc_stages[ch] > 2) {
995 /* Exponent mapping into PSD and PSD integration */
d802d7ca
JR
996 ff_ac3_bit_alloc_calc_psd(s->dexps[ch],
997 s->start_freq[ch], s->end_freq[ch],
998 s->psd[ch], s->band_psd[ch]);
eaf84d97 999 }
7b4076a7
JR
1000 if(bit_alloc_stages[ch] > 1) {
1001 /* Compute excitation function, Compute masking curve, and
1002 Apply delta bit allocation */
d802d7ca
JR
1003 ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch],
1004 s->start_freq[ch], s->end_freq[ch],
1005 s->fast_gain[ch], (ch == s->lfe_ch),
1006 s->dba_mode[ch], s->dba_nsegs[ch],
1007 s->dba_offsets[ch], s->dba_lengths[ch],
1008 s->dba_values[ch], s->mask[ch]);
eaf84d97 1009 }
7b4076a7
JR
1010 if(bit_alloc_stages[ch] > 0) {
1011 /* Compute bit allocation */
d802d7ca
JR
1012 ff_ac3_bit_alloc_calc_bap(s->mask[ch], s->psd[ch],
1013 s->start_freq[ch], s->end_freq[ch],
1014 s->snr_offset[ch],
1015 s->bit_alloc_params.floor,
1016 s->bap[ch]);
eaf84d97 1017 }
2fbbd087 1018 }
98a27a8a 1019
5066f515 1020 /* unused dummy data */
23c8cb89
JR
1021 if (get_bits1(gbc)) {
1022 int skipl = get_bits(gbc, 9);
98a27a8a 1023 while(skipl--)
23c8cb89 1024 skip_bits(gbc, 8);
1b293437 1025 }
f5cefb21 1026
1b293437 1027 /* unpack the transform coefficients
5066f515 1028 this also uncouples channels if coupling is in use. */
d802d7ca
JR
1029 if (get_transform_coeffs(s)) {
1030 av_log(s->avctx, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
1b293437
JR
1031 return -1;
1032 }
486637af 1033
1b293437 1034 /* recover coefficients if rematrixing is in use */
d802d7ca
JR
1035 if(s->channel_mode == AC3_CHMODE_STEREO)
1036 do_rematrixing(s);
1b293437 1037
03726b70 1038 /* apply scaling to coefficients (headroom, dynrng) */
d802d7ca 1039 for(ch=1; ch<=s->channels; ch++) {
a4de6dd2 1040 float gain = s->mul_bias / 4194304.0f;
d802d7ca
JR
1041 if(s->channel_mode == AC3_CHMODE_DUALMONO) {
1042 gain *= s->dynamic_range[ch-1];
7bfd22f2 1043 } else {
d802d7ca 1044 gain *= s->dynamic_range[0];
7bfd22f2 1045 }
a4de6dd2
JR
1046 for(i=0; i<256; i++) {
1047 s->transform_coeffs[ch][i] = s->fixed_coeffs[ch][i] * gain;
7bfd22f2
JR
1048 }
1049 }
d7bcc4ad 1050
d802d7ca 1051 do_imdct(s);
486637af 1052
224bc440 1053 /* downmix output if needed */
d802d7ca
JR
1054 if(s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
1055 s->fbw_channels == s->out_channels)) {
b35c67e5 1056 ac3_downmix(s);
3bbb0bf8
JR
1057 }
1058
4e092320 1059 /* convert float to 16-bit integer */
d802d7ca 1060 for(ch=0; ch<s->out_channels; ch++) {
3bbb0bf8 1061 for(i=0; i<256; i++) {
d802d7ca 1062 s->output[ch][i] += s->add_bias;
3bbb0bf8 1063 }
d802d7ca 1064 s->dsp.float_to_int16(s->int_output[ch], s->output[ch], 256);
4e092320 1065 }
1b293437 1066
4e092320 1067 return 0;
486637af
JR
1068}
1069
5066f515
JR
1070/**
1071 * Decode a single AC-3 frame.
c7cfc48f 1072 */
00585845 1073static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
1b293437 1074{
0345fade 1075 AC3DecodeContext *s = avctx->priv_data;
00585845 1076 int16_t *out_samples = (int16_t *)data;
3df88093 1077 int i, blk, ch, err;
d7bcc4ad 1078
5066f515 1079 /* initialize the GetBitContext with the start of valid AC-3 Frame */
d802d7ca 1080 init_get_bits(&s->gbc, buf, buf_size * 8);
00585845 1081
5066f515 1082 /* parse the syncinfo */
d802d7ca 1083 err = ac3_parse_header(s);
3df88093
JR
1084 if(err) {
1085 switch(err) {
1086 case AC3_PARSE_ERROR_SYNC:
1087 av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
1088 break;
1089 case AC3_PARSE_ERROR_BSID:
1090 av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
1091 break;
1092 case AC3_PARSE_ERROR_SAMPLE_RATE:
1093 av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
1094 break;
1095 case AC3_PARSE_ERROR_FRAME_SIZE:
1096 av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
1097 break;
1098 default:
1099 av_log(avctx, AV_LOG_ERROR, "invalid header\n");
1100 break;
1101 }
1102 return -1;
1b293437 1103 }
2aa2c5c4 1104
a135bea5 1105 /* check that reported frame size fits in input buffer */
d802d7ca 1106 if(s->frame_size > buf_size) {
a135bea5
JR
1107 av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
1108 return -1;
1109 }
1110
d6939960 1111 /* check for crc mismatch */
f34b221b 1112 if(avctx->error_resilience >= FF_ER_CAREFUL) {
3abe5fbd 1113 if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2], s->frame_size-2)) {
7564658b
JR
1114 av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
1115 return -1;
1116 }
1117 /* TODO: error concealment */
471db688 1118 }
d6939960
JR
1119
1120 avctx->sample_rate = s->sample_rate;
1121 avctx->bit_rate = s->bit_rate;
1122
7bfd22f2 1123 /* channel config */
d802d7ca 1124 s->out_channels = s->channels;
6708eefe 1125 if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&
2816d323 1126 avctx->request_channels < s->channels) {
d802d7ca
JR
1127 s->out_channels = avctx->request_channels;
1128 s->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
1b293437 1129 }
d802d7ca 1130 avctx->channels = s->out_channels;
1b293437 1131
f0b3a7ba
JR
1132 /* set downmixing coefficients if needed */
1133 if(s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
1134 s->fbw_channels == s->out_channels)) {
1135 set_downmix_coeffs(s);
1136 }
1137
5066f515 1138 /* parse the audio blocks */
75b9b036 1139 for (blk = 0; blk < NB_BLOCKS; blk++) {
d802d7ca 1140 if (ac3_parse_audio_block(s, blk)) {
1b293437
JR
1141 av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
1142 *data_size = 0;
d802d7ca 1143 return s->frame_size;
1b293437 1144 }
75b9b036 1145 for (i = 0; i < 256; i++)
d802d7ca
JR
1146 for (ch = 0; ch < s->out_channels; ch++)
1147 *(out_samples++) = s->int_output[ch][i];
1b293437 1148 }
8fbb368d 1149 *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t);
d802d7ca 1150 return s->frame_size;
2aa2c5c4 1151}
1b293437 1152
5066f515
JR
1153/**
1154 * Uninitialize the AC-3 decoder.
c7cfc48f
JR
1155 */
1156static int ac3_decode_end(AVCodecContext *avctx)
1b293437 1157{
0345fade 1158 AC3DecodeContext *s = avctx->priv_data;
d802d7ca
JR
1159 ff_mdct_end(&s->imdct_512);
1160 ff_mdct_end(&s->imdct_256);
c7cfc48f 1161
1b293437
JR
1162 return 0;
1163}
1164
fa67992d 1165AVCodec ac3_decoder = {
e6bca37c
JR
1166 .name = "ac3",
1167 .type = CODEC_TYPE_AUDIO,
1168 .id = CODEC_ID_AC3,
1169 .priv_data_size = sizeof (AC3DecodeContext),
1170 .init = ac3_decode_init,
1171 .close = ac3_decode_end,
1172 .decode = ac3_decode_frame,
1b293437 1173};