1 /*
2 * The simplest AC-3 encoder
3 * Copyright (c) 2000 Fabrice Bellard
4 * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
5 * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 /**
25 * @file
26 * The simplest AC-3 encoder.
27 */
28
29 #include <stdint.h>
30
31 #include "libavutil/attributes.h"
32 #include "libavutil/avassert.h"
33 #include "libavutil/avstring.h"
34 #include "libavutil/channel_layout.h"
35 #include "libavutil/crc.h"
36 #include "libavutil/internal.h"
37 #include "libavutil/opt.h"
38 #include "avcodec.h"
39 #include "me_cmp.h"
40 #include "put_bits.h"
41 #include "audiodsp.h"
42 #include "ac3dsp.h"
43 #include "ac3.h"
44 #include "fft.h"
45 #include "ac3enc.h"
46 #include "eac3enc.h"
47
48 typedef struct AC3Mant {
49 int16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr; ///< mantissa pointers for bap=1,2,4
50 int mant1_cnt, mant2_cnt, mant4_cnt; ///< mantissa counts for bap=1,2,4
51 } AC3Mant;
52
53 #define CMIXLEV_NUM_OPTIONS 3
54 static const float cmixlev_options[CMIXLEV_NUM_OPTIONS] = {
55 LEVEL_MINUS_3DB, LEVEL_MINUS_4POINT5DB, LEVEL_MINUS_6DB
56 };
57
58 #define SURMIXLEV_NUM_OPTIONS 3
59 static const float surmixlev_options[SURMIXLEV_NUM_OPTIONS] = {
60 LEVEL_MINUS_3DB, LEVEL_MINUS_6DB, LEVEL_ZERO
61 };
62
63 #define EXTMIXLEV_NUM_OPTIONS 8
64 static const float extmixlev_options[EXTMIXLEV_NUM_OPTIONS] = {
65 LEVEL_PLUS_3DB, LEVEL_PLUS_1POINT5DB, LEVEL_ONE, LEVEL_MINUS_4POINT5DB,
66 LEVEL_MINUS_3DB, LEVEL_MINUS_4POINT5DB, LEVEL_MINUS_6DB, LEVEL_ZERO
67 };
68
69
70 /**
71 * LUT for number of exponent groups.
72 * exponent_group_tab[coupling][exponent strategy-1][number of coefficients]
73 */
74 static uint8_t exponent_group_tab[2][3][256];
75
76
77 /**
78 * List of supported channel layouts.
79 */
80 const uint64_t ff_ac3_channel_layouts[19] = {
81 AV_CH_LAYOUT_MONO,
82 AV_CH_LAYOUT_STEREO,
83 AV_CH_LAYOUT_2_1,
84 AV_CH_LAYOUT_SURROUND,
85 AV_CH_LAYOUT_2_2,
86 AV_CH_LAYOUT_QUAD,
87 AV_CH_LAYOUT_4POINT0,
88 AV_CH_LAYOUT_5POINT0,
89 AV_CH_LAYOUT_5POINT0_BACK,
90 (AV_CH_LAYOUT_MONO | AV_CH_LOW_FREQUENCY),
91 (AV_CH_LAYOUT_STEREO | AV_CH_LOW_FREQUENCY),
92 (AV_CH_LAYOUT_2_1 | AV_CH_LOW_FREQUENCY),
93 (AV_CH_LAYOUT_SURROUND | AV_CH_LOW_FREQUENCY),
94 (AV_CH_LAYOUT_2_2 | AV_CH_LOW_FREQUENCY),
95 (AV_CH_LAYOUT_QUAD | AV_CH_LOW_FREQUENCY),
96 (AV_CH_LAYOUT_4POINT0 | AV_CH_LOW_FREQUENCY),
97 AV_CH_LAYOUT_5POINT1,
98 AV_CH_LAYOUT_5POINT1_BACK,
99 0
100 };
101
102
103 /**
104 * LUT to select the bandwidth code based on the bit rate, sample rate, and
105 * number of full-bandwidth channels.
106 * bandwidth_tab[fbw_channels-1][sample rate code][bit rate code]
107 */
108 static const uint8_t ac3_bandwidth_tab[5][3][19] = {
109 // 32 40 48 56 64 80 96 112 128 160 192 224 256 320 384 448 512 576 640
110
111 { { 0, 0, 0, 12, 16, 32, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48 },
112 { 0, 0, 0, 16, 20, 36, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56 },
113 { 0, 0, 0, 32, 40, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60 } },
114
115 { { 0, 0, 0, 0, 0, 0, 0, 20, 24, 32, 48, 48, 48, 48, 48, 48, 48, 48, 48 },
116 { 0, 0, 0, 0, 0, 0, 4, 24, 28, 36, 56, 56, 56, 56, 56, 56, 56, 56, 56 },
117 { 0, 0, 0, 0, 0, 0, 20, 44, 52, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60 } },
118
119 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 24, 32, 40, 48, 48, 48, 48, 48, 48 },
120 { 0, 0, 0, 0, 0, 0, 0, 0, 4, 20, 28, 36, 44, 56, 56, 56, 56, 56, 56 },
121 { 0, 0, 0, 0, 0, 0, 0, 0, 20, 40, 48, 60, 60, 60, 60, 60, 60, 60, 60 } },
122
123 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12, 24, 32, 48, 48, 48, 48, 48, 48 },
124 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 28, 36, 56, 56, 56, 56, 56, 56 },
125 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 48, 60, 60, 60, 60, 60, 60, 60 } },
126
127 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 20, 32, 40, 48, 48, 48, 48 },
128 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12, 24, 36, 44, 56, 56, 56, 56 },
129 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 28, 44, 60, 60, 60, 60, 60, 60 } }
130 };
131
132
133 /**
134 * LUT to select the coupling start band based on the bit rate, sample rate, and
135 * number of full-bandwidth channels. -1 = coupling off
136 * ac3_coupling_start_tab[channel_mode-2][sample rate code][bit rate code]
137 *
138 * TODO: more testing for optimal parameters.
139 * multi-channel tests at 44.1kHz and 32kHz.
140 */
141 static const int8_t ac3_coupling_start_tab[6][3][19] = {
142 // 32 40 48 56 64 80 96 112 128 160 192 224 256 320 384 448 512 576 640
143
144 // 2/0
145 { { 0, 0, 0, 0, 0, 0, 0, 1, 1, 7, 8, 11, 12, -1, -1, -1, -1, -1, -1 },
146 { 0, 0, 0, 0, 0, 0, 1, 3, 5, 7, 10, 12, 13, -1, -1, -1, -1, -1, -1 },
147 { 0, 0, 0, 0, 1, 2, 2, 9, 13, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
148
149 // 3/0
150 { { 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 6, 9, 11, 12, 13, -1, -1, -1, -1 },
151 { 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 6, 9, 11, 12, 13, -1, -1, -1, -1 },
152 { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
153
154 // 2/1 - untested
155 { { 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 6, 9, 11, 12, 13, -1, -1, -1, -1 },
156 { 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 6, 9, 11, 12, 13, -1, -1, -1, -1 },
157 { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
158
159 // 3/1
160 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 10, 11, 11, 12, 12, 14, -1 },
161 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 10, 11, 11, 12, 12, 14, -1 },
162 { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
163
164 // 2/2 - untested
165 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 10, 11, 11, 12, 12, 14, -1 },
166 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 10, 11, 11, 12, 12, 14, -1 },
167 { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
168
169 // 3/2
170 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 8, 11, 12, 12, -1, -1 },
171 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 8, 11, 12, 12, -1, -1 },
172 { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
173 };
174
175
176 /**
177 * Adjust the frame size to make the average bit rate match the target bit rate.
178 * This is only needed for 11025, 22050, and 44100 sample rates or any E-AC-3.
179 *
180 * @param s AC-3 encoder private context
181 */
ff_ac3_adjust_frame_size(AC3EncodeContext * s)182 void ff_ac3_adjust_frame_size(AC3EncodeContext *s)
183 {
184 while (s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
185 s->bits_written -= s->bit_rate;
186 s->samples_written -= s->sample_rate;
187 }
188 s->frame_size = s->frame_size_min +
189 2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
190 s->bits_written += s->frame_size * 8;
191 s->samples_written += AC3_BLOCK_SIZE * s->num_blocks;
192 }
193
194
195 /**
196 * Set the initial coupling strategy parameters prior to coupling analysis.
197 *
198 * @param s AC-3 encoder private context
199 */
ff_ac3_compute_coupling_strategy(AC3EncodeContext * s)200 void ff_ac3_compute_coupling_strategy(AC3EncodeContext *s)
201 {
202 int blk, ch;
203 int got_cpl_snr;
204 int num_cpl_blocks;
205
206 /* set coupling use flags for each block/channel */
207 /* TODO: turn coupling on/off and adjust start band based on bit usage */
208 for (blk = 0; blk < s->num_blocks; blk++) {
209 AC3Block *block = &s->blocks[blk];
210 for (ch = 1; ch <= s->fbw_channels; ch++)
211 block->channel_in_cpl[ch] = s->cpl_on;
212 }
213
214 /* enable coupling for each block if at least 2 channels have coupling
215 enabled for that block */
216 got_cpl_snr = 0;
217 num_cpl_blocks = 0;
218 for (blk = 0; blk < s->num_blocks; blk++) {
219 AC3Block *block = &s->blocks[blk];
220 block->num_cpl_channels = 0;
221 for (ch = 1; ch <= s->fbw_channels; ch++)
222 block->num_cpl_channels += block->channel_in_cpl[ch];
223 block->cpl_in_use = block->num_cpl_channels > 1;
224 num_cpl_blocks += block->cpl_in_use;
225 if (!block->cpl_in_use) {
226 block->num_cpl_channels = 0;
227 for (ch = 1; ch <= s->fbw_channels; ch++)
228 block->channel_in_cpl[ch] = 0;
229 }
230
231 block->new_cpl_strategy = !blk;
232 if (blk) {
233 for (ch = 1; ch <= s->fbw_channels; ch++) {
234 if (block->channel_in_cpl[ch] != s->blocks[blk-1].channel_in_cpl[ch]) {
235 block->new_cpl_strategy = 1;
236 break;
237 }
238 }
239 }
240 block->new_cpl_leak = block->new_cpl_strategy;
241
242 if (!blk || (block->cpl_in_use && !got_cpl_snr)) {
243 block->new_snr_offsets = 1;
244 if (block->cpl_in_use)
245 got_cpl_snr = 1;
246 } else {
247 block->new_snr_offsets = 0;
248 }
249 }
250 if (!num_cpl_blocks)
251 s->cpl_on = 0;
252
253 /* set bandwidth for each channel */
254 for (blk = 0; blk < s->num_blocks; blk++) {
255 AC3Block *block = &s->blocks[blk];
256 for (ch = 1; ch <= s->fbw_channels; ch++) {
257 if (block->channel_in_cpl[ch])
258 block->end_freq[ch] = s->start_freq[CPL_CH];
259 else
260 block->end_freq[ch] = s->bandwidth_code * 3 + 73;
261 }
262 }
263 }
264
265
266 /**
267 * Apply stereo rematrixing to coefficients based on rematrixing flags.
268 *
269 * @param s AC-3 encoder private context
270 */
ff_ac3_apply_rematrixing(AC3EncodeContext * s)271 void ff_ac3_apply_rematrixing(AC3EncodeContext *s)
272 {
273 int nb_coefs;
274 int blk, bnd, i;
275 int start, end;
276 uint8_t *flags = NULL;
277
278 if (!s->rematrixing_enabled)
279 return;
280
281 for (blk = 0; blk < s->num_blocks; blk++) {
282 AC3Block *block = &s->blocks[blk];
283 if (block->new_rematrixing_strategy)
284 flags = block->rematrixing_flags;
285 nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]);
286 for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) {
287 if (flags[bnd]) {
288 start = ff_ac3_rematrix_band_tab[bnd];
289 end = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
290 for (i = start; i < end; i++) {
291 int32_t lt = block->fixed_coef[1][i];
292 int32_t rt = block->fixed_coef[2][i];
293 block->fixed_coef[1][i] = (lt + rt) >> 1;
294 block->fixed_coef[2][i] = (lt - rt) >> 1;
295 }
296 }
297 }
298 }
299 }
300
301
302 /*
303 * Initialize exponent tables.
304 */
exponent_init(AC3EncodeContext * s)305 static av_cold void exponent_init(AC3EncodeContext *s)
306 {
307 int expstr, i, grpsize;
308
309 for (expstr = EXP_D15-1; expstr <= EXP_D45-1; expstr++) {
310 grpsize = 3 << expstr;
311 for (i = 12; i < 256; i++) {
312 exponent_group_tab[0][expstr][i] = (i + grpsize - 4) / grpsize;
313 exponent_group_tab[1][expstr][i] = (i ) / grpsize;
314 }
315 }
316 /* LFE */
317 exponent_group_tab[0][0][7] = 2;
318
319 if (CONFIG_EAC3_ENCODER && s->eac3)
320 ff_eac3_exponent_init();
321 }
322
323
324 /*
325 * Extract exponents from the MDCT coefficients.
326 */
extract_exponents(AC3EncodeContext * s)327 static void extract_exponents(AC3EncodeContext *s)
328 {
329 int ch = !s->cpl_on;
330 int chan_size = AC3_MAX_COEFS * s->num_blocks * (s->channels - ch + 1);
331 AC3Block *block = &s->blocks[0];
332
333 s->ac3dsp.extract_exponents(block->exp[ch], block->fixed_coef[ch], chan_size);
334 }
335
336
337 /**
338 * Exponent Difference Threshold.
339 * New exponents are sent if their SAD exceed this number.
340 */
341 #define EXP_DIFF_THRESHOLD 500
342
343 /**
344 * Table used to select exponent strategy based on exponent reuse block interval.
345 */
346 static const uint8_t exp_strategy_reuse_tab[4][6] = {
347 { EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
348 { EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
349 { EXP_D25, EXP_D25, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
350 { EXP_D45, EXP_D25, EXP_D25, EXP_D15, EXP_D15, EXP_D15 }
351 };
352
353 /*
354 * Calculate exponent strategies for all channels.
355 * Array arrangement is reversed to simplify the per-channel calculation.
356 */
compute_exp_strategy(AC3EncodeContext * s)357 static void compute_exp_strategy(AC3EncodeContext *s)
358 {
359 int ch, blk, blk1;
360
361 for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
362 uint8_t *exp_strategy = s->exp_strategy[ch];
363 uint8_t *exp = s->blocks[0].exp[ch];
364 int exp_diff;
365
366 /* estimate if the exponent variation & decide if they should be
367 reused in the next frame */
368 exp_strategy[0] = EXP_NEW;
369 exp += AC3_MAX_COEFS;
370 for (blk = 1; blk < s->num_blocks; blk++, exp += AC3_MAX_COEFS) {
371 if (ch == CPL_CH) {
372 if (!s->blocks[blk-1].cpl_in_use) {
373 exp_strategy[blk] = EXP_NEW;
374 continue;
375 } else if (!s->blocks[blk].cpl_in_use) {
376 exp_strategy[blk] = EXP_REUSE;
377 continue;
378 }
379 } else if (s->blocks[blk].channel_in_cpl[ch] != s->blocks[blk-1].channel_in_cpl[ch]) {
380 exp_strategy[blk] = EXP_NEW;
381 continue;
382 }
383 exp_diff = s->mecc.sad[0](NULL, exp, exp - AC3_MAX_COEFS, 16, 16);
384 exp_strategy[blk] = EXP_REUSE;
385 if (ch == CPL_CH && exp_diff > (EXP_DIFF_THRESHOLD * (s->blocks[blk].end_freq[ch] - s->start_freq[ch]) / AC3_MAX_COEFS))
386 exp_strategy[blk] = EXP_NEW;
387 else if (ch > CPL_CH && exp_diff > EXP_DIFF_THRESHOLD)
388 exp_strategy[blk] = EXP_NEW;
389 }
390
391 /* now select the encoding strategy type : if exponents are often
392 recoded, we use a coarse encoding */
393 blk = 0;
394 while (blk < s->num_blocks) {
395 blk1 = blk + 1;
396 while (blk1 < s->num_blocks && exp_strategy[blk1] == EXP_REUSE)
397 blk1++;
398 exp_strategy[blk] = exp_strategy_reuse_tab[s->num_blks_code][blk1-blk-1];
399 blk = blk1;
400 }
401 }
402 if (s->lfe_on) {
403 ch = s->lfe_channel;
404 s->exp_strategy[ch][0] = EXP_D15;
405 for (blk = 1; blk < s->num_blocks; blk++)
406 s->exp_strategy[ch][blk] = EXP_REUSE;
407 }
408
409 /* for E-AC-3, determine frame exponent strategy */
410 if (CONFIG_EAC3_ENCODER && s->eac3)
411 ff_eac3_get_frame_exp_strategy(s);
412 }
413
414
415 /**
416 * Update the exponents so that they are the ones the decoder will decode.
417 *
418 * @param[in,out] exp array of exponents for 1 block in 1 channel
419 * @param nb_exps number of exponents in active bandwidth
420 * @param exp_strategy exponent strategy for the block
421 * @param cpl indicates if the block is in the coupling channel
422 */
encode_exponents_blk_ch(uint8_t * exp,int nb_exps,int exp_strategy,int cpl)423 static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy,
424 int cpl)
425 {
426 int nb_groups, i, k;
427
428 nb_groups = exponent_group_tab[cpl][exp_strategy-1][nb_exps] * 3;
429
430 /* for each group, compute the minimum exponent */
431 switch(exp_strategy) {
432 case EXP_D25:
433 for (i = 1, k = 1-cpl; i <= nb_groups; i++) {
434 uint8_t exp_min = exp[k];
435 if (exp[k+1] < exp_min)
436 exp_min = exp[k+1];
437 exp[i-cpl] = exp_min;
438 k += 2;
439 }
440 break;
441 case EXP_D45:
442 for (i = 1, k = 1-cpl; i <= nb_groups; i++) {
443 uint8_t exp_min = exp[k];
444 if (exp[k+1] < exp_min)
445 exp_min = exp[k+1];
446 if (exp[k+2] < exp_min)
447 exp_min = exp[k+2];
448 if (exp[k+3] < exp_min)
449 exp_min = exp[k+3];
450 exp[i-cpl] = exp_min;
451 k += 4;
452 }
453 break;
454 }
455
456 /* constraint for DC exponent */
457 if (!cpl && exp[0] > 15)
458 exp[0] = 15;
459
460 /* decrease the delta between each groups to within 2 so that they can be
461 differentially encoded */
462 for (i = 1; i <= nb_groups; i++)
463 exp[i] = FFMIN(exp[i], exp[i-1] + 2);
464 i--;
465 while (--i >= 0)
466 exp[i] = FFMIN(exp[i], exp[i+1] + 2);
467
468 if (cpl)
469 exp[-1] = exp[0] & ~1;
470
471 /* now we have the exponent values the decoder will see */
472 switch (exp_strategy) {
473 case EXP_D25:
474 for (i = nb_groups, k = (nb_groups * 2)-cpl; i > 0; i--) {
475 uint8_t exp1 = exp[i-cpl];
476 exp[k--] = exp1;
477 exp[k--] = exp1;
478 }
479 break;
480 case EXP_D45:
481 for (i = nb_groups, k = (nb_groups * 4)-cpl; i > 0; i--) {
482 exp[k] = exp[k-1] = exp[k-2] = exp[k-3] = exp[i-cpl];
483 k -= 4;
484 }
485 break;
486 }
487 }
488
489
490 /*
491 * Encode exponents from original extracted form to what the decoder will see.
492 * This copies and groups exponents based on exponent strategy and reduces
493 * deltas between adjacent exponent groups so that they can be differentially
494 * encoded.
495 */
encode_exponents(AC3EncodeContext * s)496 static void encode_exponents(AC3EncodeContext *s)
497 {
498 int blk, blk1, ch, cpl;
499 uint8_t *exp, *exp_strategy;
500 int nb_coefs, num_reuse_blocks;
501
502 for (ch = !s->cpl_on; ch <= s->channels; ch++) {
503 exp = s->blocks[0].exp[ch] + s->start_freq[ch];
504 exp_strategy = s->exp_strategy[ch];
505
506 cpl = (ch == CPL_CH);
507 blk = 0;
508 while (blk < s->num_blocks) {
509 AC3Block *block = &s->blocks[blk];
510 if (cpl && !block->cpl_in_use) {
511 exp += AC3_MAX_COEFS;
512 blk++;
513 continue;
514 }
515 nb_coefs = block->end_freq[ch] - s->start_freq[ch];
516 blk1 = blk + 1;
517
518 /* count the number of EXP_REUSE blocks after the current block
519 and set exponent reference block numbers */
520 s->exp_ref_block[ch][blk] = blk;
521 while (blk1 < s->num_blocks && exp_strategy[blk1] == EXP_REUSE) {
522 s->exp_ref_block[ch][blk1] = blk;
523 blk1++;
524 }
525 num_reuse_blocks = blk1 - blk - 1;
526
527 /* for the EXP_REUSE case we select the min of the exponents */
528 s->ac3dsp.ac3_exponent_min(exp-s->start_freq[ch], num_reuse_blocks,
529 AC3_MAX_COEFS);
530
531 encode_exponents_blk_ch(exp, nb_coefs, exp_strategy[blk], cpl);
532
533 exp += AC3_MAX_COEFS * (num_reuse_blocks + 1);
534 blk = blk1;
535 }
536 }
537
538 /* reference block numbers have been changed, so reset ref_bap_set */
539 s->ref_bap_set = 0;
540 }
541
542
543 /*
544 * Count exponent bits based on bandwidth, coupling, and exponent strategies.
545 */
count_exponent_bits(AC3EncodeContext * s)546 static int count_exponent_bits(AC3EncodeContext *s)
547 {
548 int blk, ch;
549 int nb_groups, bit_count;
550
551 bit_count = 0;
552 for (blk = 0; blk < s->num_blocks; blk++) {
553 AC3Block *block = &s->blocks[blk];
554 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
555 int exp_strategy = s->exp_strategy[ch][blk];
556 int cpl = (ch == CPL_CH);
557 int nb_coefs = block->end_freq[ch] - s->start_freq[ch];
558
559 if (exp_strategy == EXP_REUSE)
560 continue;
561
562 nb_groups = exponent_group_tab[cpl][exp_strategy-1][nb_coefs];
563 bit_count += 4 + (nb_groups * 7);
564 }
565 }
566
567 return bit_count;
568 }
569
570
571 /**
572 * Group exponents.
573 * 3 delta-encoded exponents are in each 7-bit group. The number of groups
574 * varies depending on exponent strategy and bandwidth.
575 *
576 * @param s AC-3 encoder private context
577 */
ff_ac3_group_exponents(AC3EncodeContext * s)578 void ff_ac3_group_exponents(AC3EncodeContext *s)
579 {
580 int blk, ch, i, cpl;
581 int group_size, nb_groups;
582 uint8_t *p;
583 int delta0, delta1, delta2;
584 int exp0, exp1;
585
586 for (blk = 0; blk < s->num_blocks; blk++) {
587 AC3Block *block = &s->blocks[blk];
588 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
589 int exp_strategy = s->exp_strategy[ch][blk];
590 if (exp_strategy == EXP_REUSE)
591 continue;
592 cpl = (ch == CPL_CH);
593 group_size = exp_strategy + (exp_strategy == EXP_D45);
594 nb_groups = exponent_group_tab[cpl][exp_strategy-1][block->end_freq[ch]-s->start_freq[ch]];
595 p = block->exp[ch] + s->start_freq[ch] - cpl;
596
597 /* DC exponent */
598 exp1 = *p++;
599 block->grouped_exp[ch][0] = exp1;
600
601 /* remaining exponents are delta encoded */
602 for (i = 1; i <= nb_groups; i++) {
603 /* merge three delta in one code */
604 exp0 = exp1;
605 exp1 = p[0];
606 p += group_size;
607 delta0 = exp1 - exp0 + 2;
608 av_assert2(delta0 >= 0 && delta0 <= 4);
609
610 exp0 = exp1;
611 exp1 = p[0];
612 p += group_size;
613 delta1 = exp1 - exp0 + 2;
614 av_assert2(delta1 >= 0 && delta1 <= 4);
615
616 exp0 = exp1;
617 exp1 = p[0];
618 p += group_size;
619 delta2 = exp1 - exp0 + 2;
620 av_assert2(delta2 >= 0 && delta2 <= 4);
621
622 block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
623 }
624 }
625 }
626 }
627
628
629 /**
630 * Calculate final exponents from the supplied MDCT coefficients and exponent shift.
631 * Extract exponents from MDCT coefficients, calculate exponent strategies,
632 * and encode final exponents.
633 *
634 * @param s AC-3 encoder private context
635 */
ff_ac3_process_exponents(AC3EncodeContext * s)636 void ff_ac3_process_exponents(AC3EncodeContext *s)
637 {
638 extract_exponents(s);
639
640 compute_exp_strategy(s);
641
642 encode_exponents(s);
643
644 emms_c();
645 }
646
647
648 /*
649 * Count frame bits that are based solely on fixed parameters.
650 * This only has to be run once when the encoder is initialized.
651 */
count_frame_bits_fixed(AC3EncodeContext * s)652 static void count_frame_bits_fixed(AC3EncodeContext *s)
653 {
654 static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
655 int blk;
656 int frame_bits;
657
658 /* assumptions:
659 * no dynamic range codes
660 * bit allocation parameters do not change between blocks
661 * no delta bit allocation
662 * no skipped data
663 * no auxiliary data
664 * no E-AC-3 metadata
665 */
666
667 /* header */
668 frame_bits = 16; /* sync info */
669 if (s->eac3) {
670 /* bitstream info header */
671 frame_bits += 35;
672 frame_bits += 1 + 1;
673 if (s->num_blocks != 0x6)
674 frame_bits++;
675 frame_bits++;
676 /* audio frame header */
677 if (s->num_blocks == 6)
678 frame_bits += 2;
679 frame_bits += 10;
680 /* exponent strategy */
681 if (s->use_frame_exp_strategy)
682 frame_bits += 5 * s->fbw_channels;
683 else
684 frame_bits += s->num_blocks * 2 * s->fbw_channels;
685 if (s->lfe_on)
686 frame_bits += s->num_blocks;
687 /* converter exponent strategy */
688 if (s->num_blks_code != 0x3)
689 frame_bits++;
690 else
691 frame_bits += s->fbw_channels * 5;
692 /* snr offsets */
693 frame_bits += 10;
694 /* block start info */
695 if (s->num_blocks != 1)
696 frame_bits++;
697 } else {
698 frame_bits += 49;
699 frame_bits += frame_bits_inc[s->channel_mode];
700 }
701
702 /* audio blocks */
703 for (blk = 0; blk < s->num_blocks; blk++) {
704 if (!s->eac3) {
705 /* block switch flags */
706 frame_bits += s->fbw_channels;
707
708 /* dither flags */
709 frame_bits += s->fbw_channels;
710 }
711
712 /* dynamic range */
713 frame_bits++;
714
715 /* spectral extension */
716 if (s->eac3)
717 frame_bits++;
718
719 if (!s->eac3) {
720 /* exponent strategy */
721 frame_bits += 2 * s->fbw_channels;
722 if (s->lfe_on)
723 frame_bits++;
724
725 /* bit allocation params */
726 frame_bits++;
727 if (!blk)
728 frame_bits += 2 + 2 + 2 + 2 + 3;
729 }
730
731 /* converter snr offset */
732 if (s->eac3)
733 frame_bits++;
734
735 if (!s->eac3) {
736 /* delta bit allocation */
737 frame_bits++;
738
739 /* skipped data */
740 frame_bits++;
741 }
742 }
743
744 /* auxiliary data */
745 frame_bits++;
746
747 /* CRC */
748 frame_bits += 1 + 16;
749
750 s->frame_bits_fixed = frame_bits;
751 }
752
753
754 /*
755 * Initialize bit allocation.
756 * Set default parameter codes and calculate parameter values.
757 */
bit_alloc_init(AC3EncodeContext * s)758 static av_cold void bit_alloc_init(AC3EncodeContext *s)
759 {
760 int ch;
761
762 /* init default parameters */
763 s->slow_decay_code = 2;
764 s->fast_decay_code = 1;
765 s->slow_gain_code = 1;
766 s->db_per_bit_code = s->eac3 ? 2 : 3;
767 s->floor_code = 7;
768 for (ch = 0; ch <= s->channels; ch++)
769 s->fast_gain_code[ch] = 4;
770
771 /* initial snr offset */
772 s->coarse_snr_offset = 40;
773
774 /* compute real values */
775 /* currently none of these values change during encoding, so we can just
776 set them once at initialization */
777 s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->bit_alloc.sr_shift;
778 s->bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s->fast_decay_code] >> s->bit_alloc.sr_shift;
779 s->bit_alloc.slow_gain = ff_ac3_slow_gain_tab[s->slow_gain_code];
780 s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
781 s->bit_alloc.floor = ff_ac3_floor_tab[s->floor_code];
782 s->bit_alloc.cpl_fast_leak = 0;
783 s->bit_alloc.cpl_slow_leak = 0;
784
785 count_frame_bits_fixed(s);
786 }
787
788
789 /*
790 * Count the bits used to encode the frame, minus exponents and mantissas.
791 * Bits based on fixed parameters have already been counted, so now we just
792 * have to add the bits based on parameters that change during encoding.
793 */
count_frame_bits(AC3EncodeContext * s)794 static void count_frame_bits(AC3EncodeContext *s)
795 {
796 AC3EncOptions *opt = &s->options;
797 int blk, ch;
798 int frame_bits = 0;
799
800 /* header */
801 if (s->eac3) {
802 if (opt->eac3_mixing_metadata) {
803 if (s->channel_mode > AC3_CHMODE_STEREO)
804 frame_bits += 2;
805 if (s->has_center)
806 frame_bits += 6;
807 if (s->has_surround)
808 frame_bits += 6;
809 frame_bits += s->lfe_on;
810 frame_bits += 1 + 1 + 2;
811 if (s->channel_mode < AC3_CHMODE_STEREO)
812 frame_bits++;
813 frame_bits++;
814 }
815 if (opt->eac3_info_metadata) {
816 frame_bits += 3 + 1 + 1;
817 if (s->channel_mode == AC3_CHMODE_STEREO)
818 frame_bits += 2 + 2;
819 if (s->channel_mode >= AC3_CHMODE_2F2R)
820 frame_bits += 2;
821 frame_bits++;
822 if (opt->audio_production_info)
823 frame_bits += 5 + 2 + 1;
824 frame_bits++;
825 }
826 /* coupling */
827 if (s->channel_mode > AC3_CHMODE_MONO) {
828 frame_bits++;
829 for (blk = 1; blk < s->num_blocks; blk++) {
830 AC3Block *block = &s->blocks[blk];
831 frame_bits++;
832 if (block->new_cpl_strategy)
833 frame_bits++;
834 }
835 }
836 /* coupling exponent strategy */
837 if (s->cpl_on) {
838 if (s->use_frame_exp_strategy) {
839 frame_bits += 5 * s->cpl_on;
840 } else {
841 for (blk = 0; blk < s->num_blocks; blk++)
842 frame_bits += 2 * s->blocks[blk].cpl_in_use;
843 }
844 }
845 } else {
846 if (opt->audio_production_info)
847 frame_bits += 7;
848 if (s->bitstream_id == 6) {
849 if (opt->extended_bsi_1)
850 frame_bits += 14;
851 if (opt->extended_bsi_2)
852 frame_bits += 14;
853 }
854 }
855
856 /* audio blocks */
857 for (blk = 0; blk < s->num_blocks; blk++) {
858 AC3Block *block = &s->blocks[blk];
859
860 /* coupling strategy */
861 if (!s->eac3)
862 frame_bits++;
863 if (block->new_cpl_strategy) {
864 if (!s->eac3)
865 frame_bits++;
866 if (block->cpl_in_use) {
867 if (s->eac3)
868 frame_bits++;
869 if (!s->eac3 || s->channel_mode != AC3_CHMODE_STEREO)
870 frame_bits += s->fbw_channels;
871 if (s->channel_mode == AC3_CHMODE_STEREO)
872 frame_bits++;
873 frame_bits += 4 + 4;
874 if (s->eac3)
875 frame_bits++;
876 else
877 frame_bits += s->num_cpl_subbands - 1;
878 }
879 }
880
881 /* coupling coordinates */
882 if (block->cpl_in_use) {
883 for (ch = 1; ch <= s->fbw_channels; ch++) {
884 if (block->channel_in_cpl[ch]) {
885 if (!s->eac3 || block->new_cpl_coords[ch] != 2)
886 frame_bits++;
887 if (block->new_cpl_coords[ch]) {
888 frame_bits += 2;
889 frame_bits += (4 + 4) * s->num_cpl_bands;
890 }
891 }
892 }
893 }
894
895 /* stereo rematrixing */
896 if (s->channel_mode == AC3_CHMODE_STEREO) {
897 if (!s->eac3 || blk > 0)
898 frame_bits++;
899 if (s->blocks[blk].new_rematrixing_strategy)
900 frame_bits += block->num_rematrixing_bands;
901 }
902
903 /* bandwidth codes & gain range */
904 for (ch = 1; ch <= s->fbw_channels; ch++) {
905 if (s->exp_strategy[ch][blk] != EXP_REUSE) {
906 if (!block->channel_in_cpl[ch])
907 frame_bits += 6;
908 frame_bits += 2;
909 }
910 }
911
912 /* coupling exponent strategy */
913 if (!s->eac3 && block->cpl_in_use)
914 frame_bits += 2;
915
916 /* snr offsets and fast gain codes */
917 if (!s->eac3) {
918 frame_bits++;
919 if (block->new_snr_offsets)
920 frame_bits += 6 + (s->channels + block->cpl_in_use) * (4 + 3);
921 }
922
923 /* coupling leak info */
924 if (block->cpl_in_use) {
925 if (!s->eac3 || block->new_cpl_leak != 2)
926 frame_bits++;
927 if (block->new_cpl_leak)
928 frame_bits += 3 + 3;
929 }
930 }
931
932 s->frame_bits = s->frame_bits_fixed + frame_bits;
933 }
934
935
936 /*
937 * Calculate masking curve based on the final exponents.
938 * Also calculate the power spectral densities to use in future calculations.
939 */
bit_alloc_masking(AC3EncodeContext * s)940 static void bit_alloc_masking(AC3EncodeContext *s)
941 {
942 int blk, ch;
943
944 for (blk = 0; blk < s->num_blocks; blk++) {
945 AC3Block *block = &s->blocks[blk];
946 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
947 /* We only need psd and mask for calculating bap.
948 Since we currently do not calculate bap when exponent
949 strategy is EXP_REUSE we do not need to calculate psd or mask. */
950 if (s->exp_strategy[ch][blk] != EXP_REUSE) {
951 ff_ac3_bit_alloc_calc_psd(block->exp[ch], s->start_freq[ch],
952 block->end_freq[ch], block->psd[ch],
953 block->band_psd[ch]);
954 ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, block->band_psd[ch],
955 s->start_freq[ch], block->end_freq[ch],
956 ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
957 ch == s->lfe_channel,
958 DBA_NONE, 0, NULL, NULL, NULL,
959 block->mask[ch]);
960 }
961 }
962 }
963 }
964
965
966 /*
967 * Ensure that bap for each block and channel point to the current bap_buffer.
968 * They may have been switched during the bit allocation search.
969 */
reset_block_bap(AC3EncodeContext * s)970 static void reset_block_bap(AC3EncodeContext *s)
971 {
972 int blk, ch;
973 uint8_t *ref_bap;
974
975 if (s->ref_bap[0][0] == s->bap_buffer && s->ref_bap_set)
976 return;
977
978 ref_bap = s->bap_buffer;
979 for (ch = 0; ch <= s->channels; ch++) {
980 for (blk = 0; blk < s->num_blocks; blk++)
981 s->ref_bap[ch][blk] = ref_bap + AC3_MAX_COEFS * s->exp_ref_block[ch][blk];
982 ref_bap += AC3_MAX_COEFS * s->num_blocks;
983 }
984 s->ref_bap_set = 1;
985 }
986
987
988 /**
989 * Initialize mantissa counts.
990 * These are set so that they are padded to the next whole group size when bits
991 * are counted in compute_mantissa_size.
992 *
993 * @param[in,out] mant_cnt running counts for each bap value for each block
994 */
count_mantissa_bits_init(uint16_t mant_cnt[AC3_MAX_BLOCKS][16])995 static void count_mantissa_bits_init(uint16_t mant_cnt[AC3_MAX_BLOCKS][16])
996 {
997 int blk;
998
999 for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1000 memset(mant_cnt[blk], 0, sizeof(mant_cnt[blk]));
1001 mant_cnt[blk][1] = mant_cnt[blk][2] = 2;
1002 mant_cnt[blk][4] = 1;
1003 }
1004 }
1005
1006
1007 /**
1008 * Update mantissa bit counts for all blocks in 1 channel in a given bandwidth
1009 * range.
1010 *
1011 * @param s AC-3 encoder private context
1012 * @param ch channel index
1013 * @param[in,out] mant_cnt running counts for each bap value for each block
1014 * @param start starting coefficient bin
1015 * @param end ending coefficient bin
1016 */
count_mantissa_bits_update_ch(AC3EncodeContext * s,int ch,uint16_t mant_cnt[AC3_MAX_BLOCKS][16],int start,int end)1017 static void count_mantissa_bits_update_ch(AC3EncodeContext *s, int ch,
1018 uint16_t mant_cnt[AC3_MAX_BLOCKS][16],
1019 int start, int end)
1020 {
1021 int blk;
1022
1023 for (blk = 0; blk < s->num_blocks; blk++) {
1024 AC3Block *block = &s->blocks[blk];
1025 if (ch == CPL_CH && !block->cpl_in_use)
1026 continue;
1027 s->ac3dsp.update_bap_counts(mant_cnt[blk],
1028 s->ref_bap[ch][blk] + start,
1029 FFMIN(end, block->end_freq[ch]) - start);
1030 }
1031 }
1032
1033
1034 /*
1035 * Count the number of mantissa bits in the frame based on the bap values.
1036 */
count_mantissa_bits(AC3EncodeContext * s)1037 static int count_mantissa_bits(AC3EncodeContext *s)
1038 {
1039 int ch, max_end_freq;
1040
1041 LOCAL_ALIGNED_16(uint16_t, mant_cnt, [AC3_MAX_BLOCKS], [16]);
1042
1043 count_mantissa_bits_init(mant_cnt);
1044
1045 max_end_freq = s->bandwidth_code * 3 + 73;
1046 for (ch = !s->cpl_enabled; ch <= s->channels; ch++)
1047 count_mantissa_bits_update_ch(s, ch, mant_cnt, s->start_freq[ch],
1048 max_end_freq);
1049
1050 return s->ac3dsp.compute_mantissa_size(mant_cnt);
1051 }
1052
1053
1054 /**
1055 * Run the bit allocation with a given SNR offset.
1056 * This calculates the bit allocation pointers that will be used to determine
1057 * the quantization of each mantissa.
1058 *
1059 * @param s AC-3 encoder private context
1060 * @param snr_offset SNR offset, 0 to 1023
1061 * @return the number of bits needed for mantissas if the given SNR offset is
1062 * is used.
1063 */
bit_alloc(AC3EncodeContext * s,int snr_offset)1064 static int bit_alloc(AC3EncodeContext *s, int snr_offset)
1065 {
1066 int blk, ch;
1067
1068 snr_offset = (snr_offset - 240) << 2;
1069
1070 reset_block_bap(s);
1071 for (blk = 0; blk < s->num_blocks; blk++) {
1072 AC3Block *block = &s->blocks[blk];
1073
1074 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
1075 /* Currently the only bit allocation parameters which vary across
1076 blocks within a frame are the exponent values. We can take
1077 advantage of that by reusing the bit allocation pointers
1078 whenever we reuse exponents. */
1079 if (s->exp_strategy[ch][blk] != EXP_REUSE) {
1080 s->ac3dsp.bit_alloc_calc_bap(block->mask[ch], block->psd[ch],
1081 s->start_freq[ch], block->end_freq[ch],
1082 snr_offset, s->bit_alloc.floor,
1083 ff_ac3_bap_tab, s->ref_bap[ch][blk]);
1084 }
1085 }
1086 }
1087 return count_mantissa_bits(s);
1088 }
1089
1090
1091 /*
1092 * Constant bitrate bit allocation search.
1093 * Find the largest SNR offset that will allow data to fit in the frame.
1094 */
cbr_bit_allocation(AC3EncodeContext * s)1095 static int cbr_bit_allocation(AC3EncodeContext *s)
1096 {
1097 int ch;
1098 int bits_left;
1099 int snr_offset, snr_incr;
1100
1101 bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
1102 if (bits_left < 0)
1103 return AVERROR(EINVAL);
1104
1105 snr_offset = s->coarse_snr_offset << 4;
1106
1107 /* if previous frame SNR offset was 1023, check if current frame can also
1108 use SNR offset of 1023. if so, skip the search. */
1109 if ((snr_offset | s->fine_snr_offset[1]) == 1023) {
1110 if (bit_alloc(s, 1023) <= bits_left)
1111 return 0;
1112 }
1113
1114 while (snr_offset >= 0 &&
1115 bit_alloc(s, snr_offset) > bits_left) {
1116 snr_offset -= 64;
1117 }
1118 if (snr_offset < 0)
1119 return AVERROR(EINVAL);
1120
1121 FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
1122 for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
1123 while (snr_offset + snr_incr <= 1023 &&
1124 bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
1125 snr_offset += snr_incr;
1126 FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
1127 }
1128 }
1129 FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
1130 reset_block_bap(s);
1131
1132 s->coarse_snr_offset = snr_offset >> 4;
1133 for (ch = !s->cpl_on; ch <= s->channels; ch++)
1134 s->fine_snr_offset[ch] = snr_offset & 0xF;
1135
1136 return 0;
1137 }
1138
1139
1140 /*
1141 * Perform bit allocation search.
1142 * Finds the SNR offset value that maximizes quality and fits in the specified
1143 * frame size. Output is the SNR offset and a set of bit allocation pointers
1144 * used to quantize the mantissas.
1145 */
ff_ac3_compute_bit_allocation(AC3EncodeContext * s)1146 int ff_ac3_compute_bit_allocation(AC3EncodeContext *s)
1147 {
1148 count_frame_bits(s);
1149
1150 s->exponent_bits = count_exponent_bits(s);
1151
1152 bit_alloc_masking(s);
1153
1154 return cbr_bit_allocation(s);
1155 }
1156
1157
1158 /**
1159 * Symmetric quantization on 'levels' levels.
1160 *
1161 * @param c unquantized coefficient
1162 * @param e exponent
1163 * @param levels number of quantization levels
1164 * @return quantized coefficient
1165 */
sym_quant(int c,int e,int levels)1166 static inline int sym_quant(int c, int e, int levels)
1167 {
1168 int v = (((levels * c) >> (24 - e)) + levels) >> 1;
1169 av_assert2(v >= 0 && v < levels);
1170 return v;
1171 }
1172
1173
1174 /**
1175 * Asymmetric quantization on 2^qbits levels.
1176 *
1177 * @param c unquantized coefficient
1178 * @param e exponent
1179 * @param qbits number of quantization bits
1180 * @return quantized coefficient
1181 */
asym_quant(int c,int e,int qbits)1182 static inline int asym_quant(int c, int e, int qbits)
1183 {
1184 int m;
1185
1186 c = (((c << e) >> (24 - qbits)) + 1) >> 1;
1187 m = (1 << (qbits-1));
1188 if (c >= m)
1189 c = m - 1;
1190 av_assert2(c >= -m);
1191 return c;
1192 }
1193
1194
1195 /**
1196 * Quantize a set of mantissas for a single channel in a single block.
1197 *
1198 * @param s Mantissa count context
1199 * @param fixed_coef unquantized fixed-point coefficients
1200 * @param exp exponents
1201 * @param bap bit allocation pointer indices
1202 * @param[out] qmant quantized coefficients
1203 * @param start_freq starting coefficient bin
1204 * @param end_freq ending coefficient bin
1205 */
quantize_mantissas_blk_ch(AC3Mant * s,int32_t * fixed_coef,uint8_t * exp,uint8_t * bap,int16_t * qmant,int start_freq,int end_freq)1206 static void quantize_mantissas_blk_ch(AC3Mant *s, int32_t *fixed_coef,
1207 uint8_t *exp, uint8_t *bap,
1208 int16_t *qmant, int start_freq,
1209 int end_freq)
1210 {
1211 int i;
1212
1213 for (i = start_freq; i < end_freq; i++) {
1214 int c = fixed_coef[i];
1215 int e = exp[i];
1216 int v = bap[i];
1217 if (v)
1218 switch (v) {
1219 case 1:
1220 v = sym_quant(c, e, 3);
1221 switch (s->mant1_cnt) {
1222 case 0:
1223 s->qmant1_ptr = &qmant[i];
1224 v = 9 * v;
1225 s->mant1_cnt = 1;
1226 break;
1227 case 1:
1228 *s->qmant1_ptr += 3 * v;
1229 s->mant1_cnt = 2;
1230 v = 128;
1231 break;
1232 default:
1233 *s->qmant1_ptr += v;
1234 s->mant1_cnt = 0;
1235 v = 128;
1236 break;
1237 }
1238 break;
1239 case 2:
1240 v = sym_quant(c, e, 5);
1241 switch (s->mant2_cnt) {
1242 case 0:
1243 s->qmant2_ptr = &qmant[i];
1244 v = 25 * v;
1245 s->mant2_cnt = 1;
1246 break;
1247 case 1:
1248 *s->qmant2_ptr += 5 * v;
1249 s->mant2_cnt = 2;
1250 v = 128;
1251 break;
1252 default:
1253 *s->qmant2_ptr += v;
1254 s->mant2_cnt = 0;
1255 v = 128;
1256 break;
1257 }
1258 break;
1259 case 3:
1260 v = sym_quant(c, e, 7);
1261 break;
1262 case 4:
1263 v = sym_quant(c, e, 11);
1264 switch (s->mant4_cnt) {
1265 case 0:
1266 s->qmant4_ptr = &qmant[i];
1267 v = 11 * v;
1268 s->mant4_cnt = 1;
1269 break;
1270 default:
1271 *s->qmant4_ptr += v;
1272 s->mant4_cnt = 0;
1273 v = 128;
1274 break;
1275 }
1276 break;
1277 case 5:
1278 v = sym_quant(c, e, 15);
1279 break;
1280 case 14:
1281 v = asym_quant(c, e, 14);
1282 break;
1283 case 15:
1284 v = asym_quant(c, e, 16);
1285 break;
1286 default:
1287 v = asym_quant(c, e, v - 1);
1288 break;
1289 }
1290 qmant[i] = v;
1291 }
1292 }
1293
1294
1295 /**
1296 * Quantize mantissas using coefficients, exponents, and bit allocation pointers.
1297 *
1298 * @param s AC-3 encoder private context
1299 */
ff_ac3_quantize_mantissas(AC3EncodeContext * s)1300 void ff_ac3_quantize_mantissas(AC3EncodeContext *s)
1301 {
1302 int blk, ch, ch0=0, got_cpl;
1303
1304 for (blk = 0; blk < s->num_blocks; blk++) {
1305 AC3Block *block = &s->blocks[blk];
1306 AC3Mant m = { 0 };
1307
1308 got_cpl = !block->cpl_in_use;
1309 for (ch = 1; ch <= s->channels; ch++) {
1310 if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {
1311 ch0 = ch - 1;
1312 ch = CPL_CH;
1313 got_cpl = 1;
1314 }
1315 quantize_mantissas_blk_ch(&m, block->fixed_coef[ch],
1316 s->blocks[s->exp_ref_block[ch][blk]].exp[ch],
1317 s->ref_bap[ch][blk], block->qmant[ch],
1318 s->start_freq[ch], block->end_freq[ch]);
1319 if (ch == CPL_CH)
1320 ch = ch0;
1321 }
1322 }
1323 }
1324
1325
1326 /*
1327 * Write the AC-3 frame header to the output bitstream.
1328 */
ac3_output_frame_header(AC3EncodeContext * s)1329 static void ac3_output_frame_header(AC3EncodeContext *s)
1330 {
1331 AC3EncOptions *opt = &s->options;
1332
1333 put_bits(&s->pb, 16, 0x0b77); /* frame header */
1334 put_bits(&s->pb, 16, 0); /* crc1: will be filled later */
1335 put_bits(&s->pb, 2, s->bit_alloc.sr_code);
1336 put_bits(&s->pb, 6, s->frame_size_code + (s->frame_size - s->frame_size_min) / 2);
1337 put_bits(&s->pb, 5, s->bitstream_id);
1338 put_bits(&s->pb, 3, s->bitstream_mode);
1339 put_bits(&s->pb, 3, s->channel_mode);
1340 if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
1341 put_bits(&s->pb, 2, s->center_mix_level);
1342 if (s->channel_mode & 0x04)
1343 put_bits(&s->pb, 2, s->surround_mix_level);
1344 if (s->channel_mode == AC3_CHMODE_STEREO)
1345 put_bits(&s->pb, 2, opt->dolby_surround_mode);
1346 put_bits(&s->pb, 1, s->lfe_on); /* LFE */
1347 put_bits(&s->pb, 5, -opt->dialogue_level);
1348 put_bits(&s->pb, 1, 0); /* no compression control word */
1349 put_bits(&s->pb, 1, 0); /* no lang code */
1350 put_bits(&s->pb, 1, opt->audio_production_info);
1351 if (opt->audio_production_info) {
1352 put_bits(&s->pb, 5, opt->mixing_level - 80);
1353 put_bits(&s->pb, 2, opt->room_type);
1354 }
1355 put_bits(&s->pb, 1, opt->copyright);
1356 put_bits(&s->pb, 1, opt->original);
1357 if (s->bitstream_id == 6) {
1358 /* alternate bit stream syntax */
1359 put_bits(&s->pb, 1, opt->extended_bsi_1);
1360 if (opt->extended_bsi_1) {
1361 put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
1362 put_bits(&s->pb, 3, s->ltrt_center_mix_level);
1363 put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
1364 put_bits(&s->pb, 3, s->loro_center_mix_level);
1365 put_bits(&s->pb, 3, s->loro_surround_mix_level);
1366 }
1367 put_bits(&s->pb, 1, opt->extended_bsi_2);
1368 if (opt->extended_bsi_2) {
1369 put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
1370 put_bits(&s->pb, 2, opt->dolby_headphone_mode);
1371 put_bits(&s->pb, 1, opt->ad_converter_type);
1372 put_bits(&s->pb, 9, 0); /* xbsi2 and encinfo : reserved */
1373 }
1374 } else {
1375 put_bits(&s->pb, 1, 0); /* no time code 1 */
1376 put_bits(&s->pb, 1, 0); /* no time code 2 */
1377 }
1378 put_bits(&s->pb, 1, 0); /* no additional bit stream info */
1379 }
1380
1381
1382 /*
1383 * Write one audio block to the output bitstream.
1384 */
output_audio_block(AC3EncodeContext * s,int blk)1385 static void output_audio_block(AC3EncodeContext *s, int blk)
1386 {
1387 int ch, i, baie, bnd, got_cpl, av_uninit(ch0);
1388 AC3Block *block = &s->blocks[blk];
1389
1390 /* block switching */
1391 if (!s->eac3) {
1392 for (ch = 0; ch < s->fbw_channels; ch++)
1393 put_bits(&s->pb, 1, 0);
1394 }
1395
1396 /* dither flags */
1397 if (!s->eac3) {
1398 for (ch = 0; ch < s->fbw_channels; ch++)
1399 put_bits(&s->pb, 1, 1);
1400 }
1401
1402 /* dynamic range codes */
1403 put_bits(&s->pb, 1, 0);
1404
1405 /* spectral extension */
1406 if (s->eac3)
1407 put_bits(&s->pb, 1, 0);
1408
1409 /* channel coupling */
1410 if (!s->eac3)
1411 put_bits(&s->pb, 1, block->new_cpl_strategy);
1412 if (block->new_cpl_strategy) {
1413 if (!s->eac3)
1414 put_bits(&s->pb, 1, block->cpl_in_use);
1415 if (block->cpl_in_use) {
1416 int start_sub, end_sub;
1417 if (s->eac3)
1418 put_bits(&s->pb, 1, 0); /* enhanced coupling */
1419 if (!s->eac3 || s->channel_mode != AC3_CHMODE_STEREO) {
1420 for (ch = 1; ch <= s->fbw_channels; ch++)
1421 put_bits(&s->pb, 1, block->channel_in_cpl[ch]);
1422 }
1423 if (s->channel_mode == AC3_CHMODE_STEREO)
1424 put_bits(&s->pb, 1, 0); /* phase flags in use */
1425 start_sub = (s->start_freq[CPL_CH] - 37) / 12;
1426 end_sub = (s->cpl_end_freq - 37) / 12;
1427 put_bits(&s->pb, 4, start_sub);
1428 put_bits(&s->pb, 4, end_sub - 3);
1429 /* coupling band structure */
1430 if (s->eac3) {
1431 put_bits(&s->pb, 1, 0); /* use default */
1432 } else {
1433 for (bnd = start_sub+1; bnd < end_sub; bnd++)
1434 put_bits(&s->pb, 1, ff_eac3_default_cpl_band_struct[bnd]);
1435 }
1436 }
1437 }
1438
1439 /* coupling coordinates */
1440 if (block->cpl_in_use) {
1441 for (ch = 1; ch <= s->fbw_channels; ch++) {
1442 if (block->channel_in_cpl[ch]) {
1443 if (!s->eac3 || block->new_cpl_coords[ch] != 2)
1444 put_bits(&s->pb, 1, block->new_cpl_coords[ch]);
1445 if (block->new_cpl_coords[ch]) {
1446 put_bits(&s->pb, 2, block->cpl_master_exp[ch]);
1447 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
1448 put_bits(&s->pb, 4, block->cpl_coord_exp [ch][bnd]);
1449 put_bits(&s->pb, 4, block->cpl_coord_mant[ch][bnd]);
1450 }
1451 }
1452 }
1453 }
1454 }
1455
1456 /* stereo rematrixing */
1457 if (s->channel_mode == AC3_CHMODE_STEREO) {
1458 if (!s->eac3 || blk > 0)
1459 put_bits(&s->pb, 1, block->new_rematrixing_strategy);
1460 if (block->new_rematrixing_strategy) {
1461 /* rematrixing flags */
1462 for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++)
1463 put_bits(&s->pb, 1, block->rematrixing_flags[bnd]);
1464 }
1465 }
1466
1467 /* exponent strategy */
1468 if (!s->eac3) {
1469 for (ch = !block->cpl_in_use; ch <= s->fbw_channels; ch++)
1470 put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
1471 if (s->lfe_on)
1472 put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
1473 }
1474
1475 /* bandwidth */
1476 for (ch = 1; ch <= s->fbw_channels; ch++) {
1477 if (s->exp_strategy[ch][blk] != EXP_REUSE && !block->channel_in_cpl[ch])
1478 put_bits(&s->pb, 6, s->bandwidth_code);
1479 }
1480
1481 /* exponents */
1482 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
1483 int nb_groups;
1484 int cpl = (ch == CPL_CH);
1485
1486 if (s->exp_strategy[ch][blk] == EXP_REUSE)
1487 continue;
1488
1489 /* DC exponent */
1490 put_bits(&s->pb, 4, block->grouped_exp[ch][0] >> cpl);
1491
1492 /* exponent groups */
1493 nb_groups = exponent_group_tab[cpl][s->exp_strategy[ch][blk]-1][block->end_freq[ch]-s->start_freq[ch]];
1494 for (i = 1; i <= nb_groups; i++)
1495 put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
1496
1497 /* gain range info */
1498 if (ch != s->lfe_channel && !cpl)
1499 put_bits(&s->pb, 2, 0);
1500 }
1501
1502 /* bit allocation info */
1503 if (!s->eac3) {
1504 baie = (blk == 0);
1505 put_bits(&s->pb, 1, baie);
1506 if (baie) {
1507 put_bits(&s->pb, 2, s->slow_decay_code);
1508 put_bits(&s->pb, 2, s->fast_decay_code);
1509 put_bits(&s->pb, 2, s->slow_gain_code);
1510 put_bits(&s->pb, 2, s->db_per_bit_code);
1511 put_bits(&s->pb, 3, s->floor_code);
1512 }
1513 }
1514
1515 /* snr offset */
1516 if (!s->eac3) {
1517 put_bits(&s->pb, 1, block->new_snr_offsets);
1518 if (block->new_snr_offsets) {
1519 put_bits(&s->pb, 6, s->coarse_snr_offset);
1520 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
1521 put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
1522 put_bits(&s->pb, 3, s->fast_gain_code[ch]);
1523 }
1524 }
1525 } else {
1526 put_bits(&s->pb, 1, 0); /* no converter snr offset */
1527 }
1528
1529 /* coupling leak */
1530 if (block->cpl_in_use) {
1531 if (!s->eac3 || block->new_cpl_leak != 2)
1532 put_bits(&s->pb, 1, block->new_cpl_leak);
1533 if (block->new_cpl_leak) {
1534 put_bits(&s->pb, 3, s->bit_alloc.cpl_fast_leak);
1535 put_bits(&s->pb, 3, s->bit_alloc.cpl_slow_leak);
1536 }
1537 }
1538
1539 if (!s->eac3) {
1540 put_bits(&s->pb, 1, 0); /* no delta bit allocation */
1541 put_bits(&s->pb, 1, 0); /* no data to skip */
1542 }
1543
1544 /* mantissas */
1545 got_cpl = !block->cpl_in_use;
1546 for (ch = 1; ch <= s->channels; ch++) {
1547 int b, q;
1548
1549 if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {
1550 ch0 = ch - 1;
1551 ch = CPL_CH;
1552 got_cpl = 1;
1553 }
1554 for (i = s->start_freq[ch]; i < block->end_freq[ch]; i++) {
1555 q = block->qmant[ch][i];
1556 b = s->ref_bap[ch][blk][i];
1557 switch (b) {
1558 case 0: break;
1559 case 1: if (q != 128) put_bits (&s->pb, 5, q); break;
1560 case 2: if (q != 128) put_bits (&s->pb, 7, q); break;
1561 case 3: put_sbits(&s->pb, 3, q); break;
1562 case 4: if (q != 128) put_bits (&s->pb, 7, q); break;
1563 case 14: put_sbits(&s->pb, 14, q); break;
1564 case 15: put_sbits(&s->pb, 16, q); break;
1565 default: put_sbits(&s->pb, b-1, q); break;
1566 }
1567 }
1568 if (ch == CPL_CH)
1569 ch = ch0;
1570 }
1571 }
1572
1573
1574 /** CRC-16 Polynomial */
1575 #define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
1576
1577
mul_poly(unsigned int a,unsigned int b,unsigned int poly)1578 static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
1579 {
1580 unsigned int c;
1581
1582 c = 0;
1583 while (a) {
1584 if (a & 1)
1585 c ^= b;
1586 a = a >> 1;
1587 b = b << 1;
1588 if (b & (1 << 16))
1589 b ^= poly;
1590 }
1591 return c;
1592 }
1593
1594
pow_poly(unsigned int a,unsigned int n,unsigned int poly)1595 static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
1596 {
1597 unsigned int r;
1598 r = 1;
1599 while (n) {
1600 if (n & 1)
1601 r = mul_poly(r, a, poly);
1602 a = mul_poly(a, a, poly);
1603 n >>= 1;
1604 }
1605 return r;
1606 }
1607
1608
1609 /*
1610 * Fill the end of the frame with 0's and compute the two CRCs.
1611 */
output_frame_end(AC3EncodeContext * s)1612 static void output_frame_end(AC3EncodeContext *s)
1613 {
1614 const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);
1615 int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;
1616 uint8_t *frame;
1617
1618 frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1;
1619
1620 /* pad the remainder of the frame with zeros */
1621 av_assert2(s->frame_size * 8 - put_bits_count(&s->pb) >= 18);
1622 flush_put_bits(&s->pb);
1623 frame = s->pb.buf;
1624 pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
1625 av_assert2(pad_bytes >= 0);
1626 if (pad_bytes > 0)
1627 memset(put_bits_ptr(&s->pb), 0, pad_bytes);
1628
1629 if (s->eac3) {
1630 /* compute crc2 */
1631 crc2_partial = av_crc(crc_ctx, 0, frame + 2, s->frame_size - 5);
1632 } else {
1633 /* compute crc1 */
1634 /* this is not so easy because it is at the beginning of the data... */
1635 crc1 = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4));
1636 crc_inv = s->crc_inv[s->frame_size > s->frame_size_min];
1637 crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
1638 AV_WB16(frame + 2, crc1);
1639
1640 /* compute crc2 */
1641 crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,
1642 s->frame_size - frame_size_58 - 3);
1643 }
1644 crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
1645 /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */
1646 if (crc2 == 0x770B) {
1647 frame[s->frame_size - 3] ^= 0x1;
1648 crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
1649 }
1650 crc2 = av_bswap16(crc2);
1651 AV_WB16(frame + s->frame_size - 2, crc2);
1652 }
1653
1654
1655 /**
1656 * Write the frame to the output bitstream.
1657 *
1658 * @param s AC-3 encoder private context
1659 * @param frame output data buffer
1660 */
ff_ac3_output_frame(AC3EncodeContext * s,unsigned char * frame)1661 void ff_ac3_output_frame(AC3EncodeContext *s, unsigned char *frame)
1662 {
1663 int blk;
1664
1665 init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
1666
1667 s->output_frame_header(s);
1668
1669 for (blk = 0; blk < s->num_blocks; blk++)
1670 output_audio_block(s, blk);
1671
1672 output_frame_end(s);
1673 }
1674
1675
dprint_options(AC3EncodeContext * s)1676 static void dprint_options(AC3EncodeContext *s)
1677 {
1678 #ifdef DEBUG
1679 AVCodecContext *avctx = s->avctx;
1680 AC3EncOptions *opt = &s->options;
1681 char strbuf[32];
1682
1683 switch (s->bitstream_id) {
1684 case 6: av_strlcpy(strbuf, "AC-3 (alt syntax)", 32); break;
1685 case 8: av_strlcpy(strbuf, "AC-3 (standard)", 32); break;
1686 case 9: av_strlcpy(strbuf, "AC-3 (dnet half-rate)", 32); break;
1687 case 10: av_strlcpy(strbuf, "AC-3 (dnet quater-rate)", 32); break;
1688 case 16: av_strlcpy(strbuf, "E-AC-3 (enhanced)", 32); break;
1689 default: snprintf(strbuf, 32, "ERROR");
1690 }
1691 av_dlog(avctx, "bitstream_id: %s (%d)\n", strbuf, s->bitstream_id);
1692 av_dlog(avctx, "sample_fmt: %s\n", av_get_sample_fmt_name(avctx->sample_fmt));
1693 av_get_channel_layout_string(strbuf, 32, s->channels, avctx->channel_layout);
1694 av_dlog(avctx, "channel_layout: %s\n", strbuf);
1695 av_dlog(avctx, "sample_rate: %d\n", s->sample_rate);
1696 av_dlog(avctx, "bit_rate: %d\n", s->bit_rate);
1697 av_dlog(avctx, "blocks/frame: %d (code=%d)\n", s->num_blocks, s->num_blks_code);
1698 if (s->cutoff)
1699 av_dlog(avctx, "cutoff: %d\n", s->cutoff);
1700
1701 av_dlog(avctx, "per_frame_metadata: %s\n",
1702 opt->allow_per_frame_metadata?"on":"off");
1703 if (s->has_center)
1704 av_dlog(avctx, "center_mixlev: %0.3f (%d)\n", opt->center_mix_level,
1705 s->center_mix_level);
1706 else
1707 av_dlog(avctx, "center_mixlev: {not written}\n");
1708 if (s->has_surround)
1709 av_dlog(avctx, "surround_mixlev: %0.3f (%d)\n", opt->surround_mix_level,
1710 s->surround_mix_level);
1711 else
1712 av_dlog(avctx, "surround_mixlev: {not written}\n");
1713 if (opt->audio_production_info) {
1714 av_dlog(avctx, "mixing_level: %ddB\n", opt->mixing_level);
1715 switch (opt->room_type) {
1716 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1717 case AC3ENC_OPT_LARGE_ROOM: av_strlcpy(strbuf, "large", 32); break;
1718 case AC3ENC_OPT_SMALL_ROOM: av_strlcpy(strbuf, "small", 32); break;
1719 default: snprintf(strbuf, 32, "ERROR (%d)", opt->room_type);
1720 }
1721 av_dlog(avctx, "room_type: %s\n", strbuf);
1722 } else {
1723 av_dlog(avctx, "mixing_level: {not written}\n");
1724 av_dlog(avctx, "room_type: {not written}\n");
1725 }
1726 av_dlog(avctx, "copyright: %s\n", opt->copyright?"on":"off");
1727 av_dlog(avctx, "dialnorm: %ddB\n", opt->dialogue_level);
1728 if (s->channel_mode == AC3_CHMODE_STEREO) {
1729 switch (opt->dolby_surround_mode) {
1730 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1731 case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break;
1732 case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break;
1733 default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_surround_mode);
1734 }
1735 av_dlog(avctx, "dsur_mode: %s\n", strbuf);
1736 } else {
1737 av_dlog(avctx, "dsur_mode: {not written}\n");
1738 }
1739 av_dlog(avctx, "original: %s\n", opt->original?"on":"off");
1740
1741 if (s->bitstream_id == 6) {
1742 if (opt->extended_bsi_1) {
1743 switch (opt->preferred_stereo_downmix) {
1744 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1745 case AC3ENC_OPT_DOWNMIX_LTRT: av_strlcpy(strbuf, "ltrt", 32); break;
1746 case AC3ENC_OPT_DOWNMIX_LORO: av_strlcpy(strbuf, "loro", 32); break;
1747 default: snprintf(strbuf, 32, "ERROR (%d)", opt->preferred_stereo_downmix);
1748 }
1749 av_dlog(avctx, "dmix_mode: %s\n", strbuf);
1750 av_dlog(avctx, "ltrt_cmixlev: %0.3f (%d)\n",
1751 opt->ltrt_center_mix_level, s->ltrt_center_mix_level);
1752 av_dlog(avctx, "ltrt_surmixlev: %0.3f (%d)\n",
1753 opt->ltrt_surround_mix_level, s->ltrt_surround_mix_level);
1754 av_dlog(avctx, "loro_cmixlev: %0.3f (%d)\n",
1755 opt->loro_center_mix_level, s->loro_center_mix_level);
1756 av_dlog(avctx, "loro_surmixlev: %0.3f (%d)\n",
1757 opt->loro_surround_mix_level, s->loro_surround_mix_level);
1758 } else {
1759 av_dlog(avctx, "extended bitstream info 1: {not written}\n");
1760 }
1761 if (opt->extended_bsi_2) {
1762 switch (opt->dolby_surround_ex_mode) {
1763 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1764 case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break;
1765 case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break;
1766 default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_surround_ex_mode);
1767 }
1768 av_dlog(avctx, "dsurex_mode: %s\n", strbuf);
1769 switch (opt->dolby_headphone_mode) {
1770 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1771 case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break;
1772 case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break;
1773 default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_headphone_mode);
1774 }
1775 av_dlog(avctx, "dheadphone_mode: %s\n", strbuf);
1776
1777 switch (opt->ad_converter_type) {
1778 case AC3ENC_OPT_ADCONV_STANDARD: av_strlcpy(strbuf, "standard", 32); break;
1779 case AC3ENC_OPT_ADCONV_HDCD: av_strlcpy(strbuf, "hdcd", 32); break;
1780 default: snprintf(strbuf, 32, "ERROR (%d)", opt->ad_converter_type);
1781 }
1782 av_dlog(avctx, "ad_conv_type: %s\n", strbuf);
1783 } else {
1784 av_dlog(avctx, "extended bitstream info 2: {not written}\n");
1785 }
1786 }
1787 #endif
1788 }
1789
1790
1791 #define FLT_OPTION_THRESHOLD 0.01
1792
validate_float_option(float v,const float * v_list,int v_list_size)1793 static int validate_float_option(float v, const float *v_list, int v_list_size)
1794 {
1795 int i;
1796
1797 for (i = 0; i < v_list_size; i++) {
1798 if (v < (v_list[i] + FLT_OPTION_THRESHOLD) &&
1799 v > (v_list[i] - FLT_OPTION_THRESHOLD))
1800 break;
1801 }
1802 if (i == v_list_size)
1803 return -1;
1804
1805 return i;
1806 }
1807
1808
validate_mix_level(void * log_ctx,const char * opt_name,float * opt_param,const float * list,int list_size,int default_value,int min_value,int * ctx_param)1809 static void validate_mix_level(void *log_ctx, const char *opt_name,
1810 float *opt_param, const float *list,
1811 int list_size, int default_value, int min_value,
1812 int *ctx_param)
1813 {
1814 int mixlev = validate_float_option(*opt_param, list, list_size);
1815 if (mixlev < min_value) {
1816 mixlev = default_value;
1817 if (*opt_param >= 0.0) {
1818 av_log(log_ctx, AV_LOG_WARNING, "requested %s is not valid. using "
1819 "default value: %0.3f\n", opt_name, list[mixlev]);
1820 }
1821 }
1822 *opt_param = list[mixlev];
1823 *ctx_param = mixlev;
1824 }
1825
1826
1827 /**
1828 * Validate metadata options as set by AVOption system.
1829 * These values can optionally be changed per-frame.
1830 *
1831 * @param s AC-3 encoder private context
1832 */
ff_ac3_validate_metadata(AC3EncodeContext * s)1833 int ff_ac3_validate_metadata(AC3EncodeContext *s)
1834 {
1835 AVCodecContext *avctx = s->avctx;
1836 AC3EncOptions *opt = &s->options;
1837
1838 opt->audio_production_info = 0;
1839 opt->extended_bsi_1 = 0;
1840 opt->extended_bsi_2 = 0;
1841 opt->eac3_mixing_metadata = 0;
1842 opt->eac3_info_metadata = 0;
1843
1844 /* determine mixing metadata / xbsi1 use */
1845 if (s->channel_mode > AC3_CHMODE_STEREO && opt->preferred_stereo_downmix != AC3ENC_OPT_NONE) {
1846 opt->extended_bsi_1 = 1;
1847 opt->eac3_mixing_metadata = 1;
1848 }
1849 if (s->has_center &&
1850 (opt->ltrt_center_mix_level >= 0 || opt->loro_center_mix_level >= 0)) {
1851 opt->extended_bsi_1 = 1;
1852 opt->eac3_mixing_metadata = 1;
1853 }
1854 if (s->has_surround &&
1855 (opt->ltrt_surround_mix_level >= 0 || opt->loro_surround_mix_level >= 0)) {
1856 opt->extended_bsi_1 = 1;
1857 opt->eac3_mixing_metadata = 1;
1858 }
1859
1860 if (s->eac3) {
1861 /* determine info metadata use */
1862 if (avctx->audio_service_type != AV_AUDIO_SERVICE_TYPE_MAIN)
1863 opt->eac3_info_metadata = 1;
1864 if (opt->copyright != AC3ENC_OPT_NONE || opt->original != AC3ENC_OPT_NONE)
1865 opt->eac3_info_metadata = 1;
1866 if (s->channel_mode == AC3_CHMODE_STEREO &&
1867 (opt->dolby_headphone_mode != AC3ENC_OPT_NONE || opt->dolby_surround_mode != AC3ENC_OPT_NONE))
1868 opt->eac3_info_metadata = 1;
1869 if (s->channel_mode >= AC3_CHMODE_2F2R && opt->dolby_surround_ex_mode != AC3ENC_OPT_NONE)
1870 opt->eac3_info_metadata = 1;
1871 if (opt->mixing_level != AC3ENC_OPT_NONE || opt->room_type != AC3ENC_OPT_NONE ||
1872 opt->ad_converter_type != AC3ENC_OPT_NONE) {
1873 opt->audio_production_info = 1;
1874 opt->eac3_info_metadata = 1;
1875 }
1876 } else {
1877 /* determine audio production info use */
1878 if (opt->mixing_level != AC3ENC_OPT_NONE || opt->room_type != AC3ENC_OPT_NONE)
1879 opt->audio_production_info = 1;
1880
1881 /* determine xbsi2 use */
1882 if (s->channel_mode >= AC3_CHMODE_2F2R && opt->dolby_surround_ex_mode != AC3ENC_OPT_NONE)
1883 opt->extended_bsi_2 = 1;
1884 if (s->channel_mode == AC3_CHMODE_STEREO && opt->dolby_headphone_mode != AC3ENC_OPT_NONE)
1885 opt->extended_bsi_2 = 1;
1886 if (opt->ad_converter_type != AC3ENC_OPT_NONE)
1887 opt->extended_bsi_2 = 1;
1888 }
1889
1890 /* validate AC-3 mixing levels */
1891 if (!s->eac3) {
1892 if (s->has_center) {
1893 validate_mix_level(avctx, "center_mix_level", &opt->center_mix_level,
1894 cmixlev_options, CMIXLEV_NUM_OPTIONS, 1, 0,
1895 &s->center_mix_level);
1896 }
1897 if (s->has_surround) {
1898 validate_mix_level(avctx, "surround_mix_level", &opt->surround_mix_level,
1899 surmixlev_options, SURMIXLEV_NUM_OPTIONS, 1, 0,
1900 &s->surround_mix_level);
1901 }
1902 }
1903
1904 /* validate extended bsi 1 / mixing metadata */
1905 if (opt->extended_bsi_1 || opt->eac3_mixing_metadata) {
1906 /* default preferred stereo downmix */
1907 if (opt->preferred_stereo_downmix == AC3ENC_OPT_NONE)
1908 opt->preferred_stereo_downmix = AC3ENC_OPT_NOT_INDICATED;
1909 if (!s->eac3 || s->has_center) {
1910 /* validate Lt/Rt center mix level */
1911 validate_mix_level(avctx, "ltrt_center_mix_level",
1912 &opt->ltrt_center_mix_level, extmixlev_options,
1913 EXTMIXLEV_NUM_OPTIONS, 5, 0,
1914 &s->ltrt_center_mix_level);
1915 /* validate Lo/Ro center mix level */
1916 validate_mix_level(avctx, "loro_center_mix_level",
1917 &opt->loro_center_mix_level, extmixlev_options,
1918 EXTMIXLEV_NUM_OPTIONS, 5, 0,
1919 &s->loro_center_mix_level);
1920 }
1921 if (!s->eac3 || s->has_surround) {
1922 /* validate Lt/Rt surround mix level */
1923 validate_mix_level(avctx, "ltrt_surround_mix_level",
1924 &opt->ltrt_surround_mix_level, extmixlev_options,
1925 EXTMIXLEV_NUM_OPTIONS, 6, 3,
1926 &s->ltrt_surround_mix_level);
1927 /* validate Lo/Ro surround mix level */
1928 validate_mix_level(avctx, "loro_surround_mix_level",
1929 &opt->loro_surround_mix_level, extmixlev_options,
1930 EXTMIXLEV_NUM_OPTIONS, 6, 3,
1931 &s->loro_surround_mix_level);
1932 }
1933 }
1934
1935 /* validate audio service type / channels combination */
1936 if ((avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_KARAOKE &&
1937 avctx->channels == 1) ||
1938 ((avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_COMMENTARY ||
1939 avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_EMERGENCY ||
1940 avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_VOICE_OVER)
1941 && avctx->channels > 1)) {
1942 av_log(avctx, AV_LOG_ERROR, "invalid audio service type for the "
1943 "specified number of channels\n");
1944 return AVERROR(EINVAL);
1945 }
1946
1947 /* validate extended bsi 2 / info metadata */
1948 if (opt->extended_bsi_2 || opt->eac3_info_metadata) {
1949 /* default dolby headphone mode */
1950 if (opt->dolby_headphone_mode == AC3ENC_OPT_NONE)
1951 opt->dolby_headphone_mode = AC3ENC_OPT_NOT_INDICATED;
1952 /* default dolby surround ex mode */
1953 if (opt->dolby_surround_ex_mode == AC3ENC_OPT_NONE)
1954 opt->dolby_surround_ex_mode = AC3ENC_OPT_NOT_INDICATED;
1955 /* default A/D converter type */
1956 if (opt->ad_converter_type == AC3ENC_OPT_NONE)
1957 opt->ad_converter_type = AC3ENC_OPT_ADCONV_STANDARD;
1958 }
1959
1960 /* copyright & original defaults */
1961 if (!s->eac3 || opt->eac3_info_metadata) {
1962 /* default copyright */
1963 if (opt->copyright == AC3ENC_OPT_NONE)
1964 opt->copyright = AC3ENC_OPT_OFF;
1965 /* default original */
1966 if (opt->original == AC3ENC_OPT_NONE)
1967 opt->original = AC3ENC_OPT_ON;
1968 }
1969
1970 /* dolby surround mode default */
1971 if (!s->eac3 || opt->eac3_info_metadata) {
1972 if (opt->dolby_surround_mode == AC3ENC_OPT_NONE)
1973 opt->dolby_surround_mode = AC3ENC_OPT_NOT_INDICATED;
1974 }
1975
1976 /* validate audio production info */
1977 if (opt->audio_production_info) {
1978 if (opt->mixing_level == AC3ENC_OPT_NONE) {
1979 av_log(avctx, AV_LOG_ERROR, "mixing_level must be set if "
1980 "room_type is set\n");
1981 return AVERROR(EINVAL);
1982 }
1983 if (opt->mixing_level < 80) {
1984 av_log(avctx, AV_LOG_ERROR, "invalid mixing level. must be between "
1985 "80dB and 111dB\n");
1986 return AVERROR(EINVAL);
1987 }
1988 /* default room type */
1989 if (opt->room_type == AC3ENC_OPT_NONE)
1990 opt->room_type = AC3ENC_OPT_NOT_INDICATED;
1991 }
1992
1993 /* set bitstream id for alternate bitstream syntax */
1994 if (!s->eac3 && (opt->extended_bsi_1 || opt->extended_bsi_2)) {
1995 if (s->bitstream_id > 8 && s->bitstream_id < 11) {
1996 static int warn_once = 1;
1997 if (warn_once) {
1998 av_log(avctx, AV_LOG_WARNING, "alternate bitstream syntax is "
1999 "not compatible with reduced samplerates. writing of "
2000 "extended bitstream information will be disabled.\n");
2001 warn_once = 0;
2002 }
2003 } else {
2004 s->bitstream_id = 6;
2005 }
2006 }
2007
2008 return 0;
2009 }
2010
2011
2012 /**
2013 * Finalize encoding and free any memory allocated by the encoder.
2014 *
2015 * @param avctx Codec context
2016 */
ff_ac3_encode_close(AVCodecContext * avctx)2017 av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
2018 {
2019 int blk, ch;
2020 AC3EncodeContext *s = avctx->priv_data;
2021
2022 av_freep(&s->windowed_samples);
2023 if (s->planar_samples)
2024 for (ch = 0; ch < s->channels; ch++)
2025 av_freep(&s->planar_samples[ch]);
2026 av_freep(&s->planar_samples);
2027 av_freep(&s->bap_buffer);
2028 av_freep(&s->bap1_buffer);
2029 av_freep(&s->mdct_coef_buffer);
2030 av_freep(&s->fixed_coef_buffer);
2031 av_freep(&s->exp_buffer);
2032 av_freep(&s->grouped_exp_buffer);
2033 av_freep(&s->psd_buffer);
2034 av_freep(&s->band_psd_buffer);
2035 av_freep(&s->mask_buffer);
2036 av_freep(&s->qmant_buffer);
2037 av_freep(&s->cpl_coord_exp_buffer);
2038 av_freep(&s->cpl_coord_mant_buffer);
2039 for (blk = 0; blk < s->num_blocks; blk++) {
2040 AC3Block *block = &s->blocks[blk];
2041 av_freep(&block->mdct_coef);
2042 av_freep(&block->fixed_coef);
2043 av_freep(&block->exp);
2044 av_freep(&block->grouped_exp);
2045 av_freep(&block->psd);
2046 av_freep(&block->band_psd);
2047 av_freep(&block->mask);
2048 av_freep(&block->qmant);
2049 av_freep(&block->cpl_coord_exp);
2050 av_freep(&block->cpl_coord_mant);
2051 }
2052
2053 s->mdct_end(s);
2054
2055 return 0;
2056 }
2057
2058
2059 /*
2060 * Set channel information during initialization.
2061 */
set_channel_info(AC3EncodeContext * s,int channels,uint64_t * channel_layout)2062 static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
2063 uint64_t *channel_layout)
2064 {
2065 int ch_layout;
2066
2067 if (channels < 1 || channels > AC3_MAX_CHANNELS)
2068 return AVERROR(EINVAL);
2069 if (*channel_layout > 0x7FF)
2070 return AVERROR(EINVAL);
2071 ch_layout = *channel_layout;
2072 if (!ch_layout)
2073 ch_layout = av_get_default_channel_layout(channels);
2074
2075 s->lfe_on = !!(ch_layout & AV_CH_LOW_FREQUENCY);
2076 s->channels = channels;
2077 s->fbw_channels = channels - s->lfe_on;
2078 s->lfe_channel = s->lfe_on ? s->fbw_channels + 1 : -1;
2079 if (s->lfe_on)
2080 ch_layout -= AV_CH_LOW_FREQUENCY;
2081
2082 switch (ch_layout) {
2083 case AV_CH_LAYOUT_MONO: s->channel_mode = AC3_CHMODE_MONO; break;
2084 case AV_CH_LAYOUT_STEREO: s->channel_mode = AC3_CHMODE_STEREO; break;
2085 case AV_CH_LAYOUT_SURROUND: s->channel_mode = AC3_CHMODE_3F; break;
2086 case AV_CH_LAYOUT_2_1: s->channel_mode = AC3_CHMODE_2F1R; break;
2087 case AV_CH_LAYOUT_4POINT0: s->channel_mode = AC3_CHMODE_3F1R; break;
2088 case AV_CH_LAYOUT_QUAD:
2089 case AV_CH_LAYOUT_2_2: s->channel_mode = AC3_CHMODE_2F2R; break;
2090 case AV_CH_LAYOUT_5POINT0:
2091 case AV_CH_LAYOUT_5POINT0_BACK: s->channel_mode = AC3_CHMODE_3F2R; break;
2092 default:
2093 return AVERROR(EINVAL);
2094 }
2095 s->has_center = (s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO;
2096 s->has_surround = s->channel_mode & 0x04;
2097
2098 s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe_on];
2099 *channel_layout = ch_layout;
2100 if (s->lfe_on)
2101 *channel_layout |= AV_CH_LOW_FREQUENCY;
2102
2103 return 0;
2104 }
2105
2106
validate_options(AC3EncodeContext * s)2107 static av_cold int validate_options(AC3EncodeContext *s)
2108 {
2109 AVCodecContext *avctx = s->avctx;
2110 int i, ret, max_sr;
2111
2112 /* validate channel layout */
2113 if (!avctx->channel_layout) {
2114 av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "
2115 "encoder will guess the layout, but it "
2116 "might be incorrect.\n");
2117 }
2118 ret = set_channel_info(s, avctx->channels, &avctx->channel_layout);
2119 if (ret) {
2120 av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
2121 return ret;
2122 }
2123
2124 /* validate sample rate */
2125 /* note: max_sr could be changed from 2 to 5 for E-AC-3 once we find a
2126 decoder that supports half sample rate so we can validate that
2127 the generated files are correct. */
2128 max_sr = s->eac3 ? 2 : 8;
2129 for (i = 0; i <= max_sr; i++) {
2130 if ((ff_ac3_sample_rate_tab[i % 3] >> (i / 3)) == avctx->sample_rate)
2131 break;
2132 }
2133 if (i > max_sr) {
2134 av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
2135 return AVERROR(EINVAL);
2136 }
2137 s->sample_rate = avctx->sample_rate;
2138 s->bit_alloc.sr_shift = i / 3;
2139 s->bit_alloc.sr_code = i % 3;
2140 s->bitstream_id = s->eac3 ? 16 : 8 + s->bit_alloc.sr_shift;
2141
2142 /* select a default bit rate if not set by the user */
2143 if (!avctx->bit_rate) {
2144 switch (s->fbw_channels) {
2145 case 1: avctx->bit_rate = 96000; break;
2146 case 2: avctx->bit_rate = 192000; break;
2147 case 3: avctx->bit_rate = 320000; break;
2148 case 4: avctx->bit_rate = 384000; break;
2149 case 5: avctx->bit_rate = 448000; break;
2150 }
2151 }
2152
2153 /* validate bit rate */
2154 if (s->eac3) {
2155 int max_br, min_br, wpf, min_br_dist, min_br_code;
2156 int num_blks_code, num_blocks, frame_samples;
2157
2158 /* calculate min/max bitrate */
2159 /* TODO: More testing with 3 and 2 blocks. All E-AC-3 samples I've
2160 found use either 6 blocks or 1 block, even though 2 or 3 blocks
2161 would work as far as the bit rate is concerned. */
2162 for (num_blks_code = 3; num_blks_code >= 0; num_blks_code--) {
2163 num_blocks = ((int[]){ 1, 2, 3, 6 })[num_blks_code];
2164 frame_samples = AC3_BLOCK_SIZE * num_blocks;
2165 max_br = 2048 * s->sample_rate / frame_samples * 16;
2166 min_br = ((s->sample_rate + (frame_samples-1)) / frame_samples) * 16;
2167 if (avctx->bit_rate <= max_br)
2168 break;
2169 }
2170 if (avctx->bit_rate < min_br || avctx->bit_rate > max_br) {
2171 av_log(avctx, AV_LOG_ERROR, "invalid bit rate. must be %d to %d "
2172 "for this sample rate\n", min_br, max_br);
2173 return AVERROR(EINVAL);
2174 }
2175 s->num_blks_code = num_blks_code;
2176 s->num_blocks = num_blocks;
2177
2178 /* calculate words-per-frame for the selected bitrate */
2179 wpf = (avctx->bit_rate / 16) * frame_samples / s->sample_rate;
2180 av_assert1(wpf > 0 && wpf <= 2048);
2181
2182 /* find the closest AC-3 bitrate code to the selected bitrate.
2183 this is needed for lookup tables for bandwidth and coupling
2184 parameter selection */
2185 min_br_code = -1;
2186 min_br_dist = INT_MAX;
2187 for (i = 0; i < 19; i++) {
2188 int br_dist = abs(ff_ac3_bitrate_tab[i] * 1000 - avctx->bit_rate);
2189 if (br_dist < min_br_dist) {
2190 min_br_dist = br_dist;
2191 min_br_code = i;
2192 }
2193 }
2194
2195 /* make sure the minimum frame size is below the average frame size */
2196 s->frame_size_code = min_br_code << 1;
2197 while (wpf > 1 && wpf * s->sample_rate / AC3_FRAME_SIZE * 16 > avctx->bit_rate)
2198 wpf--;
2199 s->frame_size_min = 2 * wpf;
2200 } else {
2201 int best_br = 0, best_code = 0, best_diff = INT_MAX;
2202 for (i = 0; i < 19; i++) {
2203 int br = (ff_ac3_bitrate_tab[i] >> s->bit_alloc.sr_shift) * 1000;
2204 int diff = abs(br - avctx->bit_rate);
2205 if (diff < best_diff) {
2206 best_br = br;
2207 best_code = i;
2208 best_diff = diff;
2209 }
2210 if (!best_diff)
2211 break;
2212 }
2213 avctx->bit_rate = best_br;
2214 s->frame_size_code = best_code << 1;
2215 s->frame_size_min = 2 * ff_ac3_frame_size_tab[s->frame_size_code][s->bit_alloc.sr_code];
2216 s->num_blks_code = 0x3;
2217 s->num_blocks = 6;
2218 }
2219 s->bit_rate = avctx->bit_rate;
2220 s->frame_size = s->frame_size_min;
2221
2222 /* validate cutoff */
2223 if (avctx->cutoff < 0) {
2224 av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");
2225 return AVERROR(EINVAL);
2226 }
2227 s->cutoff = avctx->cutoff;
2228 if (s->cutoff > (s->sample_rate >> 1))
2229 s->cutoff = s->sample_rate >> 1;
2230
2231 ret = ff_ac3_validate_metadata(s);
2232 if (ret)
2233 return ret;
2234
2235 s->rematrixing_enabled = s->options.stereo_rematrixing &&
2236 (s->channel_mode == AC3_CHMODE_STEREO);
2237
2238 s->cpl_enabled = s->options.channel_coupling &&
2239 s->channel_mode >= AC3_CHMODE_STEREO;
2240
2241 return 0;
2242 }
2243
2244
2245 /*
2246 * Set bandwidth for all channels.
2247 * The user can optionally supply a cutoff frequency. Otherwise an appropriate
2248 * default value will be used.
2249 */
set_bandwidth(AC3EncodeContext * s)2250 static av_cold void set_bandwidth(AC3EncodeContext *s)
2251 {
2252 int blk, ch, av_uninit(cpl_start);
2253
2254 if (s->cutoff) {
2255 /* calculate bandwidth based on user-specified cutoff frequency */
2256 int fbw_coeffs;
2257 fbw_coeffs = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
2258 s->bandwidth_code = av_clip((fbw_coeffs - 73) / 3, 0, 60);
2259 } else {
2260 /* use default bandwidth setting */
2261 s->bandwidth_code = ac3_bandwidth_tab[s->fbw_channels-1][s->bit_alloc.sr_code][s->frame_size_code/2];
2262 }
2263
2264 /* set number of coefficients for each channel */
2265 for (ch = 1; ch <= s->fbw_channels; ch++) {
2266 s->start_freq[ch] = 0;
2267 for (blk = 0; blk < s->num_blocks; blk++)
2268 s->blocks[blk].end_freq[ch] = s->bandwidth_code * 3 + 73;
2269 }
2270 /* LFE channel always has 7 coefs */
2271 if (s->lfe_on) {
2272 s->start_freq[s->lfe_channel] = 0;
2273 for (blk = 0; blk < s->num_blocks; blk++)
2274 s->blocks[blk].end_freq[ch] = 7;
2275 }
2276
2277 /* initialize coupling strategy */
2278 if (s->cpl_enabled) {
2279 if (s->options.cpl_start != AC3ENC_OPT_AUTO) {
2280 cpl_start = s->options.cpl_start;
2281 } else {
2282 cpl_start = ac3_coupling_start_tab[s->channel_mode-2][s->bit_alloc.sr_code][s->frame_size_code/2];
2283 if (cpl_start < 0) {
2284 if (s->options.channel_coupling == AC3ENC_OPT_AUTO)
2285 s->cpl_enabled = 0;
2286 else
2287 cpl_start = 15;
2288 }
2289 }
2290 }
2291 if (s->cpl_enabled) {
2292 int i, cpl_start_band, cpl_end_band;
2293 uint8_t *cpl_band_sizes = s->cpl_band_sizes;
2294
2295 cpl_end_band = s->bandwidth_code / 4 + 3;
2296 cpl_start_band = av_clip(cpl_start, 0, FFMIN(cpl_end_band-1, 15));
2297
2298 s->num_cpl_subbands = cpl_end_band - cpl_start_band;
2299
2300 s->num_cpl_bands = 1;
2301 *cpl_band_sizes = 12;
2302 for (i = cpl_start_band + 1; i < cpl_end_band; i++) {
2303 if (ff_eac3_default_cpl_band_struct[i]) {
2304 *cpl_band_sizes += 12;
2305 } else {
2306 s->num_cpl_bands++;
2307 cpl_band_sizes++;
2308 *cpl_band_sizes = 12;
2309 }
2310 }
2311
2312 s->start_freq[CPL_CH] = cpl_start_band * 12 + 37;
2313 s->cpl_end_freq = cpl_end_band * 12 + 37;
2314 for (blk = 0; blk < s->num_blocks; blk++)
2315 s->blocks[blk].end_freq[CPL_CH] = s->cpl_end_freq;
2316 }
2317 }
2318
2319
allocate_buffers(AC3EncodeContext * s)2320 static av_cold int allocate_buffers(AC3EncodeContext *s)
2321 {
2322 AVCodecContext *avctx = s->avctx;
2323 int blk, ch;
2324 int channels = s->channels + 1; /* includes coupling channel */
2325 int channel_blocks = channels * s->num_blocks;
2326 int total_coefs = AC3_MAX_COEFS * channel_blocks;
2327
2328 if (s->allocate_sample_buffers(s))
2329 goto alloc_fail;
2330
2331 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->bap_buffer, total_coefs,
2332 sizeof(*s->bap_buffer), alloc_fail);
2333 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->bap1_buffer, total_coefs,
2334 sizeof(*s->bap1_buffer), alloc_fail);
2335 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, s->mdct_coef_buffer, total_coefs,
2336 sizeof(*s->mdct_coef_buffer), alloc_fail);
2337 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->exp_buffer, total_coefs,
2338 sizeof(*s->exp_buffer), alloc_fail);
2339 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->grouped_exp_buffer, channel_blocks, 128 *
2340 sizeof(*s->grouped_exp_buffer), alloc_fail);
2341 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->psd_buffer, total_coefs,
2342 sizeof(*s->psd_buffer), alloc_fail);
2343 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->band_psd_buffer, channel_blocks, 64 *
2344 sizeof(*s->band_psd_buffer), alloc_fail);
2345 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->mask_buffer, channel_blocks, 64 *
2346 sizeof(*s->mask_buffer), alloc_fail);
2347 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->qmant_buffer, total_coefs,
2348 sizeof(*s->qmant_buffer), alloc_fail);
2349 if (s->cpl_enabled) {
2350 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->cpl_coord_exp_buffer, channel_blocks, 16 *
2351 sizeof(*s->cpl_coord_exp_buffer), alloc_fail);
2352 FF_ALLOC_ARRAY_OR_GOTO(avctx, s->cpl_coord_mant_buffer, channel_blocks, 16 *
2353 sizeof(*s->cpl_coord_mant_buffer), alloc_fail);
2354 }
2355 for (blk = 0; blk < s->num_blocks; blk++) {
2356 AC3Block *block = &s->blocks[blk];
2357 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->mdct_coef, channels, sizeof(*block->mdct_coef),
2358 alloc_fail);
2359 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->exp, channels, sizeof(*block->exp),
2360 alloc_fail);
2361 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->grouped_exp, channels, sizeof(*block->grouped_exp),
2362 alloc_fail);
2363 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->psd, channels, sizeof(*block->psd),
2364 alloc_fail);
2365 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->band_psd, channels, sizeof(*block->band_psd),
2366 alloc_fail);
2367 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->mask, channels, sizeof(*block->mask),
2368 alloc_fail);
2369 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->qmant, channels, sizeof(*block->qmant),
2370 alloc_fail);
2371 if (s->cpl_enabled) {
2372 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->cpl_coord_exp, channels, sizeof(*block->cpl_coord_exp),
2373 alloc_fail);
2374 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->cpl_coord_mant, channels, sizeof(*block->cpl_coord_mant),
2375 alloc_fail);
2376 }
2377
2378 for (ch = 0; ch < channels; ch++) {
2379 /* arrangement: block, channel, coeff */
2380 block->grouped_exp[ch] = &s->grouped_exp_buffer[128 * (blk * channels + ch)];
2381 block->psd[ch] = &s->psd_buffer [AC3_MAX_COEFS * (blk * channels + ch)];
2382 block->band_psd[ch] = &s->band_psd_buffer [64 * (blk * channels + ch)];
2383 block->mask[ch] = &s->mask_buffer [64 * (blk * channels + ch)];
2384 block->qmant[ch] = &s->qmant_buffer [AC3_MAX_COEFS * (blk * channels + ch)];
2385 if (s->cpl_enabled) {
2386 block->cpl_coord_exp[ch] = &s->cpl_coord_exp_buffer [16 * (blk * channels + ch)];
2387 block->cpl_coord_mant[ch] = &s->cpl_coord_mant_buffer[16 * (blk * channels + ch)];
2388 }
2389
2390 /* arrangement: channel, block, coeff */
2391 block->exp[ch] = &s->exp_buffer [AC3_MAX_COEFS * (s->num_blocks * ch + blk)];
2392 block->mdct_coef[ch] = &s->mdct_coef_buffer [AC3_MAX_COEFS * (s->num_blocks * ch + blk)];
2393 }
2394 }
2395
2396 if (!s->fixed_point) {
2397 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, s->fixed_coef_buffer, total_coefs,
2398 sizeof(*s->fixed_coef_buffer), alloc_fail);
2399 for (blk = 0; blk < s->num_blocks; blk++) {
2400 AC3Block *block = &s->blocks[blk];
2401 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->fixed_coef, channels,
2402 sizeof(*block->fixed_coef), alloc_fail);
2403 for (ch = 0; ch < channels; ch++)
2404 block->fixed_coef[ch] = &s->fixed_coef_buffer[AC3_MAX_COEFS * (s->num_blocks * ch + blk)];
2405 }
2406 } else {
2407 for (blk = 0; blk < s->num_blocks; blk++) {
2408 AC3Block *block = &s->blocks[blk];
2409 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->fixed_coef, channels,
2410 sizeof(*block->fixed_coef), alloc_fail);
2411 for (ch = 0; ch < channels; ch++)
2412 block->fixed_coef[ch] = (int32_t *)block->mdct_coef[ch];
2413 }
2414 }
2415
2416 return 0;
2417 alloc_fail:
2418 return AVERROR(ENOMEM);
2419 }
2420
2421
ff_ac3_encode_init(AVCodecContext * avctx)2422 av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
2423 {
2424 AC3EncodeContext *s = avctx->priv_data;
2425 int ret, frame_size_58;
2426
2427 s->avctx = avctx;
2428
2429 s->eac3 = avctx->codec_id == AV_CODEC_ID_EAC3;
2430
2431 ff_ac3_common_init();
2432
2433 ret = validate_options(s);
2434 if (ret)
2435 return ret;
2436
2437 avctx->frame_size = AC3_BLOCK_SIZE * s->num_blocks;
2438 avctx->delay = AC3_BLOCK_SIZE;
2439
2440 s->bitstream_mode = avctx->audio_service_type;
2441 if (s->bitstream_mode == AV_AUDIO_SERVICE_TYPE_KARAOKE)
2442 s->bitstream_mode = 0x7;
2443
2444 s->bits_written = 0;
2445 s->samples_written = 0;
2446
2447 /* calculate crc_inv for both possible frame sizes */
2448 frame_size_58 = (( s->frame_size >> 2) + ( s->frame_size >> 4)) << 1;
2449 s->crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
2450 if (s->bit_alloc.sr_code == 1) {
2451 frame_size_58 = (((s->frame_size+2) >> 2) + ((s->frame_size+2) >> 4)) << 1;
2452 s->crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
2453 }
2454
2455 /* set function pointers */
2456 if (CONFIG_AC3_FIXED_ENCODER && s->fixed_point) {
2457 s->mdct_end = ff_ac3_fixed_mdct_end;
2458 s->mdct_init = ff_ac3_fixed_mdct_init;
2459 s->allocate_sample_buffers = ff_ac3_fixed_allocate_sample_buffers;
2460 } else if (CONFIG_AC3_ENCODER || CONFIG_EAC3_ENCODER) {
2461 s->mdct_end = ff_ac3_float_mdct_end;
2462 s->mdct_init = ff_ac3_float_mdct_init;
2463 s->allocate_sample_buffers = ff_ac3_float_allocate_sample_buffers;
2464 }
2465 if (CONFIG_EAC3_ENCODER && s->eac3)
2466 s->output_frame_header = ff_eac3_output_frame_header;
2467 else
2468 s->output_frame_header = ac3_output_frame_header;
2469
2470 set_bandwidth(s);
2471
2472 exponent_init(s);
2473
2474 bit_alloc_init(s);
2475
2476 ret = s->mdct_init(s);
2477 if (ret)
2478 goto init_fail;
2479
2480 ret = allocate_buffers(s);
2481 if (ret)
2482 goto init_fail;
2483
2484 ff_audiodsp_init(&s->adsp);
2485 ff_me_cmp_init(&s->mecc, avctx);
2486 ff_ac3dsp_init(&s->ac3dsp, avctx->flags & CODEC_FLAG_BITEXACT);
2487
2488 dprint_options(s);
2489
2490 return 0;
2491 init_fail:
2492 ff_ac3_encode_close(avctx);
2493 return ret;
2494 }
2495