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>
7 * This file is part of FFmpeg.
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.
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.
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
26 * The simplest AC-3 encoder.
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"
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
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
58 #define SURMIXLEV_NUM_OPTIONS 3
59 static const float surmixlev_options[SURMIXLEV_NUM_OPTIONS] = {
60 LEVEL_MINUS_3DB, LEVEL_MINUS_6DB, LEVEL_ZERO
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
71 * LUT for number of exponent groups.
72 * exponent_group_tab[coupling][exponent strategy-1][number of coefficients]
74 static uint8_t exponent_group_tab[2][3][256];
78 * List of supported channel layouts.
80 const uint64_t ff_ac3_channel_layouts[19] = {
84 AV_CH_LAYOUT_SURROUND,
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),
98 AV_CH_LAYOUT_5POINT1_BACK,
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]
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
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 } },
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 } },
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 } },
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 } },
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 } }
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]
138 * TODO: more testing for optimal parameters.
139 * multi-channel tests at 44.1kHz and 32kHz.
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
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 } },
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 } },
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 } },
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 } },
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 } },
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 } },
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.
180 * @param s AC-3 encoder private context
182 void ff_ac3_adjust_frame_size(AC3EncodeContext *s)
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;
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;
196 * Set the initial coupling strategy parameters prior to coupling analysis.
198 * @param s AC-3 encoder private context
200 void ff_ac3_compute_coupling_strategy(AC3EncodeContext *s)
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;
214 /* enable coupling for each block if at least 2 channels have coupling
215 enabled for that block */
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;
231 block->new_cpl_strategy = !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;
240 block->new_cpl_leak = block->new_cpl_strategy;
242 if (!blk || (block->cpl_in_use && !got_cpl_snr)) {
243 block->new_snr_offsets = 1;
244 if (block->cpl_in_use)
247 block->new_snr_offsets = 0;
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];
260 block->end_freq[ch] = s->bandwidth_code * 3 + 73;
267 * Apply stereo rematrixing to coefficients based on rematrixing flags.
269 * @param s AC-3 encoder private context
271 void ff_ac3_apply_rematrixing(AC3EncodeContext *s)
276 uint8_t *flags = NULL;
278 if (!s->rematrixing_enabled)
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++) {
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;
303 * Initialize exponent tables.
305 static av_cold void exponent_init(AC3EncodeContext *s)
307 int expstr, i, grpsize;
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;
317 exponent_group_tab[0][0][7] = 2;
319 if (CONFIG_EAC3_ENCODER && s->eac3)
320 ff_eac3_exponent_init();
325 * Extract exponents from the MDCT coefficients.
327 static void extract_exponents(AC3EncodeContext *s)
330 int chan_size = AC3_MAX_COEFS * s->num_blocks * (s->channels - ch + 1);
331 AC3Block *block = &s->blocks[0];
333 s->ac3dsp.extract_exponents(block->exp[ch], block->fixed_coef[ch], chan_size);
338 * Exponent Difference Threshold.
339 * New exponents are sent if their SAD exceed this number.
341 #define EXP_DIFF_THRESHOLD 500
344 * Table used to select exponent strategy based on exponent reuse block interval.
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 }
354 * Calculate exponent strategies for all channels.
355 * Array arrangement is reversed to simplify the per-channel calculation.
357 static void compute_exp_strategy(AC3EncodeContext *s)
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];
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) {
372 if (!s->blocks[blk-1].cpl_in_use) {
373 exp_strategy[blk] = EXP_NEW;
375 } else if (!s->blocks[blk].cpl_in_use) {
376 exp_strategy[blk] = EXP_REUSE;
379 } else if (s->blocks[blk].channel_in_cpl[ch] != s->blocks[blk-1].channel_in_cpl[ch]) {
380 exp_strategy[blk] = EXP_NEW;
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;
391 /* now select the encoding strategy type : if exponents are often
392 recoded, we use a coarse encoding */
394 while (blk < s->num_blocks) {
396 while (blk1 < s->num_blocks && exp_strategy[blk1] == EXP_REUSE)
398 exp_strategy[blk] = exp_strategy_reuse_tab[s->num_blks_code][blk1-blk-1];
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;
409 /* for E-AC-3, determine frame exponent strategy */
410 if (CONFIG_EAC3_ENCODER && s->eac3)
411 ff_eac3_get_frame_exp_strategy(s);
416 * Update the exponents so that they are the ones the decoder will decode.
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
423 static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy,
428 nb_groups = exponent_group_tab[cpl][exp_strategy-1][nb_exps] * 3;
430 /* for each group, compute the minimum exponent */
431 switch(exp_strategy) {
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)
437 exp[i-cpl] = exp_min;
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)
446 if (exp[k+2] < exp_min)
448 if (exp[k+3] < exp_min)
450 exp[i-cpl] = exp_min;
456 /* constraint for DC exponent */
457 if (!cpl && exp[0] > 15)
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);
466 exp[i] = FFMIN(exp[i], exp[i+1] + 2);
469 exp[-1] = exp[0] & ~1;
471 /* now we have the exponent values the decoder will see */
472 switch (exp_strategy) {
474 for (i = nb_groups, k = (nb_groups * 2)-cpl; i > 0; i--) {
475 uint8_t exp1 = exp[i-cpl];
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];
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
496 static void encode_exponents(AC3EncodeContext *s)
498 int blk, blk1, ch, cpl;
499 uint8_t *exp, *exp_strategy;
500 int nb_coefs, num_reuse_blocks;
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];
506 cpl = (ch == CPL_CH);
508 while (blk < s->num_blocks) {
509 AC3Block *block = &s->blocks[blk];
510 if (cpl && !block->cpl_in_use) {
511 exp += AC3_MAX_COEFS;
515 nb_coefs = block->end_freq[ch] - s->start_freq[ch];
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;
525 num_reuse_blocks = blk1 - blk - 1;
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,
531 encode_exponents_blk_ch(exp, nb_coefs, exp_strategy[blk], cpl);
533 exp += AC3_MAX_COEFS * (num_reuse_blocks + 1);
538 /* reference block numbers have been changed, so reset ref_bap_set */
544 * Count exponent bits based on bandwidth, coupling, and exponent strategies.
546 static int count_exponent_bits(AC3EncodeContext *s)
549 int nb_groups, bit_count;
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];
559 if (exp_strategy == EXP_REUSE)
562 nb_groups = exponent_group_tab[cpl][exp_strategy-1][nb_coefs];
563 bit_count += 4 + (nb_groups * 7);
573 * 3 delta-encoded exponents are in each 7-bit group. The number of groups
574 * varies depending on exponent strategy and bandwidth.
576 * @param s AC-3 encoder private context
578 void ff_ac3_group_exponents(AC3EncodeContext *s)
581 int group_size, nb_groups;
583 int delta0, delta1, delta2;
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)
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;
599 block->grouped_exp[ch][0] = exp1;
601 /* remaining exponents are delta encoded */
602 for (i = 1; i <= nb_groups; i++) {
603 /* merge three delta in one code */
607 delta0 = exp1 - exp0 + 2;
608 av_assert2(delta0 >= 0 && delta0 <= 4);
613 delta1 = exp1 - exp0 + 2;
614 av_assert2(delta1 >= 0 && delta1 <= 4);
619 delta2 = exp1 - exp0 + 2;
620 av_assert2(delta2 >= 0 && delta2 <= 4);
622 block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
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.
634 * @param s AC-3 encoder private context
636 void ff_ac3_process_exponents(AC3EncodeContext *s)
638 extract_exponents(s);
640 compute_exp_strategy(s);
649 * Count frame bits that are based solely on fixed parameters.
650 * This only has to be run once when the encoder is initialized.
652 static void count_frame_bits_fixed(AC3EncodeContext *s)
654 static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
659 * no dynamic range codes
660 * bit allocation parameters do not change between blocks
661 * no delta bit allocation
668 frame_bits = 16; /* sync info */
670 /* bitstream info header */
673 if (s->num_blocks != 0x6)
676 /* audio frame header */
677 if (s->num_blocks == 6)
680 /* exponent strategy */
681 if (s->use_frame_exp_strategy)
682 frame_bits += 5 * s->fbw_channels;
684 frame_bits += s->num_blocks * 2 * s->fbw_channels;
686 frame_bits += s->num_blocks;
687 /* converter exponent strategy */
688 if (s->num_blks_code != 0x3)
691 frame_bits += s->fbw_channels * 5;
694 /* block start info */
695 if (s->num_blocks != 1)
699 frame_bits += frame_bits_inc[s->channel_mode];
703 for (blk = 0; blk < s->num_blocks; blk++) {
705 /* block switch flags */
706 frame_bits += s->fbw_channels;
709 frame_bits += s->fbw_channels;
715 /* spectral extension */
720 /* exponent strategy */
721 frame_bits += 2 * s->fbw_channels;
725 /* bit allocation params */
728 frame_bits += 2 + 2 + 2 + 2 + 3;
731 /* converter snr offset */
736 /* delta bit allocation */
748 frame_bits += 1 + 16;
750 s->frame_bits_fixed = frame_bits;
755 * Initialize bit allocation.
756 * Set default parameter codes and calculate parameter values.
758 static av_cold void bit_alloc_init(AC3EncodeContext *s)
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;
768 for (ch = 0; ch <= s->channels; ch++)
769 s->fast_gain_code[ch] = 4;
771 /* initial snr offset */
772 s->coarse_snr_offset = 40;
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;
785 count_frame_bits_fixed(s);
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.
794 static void count_frame_bits(AC3EncodeContext *s)
796 AC3EncOptions *opt = &s->options;
802 if (opt->eac3_mixing_metadata) {
803 if (s->channel_mode > AC3_CHMODE_STEREO)
809 frame_bits += s->lfe_on;
810 frame_bits += 1 + 1 + 2;
811 if (s->channel_mode < AC3_CHMODE_STEREO)
815 if (opt->eac3_info_metadata) {
816 frame_bits += 3 + 1 + 1;
817 if (s->channel_mode == AC3_CHMODE_STEREO)
819 if (s->channel_mode >= AC3_CHMODE_2F2R)
822 if (opt->audio_production_info)
823 frame_bits += 5 + 2 + 1;
827 if (s->channel_mode > AC3_CHMODE_MONO) {
829 for (blk = 1; blk < s->num_blocks; blk++) {
830 AC3Block *block = &s->blocks[blk];
832 if (block->new_cpl_strategy)
836 /* coupling exponent strategy */
838 if (s->use_frame_exp_strategy) {
839 frame_bits += 5 * s->cpl_on;
841 for (blk = 0; blk < s->num_blocks; blk++)
842 frame_bits += 2 * s->blocks[blk].cpl_in_use;
846 if (opt->audio_production_info)
848 if (s->bitstream_id == 6) {
849 if (opt->extended_bsi_1)
851 if (opt->extended_bsi_2)
857 for (blk = 0; blk < s->num_blocks; blk++) {
858 AC3Block *block = &s->blocks[blk];
860 /* coupling strategy */
863 if (block->new_cpl_strategy) {
866 if (block->cpl_in_use) {
869 if (!s->eac3 || s->channel_mode != AC3_CHMODE_STEREO)
870 frame_bits += s->fbw_channels;
871 if (s->channel_mode == AC3_CHMODE_STEREO)
877 frame_bits += s->num_cpl_subbands - 1;
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)
887 if (block->new_cpl_coords[ch]) {
889 frame_bits += (4 + 4) * s->num_cpl_bands;
895 /* stereo rematrixing */
896 if (s->channel_mode == AC3_CHMODE_STEREO) {
897 if (!s->eac3 || blk > 0)
899 if (s->blocks[blk].new_rematrixing_strategy)
900 frame_bits += block->num_rematrixing_bands;
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])
912 /* coupling exponent strategy */
913 if (!s->eac3 && block->cpl_in_use)
916 /* snr offsets and fast gain codes */
919 if (block->new_snr_offsets)
920 frame_bits += 6 + (s->channels + block->cpl_in_use) * (4 + 3);
923 /* coupling leak info */
924 if (block->cpl_in_use) {
925 if (!s->eac3 || block->new_cpl_leak != 2)
927 if (block->new_cpl_leak)
932 s->frame_bits = s->frame_bits_fixed + frame_bits;
937 * Calculate masking curve based on the final exponents.
938 * Also calculate the power spectral densities to use in future calculations.
940 static void bit_alloc_masking(AC3EncodeContext *s)
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,
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.
970 static void reset_block_bap(AC3EncodeContext *s)
975 if (s->ref_bap[0][0] == s->bap_buffer && s->ref_bap_set)
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;
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.
993 * @param[in,out] mant_cnt running counts for each bap value for each block
995 static void count_mantissa_bits_init(uint16_t mant_cnt[AC3_MAX_BLOCKS][16])
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;
1008 * Update mantissa bit counts for all blocks in 1 channel in a given bandwidth
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
1017 static void count_mantissa_bits_update_ch(AC3EncodeContext *s, int ch,
1018 uint16_t mant_cnt[AC3_MAX_BLOCKS][16],
1023 for (blk = 0; blk < s->num_blocks; blk++) {
1024 AC3Block *block = &s->blocks[blk];
1025 if (ch == CPL_CH && !block->cpl_in_use)
1027 s->ac3dsp.update_bap_counts(mant_cnt[blk],
1028 s->ref_bap[ch][blk] + start,
1029 FFMIN(end, block->end_freq[ch]) - start);
1035 * Count the number of mantissa bits in the frame based on the bap values.
1037 static int count_mantissa_bits(AC3EncodeContext *s)
1039 int ch, max_end_freq;
1040 LOCAL_ALIGNED_16(uint16_t, mant_cnt, [AC3_MAX_BLOCKS], [16]);
1042 count_mantissa_bits_init(mant_cnt);
1044 max_end_freq = s->bandwidth_code * 3 + 73;
1045 for (ch = !s->cpl_enabled; ch <= s->channels; ch++)
1046 count_mantissa_bits_update_ch(s, ch, mant_cnt, s->start_freq[ch],
1049 return s->ac3dsp.compute_mantissa_size(mant_cnt);
1054 * Run the bit allocation with a given SNR offset.
1055 * This calculates the bit allocation pointers that will be used to determine
1056 * the quantization of each mantissa.
1058 * @param s AC-3 encoder private context
1059 * @param snr_offset SNR offset, 0 to 1023
1060 * @return the number of bits needed for mantissas if the given SNR offset is
1063 static int bit_alloc(AC3EncodeContext *s, int snr_offset)
1067 snr_offset = (snr_offset - 240) << 2;
1070 for (blk = 0; blk < s->num_blocks; blk++) {
1071 AC3Block *block = &s->blocks[blk];
1073 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
1074 /* Currently the only bit allocation parameters which vary across
1075 blocks within a frame are the exponent values. We can take
1076 advantage of that by reusing the bit allocation pointers
1077 whenever we reuse exponents. */
1078 if (s->exp_strategy[ch][blk] != EXP_REUSE) {
1079 s->ac3dsp.bit_alloc_calc_bap(block->mask[ch], block->psd[ch],
1080 s->start_freq[ch], block->end_freq[ch],
1081 snr_offset, s->bit_alloc.floor,
1082 ff_ac3_bap_tab, s->ref_bap[ch][blk]);
1086 return count_mantissa_bits(s);
1091 * Constant bitrate bit allocation search.
1092 * Find the largest SNR offset that will allow data to fit in the frame.
1094 static int cbr_bit_allocation(AC3EncodeContext *s)
1098 int snr_offset, snr_incr;
1100 bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
1102 return AVERROR(EINVAL);
1104 snr_offset = s->coarse_snr_offset << 4;
1106 /* if previous frame SNR offset was 1023, check if current frame can also
1107 use SNR offset of 1023. if so, skip the search. */
1108 if ((snr_offset | s->fine_snr_offset[1]) == 1023) {
1109 if (bit_alloc(s, 1023) <= bits_left)
1113 while (snr_offset >= 0 &&
1114 bit_alloc(s, snr_offset) > bits_left) {
1118 return AVERROR(EINVAL);
1120 FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
1121 for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
1122 while (snr_offset + snr_incr <= 1023 &&
1123 bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
1124 snr_offset += snr_incr;
1125 FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
1128 FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
1131 s->coarse_snr_offset = snr_offset >> 4;
1132 for (ch = !s->cpl_on; ch <= s->channels; ch++)
1133 s->fine_snr_offset[ch] = snr_offset & 0xF;
1140 * Perform bit allocation search.
1141 * Finds the SNR offset value that maximizes quality and fits in the specified
1142 * frame size. Output is the SNR offset and a set of bit allocation pointers
1143 * used to quantize the mantissas.
1145 int ff_ac3_compute_bit_allocation(AC3EncodeContext *s)
1147 count_frame_bits(s);
1149 s->exponent_bits = count_exponent_bits(s);
1151 bit_alloc_masking(s);
1153 return cbr_bit_allocation(s);
1158 * Symmetric quantization on 'levels' levels.
1160 * @param c unquantized coefficient
1162 * @param levels number of quantization levels
1163 * @return quantized coefficient
1165 static inline int sym_quant(int c, int e, int levels)
1167 int v = (((levels * c) >> (24 - e)) + levels) >> 1;
1168 av_assert2(v >= 0 && v < levels);
1174 * Asymmetric quantization on 2^qbits levels.
1176 * @param c unquantized coefficient
1178 * @param qbits number of quantization bits
1179 * @return quantized coefficient
1181 static inline int asym_quant(int c, int e, int qbits)
1185 c = (((c << e) >> (24 - qbits)) + 1) >> 1;
1186 m = (1 << (qbits-1));
1189 av_assert2(c >= -m);
1195 * Quantize a set of mantissas for a single channel in a single block.
1197 * @param s Mantissa count context
1198 * @param fixed_coef unquantized fixed-point coefficients
1199 * @param exp exponents
1200 * @param bap bit allocation pointer indices
1201 * @param[out] qmant quantized coefficients
1202 * @param start_freq starting coefficient bin
1203 * @param end_freq ending coefficient bin
1205 static void quantize_mantissas_blk_ch(AC3Mant *s, int32_t *fixed_coef,
1206 uint8_t *exp, uint8_t *bap,
1207 int16_t *qmant, int start_freq,
1212 for (i = start_freq; i < end_freq; i++) {
1213 int c = fixed_coef[i];
1219 v = sym_quant(c, e, 3);
1220 switch (s->mant1_cnt) {
1222 s->qmant1_ptr = &qmant[i];
1227 *s->qmant1_ptr += 3 * v;
1232 *s->qmant1_ptr += v;
1239 v = sym_quant(c, e, 5);
1240 switch (s->mant2_cnt) {
1242 s->qmant2_ptr = &qmant[i];
1247 *s->qmant2_ptr += 5 * v;
1252 *s->qmant2_ptr += v;
1259 v = sym_quant(c, e, 7);
1262 v = sym_quant(c, e, 11);
1263 switch (s->mant4_cnt) {
1265 s->qmant4_ptr = &qmant[i];
1270 *s->qmant4_ptr += v;
1277 v = sym_quant(c, e, 15);
1280 v = asym_quant(c, e, 14);
1283 v = asym_quant(c, e, 16);
1286 v = asym_quant(c, e, v - 1);
1295 * Quantize mantissas using coefficients, exponents, and bit allocation pointers.
1297 * @param s AC-3 encoder private context
1299 void ff_ac3_quantize_mantissas(AC3EncodeContext *s)
1301 int blk, ch, ch0=0, got_cpl;
1303 for (blk = 0; blk < s->num_blocks; blk++) {
1304 AC3Block *block = &s->blocks[blk];
1307 got_cpl = !block->cpl_in_use;
1308 for (ch = 1; ch <= s->channels; ch++) {
1309 if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {
1314 quantize_mantissas_blk_ch(&m, block->fixed_coef[ch],
1315 s->blocks[s->exp_ref_block[ch][blk]].exp[ch],
1316 s->ref_bap[ch][blk], block->qmant[ch],
1317 s->start_freq[ch], block->end_freq[ch]);
1326 * Write the AC-3 frame header to the output bitstream.
1328 static void ac3_output_frame_header(AC3EncodeContext *s)
1330 AC3EncOptions *opt = &s->options;
1332 put_bits(&s->pb, 16, 0x0b77); /* frame header */
1333 put_bits(&s->pb, 16, 0); /* crc1: will be filled later */
1334 put_bits(&s->pb, 2, s->bit_alloc.sr_code);
1335 put_bits(&s->pb, 6, s->frame_size_code + (s->frame_size - s->frame_size_min) / 2);
1336 put_bits(&s->pb, 5, s->bitstream_id);
1337 put_bits(&s->pb, 3, s->bitstream_mode);
1338 put_bits(&s->pb, 3, s->channel_mode);
1339 if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
1340 put_bits(&s->pb, 2, s->center_mix_level);
1341 if (s->channel_mode & 0x04)
1342 put_bits(&s->pb, 2, s->surround_mix_level);
1343 if (s->channel_mode == AC3_CHMODE_STEREO)
1344 put_bits(&s->pb, 2, opt->dolby_surround_mode);
1345 put_bits(&s->pb, 1, s->lfe_on); /* LFE */
1346 put_bits(&s->pb, 5, -opt->dialogue_level);
1347 put_bits(&s->pb, 1, 0); /* no compression control word */
1348 put_bits(&s->pb, 1, 0); /* no lang code */
1349 put_bits(&s->pb, 1, opt->audio_production_info);
1350 if (opt->audio_production_info) {
1351 put_bits(&s->pb, 5, opt->mixing_level - 80);
1352 put_bits(&s->pb, 2, opt->room_type);
1354 put_bits(&s->pb, 1, opt->copyright);
1355 put_bits(&s->pb, 1, opt->original);
1356 if (s->bitstream_id == 6) {
1357 /* alternate bit stream syntax */
1358 put_bits(&s->pb, 1, opt->extended_bsi_1);
1359 if (opt->extended_bsi_1) {
1360 put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
1361 put_bits(&s->pb, 3, s->ltrt_center_mix_level);
1362 put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
1363 put_bits(&s->pb, 3, s->loro_center_mix_level);
1364 put_bits(&s->pb, 3, s->loro_surround_mix_level);
1366 put_bits(&s->pb, 1, opt->extended_bsi_2);
1367 if (opt->extended_bsi_2) {
1368 put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
1369 put_bits(&s->pb, 2, opt->dolby_headphone_mode);
1370 put_bits(&s->pb, 1, opt->ad_converter_type);
1371 put_bits(&s->pb, 9, 0); /* xbsi2 and encinfo : reserved */
1374 put_bits(&s->pb, 1, 0); /* no time code 1 */
1375 put_bits(&s->pb, 1, 0); /* no time code 2 */
1377 put_bits(&s->pb, 1, 0); /* no additional bit stream info */
1382 * Write one audio block to the output bitstream.
1384 static void output_audio_block(AC3EncodeContext *s, int blk)
1386 int ch, i, baie, bnd, got_cpl, av_uninit(ch0);
1387 AC3Block *block = &s->blocks[blk];
1389 /* block switching */
1391 for (ch = 0; ch < s->fbw_channels; ch++)
1392 put_bits(&s->pb, 1, 0);
1397 for (ch = 0; ch < s->fbw_channels; ch++)
1398 put_bits(&s->pb, 1, 1);
1401 /* dynamic range codes */
1402 put_bits(&s->pb, 1, 0);
1404 /* spectral extension */
1406 put_bits(&s->pb, 1, 0);
1408 /* channel coupling */
1410 put_bits(&s->pb, 1, block->new_cpl_strategy);
1411 if (block->new_cpl_strategy) {
1413 put_bits(&s->pb, 1, block->cpl_in_use);
1414 if (block->cpl_in_use) {
1415 int start_sub, end_sub;
1417 put_bits(&s->pb, 1, 0); /* enhanced coupling */
1418 if (!s->eac3 || s->channel_mode != AC3_CHMODE_STEREO) {
1419 for (ch = 1; ch <= s->fbw_channels; ch++)
1420 put_bits(&s->pb, 1, block->channel_in_cpl[ch]);
1422 if (s->channel_mode == AC3_CHMODE_STEREO)
1423 put_bits(&s->pb, 1, 0); /* phase flags in use */
1424 start_sub = (s->start_freq[CPL_CH] - 37) / 12;
1425 end_sub = (s->cpl_end_freq - 37) / 12;
1426 put_bits(&s->pb, 4, start_sub);
1427 put_bits(&s->pb, 4, end_sub - 3);
1428 /* coupling band structure */
1430 put_bits(&s->pb, 1, 0); /* use default */
1432 for (bnd = start_sub+1; bnd < end_sub; bnd++)
1433 put_bits(&s->pb, 1, ff_eac3_default_cpl_band_struct[bnd]);
1438 /* coupling coordinates */
1439 if (block->cpl_in_use) {
1440 for (ch = 1; ch <= s->fbw_channels; ch++) {
1441 if (block->channel_in_cpl[ch]) {
1442 if (!s->eac3 || block->new_cpl_coords[ch] != 2)
1443 put_bits(&s->pb, 1, block->new_cpl_coords[ch]);
1444 if (block->new_cpl_coords[ch]) {
1445 put_bits(&s->pb, 2, block->cpl_master_exp[ch]);
1446 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
1447 put_bits(&s->pb, 4, block->cpl_coord_exp [ch][bnd]);
1448 put_bits(&s->pb, 4, block->cpl_coord_mant[ch][bnd]);
1455 /* stereo rematrixing */
1456 if (s->channel_mode == AC3_CHMODE_STEREO) {
1457 if (!s->eac3 || blk > 0)
1458 put_bits(&s->pb, 1, block->new_rematrixing_strategy);
1459 if (block->new_rematrixing_strategy) {
1460 /* rematrixing flags */
1461 for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++)
1462 put_bits(&s->pb, 1, block->rematrixing_flags[bnd]);
1466 /* exponent strategy */
1468 for (ch = !block->cpl_in_use; ch <= s->fbw_channels; ch++)
1469 put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
1471 put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
1475 for (ch = 1; ch <= s->fbw_channels; ch++) {
1476 if (s->exp_strategy[ch][blk] != EXP_REUSE && !block->channel_in_cpl[ch])
1477 put_bits(&s->pb, 6, s->bandwidth_code);
1481 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
1483 int cpl = (ch == CPL_CH);
1485 if (s->exp_strategy[ch][blk] == EXP_REUSE)
1489 put_bits(&s->pb, 4, block->grouped_exp[ch][0] >> cpl);
1491 /* exponent groups */
1492 nb_groups = exponent_group_tab[cpl][s->exp_strategy[ch][blk]-1][block->end_freq[ch]-s->start_freq[ch]];
1493 for (i = 1; i <= nb_groups; i++)
1494 put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
1496 /* gain range info */
1497 if (ch != s->lfe_channel && !cpl)
1498 put_bits(&s->pb, 2, 0);
1501 /* bit allocation info */
1504 put_bits(&s->pb, 1, baie);
1506 put_bits(&s->pb, 2, s->slow_decay_code);
1507 put_bits(&s->pb, 2, s->fast_decay_code);
1508 put_bits(&s->pb, 2, s->slow_gain_code);
1509 put_bits(&s->pb, 2, s->db_per_bit_code);
1510 put_bits(&s->pb, 3, s->floor_code);
1516 put_bits(&s->pb, 1, block->new_snr_offsets);
1517 if (block->new_snr_offsets) {
1518 put_bits(&s->pb, 6, s->coarse_snr_offset);
1519 for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
1520 put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
1521 put_bits(&s->pb, 3, s->fast_gain_code[ch]);
1525 put_bits(&s->pb, 1, 0); /* no converter snr offset */
1529 if (block->cpl_in_use) {
1530 if (!s->eac3 || block->new_cpl_leak != 2)
1531 put_bits(&s->pb, 1, block->new_cpl_leak);
1532 if (block->new_cpl_leak) {
1533 put_bits(&s->pb, 3, s->bit_alloc.cpl_fast_leak);
1534 put_bits(&s->pb, 3, s->bit_alloc.cpl_slow_leak);
1539 put_bits(&s->pb, 1, 0); /* no delta bit allocation */
1540 put_bits(&s->pb, 1, 0); /* no data to skip */
1544 got_cpl = !block->cpl_in_use;
1545 for (ch = 1; ch <= s->channels; ch++) {
1548 if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {
1553 for (i = s->start_freq[ch]; i < block->end_freq[ch]; i++) {
1554 q = block->qmant[ch][i];
1555 b = s->ref_bap[ch][blk][i];
1558 case 1: if (q != 128) put_bits (&s->pb, 5, q); break;
1559 case 2: if (q != 128) put_bits (&s->pb, 7, q); break;
1560 case 3: put_sbits(&s->pb, 3, q); break;
1561 case 4: if (q != 128) put_bits (&s->pb, 7, q); break;
1562 case 14: put_sbits(&s->pb, 14, q); break;
1563 case 15: put_sbits(&s->pb, 16, q); break;
1564 default: put_sbits(&s->pb, b-1, q); break;
1573 /** CRC-16 Polynomial */
1574 #define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
1577 static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
1594 static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
1600 r = mul_poly(r, a, poly);
1601 a = mul_poly(a, a, poly);
1609 * Fill the end of the frame with 0's and compute the two CRCs.
1611 static void output_frame_end(AC3EncodeContext *s)
1613 const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);
1614 int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;
1617 frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1;
1619 /* pad the remainder of the frame with zeros */
1620 av_assert2(s->frame_size * 8 - put_bits_count(&s->pb) >= 18);
1621 flush_put_bits(&s->pb);
1623 pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
1624 av_assert2(pad_bytes >= 0);
1626 memset(put_bits_ptr(&s->pb), 0, pad_bytes);
1630 crc2_partial = av_crc(crc_ctx, 0, frame + 2, s->frame_size - 5);
1633 /* this is not so easy because it is at the beginning of the data... */
1634 crc1 = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4));
1635 crc_inv = s->crc_inv[s->frame_size > s->frame_size_min];
1636 crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
1637 AV_WB16(frame + 2, crc1);
1640 crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,
1641 s->frame_size - frame_size_58 - 3);
1643 crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
1644 /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */
1645 if (crc2 == 0x770B) {
1646 frame[s->frame_size - 3] ^= 0x1;
1647 crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
1649 crc2 = av_bswap16(crc2);
1650 AV_WB16(frame + s->frame_size - 2, crc2);
1655 * Write the frame to the output bitstream.
1657 * @param s AC-3 encoder private context
1658 * @param frame output data buffer
1660 void ff_ac3_output_frame(AC3EncodeContext *s, unsigned char *frame)
1664 init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
1666 s->output_frame_header(s);
1668 for (blk = 0; blk < s->num_blocks; blk++)
1669 output_audio_block(s, blk);
1671 output_frame_end(s);
1675 static void dprint_options(AC3EncodeContext *s)
1678 AVCodecContext *avctx = s->avctx;
1679 AC3EncOptions *opt = &s->options;
1682 switch (s->bitstream_id) {
1683 case 6: av_strlcpy(strbuf, "AC-3 (alt syntax)", 32); break;
1684 case 8: av_strlcpy(strbuf, "AC-3 (standard)", 32); break;
1685 case 9: av_strlcpy(strbuf, "AC-3 (dnet half-rate)", 32); break;
1686 case 10: av_strlcpy(strbuf, "AC-3 (dnet quater-rate)", 32); break;
1687 case 16: av_strlcpy(strbuf, "E-AC-3 (enhanced)", 32); break;
1688 default: snprintf(strbuf, 32, "ERROR");
1690 av_dlog(avctx, "bitstream_id: %s (%d)\n", strbuf, s->bitstream_id);
1691 av_dlog(avctx, "sample_fmt: %s\n", av_get_sample_fmt_name(avctx->sample_fmt));
1692 av_get_channel_layout_string(strbuf, 32, s->channels, avctx->channel_layout);
1693 av_dlog(avctx, "channel_layout: %s\n", strbuf);
1694 av_dlog(avctx, "sample_rate: %d\n", s->sample_rate);
1695 av_dlog(avctx, "bit_rate: %d\n", s->bit_rate);
1696 av_dlog(avctx, "blocks/frame: %d (code=%d)\n", s->num_blocks, s->num_blks_code);
1698 av_dlog(avctx, "cutoff: %d\n", s->cutoff);
1700 av_dlog(avctx, "per_frame_metadata: %s\n",
1701 opt->allow_per_frame_metadata?"on":"off");
1703 av_dlog(avctx, "center_mixlev: %0.3f (%d)\n", opt->center_mix_level,
1704 s->center_mix_level);
1706 av_dlog(avctx, "center_mixlev: {not written}\n");
1707 if (s->has_surround)
1708 av_dlog(avctx, "surround_mixlev: %0.3f (%d)\n", opt->surround_mix_level,
1709 s->surround_mix_level);
1711 av_dlog(avctx, "surround_mixlev: {not written}\n");
1712 if (opt->audio_production_info) {
1713 av_dlog(avctx, "mixing_level: %ddB\n", opt->mixing_level);
1714 switch (opt->room_type) {
1715 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1716 case AC3ENC_OPT_LARGE_ROOM: av_strlcpy(strbuf, "large", 32); break;
1717 case AC3ENC_OPT_SMALL_ROOM: av_strlcpy(strbuf, "small", 32); break;
1718 default: snprintf(strbuf, 32, "ERROR (%d)", opt->room_type);
1720 av_dlog(avctx, "room_type: %s\n", strbuf);
1722 av_dlog(avctx, "mixing_level: {not written}\n");
1723 av_dlog(avctx, "room_type: {not written}\n");
1725 av_dlog(avctx, "copyright: %s\n", opt->copyright?"on":"off");
1726 av_dlog(avctx, "dialnorm: %ddB\n", opt->dialogue_level);
1727 if (s->channel_mode == AC3_CHMODE_STEREO) {
1728 switch (opt->dolby_surround_mode) {
1729 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1730 case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break;
1731 case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break;
1732 default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_surround_mode);
1734 av_dlog(avctx, "dsur_mode: %s\n", strbuf);
1736 av_dlog(avctx, "dsur_mode: {not written}\n");
1738 av_dlog(avctx, "original: %s\n", opt->original?"on":"off");
1740 if (s->bitstream_id == 6) {
1741 if (opt->extended_bsi_1) {
1742 switch (opt->preferred_stereo_downmix) {
1743 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1744 case AC3ENC_OPT_DOWNMIX_LTRT: av_strlcpy(strbuf, "ltrt", 32); break;
1745 case AC3ENC_OPT_DOWNMIX_LORO: av_strlcpy(strbuf, "loro", 32); break;
1746 default: snprintf(strbuf, 32, "ERROR (%d)", opt->preferred_stereo_downmix);
1748 av_dlog(avctx, "dmix_mode: %s\n", strbuf);
1749 av_dlog(avctx, "ltrt_cmixlev: %0.3f (%d)\n",
1750 opt->ltrt_center_mix_level, s->ltrt_center_mix_level);
1751 av_dlog(avctx, "ltrt_surmixlev: %0.3f (%d)\n",
1752 opt->ltrt_surround_mix_level, s->ltrt_surround_mix_level);
1753 av_dlog(avctx, "loro_cmixlev: %0.3f (%d)\n",
1754 opt->loro_center_mix_level, s->loro_center_mix_level);
1755 av_dlog(avctx, "loro_surmixlev: %0.3f (%d)\n",
1756 opt->loro_surround_mix_level, s->loro_surround_mix_level);
1758 av_dlog(avctx, "extended bitstream info 1: {not written}\n");
1760 if (opt->extended_bsi_2) {
1761 switch (opt->dolby_surround_ex_mode) {
1762 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1763 case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break;
1764 case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break;
1765 default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_surround_ex_mode);
1767 av_dlog(avctx, "dsurex_mode: %s\n", strbuf);
1768 switch (opt->dolby_headphone_mode) {
1769 case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
1770 case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break;
1771 case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break;
1772 default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_headphone_mode);
1774 av_dlog(avctx, "dheadphone_mode: %s\n", strbuf);
1776 switch (opt->ad_converter_type) {
1777 case AC3ENC_OPT_ADCONV_STANDARD: av_strlcpy(strbuf, "standard", 32); break;
1778 case AC3ENC_OPT_ADCONV_HDCD: av_strlcpy(strbuf, "hdcd", 32); break;
1779 default: snprintf(strbuf, 32, "ERROR (%d)", opt->ad_converter_type);
1781 av_dlog(avctx, "ad_conv_type: %s\n", strbuf);
1783 av_dlog(avctx, "extended bitstream info 2: {not written}\n");
1790 #define FLT_OPTION_THRESHOLD 0.01
1792 static int validate_float_option(float v, const float *v_list, int v_list_size)
1796 for (i = 0; i < v_list_size; i++) {
1797 if (v < (v_list[i] + FLT_OPTION_THRESHOLD) &&
1798 v > (v_list[i] - FLT_OPTION_THRESHOLD))
1801 if (i == v_list_size)
1808 static void validate_mix_level(void *log_ctx, const char *opt_name,
1809 float *opt_param, const float *list,
1810 int list_size, int default_value, int min_value,
1813 int mixlev = validate_float_option(*opt_param, list, list_size);
1814 if (mixlev < min_value) {
1815 mixlev = default_value;
1816 if (*opt_param >= 0.0) {
1817 av_log(log_ctx, AV_LOG_WARNING, "requested %s is not valid. using "
1818 "default value: %0.3f\n", opt_name, list[mixlev]);
1821 *opt_param = list[mixlev];
1822 *ctx_param = mixlev;
1827 * Validate metadata options as set by AVOption system.
1828 * These values can optionally be changed per-frame.
1830 * @param s AC-3 encoder private context
1832 int ff_ac3_validate_metadata(AC3EncodeContext *s)
1834 AVCodecContext *avctx = s->avctx;
1835 AC3EncOptions *opt = &s->options;
1837 opt->audio_production_info = 0;
1838 opt->extended_bsi_1 = 0;
1839 opt->extended_bsi_2 = 0;
1840 opt->eac3_mixing_metadata = 0;
1841 opt->eac3_info_metadata = 0;
1843 /* determine mixing metadata / xbsi1 use */
1844 if (s->channel_mode > AC3_CHMODE_STEREO && opt->preferred_stereo_downmix != AC3ENC_OPT_NONE) {
1845 opt->extended_bsi_1 = 1;
1846 opt->eac3_mixing_metadata = 1;
1848 if (s->has_center &&
1849 (opt->ltrt_center_mix_level >= 0 || opt->loro_center_mix_level >= 0)) {
1850 opt->extended_bsi_1 = 1;
1851 opt->eac3_mixing_metadata = 1;
1853 if (s->has_surround &&
1854 (opt->ltrt_surround_mix_level >= 0 || opt->loro_surround_mix_level >= 0)) {
1855 opt->extended_bsi_1 = 1;
1856 opt->eac3_mixing_metadata = 1;
1860 /* determine info metadata use */
1861 if (avctx->audio_service_type != AV_AUDIO_SERVICE_TYPE_MAIN)
1862 opt->eac3_info_metadata = 1;
1863 if (opt->copyright != AC3ENC_OPT_NONE || opt->original != AC3ENC_OPT_NONE)
1864 opt->eac3_info_metadata = 1;
1865 if (s->channel_mode == AC3_CHMODE_STEREO &&
1866 (opt->dolby_headphone_mode != AC3ENC_OPT_NONE || opt->dolby_surround_mode != AC3ENC_OPT_NONE))
1867 opt->eac3_info_metadata = 1;
1868 if (s->channel_mode >= AC3_CHMODE_2F2R && opt->dolby_surround_ex_mode != AC3ENC_OPT_NONE)
1869 opt->eac3_info_metadata = 1;
1870 if (opt->mixing_level != AC3ENC_OPT_NONE || opt->room_type != AC3ENC_OPT_NONE ||
1871 opt->ad_converter_type != AC3ENC_OPT_NONE) {
1872 opt->audio_production_info = 1;
1873 opt->eac3_info_metadata = 1;
1876 /* determine audio production info use */
1877 if (opt->mixing_level != AC3ENC_OPT_NONE || opt->room_type != AC3ENC_OPT_NONE)
1878 opt->audio_production_info = 1;
1880 /* determine xbsi2 use */
1881 if (s->channel_mode >= AC3_CHMODE_2F2R && opt->dolby_surround_ex_mode != AC3ENC_OPT_NONE)
1882 opt->extended_bsi_2 = 1;
1883 if (s->channel_mode == AC3_CHMODE_STEREO && opt->dolby_headphone_mode != AC3ENC_OPT_NONE)
1884 opt->extended_bsi_2 = 1;
1885 if (opt->ad_converter_type != AC3ENC_OPT_NONE)
1886 opt->extended_bsi_2 = 1;
1889 /* validate AC-3 mixing levels */
1891 if (s->has_center) {
1892 validate_mix_level(avctx, "center_mix_level", &opt->center_mix_level,
1893 cmixlev_options, CMIXLEV_NUM_OPTIONS, 1, 0,
1894 &s->center_mix_level);
1896 if (s->has_surround) {
1897 validate_mix_level(avctx, "surround_mix_level", &opt->surround_mix_level,
1898 surmixlev_options, SURMIXLEV_NUM_OPTIONS, 1, 0,
1899 &s->surround_mix_level);
1903 /* validate extended bsi 1 / mixing metadata */
1904 if (opt->extended_bsi_1 || opt->eac3_mixing_metadata) {
1905 /* default preferred stereo downmix */
1906 if (opt->preferred_stereo_downmix == AC3ENC_OPT_NONE)
1907 opt->preferred_stereo_downmix = AC3ENC_OPT_NOT_INDICATED;
1908 if (!s->eac3 || s->has_center) {
1909 /* validate Lt/Rt center mix level */
1910 validate_mix_level(avctx, "ltrt_center_mix_level",
1911 &opt->ltrt_center_mix_level, extmixlev_options,
1912 EXTMIXLEV_NUM_OPTIONS, 5, 0,
1913 &s->ltrt_center_mix_level);
1914 /* validate Lo/Ro center mix level */
1915 validate_mix_level(avctx, "loro_center_mix_level",
1916 &opt->loro_center_mix_level, extmixlev_options,
1917 EXTMIXLEV_NUM_OPTIONS, 5, 0,
1918 &s->loro_center_mix_level);
1920 if (!s->eac3 || s->has_surround) {
1921 /* validate Lt/Rt surround mix level */
1922 validate_mix_level(avctx, "ltrt_surround_mix_level",
1923 &opt->ltrt_surround_mix_level, extmixlev_options,
1924 EXTMIXLEV_NUM_OPTIONS, 6, 3,
1925 &s->ltrt_surround_mix_level);
1926 /* validate Lo/Ro surround mix level */
1927 validate_mix_level(avctx, "loro_surround_mix_level",
1928 &opt->loro_surround_mix_level, extmixlev_options,
1929 EXTMIXLEV_NUM_OPTIONS, 6, 3,
1930 &s->loro_surround_mix_level);
1934 /* validate audio service type / channels combination */
1935 if ((avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_KARAOKE &&
1936 avctx->channels == 1) ||
1937 ((avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_COMMENTARY ||
1938 avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_EMERGENCY ||
1939 avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_VOICE_OVER)
1940 && avctx->channels > 1)) {
1941 av_log(avctx, AV_LOG_ERROR, "invalid audio service type for the "
1942 "specified number of channels\n");
1943 return AVERROR(EINVAL);
1946 /* validate extended bsi 2 / info metadata */
1947 if (opt->extended_bsi_2 || opt->eac3_info_metadata) {
1948 /* default dolby headphone mode */
1949 if (opt->dolby_headphone_mode == AC3ENC_OPT_NONE)
1950 opt->dolby_headphone_mode = AC3ENC_OPT_NOT_INDICATED;
1951 /* default dolby surround ex mode */
1952 if (opt->dolby_surround_ex_mode == AC3ENC_OPT_NONE)
1953 opt->dolby_surround_ex_mode = AC3ENC_OPT_NOT_INDICATED;
1954 /* default A/D converter type */
1955 if (opt->ad_converter_type == AC3ENC_OPT_NONE)
1956 opt->ad_converter_type = AC3ENC_OPT_ADCONV_STANDARD;
1959 /* copyright & original defaults */
1960 if (!s->eac3 || opt->eac3_info_metadata) {
1961 /* default copyright */
1962 if (opt->copyright == AC3ENC_OPT_NONE)
1963 opt->copyright = AC3ENC_OPT_OFF;
1964 /* default original */
1965 if (opt->original == AC3ENC_OPT_NONE)
1966 opt->original = AC3ENC_OPT_ON;
1969 /* dolby surround mode default */
1970 if (!s->eac3 || opt->eac3_info_metadata) {
1971 if (opt->dolby_surround_mode == AC3ENC_OPT_NONE)
1972 opt->dolby_surround_mode = AC3ENC_OPT_NOT_INDICATED;
1975 /* validate audio production info */
1976 if (opt->audio_production_info) {
1977 if (opt->mixing_level == AC3ENC_OPT_NONE) {
1978 av_log(avctx, AV_LOG_ERROR, "mixing_level must be set if "
1979 "room_type is set\n");
1980 return AVERROR(EINVAL);
1982 if (opt->mixing_level < 80) {
1983 av_log(avctx, AV_LOG_ERROR, "invalid mixing level. must be between "
1984 "80dB and 111dB\n");
1985 return AVERROR(EINVAL);
1987 /* default room type */
1988 if (opt->room_type == AC3ENC_OPT_NONE)
1989 opt->room_type = AC3ENC_OPT_NOT_INDICATED;
1992 /* set bitstream id for alternate bitstream syntax */
1993 if (!s->eac3 && (opt->extended_bsi_1 || opt->extended_bsi_2)) {
1994 if (s->bitstream_id > 8 && s->bitstream_id < 11) {
1995 static int warn_once = 1;
1997 av_log(avctx, AV_LOG_WARNING, "alternate bitstream syntax is "
1998 "not compatible with reduced samplerates. writing of "
1999 "extended bitstream information will be disabled.\n");
2003 s->bitstream_id = 6;
2012 * Finalize encoding and free any memory allocated by the encoder.
2014 * @param avctx Codec context
2016 av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
2019 AC3EncodeContext *s = avctx->priv_data;
2021 av_freep(&s->windowed_samples);
2022 if (s->planar_samples)
2023 for (ch = 0; ch < s->channels; ch++)
2024 av_freep(&s->planar_samples[ch]);
2025 av_freep(&s->planar_samples);
2026 av_freep(&s->bap_buffer);
2027 av_freep(&s->bap1_buffer);
2028 av_freep(&s->mdct_coef_buffer);
2029 av_freep(&s->fixed_coef_buffer);
2030 av_freep(&s->exp_buffer);
2031 av_freep(&s->grouped_exp_buffer);
2032 av_freep(&s->psd_buffer);
2033 av_freep(&s->band_psd_buffer);
2034 av_freep(&s->mask_buffer);
2035 av_freep(&s->qmant_buffer);
2036 av_freep(&s->cpl_coord_exp_buffer);
2037 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);
2060 * Set channel information during initialization.
2062 static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
2063 uint64_t *channel_layout)
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;
2073 ch_layout = av_get_default_channel_layout(channels);
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;
2080 ch_layout -= AV_CH_LOW_FREQUENCY;
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;
2093 return AVERROR(EINVAL);
2095 s->has_center = (s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO;
2096 s->has_surround = s->channel_mode & 0x04;
2098 s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe_on];
2099 *channel_layout = ch_layout;
2101 *channel_layout |= AV_CH_LOW_FREQUENCY;
2107 static av_cold int validate_options(AC3EncodeContext *s)
2109 AVCodecContext *avctx = s->avctx;
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");
2118 ret = set_channel_info(s, avctx->channels, &avctx->channel_layout);
2120 av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
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)
2134 av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
2135 return AVERROR(EINVAL);
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;
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;
2153 /* validate bit rate */
2155 int max_br, min_br, wpf, min_br_dist, min_br_code;
2156 int num_blks_code, num_blocks, frame_samples;
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)
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);
2175 s->num_blks_code = num_blks_code;
2176 s->num_blocks = num_blocks;
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);
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 */
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;
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)
2199 s->frame_size_min = 2 * wpf;
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) {
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;
2219 s->bit_rate = avctx->bit_rate;
2220 s->frame_size = s->frame_size_min;
2222 /* validate cutoff */
2223 if (avctx->cutoff < 0) {
2224 av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");
2225 return AVERROR(EINVAL);
2227 s->cutoff = avctx->cutoff;
2228 if (s->cutoff > (s->sample_rate >> 1))
2229 s->cutoff = s->sample_rate >> 1;
2231 ret = ff_ac3_validate_metadata(s);
2235 s->rematrixing_enabled = s->options.stereo_rematrixing &&
2236 (s->channel_mode == AC3_CHMODE_STEREO);
2238 s->cpl_enabled = s->options.channel_coupling &&
2239 s->channel_mode >= AC3_CHMODE_STEREO;
2246 * Set bandwidth for all channels.
2247 * The user can optionally supply a cutoff frequency. Otherwise an appropriate
2248 * default value will be used.
2250 static av_cold void set_bandwidth(AC3EncodeContext *s)
2252 int blk, ch, av_uninit(cpl_start);
2255 /* calculate bandwidth based on user-specified cutoff frequency */
2257 fbw_coeffs = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
2258 s->bandwidth_code = av_clip((fbw_coeffs - 73) / 3, 0, 60);
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];
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;
2270 /* LFE channel always has 7 coefs */
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;
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;
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)
2291 if (s->cpl_enabled) {
2292 int i, cpl_start_band, cpl_end_band;
2293 uint8_t *cpl_band_sizes = s->cpl_band_sizes;
2295 cpl_end_band = s->bandwidth_code / 4 + 3;
2296 cpl_start_band = av_clip(cpl_start, 0, FFMIN(cpl_end_band-1, 15));
2298 s->num_cpl_subbands = cpl_end_band - cpl_start_band;
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;
2308 *cpl_band_sizes = 12;
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;
2320 static av_cold int allocate_buffers(AC3EncodeContext *s)
2322 AVCodecContext *avctx = s->avctx;
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;
2328 if (s->allocate_sample_buffers(s))
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);
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),
2359 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->exp, channels, sizeof(*block->exp),
2361 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->grouped_exp, channels, sizeof(*block->grouped_exp),
2363 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->psd, channels, sizeof(*block->psd),
2365 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->band_psd, channels, sizeof(*block->band_psd),
2367 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->mask, channels, sizeof(*block->mask),
2369 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->qmant, channels, sizeof(*block->qmant),
2371 if (s->cpl_enabled) {
2372 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->cpl_coord_exp, channels, sizeof(*block->cpl_coord_exp),
2374 FF_ALLOCZ_ARRAY_OR_GOTO(avctx, block->cpl_coord_mant, channels, sizeof(*block->cpl_coord_mant),
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)];
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)];
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)];
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];
2418 return AVERROR(ENOMEM);
2422 av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
2424 AC3EncodeContext *s = avctx->priv_data;
2425 int ret, frame_size_58;
2429 s->eac3 = avctx->codec_id == AV_CODEC_ID_EAC3;
2431 ff_ac3_common_init();
2433 ret = validate_options(s);
2437 avctx->frame_size = AC3_BLOCK_SIZE * s->num_blocks;
2438 avctx->initial_padding = AC3_BLOCK_SIZE;
2440 s->bitstream_mode = avctx->audio_service_type;
2441 if (s->bitstream_mode == AV_AUDIO_SERVICE_TYPE_KARAOKE)
2442 s->bitstream_mode = 0x7;
2444 s->bits_written = 0;
2445 s->samples_written = 0;
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);
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;
2465 if (CONFIG_EAC3_ENCODER && s->eac3)
2466 s->output_frame_header = ff_eac3_output_frame_header;
2468 s->output_frame_header = ac3_output_frame_header;
2476 ret = s->mdct_init(s);
2480 ret = allocate_buffers(s);
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);
2492 ff_ac3_encode_close(avctx);