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oggenc: return error value from ogg_build_flac_headers()
[FFMpeg-mirror/lagarith.git] / libavcodec / ac3enc.c
blob7d12e04b302e8c838f6922cd1e3afdd1840039dd
1 /*
2 * The simplest AC-3 encoder
3 * Copyright (c) 2000 Fabrice Bellard
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file libavcodec/ac3enc.c
24 * The simplest AC-3 encoder.
25 */
26 //#define DEBUG
27 //#define DEBUG_BITALLOC
28 #include "libavutil/crc.h"
29 #include "avcodec.h"
30 #include "get_bits.h" // for ff_reverse
31 #include "put_bits.h"
32 #include "ac3.h"
33 #include "audioconvert.h"
34
35 typedef struct AC3EncodeContext {
36 PutBitContext pb;
37 int nb_channels;
38 int nb_all_channels;
39 int lfe_channel;
40 const uint8_t *channel_map;
41 int bit_rate;
42 unsigned int sample_rate;
43 unsigned int bitstream_id;
44 unsigned int frame_size_min; /* minimum frame size in case rounding is necessary */
45 unsigned int frame_size; /* current frame size in words */
46 unsigned int bits_written;
47 unsigned int samples_written;
48 int sr_shift;
49 unsigned int frame_size_code;
50 unsigned int sr_code; /* frequency */
51 unsigned int channel_mode;
52 int lfe;
53 unsigned int bitstream_mode;
54 short last_samples[AC3_MAX_CHANNELS][256];
55 unsigned int chbwcod[AC3_MAX_CHANNELS];
56 int nb_coefs[AC3_MAX_CHANNELS];
57
58 /* bitrate allocation control */
59 int slow_gain_code, slow_decay_code, fast_decay_code, db_per_bit_code, floor_code;
60 AC3BitAllocParameters bit_alloc;
61 int coarse_snr_offset;
62 int fast_gain_code[AC3_MAX_CHANNELS];
63 int fine_snr_offset[AC3_MAX_CHANNELS];
64 /* mantissa encoding */
65 int mant1_cnt, mant2_cnt, mant4_cnt;
66 } AC3EncodeContext;
67
68 static int16_t costab[64];
69 static int16_t sintab[64];
70 static int16_t xcos1[128];
71 static int16_t xsin1[128];
72
73 #define MDCT_NBITS 9
74 #define N (1 << MDCT_NBITS)
75
76 /* new exponents are sent if their Norm 1 exceed this number */
77 #define EXP_DIFF_THRESHOLD 1000
78
79 static inline int16_t fix15(float a)
80 {
81 int v;
82 v = (int)(a * (float)(1 << 15));
83 if (v < -32767)
84 v = -32767;
85 else if (v > 32767)
86 v = 32767;
87 return v;
88 }
89
90 typedef struct IComplex {
91 short re,im;
92 } IComplex;
93
94 static av_cold void fft_init(int ln)
95 {
96 int i, n;
97 float alpha;
98
99 n = 1 << ln;
100
101 for(i=0;i<(n/2);i++) {
102 alpha = 2 * M_PI * (float)i / (float)n;
103 costab[i] = fix15(cos(alpha));
104 sintab[i] = fix15(sin(alpha));
105 }
106 }
107
108 /* butter fly op */
109 #define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
110 {\
111 int ax, ay, bx, by;\
112 bx=pre1;\
113 by=pim1;\
114 ax=qre1;\
115 ay=qim1;\
116 pre = (bx + ax) >> 1;\
117 pim = (by + ay) >> 1;\
118 qre = (bx - ax) >> 1;\
119 qim = (by - ay) >> 1;\
120 }
121
122 #define CMUL(pre, pim, are, aim, bre, bim) \
123 {\
124 pre = (MUL16(are, bre) - MUL16(aim, bim)) >> 15;\
125 pim = (MUL16(are, bim) + MUL16(bre, aim)) >> 15;\
126 }
127
128
129 /* do a 2^n point complex fft on 2^ln points. */
130 static void fft(IComplex *z, int ln)
131 {
132 int j, l, np, np2;
133 int nblocks, nloops;
134 register IComplex *p,*q;
135 int tmp_re, tmp_im;
136
137 np = 1 << ln;
138
139 /* reverse */
140 for(j=0;j<np;j++) {
141 int k = ff_reverse[j] >> (8 - ln);
142 if (k < j)
143 FFSWAP(IComplex, z[k], z[j]);
144 }
145
146 /* pass 0 */
147
148 p=&z[0];
149 j=(np >> 1);
150 do {
151 BF(p[0].re, p[0].im, p[1].re, p[1].im,
152 p[0].re, p[0].im, p[1].re, p[1].im);
153 p+=2;
154 } while (--j != 0);
155
156 /* pass 1 */
157
158 p=&z[0];
159 j=np >> 2;
160 do {
161 BF(p[0].re, p[0].im, p[2].re, p[2].im,
162 p[0].re, p[0].im, p[2].re, p[2].im);
163 BF(p[1].re, p[1].im, p[3].re, p[3].im,
164 p[1].re, p[1].im, p[3].im, -p[3].re);
165 p+=4;
166 } while (--j != 0);
167
168 /* pass 2 .. ln-1 */
169
170 nblocks = np >> 3;
171 nloops = 1 << 2;
172 np2 = np >> 1;
173 do {
174 p = z;
175 q = z + nloops;
176 for (j = 0; j < nblocks; ++j) {
177
178 BF(p->re, p->im, q->re, q->im,
179 p->re, p->im, q->re, q->im);
180
181 p++;
182 q++;
183 for(l = nblocks; l < np2; l += nblocks) {
184 CMUL(tmp_re, tmp_im, costab[l], -sintab[l], q->re, q->im);
185 BF(p->re, p->im, q->re, q->im,
186 p->re, p->im, tmp_re, tmp_im);
187 p++;
188 q++;
189 }
190 p += nloops;
191 q += nloops;
192 }
193 nblocks = nblocks >> 1;
194 nloops = nloops << 1;
195 } while (nblocks != 0);
196 }
197
198 /* do a 512 point mdct */
199 static void mdct512(int32_t *out, int16_t *in)
200 {
201 int i, re, im, re1, im1;
202 int16_t rot[N];
203 IComplex x[N/4];
204
205 /* shift to simplify computations */
206 for(i=0;i<N/4;i++)
207 rot[i] = -in[i + 3*N/4];
208 for(i=N/4;i<N;i++)
209 rot[i] = in[i - N/4];
210
211 /* pre rotation */
212 for(i=0;i<N/4;i++) {
213 re = ((int)rot[2*i] - (int)rot[N-1-2*i]) >> 1;
214 im = -((int)rot[N/2+2*i] - (int)rot[N/2-1-2*i]) >> 1;
215 CMUL(x[i].re, x[i].im, re, im, -xcos1[i], xsin1[i]);
216 }
217
218 fft(x, MDCT_NBITS - 2);
219
220 /* post rotation */
221 for(i=0;i<N/4;i++) {
222 re = x[i].re;
223 im = x[i].im;
224 CMUL(re1, im1, re, im, xsin1[i], xcos1[i]);
225 out[2*i] = im1;
226 out[N/2-1-2*i] = re1;
227 }
228 }
229
230 /* XXX: use another norm ? */
231 static int calc_exp_diff(uint8_t *exp1, uint8_t *exp2, int n)
232 {
233 int sum, i;
234 sum = 0;
235 for(i=0;i<n;i++) {
236 sum += abs(exp1[i] - exp2[i]);
237 }
238 return sum;
239 }
240
241 static void compute_exp_strategy(uint8_t exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
242 uint8_t exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
243 int ch, int is_lfe)
244 {
245 int i, j;
246 int exp_diff;
247
248 /* estimate if the exponent variation & decide if they should be
249 reused in the next frame */
250 exp_strategy[0][ch] = EXP_NEW;
251 for(i=1;i<NB_BLOCKS;i++) {
252 exp_diff = calc_exp_diff(exp[i][ch], exp[i-1][ch], N/2);
253 #ifdef DEBUG
254 av_log(NULL, AV_LOG_DEBUG, "exp_diff=%d\n", exp_diff);
255 #endif
256 if (exp_diff > EXP_DIFF_THRESHOLD)
257 exp_strategy[i][ch] = EXP_NEW;
258 else
259 exp_strategy[i][ch] = EXP_REUSE;
260 }
261 if (is_lfe)
262 return;
263
264 /* now select the encoding strategy type : if exponents are often
265 recoded, we use a coarse encoding */
266 i = 0;
267 while (i < NB_BLOCKS) {
268 j = i + 1;
269 while (j < NB_BLOCKS && exp_strategy[j][ch] == EXP_REUSE)
270 j++;
271 switch(j - i) {
272 case 1:
273 exp_strategy[i][ch] = EXP_D45;
274 break;
275 case 2:
276 case 3:
277 exp_strategy[i][ch] = EXP_D25;
278 break;
279 default:
280 exp_strategy[i][ch] = EXP_D15;
281 break;
282 }
283 i = j;
284 }
285 }
286
287 /* set exp[i] to min(exp[i], exp1[i]) */
288 static void exponent_min(uint8_t exp[N/2], uint8_t exp1[N/2], int n)
289 {
290 int i;
291
292 for(i=0;i<n;i++) {
293 if (exp1[i] < exp[i])
294 exp[i] = exp1[i];
295 }
296 }
297
298 /* update the exponents so that they are the ones the decoder will
299 decode. Return the number of bits used to code the exponents */
300 static int encode_exp(uint8_t encoded_exp[N/2],
301 uint8_t exp[N/2],
302 int nb_exps,
303 int exp_strategy)
304 {
305 int group_size, nb_groups, i, j, k, exp_min;
306 uint8_t exp1[N/2];
307
308 switch(exp_strategy) {
309 case EXP_D15:
310 group_size = 1;
311 break;
312 case EXP_D25:
313 group_size = 2;
314 break;
315 default:
316 case EXP_D45:
317 group_size = 4;
318 break;
319 }
320 nb_groups = ((nb_exps + (group_size * 3) - 4) / (3 * group_size)) * 3;
321
322 /* for each group, compute the minimum exponent */
323 exp1[0] = exp[0]; /* DC exponent is handled separately */
324 k = 1;
325 for(i=1;i<=nb_groups;i++) {
326 exp_min = exp[k];
327 assert(exp_min >= 0 && exp_min <= 24);
328 for(j=1;j<group_size;j++) {
329 if (exp[k+j] < exp_min)
330 exp_min = exp[k+j];
331 }
332 exp1[i] = exp_min;
333 k += group_size;
334 }
335
336 /* constraint for DC exponent */
337 if (exp1[0] > 15)
338 exp1[0] = 15;
339
340 /* Decrease the delta between each groups to within 2
341 * so that they can be differentially encoded */
342 for (i=1;i<=nb_groups;i++)
343 exp1[i] = FFMIN(exp1[i], exp1[i-1] + 2);
344 for (i=nb_groups-1;i>=0;i--)
345 exp1[i] = FFMIN(exp1[i], exp1[i+1] + 2);
346
347 /* now we have the exponent values the decoder will see */
348 encoded_exp[0] = exp1[0];
349 k = 1;
350 for(i=1;i<=nb_groups;i++) {
351 for(j=0;j<group_size;j++) {
352 encoded_exp[k+j] = exp1[i];
353 }
354 k += group_size;
355 }
356
357 #if defined(DEBUG)
358 av_log(NULL, AV_LOG_DEBUG, "exponents: strategy=%d\n", exp_strategy);
359 for(i=0;i<=nb_groups * group_size;i++) {
360 av_log(NULL, AV_LOG_DEBUG, "%d ", encoded_exp[i]);
361 }
362 av_log(NULL, AV_LOG_DEBUG, "\n");
363 #endif
364
365 return 4 + (nb_groups / 3) * 7;
366 }
367
368 /* return the size in bits taken by the mantissa */
369 static int compute_mantissa_size(AC3EncodeContext *s, uint8_t *m, int nb_coefs)
370 {
371 int bits, mant, i;
372
373 bits = 0;
374 for(i=0;i<nb_coefs;i++) {
375 mant = m[i];
376 switch(mant) {
377 case 0:
378 /* nothing */
379 break;
380 case 1:
381 /* 3 mantissa in 5 bits */
382 if (s->mant1_cnt == 0)
383 bits += 5;
384 if (++s->mant1_cnt == 3)
385 s->mant1_cnt = 0;
386 break;
387 case 2:
388 /* 3 mantissa in 7 bits */
389 if (s->mant2_cnt == 0)
390 bits += 7;
391 if (++s->mant2_cnt == 3)
392 s->mant2_cnt = 0;
393 break;
394 case 3:
395 bits += 3;
396 break;
397 case 4:
398 /* 2 mantissa in 7 bits */
399 if (s->mant4_cnt == 0)
400 bits += 7;
401 if (++s->mant4_cnt == 2)
402 s->mant4_cnt = 0;
403 break;
404 case 14:
405 bits += 14;
406 break;
407 case 15:
408 bits += 16;
409 break;
410 default:
411 bits += mant - 1;
412 break;
413 }
414 }
415 return bits;
416 }
417
418
419 static void bit_alloc_masking(AC3EncodeContext *s,
420 uint8_t encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
421 uint8_t exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
422 int16_t psd[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
423 int16_t mask[NB_BLOCKS][AC3_MAX_CHANNELS][50])
424 {
425 int blk, ch;
426 int16_t band_psd[NB_BLOCKS][AC3_MAX_CHANNELS][50];
427
428 for(blk=0; blk<NB_BLOCKS; blk++) {
429 for(ch=0;ch<s->nb_all_channels;ch++) {
430 if(exp_strategy[blk][ch] == EXP_REUSE) {
431 memcpy(psd[blk][ch], psd[blk-1][ch], (N/2)*sizeof(int16_t));
432 memcpy(mask[blk][ch], mask[blk-1][ch], 50*sizeof(int16_t));
433 } else {
434 ff_ac3_bit_alloc_calc_psd(encoded_exp[blk][ch], 0,
435 s->nb_coefs[ch],
436 psd[blk][ch], band_psd[blk][ch]);
437 ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, band_psd[blk][ch],
438 0, s->nb_coefs[ch],
439 ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
440 ch == s->lfe_channel,
441 DBA_NONE, 0, NULL, NULL, NULL,
442 mask[blk][ch]);
443 }
444 }
445 }
446 }
447
448 static int bit_alloc(AC3EncodeContext *s,
449 int16_t mask[NB_BLOCKS][AC3_MAX_CHANNELS][50],
450 int16_t psd[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
451 uint8_t bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
452 int frame_bits, int coarse_snr_offset, int fine_snr_offset)
453 {
454 int i, ch;
455 int snr_offset;
456
457 snr_offset = (((coarse_snr_offset - 15) << 4) + fine_snr_offset) << 2;
458
459 /* compute size */
460 for(i=0;i<NB_BLOCKS;i++) {
461 s->mant1_cnt = 0;
462 s->mant2_cnt = 0;
463 s->mant4_cnt = 0;
464 for(ch=0;ch<s->nb_all_channels;ch++) {
465 ff_ac3_bit_alloc_calc_bap(mask[i][ch], psd[i][ch], 0,
466 s->nb_coefs[ch], snr_offset,
467 s->bit_alloc.floor, ff_ac3_bap_tab,
468 bap[i][ch]);
469 frame_bits += compute_mantissa_size(s, bap[i][ch],
470 s->nb_coefs[ch]);
471 }
472 }
473 #if 0
474 printf("csnr=%d fsnr=%d frame_bits=%d diff=%d\n",
475 coarse_snr_offset, fine_snr_offset, frame_bits,
476 16 * s->frame_size - ((frame_bits + 7) & ~7));
477 #endif
478 return 16 * s->frame_size - frame_bits;
479 }
480
481 #define SNR_INC1 4
482
483 static int compute_bit_allocation(AC3EncodeContext *s,
484 uint8_t bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
485 uint8_t encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
486 uint8_t exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
487 int frame_bits)
488 {
489 int i, ch;
490 int coarse_snr_offset, fine_snr_offset;
491 uint8_t bap1[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
492 int16_t psd[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
493 int16_t mask[NB_BLOCKS][AC3_MAX_CHANNELS][50];
494 static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
495
496 /* init default parameters */
497 s->slow_decay_code = 2;
498 s->fast_decay_code = 1;
499 s->slow_gain_code = 1;
500 s->db_per_bit_code = 2;
501 s->floor_code = 4;
502 for(ch=0;ch<s->nb_all_channels;ch++)
503 s->fast_gain_code[ch] = 4;
504
505 /* compute real values */
506 s->bit_alloc.sr_code = s->sr_code;
507 s->bit_alloc.sr_shift = s->sr_shift;
508 s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->sr_shift;
509 s->bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s->fast_decay_code] >> s->sr_shift;
510 s->bit_alloc.slow_gain = ff_ac3_slow_gain_tab[s->slow_gain_code];
511 s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
512 s->bit_alloc.floor = ff_ac3_floor_tab[s->floor_code];
513
514 /* header size */
515 frame_bits += 65;
516 // if (s->channel_mode == 2)
517 // frame_bits += 2;
518 frame_bits += frame_bits_inc[s->channel_mode];
519
520 /* audio blocks */
521 for(i=0;i<NB_BLOCKS;i++) {
522 frame_bits += s->nb_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
523 if (s->channel_mode == AC3_CHMODE_STEREO) {
524 frame_bits++; /* rematstr */
525 if(i==0) frame_bits += 4;
526 }
527 frame_bits += 2 * s->nb_channels; /* chexpstr[2] * c */
528 if (s->lfe)
529 frame_bits++; /* lfeexpstr */
530 for(ch=0;ch<s->nb_channels;ch++) {
531 if (exp_strategy[i][ch] != EXP_REUSE)
532 frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */
533 }
534 frame_bits++; /* baie */
535 frame_bits++; /* snr */
536 frame_bits += 2; /* delta / skip */
537 }
538 frame_bits++; /* cplinu for block 0 */
539 /* bit alloc info */
540 /* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */
541 /* csnroffset[6] */
542 /* (fsnoffset[4] + fgaincod[4]) * c */
543 frame_bits += 2*4 + 3 + 6 + s->nb_all_channels * (4 + 3);
544
545 /* auxdatae, crcrsv */
546 frame_bits += 2;
547
548 /* CRC */
549 frame_bits += 16;
550
551 /* calculate psd and masking curve before doing bit allocation */
552 bit_alloc_masking(s, encoded_exp, exp_strategy, psd, mask);
553
554 /* now the big work begins : do the bit allocation. Modify the snr
555 offset until we can pack everything in the requested frame size */
556
557 coarse_snr_offset = s->coarse_snr_offset;
558 while (coarse_snr_offset >= 0 &&
559 bit_alloc(s, mask, psd, bap, frame_bits, coarse_snr_offset, 0) < 0)
560 coarse_snr_offset -= SNR_INC1;
561 if (coarse_snr_offset < 0) {
562 av_log(NULL, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
563 return -1;
564 }
565 while ((coarse_snr_offset + SNR_INC1) <= 63 &&
566 bit_alloc(s, mask, psd, bap1, frame_bits,
567 coarse_snr_offset + SNR_INC1, 0) >= 0) {
568 coarse_snr_offset += SNR_INC1;
569 memcpy(bap, bap1, sizeof(bap1));
570 }
571 while ((coarse_snr_offset + 1) <= 63 &&
572 bit_alloc(s, mask, psd, bap1, frame_bits, coarse_snr_offset + 1, 0) >= 0) {
573 coarse_snr_offset++;
574 memcpy(bap, bap1, sizeof(bap1));
575 }
576
577 fine_snr_offset = 0;
578 while ((fine_snr_offset + SNR_INC1) <= 15 &&
579 bit_alloc(s, mask, psd, bap1, frame_bits,
580 coarse_snr_offset, fine_snr_offset + SNR_INC1) >= 0) {
581 fine_snr_offset += SNR_INC1;
582 memcpy(bap, bap1, sizeof(bap1));
583 }
584 while ((fine_snr_offset + 1) <= 15 &&
585 bit_alloc(s, mask, psd, bap1, frame_bits,
586 coarse_snr_offset, fine_snr_offset + 1) >= 0) {
587 fine_snr_offset++;
588 memcpy(bap, bap1, sizeof(bap1));
589 }
590
591 s->coarse_snr_offset = coarse_snr_offset;
592 for(ch=0;ch<s->nb_all_channels;ch++)
593 s->fine_snr_offset[ch] = fine_snr_offset;
594 #if defined(DEBUG_BITALLOC)
595 {
596 int j;
597
598 for(i=0;i<6;i++) {
599 for(ch=0;ch<s->nb_all_channels;ch++) {
600 printf("Block #%d Ch%d:\n", i, ch);
601 printf("bap=");
602 for(j=0;j<s->nb_coefs[ch];j++) {
603 printf("%d ",bap[i][ch][j]);
604 }
605 printf("\n");
606 }
607 }
608 }
609 #endif
610 return 0;
611 }
612
613 static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
614 int64_t *channel_layout)
615 {
616 int ch_layout;
617
618 if (channels < 1 || channels > AC3_MAX_CHANNELS)
619 return -1;
620 if ((uint64_t)*channel_layout > 0x7FF)
621 return -1;
622 ch_layout = *channel_layout;
623 if (!ch_layout)
624 ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);
625 if (avcodec_channel_layout_num_channels(ch_layout) != channels)
626 return -1;
627
628 s->lfe = !!(ch_layout & CH_LOW_FREQUENCY);
629 s->nb_all_channels = channels;
630 s->nb_channels = channels - s->lfe;
631 s->lfe_channel = s->lfe ? s->nb_channels : -1;
632 if (s->lfe)
633 ch_layout -= CH_LOW_FREQUENCY;
634
635 switch (ch_layout) {
636 case CH_LAYOUT_MONO: s->channel_mode = AC3_CHMODE_MONO; break;
637 case CH_LAYOUT_STEREO: s->channel_mode = AC3_CHMODE_STEREO; break;
638 case CH_LAYOUT_SURROUND: s->channel_mode = AC3_CHMODE_3F; break;
639 case CH_LAYOUT_2_1: s->channel_mode = AC3_CHMODE_2F1R; break;
640 case CH_LAYOUT_4POINT0: s->channel_mode = AC3_CHMODE_3F1R; break;
641 case CH_LAYOUT_QUAD:
642 case CH_LAYOUT_2_2: s->channel_mode = AC3_CHMODE_2F2R; break;
643 case CH_LAYOUT_5POINT0:
644 case CH_LAYOUT_5POINT0_BACK: s->channel_mode = AC3_CHMODE_3F2R; break;
645 default:
646 return -1;
647 }
648
649 s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe];
650 *channel_layout = ch_layout;
651 if (s->lfe)
652 *channel_layout |= CH_LOW_FREQUENCY;
653
654 return 0;
655 }
656
657 static av_cold int AC3_encode_init(AVCodecContext *avctx)
658 {
659 int freq = avctx->sample_rate;
660 int bitrate = avctx->bit_rate;
661 AC3EncodeContext *s = avctx->priv_data;
662 int i, j, ch;
663 float alpha;
664 int bw_code;
665
666 avctx->frame_size = AC3_FRAME_SIZE;
667
668 ac3_common_init();
669
670 if (!avctx->channel_layout) {
671 av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "
672 "encoder will guess the layout, but it "
673 "might be incorrect.\n");
674 }
675 if (set_channel_info(s, avctx->channels, &avctx->channel_layout)) {
676 av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
677 return -1;
678 }
679
680 /* frequency */
681 for(i=0;i<3;i++) {
682 for(j=0;j<3;j++)
683 if ((ff_ac3_sample_rate_tab[j] >> i) == freq)
684 goto found;
685 }
686 return -1;
687 found:
688 s->sample_rate = freq;
689 s->sr_shift = i;
690 s->sr_code = j;
691 s->bitstream_id = 8 + s->sr_shift;
692 s->bitstream_mode = 0; /* complete main audio service */
693
694 /* bitrate & frame size */
695 for(i=0;i<19;i++) {
696 if ((ff_ac3_bitrate_tab[i] >> s->sr_shift)*1000 == bitrate)
697 break;
698 }
699 if (i == 19)
700 return -1;
701 s->bit_rate = bitrate;
702 s->frame_size_code = i << 1;
703 s->frame_size_min = ff_ac3_frame_size_tab[s->frame_size_code][s->sr_code];
704 s->bits_written = 0;
705 s->samples_written = 0;
706 s->frame_size = s->frame_size_min;
707
708 /* bit allocation init */
709 if(avctx->cutoff) {
710 /* calculate bandwidth based on user-specified cutoff frequency */
711 int cutoff = av_clip(avctx->cutoff, 1, s->sample_rate >> 1);
712 int fbw_coeffs = cutoff * 512 / s->sample_rate;
713 bw_code = av_clip((fbw_coeffs - 73) / 3, 0, 60);
714 } else {
715 /* use default bandwidth setting */
716 /* XXX: should compute the bandwidth according to the frame
717 size, so that we avoid annoying high frequency artifacts */
718 bw_code = 50;
719 }
720 for(ch=0;ch<s->nb_channels;ch++) {
721 /* bandwidth for each channel */
722 s->chbwcod[ch] = bw_code;
723 s->nb_coefs[ch] = bw_code * 3 + 73;
724 }
725 if (s->lfe) {
726 s->nb_coefs[s->lfe_channel] = 7; /* fixed */
727 }
728 /* initial snr offset */
729 s->coarse_snr_offset = 40;
730
731 /* mdct init */
732 fft_init(MDCT_NBITS - 2);
733 for(i=0;i<N/4;i++) {
734 alpha = 2 * M_PI * (i + 1.0 / 8.0) / (float)N;
735 xcos1[i] = fix15(-cos(alpha));
736 xsin1[i] = fix15(-sin(alpha));
737 }
738
739 avctx->coded_frame= avcodec_alloc_frame();
740 avctx->coded_frame->key_frame= 1;
741
742 return 0;
743 }
744
745 /* output the AC-3 frame header */
746 static void output_frame_header(AC3EncodeContext *s, unsigned char *frame)
747 {
748 init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
749
750 put_bits(&s->pb, 16, 0x0b77); /* frame header */
751 put_bits(&s->pb, 16, 0); /* crc1: will be filled later */
752 put_bits(&s->pb, 2, s->sr_code);
753 put_bits(&s->pb, 6, s->frame_size_code + (s->frame_size - s->frame_size_min));
754 put_bits(&s->pb, 5, s->bitstream_id);
755 put_bits(&s->pb, 3, s->bitstream_mode);
756 put_bits(&s->pb, 3, s->channel_mode);
757 if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
758 put_bits(&s->pb, 2, 1); /* XXX -4.5 dB */
759 if (s->channel_mode & 0x04)
760 put_bits(&s->pb, 2, 1); /* XXX -6 dB */
761 if (s->channel_mode == AC3_CHMODE_STEREO)
762 put_bits(&s->pb, 2, 0); /* surround not indicated */
763 put_bits(&s->pb, 1, s->lfe); /* LFE */
764 put_bits(&s->pb, 5, 31); /* dialog norm: -31 db */
765 put_bits(&s->pb, 1, 0); /* no compression control word */
766 put_bits(&s->pb, 1, 0); /* no lang code */
767 put_bits(&s->pb, 1, 0); /* no audio production info */
768 put_bits(&s->pb, 1, 0); /* no copyright */
769 put_bits(&s->pb, 1, 1); /* original bitstream */
770 put_bits(&s->pb, 1, 0); /* no time code 1 */
771 put_bits(&s->pb, 1, 0); /* no time code 2 */
772 put_bits(&s->pb, 1, 0); /* no additional bit stream info */
773 }
774
775 /* symetric quantization on 'levels' levels */
776 static inline int sym_quant(int c, int e, int levels)
777 {
778 int v;
779
780 if (c >= 0) {
781 v = (levels * (c << e)) >> 24;
782 v = (v + 1) >> 1;
783 v = (levels >> 1) + v;
784 } else {
785 v = (levels * ((-c) << e)) >> 24;
786 v = (v + 1) >> 1;
787 v = (levels >> 1) - v;
788 }
789 assert (v >= 0 && v < levels);
790 return v;
791 }
792
793 /* asymetric quantization on 2^qbits levels */
794 static inline int asym_quant(int c, int e, int qbits)
795 {
796 int lshift, m, v;
797
798 lshift = e + qbits - 24;
799 if (lshift >= 0)
800 v = c << lshift;
801 else
802 v = c >> (-lshift);
803 /* rounding */
804 v = (v + 1) >> 1;
805 m = (1 << (qbits-1));
806 if (v >= m)
807 v = m - 1;
808 assert(v >= -m);
809 return v & ((1 << qbits)-1);
810 }
811
812 /* Output one audio block. There are NB_BLOCKS audio blocks in one AC-3
813 frame */
814 static void output_audio_block(AC3EncodeContext *s,
815 uint8_t exp_strategy[AC3_MAX_CHANNELS],
816 uint8_t encoded_exp[AC3_MAX_CHANNELS][N/2],
817 uint8_t bap[AC3_MAX_CHANNELS][N/2],
818 int32_t mdct_coefs[AC3_MAX_CHANNELS][N/2],
819 int8_t global_exp[AC3_MAX_CHANNELS],
820 int block_num)
821 {
822 int ch, nb_groups, group_size, i, baie, rbnd;
823 uint8_t *p;
824 uint16_t qmant[AC3_MAX_CHANNELS][N/2];
825 int exp0, exp1;
826 int mant1_cnt, mant2_cnt, mant4_cnt;
827 uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr;
828 int delta0, delta1, delta2;
829
830 for(ch=0;ch<s->nb_channels;ch++)
831 put_bits(&s->pb, 1, 0); /* 512 point MDCT */
832 for(ch=0;ch<s->nb_channels;ch++)
833 put_bits(&s->pb, 1, 1); /* no dither */
834 put_bits(&s->pb, 1, 0); /* no dynamic range */
835 if (block_num == 0) {
836 /* for block 0, even if no coupling, we must say it. This is a
837 waste of bit :-) */
838 put_bits(&s->pb, 1, 1); /* coupling strategy present */
839 put_bits(&s->pb, 1, 0); /* no coupling strategy */
840 } else {
841 put_bits(&s->pb, 1, 0); /* no new coupling strategy */
842 }
843
844 if (s->channel_mode == AC3_CHMODE_STEREO)
845 {
846 if(block_num==0)
847 {
848 /* first block must define rematrixing (rematstr) */
849 put_bits(&s->pb, 1, 1);
850
851 /* dummy rematrixing rematflg(1:4)=0 */
852 for (rbnd=0;rbnd<4;rbnd++)
853 put_bits(&s->pb, 1, 0);
854 }
855 else
856 {
857 /* no matrixing (but should be used in the future) */
858 put_bits(&s->pb, 1, 0);
859 }
860 }
861
862 #if defined(DEBUG)
863 {
864 static int count = 0;
865 av_log(NULL, AV_LOG_DEBUG, "Block #%d (%d)\n", block_num, count++);
866 }
867 #endif
868 /* exponent strategy */
869 for(ch=0;ch<s->nb_channels;ch++) {
870 put_bits(&s->pb, 2, exp_strategy[ch]);
871 }
872
873 if (s->lfe) {
874 put_bits(&s->pb, 1, exp_strategy[s->lfe_channel]);
875 }
876
877 for(ch=0;ch<s->nb_channels;ch++) {
878 if (exp_strategy[ch] != EXP_REUSE)
879 put_bits(&s->pb, 6, s->chbwcod[ch]);
880 }
881
882 /* exponents */
883 for (ch = 0; ch < s->nb_all_channels; ch++) {
884 switch(exp_strategy[ch]) {
885 case EXP_REUSE:
886 continue;
887 case EXP_D15:
888 group_size = 1;
889 break;
890 case EXP_D25:
891 group_size = 2;
892 break;
893 default:
894 case EXP_D45:
895 group_size = 4;
896 break;
897 }
898 nb_groups = (s->nb_coefs[ch] + (group_size * 3) - 4) / (3 * group_size);
899 p = encoded_exp[ch];
900
901 /* first exponent */
902 exp1 = *p++;
903 put_bits(&s->pb, 4, exp1);
904
905 /* next ones are delta encoded */
906 for(i=0;i<nb_groups;i++) {
907 /* merge three delta in one code */
908 exp0 = exp1;
909 exp1 = p[0];
910 p += group_size;
911 delta0 = exp1 - exp0 + 2;
912
913 exp0 = exp1;
914 exp1 = p[0];
915 p += group_size;
916 delta1 = exp1 - exp0 + 2;
917
918 exp0 = exp1;
919 exp1 = p[0];
920 p += group_size;
921 delta2 = exp1 - exp0 + 2;
922
923 put_bits(&s->pb, 7, ((delta0 * 5 + delta1) * 5) + delta2);
924 }
925
926 if (ch != s->lfe_channel)
927 put_bits(&s->pb, 2, 0); /* no gain range info */
928 }
929
930 /* bit allocation info */
931 baie = (block_num == 0);
932 put_bits(&s->pb, 1, baie);
933 if (baie) {
934 put_bits(&s->pb, 2, s->slow_decay_code);
935 put_bits(&s->pb, 2, s->fast_decay_code);
936 put_bits(&s->pb, 2, s->slow_gain_code);
937 put_bits(&s->pb, 2, s->db_per_bit_code);
938 put_bits(&s->pb, 3, s->floor_code);
939 }
940
941 /* snr offset */
942 put_bits(&s->pb, 1, baie); /* always present with bai */
943 if (baie) {
944 put_bits(&s->pb, 6, s->coarse_snr_offset);
945 for(ch=0;ch<s->nb_all_channels;ch++) {
946 put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
947 put_bits(&s->pb, 3, s->fast_gain_code[ch]);
948 }
949 }
950
951 put_bits(&s->pb, 1, 0); /* no delta bit allocation */
952 put_bits(&s->pb, 1, 0); /* no data to skip */
953
954 /* mantissa encoding : we use two passes to handle the grouping. A
955 one pass method may be faster, but it would necessitate to
956 modify the output stream. */
957
958 /* first pass: quantize */
959 mant1_cnt = mant2_cnt = mant4_cnt = 0;
960 qmant1_ptr = qmant2_ptr = qmant4_ptr = NULL;
961
962 for (ch = 0; ch < s->nb_all_channels; ch++) {
963 int b, c, e, v;
964
965 for(i=0;i<s->nb_coefs[ch];i++) {
966 c = mdct_coefs[ch][i];
967 e = encoded_exp[ch][i] - global_exp[ch];
968 b = bap[ch][i];
969 switch(b) {
970 case 0:
971 v = 0;
972 break;
973 case 1:
974 v = sym_quant(c, e, 3);
975 switch(mant1_cnt) {
976 case 0:
977 qmant1_ptr = &qmant[ch][i];
978 v = 9 * v;
979 mant1_cnt = 1;
980 break;
981 case 1:
982 *qmant1_ptr += 3 * v;
983 mant1_cnt = 2;
984 v = 128;
985 break;
986 default:
987 *qmant1_ptr += v;
988 mant1_cnt = 0;
989 v = 128;
990 break;
991 }
992 break;
993 case 2:
994 v = sym_quant(c, e, 5);
995 switch(mant2_cnt) {
996 case 0:
997 qmant2_ptr = &qmant[ch][i];
998 v = 25 * v;
999 mant2_cnt = 1;
1000 break;
1001 case 1:
1002 *qmant2_ptr += 5 * v;
1003 mant2_cnt = 2;
1004 v = 128;
1005 break;
1006 default:
1007 *qmant2_ptr += v;
1008 mant2_cnt = 0;
1009 v = 128;
1010 break;
1011 }
1012 break;
1013 case 3:
1014 v = sym_quant(c, e, 7);
1015 break;
1016 case 4:
1017 v = sym_quant(c, e, 11);
1018 switch(mant4_cnt) {
1019 case 0:
1020 qmant4_ptr = &qmant[ch][i];
1021 v = 11 * v;
1022 mant4_cnt = 1;
1023 break;
1024 default:
1025 *qmant4_ptr += v;
1026 mant4_cnt = 0;
1027 v = 128;
1028 break;
1029 }
1030 break;
1031 case 5:
1032 v = sym_quant(c, e, 15);
1033 break;
1034 case 14:
1035 v = asym_quant(c, e, 14);
1036 break;
1037 case 15:
1038 v = asym_quant(c, e, 16);
1039 break;
1040 default:
1041 v = asym_quant(c, e, b - 1);
1042 break;
1043 }
1044 qmant[ch][i] = v;
1045 }
1046 }
1047
1048 /* second pass : output the values */
1049 for (ch = 0; ch < s->nb_all_channels; ch++) {
1050 int b, q;
1051
1052 for(i=0;i<s->nb_coefs[ch];i++) {
1053 q = qmant[ch][i];
1054 b = bap[ch][i];
1055 switch(b) {
1056 case 0:
1057 break;
1058 case 1:
1059 if (q != 128)
1060 put_bits(&s->pb, 5, q);
1061 break;
1062 case 2:
1063 if (q != 128)
1064 put_bits(&s->pb, 7, q);
1065 break;
1066 case 3:
1067 put_bits(&s->pb, 3, q);
1068 break;
1069 case 4:
1070 if (q != 128)
1071 put_bits(&s->pb, 7, q);
1072 break;
1073 case 14:
1074 put_bits(&s->pb, 14, q);
1075 break;
1076 case 15:
1077 put_bits(&s->pb, 16, q);
1078 break;
1079 default:
1080 put_bits(&s->pb, b - 1, q);
1081 break;
1082 }
1083 }
1084 }
1085 }
1086
1087 #define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
1088
1089 static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
1090 {
1091 unsigned int c;
1092
1093 c = 0;
1094 while (a) {
1095 if (a & 1)
1096 c ^= b;
1097 a = a >> 1;
1098 b = b << 1;
1099 if (b & (1 << 16))
1100 b ^= poly;
1101 }
1102 return c;
1103 }
1104
1105 static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
1106 {
1107 unsigned int r;
1108 r = 1;
1109 while (n) {
1110 if (n & 1)
1111 r = mul_poly(r, a, poly);
1112 a = mul_poly(a, a, poly);
1113 n >>= 1;
1114 }
1115 return r;
1116 }
1117
1118
1119 /* compute log2(max(abs(tab[]))) */
1120 static int log2_tab(int16_t *tab, int n)
1121 {
1122 int i, v;
1123
1124 v = 0;
1125 for(i=0;i<n;i++) {
1126 v |= abs(tab[i]);
1127 }
1128 return av_log2(v);
1129 }
1130
1131 static void lshift_tab(int16_t *tab, int n, int lshift)
1132 {
1133 int i;
1134
1135 if (lshift > 0) {
1136 for(i=0;i<n;i++) {
1137 tab[i] <<= lshift;
1138 }
1139 } else if (lshift < 0) {
1140 lshift = -lshift;
1141 for(i=0;i<n;i++) {
1142 tab[i] >>= lshift;
1143 }
1144 }
1145 }
1146
1147 /* fill the end of the frame and compute the two crcs */
1148 static int output_frame_end(AC3EncodeContext *s)
1149 {
1150 int frame_size, frame_size_58, n, crc1, crc2, crc_inv;
1151 uint8_t *frame;
1152
1153 frame_size = s->frame_size; /* frame size in words */
1154 /* align to 8 bits */
1155 flush_put_bits(&s->pb);
1156 /* add zero bytes to reach the frame size */
1157 frame = s->pb.buf;
1158 n = 2 * s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
1159 assert(n >= 0);
1160 if(n>0)
1161 memset(put_bits_ptr(&s->pb), 0, n);
1162
1163 /* Now we must compute both crcs : this is not so easy for crc1
1164 because it is at the beginning of the data... */
1165 frame_size_58 = (frame_size >> 1) + (frame_size >> 3);
1166 crc1 = bswap_16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
1167 frame + 4, 2 * frame_size_58 - 4));
1168 /* XXX: could precompute crc_inv */
1169 crc_inv = pow_poly((CRC16_POLY >> 1), (16 * frame_size_58) - 16, CRC16_POLY);
1170 crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
1171 AV_WB16(frame+2,crc1);
1172
1173 crc2 = bswap_16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
1174 frame + 2 * frame_size_58,
1175 (frame_size - frame_size_58) * 2 - 2));
1176 AV_WB16(frame+2*frame_size-2,crc2);
1177
1178 // printf("n=%d frame_size=%d\n", n, frame_size);
1179 return frame_size * 2;
1180 }
1181
1182 static int AC3_encode_frame(AVCodecContext *avctx,
1183 unsigned char *frame, int buf_size, void *data)
1184 {
1185 AC3EncodeContext *s = avctx->priv_data;
1186 int16_t *samples = data;
1187 int i, j, k, v, ch;
1188 int16_t input_samples[N];
1189 int32_t mdct_coef[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
1190 uint8_t exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
1191 uint8_t exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS];
1192 uint8_t encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
1193 uint8_t bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
1194 int8_t exp_samples[NB_BLOCKS][AC3_MAX_CHANNELS];
1195 int frame_bits;
1196
1197 frame_bits = 0;
1198 for(ch=0;ch<s->nb_all_channels;ch++) {
1199 int ich = s->channel_map[ch];
1200 /* fixed mdct to the six sub blocks & exponent computation */
1201 for(i=0;i<NB_BLOCKS;i++) {
1202 int16_t *sptr;
1203 int sinc;
1204
1205 /* compute input samples */
1206 memcpy(input_samples, s->last_samples[ich], N/2 * sizeof(int16_t));
1207 sinc = s->nb_all_channels;
1208 sptr = samples + (sinc * (N/2) * i) + ich;
1209 for(j=0;j<N/2;j++) {
1210 v = *sptr;
1211 input_samples[j + N/2] = v;
1212 s->last_samples[ich][j] = v;
1213 sptr += sinc;
1214 }
1215
1216 /* apply the MDCT window */
1217 for(j=0;j<N/2;j++) {
1218 input_samples[j] = MUL16(input_samples[j],
1219 ff_ac3_window[j]) >> 15;
1220 input_samples[N-j-1] = MUL16(input_samples[N-j-1],
1221 ff_ac3_window[j]) >> 15;
1222 }
1223
1224 /* Normalize the samples to use the maximum available
1225 precision */
1226 v = 14 - log2_tab(input_samples, N);
1227 if (v < 0)
1228 v = 0;
1229 exp_samples[i][ch] = v - 9;
1230 lshift_tab(input_samples, N, v);
1231
1232 /* do the MDCT */
1233 mdct512(mdct_coef[i][ch], input_samples);
1234
1235 /* compute "exponents". We take into account the
1236 normalization there */
1237 for(j=0;j<N/2;j++) {
1238 int e;
1239 v = abs(mdct_coef[i][ch][j]);
1240 if (v == 0)
1241 e = 24;
1242 else {
1243 e = 23 - av_log2(v) + exp_samples[i][ch];
1244 if (e >= 24) {
1245 e = 24;
1246 mdct_coef[i][ch][j] = 0;
1247 }
1248 }
1249 exp[i][ch][j] = e;
1250 }
1251 }
1252
1253 compute_exp_strategy(exp_strategy, exp, ch, ch == s->lfe_channel);
1254
1255 /* compute the exponents as the decoder will see them. The
1256 EXP_REUSE case must be handled carefully : we select the
1257 min of the exponents */
1258 i = 0;
1259 while (i < NB_BLOCKS) {
1260 j = i + 1;
1261 while (j < NB_BLOCKS && exp_strategy[j][ch] == EXP_REUSE) {
1262 exponent_min(exp[i][ch], exp[j][ch], s->nb_coefs[ch]);
1263 j++;
1264 }
1265 frame_bits += encode_exp(encoded_exp[i][ch],
1266 exp[i][ch], s->nb_coefs[ch],
1267 exp_strategy[i][ch]);
1268 /* copy encoded exponents for reuse case */
1269 for(k=i+1;k<j;k++) {
1270 memcpy(encoded_exp[k][ch], encoded_exp[i][ch],
1271 s->nb_coefs[ch] * sizeof(uint8_t));
1272 }
1273 i = j;
1274 }
1275 }
1276
1277 /* adjust for fractional frame sizes */
1278 while(s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
1279 s->bits_written -= s->bit_rate;
1280 s->samples_written -= s->sample_rate;
1281 }
1282 s->frame_size = s->frame_size_min + (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
1283 s->bits_written += s->frame_size * 16;
1284 s->samples_written += AC3_FRAME_SIZE;
1285
1286 compute_bit_allocation(s, bap, encoded_exp, exp_strategy, frame_bits);
1287 /* everything is known... let's output the frame */
1288 output_frame_header(s, frame);
1289
1290 for(i=0;i<NB_BLOCKS;i++) {
1291 output_audio_block(s, exp_strategy[i], encoded_exp[i],
1292 bap[i], mdct_coef[i], exp_samples[i], i);
1293 }
1294 return output_frame_end(s);
1295 }
1296
1297 static av_cold int AC3_encode_close(AVCodecContext *avctx)
1298 {
1299 av_freep(&avctx->coded_frame);
1300 return 0;
1301 }
1302
1303 #if 0
1304 /*************************************************************************/
1305 /* TEST */
1306
1307 #undef random
1308 #define FN (N/4)
1309
1310 void fft_test(void)
1311 {
1312 IComplex in[FN], in1[FN];
1313 int k, n, i;
1314 float sum_re, sum_im, a;
1315
1316 /* FFT test */
1317
1318 for(i=0;i<FN;i++) {
1319 in[i].re = random() % 65535 - 32767;
1320 in[i].im = random() % 65535 - 32767;
1321 in1[i] = in[i];
1322 }
1323 fft(in, 7);
1324
1325 /* do it by hand */
1326 for(k=0;k<FN;k++) {
1327 sum_re = 0;
1328 sum_im = 0;
1329 for(n=0;n<FN;n++) {
1330 a = -2 * M_PI * (n * k) / FN;
1331 sum_re += in1[n].re * cos(a) - in1[n].im * sin(a);
1332 sum_im += in1[n].re * sin(a) + in1[n].im * cos(a);
1333 }
1334 printf("%3d: %6d,%6d %6.0f,%6.0f\n",
1335 k, in[k].re, in[k].im, sum_re / FN, sum_im / FN);
1336 }
1337 }
1338
1339 void mdct_test(void)
1340 {
1341 int16_t input[N];
1342 int32_t output[N/2];
1343 float input1[N];
1344 float output1[N/2];
1345 float s, a, err, e, emax;
1346 int i, k, n;
1347
1348 for(i=0;i<N;i++) {
1349 input[i] = (random() % 65535 - 32767) * 9 / 10;
1350 input1[i] = input[i];
1351 }
1352
1353 mdct512(output, input);
1354
1355 /* do it by hand */
1356 for(k=0;k<N/2;k++) {
1357 s = 0;
1358 for(n=0;n<N;n++) {
1359 a = (2*M_PI*(2*n+1+N/2)*(2*k+1) / (4 * N));
1360 s += input1[n] * cos(a);
1361 }
1362 output1[k] = -2 * s / N;
1363 }
1364
1365 err = 0;
1366 emax = 0;
1367 for(i=0;i<N/2;i++) {
1368 printf("%3d: %7d %7.0f\n", i, output[i], output1[i]);
1369 e = output[i] - output1[i];
1370 if (e > emax)
1371 emax = e;
1372 err += e * e;
1373 }
1374 printf("err2=%f emax=%f\n", err / (N/2), emax);
1375 }
1376
1377 void test_ac3(void)
1378 {
1379 AC3EncodeContext ctx;
1380 unsigned char frame[AC3_MAX_CODED_FRAME_SIZE];
1381 short samples[AC3_FRAME_SIZE];
1382 int ret, i;
1383
1384 AC3_encode_init(&ctx, 44100, 64000, 1);
1385
1386 fft_test();
1387 mdct_test();
1388
1389 for(i=0;i<AC3_FRAME_SIZE;i++)
1390 samples[i] = (int)(sin(2*M_PI*i*1000.0/44100) * 10000);
1391 ret = AC3_encode_frame(&ctx, frame, samples);
1392 printf("ret=%d\n", ret);
1393 }
1394 #endif
1395
1396 AVCodec ac3_encoder = {
1397 "ac3",
1398 CODEC_TYPE_AUDIO,
1399 CODEC_ID_AC3,
1400 sizeof(AC3EncodeContext),
1401 AC3_encode_init,
1402 AC3_encode_frame,
1403 AC3_encode_close,
1404 NULL,
1405 .sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
1406 .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
1407 .channel_layouts = (int64_t[]){
1408 CH_LAYOUT_MONO,
1409 CH_LAYOUT_STEREO,
1410 CH_LAYOUT_2_1,
1411 CH_LAYOUT_SURROUND,
1412 CH_LAYOUT_2_2,
1413 CH_LAYOUT_QUAD,
1414 CH_LAYOUT_4POINT0,
1415 CH_LAYOUT_5POINT0,
1416 CH_LAYOUT_5POINT0_BACK,
1417 (CH_LAYOUT_MONO | CH_LOW_FREQUENCY),
1418 (CH_LAYOUT_STEREO | CH_LOW_FREQUENCY),
1419 (CH_LAYOUT_2_1 | CH_LOW_FREQUENCY),
1420 (CH_LAYOUT_SURROUND | CH_LOW_FREQUENCY),
1421 (CH_LAYOUT_2_2 | CH_LOW_FREQUENCY),
1422 (CH_LAYOUT_QUAD | CH_LOW_FREQUENCY),
1423 (CH_LAYOUT_4POINT0 | CH_LOW_FREQUENCY),
1424 CH_LAYOUT_5POINT1,
1425 CH_LAYOUT_5POINT1_BACK,
1426 0 },
1427 };
ffmpeg Lagarith lossless decoder