If there's ever a rework of the AAC encoder, it won't start from here. The codec, with all its oddities and tweaks needed to acheive good quality has strayed far from the academic work upon which this coder was based on. Its been 20 years since this paper was released, and no known existing implementations, open-source or proprietary that we know of, are based on it.
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| @@ -292,120 +292,6 @@ typedef struct BandCodingPath { · 291 unmodified lines | ||
| 292 | 292 | int run; |
| 293 | 293 | } BandCodingPath; |
| 294 | 294 | |
| 295 | −/** | |
| 296 | − * Encode band info for single window group bands. | |
| 297 | − */ | |
| 298 | −static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce, | |
| 299 | − int win, int group_len, const float lambda) | |
| 300 | −{ | |
| 301 | − BandCodingPath path[120][CB_TOT_ALL]; | |
| 302 | − int w, swb, cb, start, size; | |
| 303 | − int i, j; | |
| 304 | − const int max_sfb = sce->ics.max_sfb; | |
| 305 | − const int run_bits = sce->ics.num_windows == 1 ? 5 : 3; | |
| 306 | − const int run_esc = (1 << run_bits) - 1; | |
| 307 | − int idx, ppos, count; | |
| 308 | − int stackrun[120], stackcb[120], stack_len; | |
| 309 | − float next_minrd = INFINITY; | |
| 310 | − int next_mincb = 0; | |
| 311 | − | |
| 312 | − s->aacdsp.abs_pow34(s->scoefs, sce->coeffs, 1024); | |
| 313 | − start = win*128; | |
| 314 | − for (cb = 0; cb < CB_TOT_ALL; cb++) { | |
| 315 | − path[0][cb].cost = 0.0f; | |
| 316 | − path[0][cb].prev_idx = -1; | |
| 317 | − path[0][cb].run = 0; | |
| 318 | − } | |
| 319 | − for (swb = 0; swb < max_sfb; swb++) { | |
| 320 | − size = sce->ics.swb_sizes[swb]; | |
| 321 | − if (sce->zeroes[win*16 + swb]) { | |
| 322 | − for (cb = 0; cb < CB_TOT_ALL; cb++) { | |
| 323 | − path[swb+1][cb].prev_idx = cb; | |
| 324 | − path[swb+1][cb].cost = path[swb][cb].cost; | |
| 325 | − path[swb+1][cb].run = path[swb][cb].run + 1; | |
| 326 | − } | |
| 327 | − } else { | |
| 328 | − float minrd = next_minrd; | |
| 329 | − int mincb = next_mincb; | |
| 330 | − next_minrd = INFINITY; | |
| 331 | − next_mincb = 0; | |
| 332 | − for (cb = 0; cb < CB_TOT_ALL; cb++) { | |
| 333 | − float cost_stay_here, cost_get_here; | |
| 334 | − float rd = 0.0f; | |
| 335 | − if (cb >= 12 && sce->band_type[win*16+swb] < aac_cb_out_map[cb] || | |
| 336 | − cb < aac_cb_in_map[sce->band_type[win*16+swb]] && sce->band_type[win*16+swb] > aac_cb_out_map[cb]) { | |
| 337 | − path[swb+1][cb].prev_idx = -1; | |
| 338 | − path[swb+1][cb].cost = INFINITY; | |
| 339 | − path[swb+1][cb].run = path[swb][cb].run + 1; | |
| 340 | − continue; | |
| 341 | − } | |
| 342 | − for (w = 0; w < group_len; w++) { | |
| 343 | − FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(win+w)*16+swb]; | |
| 344 | − rd += quantize_band_cost(s, &sce->coeffs[start + w*128], | |
| 345 | − &s->scoefs[start + w*128], size, | |
| 346 | − sce->sf_idx[(win+w)*16+swb], aac_cb_out_map[cb], | |
| 347 | − lambda / band->threshold, INFINITY, NULL, NULL); | |
| 348 | − } | |
| 349 | − cost_stay_here = path[swb][cb].cost + rd; | |
| 350 | − cost_get_here = minrd + rd + run_bits + 4; | |
| 351 | − if ( run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run] | |
| 352 | − != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1]) | |
| 353 | − cost_stay_here += run_bits; | |
| 354 | − if (cost_get_here < cost_stay_here) { | |
| 355 | − path[swb+1][cb].prev_idx = mincb; | |
| 356 | − path[swb+1][cb].cost = cost_get_here; | |
| 357 | − path[swb+1][cb].run = 1; | |
| 358 | − } else { | |
| 359 | − path[swb+1][cb].prev_idx = cb; | |
| 360 | − path[swb+1][cb].cost = cost_stay_here; | |
| 361 | − path[swb+1][cb].run = path[swb][cb].run + 1; | |
| 362 | − } | |
| 363 | − if (path[swb+1][cb].cost < next_minrd) { | |
| 364 | − next_minrd = path[swb+1][cb].cost; | |
| 365 | − next_mincb = cb; | |
| 366 | − } | |
| 367 | − } | |
| 368 | − } | |
| 369 | − start += sce->ics.swb_sizes[swb]; | |
| 370 | − } | |
| 371 | − | |
| 372 | − //convert resulting path from backward-linked list | |
| 373 | − stack_len = 0; | |
| 374 | − idx = 0; | |
| 375 | − for (cb = 1; cb < CB_TOT_ALL; cb++) | |
| 376 | − if (path[max_sfb][cb].cost < path[max_sfb][idx].cost) | |
| 377 | − idx = cb; | |
| 378 | − ppos = max_sfb; | |
| 379 | − while (ppos > 0) { | |
| 380 | − av_assert1(idx >= 0); | |
| 381 | − cb = idx; | |
| 382 | − stackrun[stack_len] = path[ppos][cb].run; | |
| 383 | − stackcb [stack_len] = cb; | |
| 384 | − idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx; | |
| 385 | − ppos -= path[ppos][cb].run; | |
| 386 | − stack_len++; | |
| 387 | − } | |
| 388 | − //perform actual band info encoding | |
| 389 | − start = 0; | |
| 390 | − for (i = stack_len - 1; i >= 0; i--) { | |
| 391 | − cb = aac_cb_out_map[stackcb[i]]; | |
| 392 | − put_bits(&s->pb, 4, cb); | |
| 393 | − count = stackrun[i]; | |
| 394 | − memset(sce->zeroes + win*16 + start, !cb, count); | |
| 395 | − //XXX: memset when band_type is also uint8_t | |
| 396 | − for (j = 0; j < count; j++) { | |
| 397 | − sce->band_type[win*16 + start] = cb; | |
| 398 | − start++; | |
| 399 | − } | |
| 400 | − while (count >= run_esc) { | |
| 401 | − put_bits(&s->pb, run_bits, run_esc); | |
| 402 | − count -= run_esc; | |
| 403 | − } | |
| 404 | − put_bits(&s->pb, run_bits, count); | |
| 405 | − } | |
| 406 | −} | |
| 407 | − | |
| 408 | − | |
| 409 | 295 | typedef struct TrellisPath { |
| 410 | 296 | float cost; |
| 411 | 297 | int prev; |
| @@ -453,166 +339,6 @@ static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement · 41 unmodified lines | ||
| 453 | 339 | } |
| 454 | 340 | } |
| 455 | 341 | |
| 456 | −static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s, | |
| 457 | − SingleChannelElement *sce, | |
| 458 | − const float lambda) | |
| 459 | −{ | |
| 460 | − int q, w, w2, g, start = 0; | |
| 461 | − int i, j; | |
| 462 | − int idx; | |
| 463 | − TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES]; | |
| 464 | − int bandaddr[TRELLIS_STAGES]; | |
| 465 | − int minq; | |
| 466 | − float mincost; | |
| 467 | − float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f; | |
| 468 | − int q0, q1, qcnt = 0; | |
| 469 | − | |
| 470 | − for (i = 0; i < 1024; i++) { | |
| 471 | − float t = fabsf(sce->coeffs[i]); | |
| 472 | − if (t > 0.0f) { | |
| 473 | − q0f = FFMIN(q0f, t); | |
| 474 | − q1f = FFMAX(q1f, t); | |
| 475 | − qnrgf += t*t; | |
| 476 | − qcnt++; | |
| 477 | − } | |
| 478 | − } | |
| 479 | − | |
| 480 | − if (!qcnt) { | |
| 481 | − memset(sce->sf_idx, 0, sizeof(sce->sf_idx)); | |
| 482 | − memset(sce->zeroes, 1, sizeof(sce->zeroes)); | |
| 483 | − return; | |
| 484 | − } | |
| 485 | − | |
| 486 | − //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped | |
| 487 | − q0 = av_clip(coef2minsf(q0f), 0, SCALE_MAX_POS-1); | |
| 488 | − //maximum scalefactor index is when maximum coefficient after quantizing is still not zero | |
| 489 | − q1 = av_clip(coef2maxsf(q1f), 1, SCALE_MAX_POS); | |
| 490 | − if (q1 - q0 > 60) { | |
| 491 | − int q0low = q0; | |
| 492 | − int q1high = q1; | |
| 493 | − //minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped | |
| 494 | − int qnrg = av_clip_uint8(log2f(sqrtf(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512); | |
| 495 | − q1 = qnrg + 30; | |
| 496 | − q0 = qnrg - 30; | |
| 497 | − if (q0 < q0low) { | |
| 498 | − q1 += q0low - q0; | |
| 499 | − q0 = q0low; | |
| 500 | − } else if (q1 > q1high) { | |
| 501 | − q0 -= q1 - q1high; | |
| 502 | − q1 = q1high; | |
| 503 | − } | |
| 504 | − } | |
| 505 | − // q0 == q1 isn't really a legal situation | |
| 506 | − if (q0 == q1) { | |
| 507 | − // the following is indirect but guarantees q1 != q0 && q1 near q0 | |
| 508 | − q1 = av_clip(q0+1, 1, SCALE_MAX_POS); | |
| 509 | − q0 = av_clip(q1-1, 0, SCALE_MAX_POS - 1); | |
| 510 | − } | |
| 511 | − | |
| 512 | − for (i = 0; i < TRELLIS_STATES; i++) { | |
| 513 | − paths[0][i].cost = 0.0f; | |
| 514 | − paths[0][i].prev = -1; | |
| 515 | − } | |
| 516 | − for (j = 1; j < TRELLIS_STAGES; j++) { | |
| 517 | − for (i = 0; i < TRELLIS_STATES; i++) { | |
| 518 | − paths[j][i].cost = INFINITY; | |
| 519 | − paths[j][i].prev = -2; | |
| 520 | − } | |
| 521 | − } | |
| 522 | − idx = 1; | |
| 523 | − s->aacdsp.abs_pow34(s->scoefs, sce->coeffs, 1024); | |
| 524 | − for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) { | |
| 525 | − start = w*128; | |
| 526 | − for (g = 0; g < sce->ics.num_swb; g++) { | |
| 527 | − const float *coefs = &sce->coeffs[start]; | |
| 528 | − float qmin, qmax; | |
| 529 | − int nz = 0; | |
| 530 | − | |
| 531 | − bandaddr[idx] = w * 16 + g; | |
| 532 | − qmin = INT_MAX; | |
| 533 | − qmax = 0.0f; | |
| 534 | − for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) { | |
| 535 | − FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g]; | |
| 536 | − if (band->energy <= band->threshold || band->threshold == 0.0f) { | |
| 537 | − sce->zeroes[(w+w2)*16+g] = 1; | |
| 538 | − continue; | |
| 539 | − } | |
| 540 | − sce->zeroes[(w+w2)*16+g] = 0; | |
| 541 | − nz = 1; | |
| 542 | − for (i = 0; i < sce->ics.swb_sizes[g]; i++) { | |
| 543 | − float t = fabsf(coefs[w2*128+i]); | |
| 544 | − if (t > 0.0f) | |
| 545 | − qmin = FFMIN(qmin, t); | |
| 546 | − qmax = FFMAX(qmax, t); | |
| 547 | − } | |
| 548 | − } | |
| 549 | − if (nz) { | |
| 550 | − int minscale, maxscale; | |
| 551 | − float minrd = INFINITY; | |
| 552 | − float maxval; | |
| 553 | − //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped | |
| 554 | − minscale = coef2minsf(qmin); | |
| 555 | − //maximum scalefactor index is when maximum coefficient after quantizing is still not zero | |
| 556 | − maxscale = coef2maxsf(qmax); | |
| 557 | − minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1); | |
| 558 | − maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES); | |
| 559 | − if (minscale == maxscale) { | |
| 560 | − maxscale = av_clip(minscale+1, 1, TRELLIS_STATES); | |
| 561 | − minscale = av_clip(maxscale-1, 0, TRELLIS_STATES - 1); | |
| 562 | − } | |
| 563 | − maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start); | |
| 564 | − for (q = minscale; q < maxscale; q++) { | |
| 565 | − float dist = 0; | |
| 566 | − int cb = find_min_book(maxval, sce->sf_idx[w*16+g]); | |
| 567 | − for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) { | |
| 568 | − FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g]; | |
| 569 | − dist += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g], | |
| 570 | − q + q0, cb, lambda / band->threshold, INFINITY, NULL, NULL); | |
| 571 | − } | |
| 572 | − minrd = FFMIN(minrd, dist); | |
| 573 | − | |
| 574 | − for (i = 0; i < q1 - q0; i++) { | |
| 575 | − float cost; | |
| 576 | − cost = paths[idx - 1][i].cost + dist | |
| 577 | − + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO]; | |
| 578 | − if (cost < paths[idx][q].cost) { | |
| 579 | − paths[idx][q].cost = cost; | |
| 580 | − paths[idx][q].prev = i; | |
| 581 | − } | |
| 582 | − } | |
| 583 | − } | |
| 584 | − } else { | |
| 585 | − for (q = 0; q < q1 - q0; q++) { | |
| 586 | − paths[idx][q].cost = paths[idx - 1][q].cost + 1; | |
| 587 | − paths[idx][q].prev = q; | |
| 588 | − } | |
| 589 | − } | |
| 590 | − sce->zeroes[w*16+g] = !nz; | |
| 591 | − start += sce->ics.swb_sizes[g]; | |
| 592 | − idx++; | |
| 593 | − } | |
| 594 | − } | |
| 595 | − idx--; | |
| 596 | − mincost = paths[idx][0].cost; | |
| 597 | − minq = 0; | |
| 598 | − for (i = 1; i < TRELLIS_STATES; i++) { | |
| 599 | − if (paths[idx][i].cost < mincost) { | |
| 600 | − mincost = paths[idx][i].cost; | |
| 601 | − minq = i; | |
| 602 | − } | |
| 603 | − } | |
| 604 | − while (idx) { | |
| 605 | − sce->sf_idx[bandaddr[idx]] = minq + q0; | |
| 606 | − minq = FFMAX(paths[idx][minq].prev, 0); | |
| 607 | − idx--; | |
| 608 | − } | |
| 609 | − //set the same quantizers inside window groups | |
| 610 | − for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) | |
| 611 | − for (g = 0; g < sce->ics.num_swb; g++) | |
| 612 | − for (w2 = 1; w2 < sce->ics.group_len[w]; w2++) | |
| 613 | − sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g]; | |
| 614 | −} | |
| 615 | − | |
| 616 | 342 | static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s, |
| 617 | 343 | SingleChannelElement *sce, |
| 618 | 344 | const float lambda) |
| @@ -1115,19 +841,6 @@ static void search_for_ms(AACEncContext *s, ChannelElement *cpe) · 496 unmodified lines | ||
| 1115 | 841 | } |
| 1116 | 842 | |
| 1117 | 843 | const AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = { |
| 1118 | − [AAC_CODER_ANMR] = { | |
| 1119 | − search_for_quantizers_anmr, | |
| 1120 | − encode_window_bands_info, | |
| 1121 | − quantize_and_encode_band, | |
| 1122 | − ff_aac_encode_tns_info, | |
| 1123 | − ff_aac_apply_tns, | |
| 1124 | − set_special_band_scalefactors, | |
| 1125 | − search_for_pns, | |
| 1126 | − mark_pns, | |
| 1127 | − ff_aac_search_for_tns, | |
| 1128 | − search_for_ms, | |
| 1129 | − ff_aac_search_for_is, | |
| 1130 | − }, | |
| 1131 | 844 | [AAC_CODER_TWOLOOP] = { |
| 1132 | 845 | search_for_quantizers_twoloop, |
| 1133 | 846 | codebook_trellis_rate, |