git.sesse.net Git - ffmpeg/blob - libavcodec/aaccoder.c

   1 /*
   2  * AAC coefficients encoder
   3  * Copyright (C) 2008-2009 Konstantin Shishkov
   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
  24  * AAC coefficients encoder
  25  */
  26
  27 /***********************************
  28  *              TODOs:
  29  * speedup quantizer selection
  30  * add sane pulse detection
  31  ***********************************/
  32
  33 #include "avcodec.h"
  34 #include "put_bits.h"
  35 #include "aac.h"
  36 #include "aacenc.h"
  37 #include "aactab.h"
  38
  39 /** bits needed to code codebook run value for long windows */
  40 static const uint8_t run_value_bits_long[64] = {
  41      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,
  42      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5, 10,
  43     10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
  44     10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 15
  45 };
  46
  47 /** bits needed to code codebook run value for short windows */
  48 static const uint8_t run_value_bits_short[16] = {
  49     3, 3, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6, 6, 6, 9
  50 };
  51
  52 static const uint8_t *run_value_bits[2] = {
  53     run_value_bits_long, run_value_bits_short
  54 };
  55
  56
  57 /**
  58  * Quantize one coefficient.
  59  * @return absolute value of the quantized coefficient
  60  * @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
  61  */
  62 static av_always_inline int quant(float coef, const float Q)
  63 {
  64     float a = coef * Q;
  65     return sqrtf(a * sqrtf(a)) + 0.4054;
  66 }
  67
  68 static void quantize_bands(int *out, const float *in, const float *scaled,
  69                            int size, float Q34, int is_signed, int maxval)
  70 {
  71     int i;
  72     double qc;
  73     for (i = 0; i < size; i++) {
  74         qc = scaled[i] * Q34;
  75         out[i] = (int)FFMIN(qc + 0.4054, (double)maxval);
  76         if (is_signed && in[i] < 0.0f) {
  77             out[i] = -out[i];
  78         }
  79     }
  80 }
  81
  82 static void abs_pow34_v(float *out, const float *in, const int size)
  83 {
  84 #ifndef USE_REALLY_FULL_SEARCH
  85     int i;
  86     for (i = 0; i < size; i++) {
  87         float a = fabsf(in[i]);
  88         out[i] = sqrtf(a * sqrtf(a));
  89     }
  90 #endif /* USE_REALLY_FULL_SEARCH */
  91 }
  92
  93 static const uint8_t aac_cb_range [12] = {0, 3, 3, 3, 3, 9, 9, 8, 8, 13, 13, 17};
  94 static const uint8_t aac_cb_maxval[12] = {0, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 16};
  95
  96 /**
  97  * Calculate rate distortion cost for quantizing with given codebook
  98  *
  99  * @return quantization distortion
 100  */
 101 static float quantize_and_encode_band_cost(struct AACEncContext *s,
 102                                 PutBitContext *pb, const float *in,
 103                                 const float *scaled, int size, int scale_idx,
 104                                 int cb, const float lambda, const float uplim,
 105                                 int *bits)
 106 {
 107     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 108     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
 109     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 110     int i, j, k;
 111     float cost = 0;
 112     const int dim = cb < FIRST_PAIR_BT ? 4 : 2;
 113     int resbits = 0;
 114     const float  Q34 = sqrtf(Q * sqrtf(Q));
 115     const int range  = aac_cb_range[cb];
 116     const int maxval = aac_cb_maxval[cb];
 117     int off;
 118
 119     if (!cb) {
 120         for (i = 0; i < size; i++)
 121             cost += in[i]*in[i];
 122         if (bits)
 123             *bits = 0;
 124         return cost * lambda;
 125     }
 126     if (!scaled) {
 127         abs_pow34_v(s->scoefs, in, size);
 128         scaled = s->scoefs;
 129     }
 130     quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
 131     if (IS_CODEBOOK_UNSIGNED(cb)) {
 132         off = 0;
 133     } else {
 134         off = maxval;
 135     }
 136     for (i = 0; i < size; i += dim) {
 137         const float *vec;
 138         int *quants = s->qcoefs + i;
 139         int curidx = 0;
 140         int curbits;
 141         float rd = 0.0f;
 142         for (j = 0; j < dim; j++) {
 143             curidx *= range;
 144             curidx += quants[j] + off;
 145         }
 146             curbits =  ff_aac_spectral_bits[cb-1][curidx];
 147             vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 148             if (IS_CODEBOOK_UNSIGNED(cb)) {
 149                 for (k = 0; k < dim; k++) {
 150                     float t = fabsf(in[i+k]);
 151                     float di;
 152                     if (vec[k] == 64.0f) { //FIXME: slow
 153                         if (t >= CLIPPED_ESCAPE) {
 154                             di = t - CLIPPED_ESCAPE;
 155                             curbits += 21;
 156                         } else {
 157                             int c = av_clip(quant(t, Q), 0, 8191);
 158                             di = t - c*cbrtf(c)*IQ;
 159                             curbits += av_log2(c)*2 - 4 + 1;
 160                         }
 161                     } else {
 162                         di = t - vec[k]*IQ;
 163                     }
 164                     if (vec[k] != 0.0f)
 165                         curbits++;
 166                     rd += di*di;
 167                 }
 168             } else {
 169                 for (k = 0; k < dim; k++) {
 170                     float di = in[i+k] - vec[k]*IQ;
 171                     rd += di*di;
 172                 }
 173             }
 174         cost    += rd * lambda + curbits;
 175         resbits += curbits;
 176         if (cost >= uplim)
 177             return uplim;
 178         if (pb) {
 179         put_bits(pb, ff_aac_spectral_bits[cb-1][curidx], ff_aac_spectral_codes[cb-1][curidx]);
 180         if (IS_CODEBOOK_UNSIGNED(cb))
 181             for (j = 0; j < dim; j++)
 182                 if (ff_aac_codebook_vectors[cb-1][curidx*dim+j] != 0.0f)
 183                     put_bits(pb, 1, in[i+j] < 0.0f);
 184         if (cb == ESC_BT) {
 185             for (j = 0; j < 2; j++) {
 186                 if (ff_aac_codebook_vectors[cb-1][curidx*2+j] == 64.0f) {
 187                     int coef = av_clip(quant(fabsf(in[i+j]), Q), 0, 8191);
 188                     int len = av_log2(coef);
 189
 190                     put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
 191                     put_bits(pb, len, coef & ((1 << len) - 1));
 192                 }
 193             }
 194         }
 195         }
 196     }
 197
 198     if (bits)
 199         *bits = resbits;
 200     return cost;
 201 }
 202 static float quantize_band_cost(struct AACEncContext *s, const float *in,
 203                                 const float *scaled, int size, int scale_idx,
 204                                 int cb, const float lambda, const float uplim,
 205                                 int *bits)
 206 {
 207     return quantize_and_encode_band_cost(s, NULL, in, scaled, size, scale_idx,
 208                                          cb, lambda, uplim, bits);
 209 }
 210
 211 static void quantize_and_encode_band(struct AACEncContext *s, PutBitContext *pb,
 212                                      const float *in, int size, int scale_idx,
 213                                      int cb, const float lambda)
 214 {
 215     quantize_and_encode_band_cost(s, pb, in, NULL, size, scale_idx, cb, lambda,
 216                                   INFINITY, NULL);
 217 }
 218
 219 /**
 220  * structure used in optimal codebook search
 221  */
 222 typedef struct BandCodingPath {
 223     int prev_idx; ///< pointer to the previous path point
 224     float cost;   ///< path cost
 225     int run;
 226 } BandCodingPath;
 227
 228 /**
 229  * Encode band info for single window group bands.
 230  */
 231 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
 232                                      int win, int group_len, const float lambda)
 233 {
 234     BandCodingPath path[120][12];
 235     int w, swb, cb, start, start2, size;
 236     int i, j;
 237     const int max_sfb  = sce->ics.max_sfb;
 238     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 239     const int run_esc  = (1 << run_bits) - 1;
 240     int idx, ppos, count;
 241     int stackrun[120], stackcb[120], stack_len;
 242     float next_minrd = INFINITY;
 243     int next_mincb = 0;
 244
 245     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 246     start = win*128;
 247     for (cb = 0; cb < 12; cb++) {
 248         path[0][cb].cost     = 0.0f;
 249         path[0][cb].prev_idx = -1;
 250         path[0][cb].run      = 0;
 251     }
 252     for (swb = 0; swb < max_sfb; swb++) {
 253         start2 = start;
 254         size = sce->ics.swb_sizes[swb];
 255         if (sce->zeroes[win*16 + swb]) {
 256             for (cb = 0; cb < 12; cb++) {
 257                 path[swb+1][cb].prev_idx = cb;
 258                 path[swb+1][cb].cost     = path[swb][cb].cost;
 259                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 260             }
 261         } else {
 262             float minrd = next_minrd;
 263             int mincb = next_mincb;
 264             next_minrd = INFINITY;
 265             next_mincb = 0;
 266             for (cb = 0; cb < 12; cb++) {
 267                 float cost_stay_here, cost_get_here;
 268                 float rd = 0.0f;
 269                 for (w = 0; w < group_len; w++) {
 270                     FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(win+w)*16+swb];
 271                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
 272                                              s->scoefs + start + w*128, size,
 273                                              sce->sf_idx[(win+w)*16+swb], cb,
 274                                              lambda / band->threshold, INFINITY, NULL);
 275                 }
 276                 cost_stay_here = path[swb][cb].cost + rd;
 277                 cost_get_here  = minrd              + rd + run_bits + 4;
 278                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 279                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 280                     cost_stay_here += run_bits;
 281                 if (cost_get_here < cost_stay_here) {
 282                     path[swb+1][cb].prev_idx = mincb;
 283                     path[swb+1][cb].cost     = cost_get_here;
 284                     path[swb+1][cb].run      = 1;
 285                 } else {
 286                     path[swb+1][cb].prev_idx = cb;
 287                     path[swb+1][cb].cost     = cost_stay_here;
 288                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 289                 }
 290                 if (path[swb+1][cb].cost < next_minrd) {
 291                     next_minrd = path[swb+1][cb].cost;
 292                     next_mincb = cb;
 293                 }
 294             }
 295         }
 296         start += sce->ics.swb_sizes[swb];
 297     }
 298
 299     //convert resulting path from backward-linked list
 300     stack_len = 0;
 301     idx       = 0;
 302     for (cb = 1; cb < 12; cb++)
 303         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 304             idx = cb;
 305     ppos = max_sfb;
 306     while (ppos > 0) {
 307         cb = idx;
 308         stackrun[stack_len] = path[ppos][cb].run;
 309         stackcb [stack_len] = cb;
 310         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 311         ppos -= path[ppos][cb].run;
 312         stack_len++;
 313     }
 314     //perform actual band info encoding
 315     start = 0;
 316     for (i = stack_len - 1; i >= 0; i--) {
 317         put_bits(&s->pb, 4, stackcb[i]);
 318         count = stackrun[i];
 319         memset(sce->zeroes + win*16 + start, !stackcb[i], count);
 320         //XXX: memset when band_type is also uint8_t
 321         for (j = 0; j < count; j++) {
 322             sce->band_type[win*16 + start] =  stackcb[i];
 323             start++;
 324         }
 325         while (count >= run_esc) {
 326             put_bits(&s->pb, run_bits, run_esc);
 327             count -= run_esc;
 328         }
 329         put_bits(&s->pb, run_bits, count);
 330     }
 331 }
 332
 333 typedef struct TrellisPath {
 334     float cost;
 335     int prev;
 336     int min_val;
 337     int max_val;
 338 } TrellisPath;
 339
 340 #define TRELLIS_STAGES 121
 341 #define TRELLIS_STATES 256
 342
 343 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 344                                        SingleChannelElement *sce,
 345                                        const float lambda)
 346 {
 347     int q, w, w2, g, start = 0;
 348     int i, j;
 349     int idx;
 350     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];
 351     int bandaddr[TRELLIS_STAGES];
 352     int minq;
 353     float mincost;
 354
 355     for (i = 0; i < TRELLIS_STATES; i++) {
 356         paths[0][i].cost    = 0.0f;
 357         paths[0][i].prev    = -1;
 358         paths[0][i].min_val = i;
 359         paths[0][i].max_val = i;
 360     }
 361     for (j = 1; j < TRELLIS_STAGES; j++) {
 362         for (i = 0; i < TRELLIS_STATES; i++) {
 363             paths[j][i].cost    = INFINITY;
 364             paths[j][i].prev    = -2;
 365             paths[j][i].min_val = INT_MAX;
 366             paths[j][i].max_val = 0;
 367         }
 368     }
 369     idx = 1;
 370     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 371     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 372         start = w*128;
 373         for (g = 0; g < sce->ics.num_swb; g++) {
 374             const float *coefs = sce->coeffs + start;
 375             float qmin, qmax;
 376             int nz = 0;
 377
 378             bandaddr[idx] = w * 16 + g;
 379             qmin = INT_MAX;
 380             qmax = 0.0f;
 381             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 382                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 383                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 384                     sce->zeroes[(w+w2)*16+g] = 1;
 385                     continue;
 386                 }
 387                 sce->zeroes[(w+w2)*16+g] = 0;
 388                 nz = 1;
 389                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 390                     float t = fabsf(coefs[w2*128+i]);
 391                     if (t > 0.0f)
 392                         qmin = FFMIN(qmin, t);
 393                     qmax = FFMAX(qmax, t);
 394                 }
 395             }
 396             if (nz) {
 397                 int minscale, maxscale;
 398                 float minrd = INFINITY;
 399                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 400                 minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 401                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 402                 maxscale = av_clip_uint8(log2(qmax)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 403                 for (q = minscale; q < maxscale; q++) {
 404                     float dists[12], dist;
 405                     memset(dists, 0, sizeof(dists));
 406                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 407                         FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 408                         int cb;
 409                         for (cb = 0; cb <= ESC_BT; cb++)
 410                             dists[cb] += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 411                                                             q, cb, lambda / band->threshold, INFINITY, NULL);
 412                     }
 413                     dist = dists[0];
 414                     for (i = 1; i <= ESC_BT; i++)
 415                         dist = FFMIN(dist, dists[i]);
 416                     minrd = FFMIN(minrd, dist);
 417
 418                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, TRELLIS_STATES); i++) {
 419                         float cost;
 420                         int minv, maxv;
 421                         if (isinf(paths[idx - 1][i].cost))
 422                             continue;
 423                         cost = paths[idx - 1][i].cost + dist
 424                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 425                         minv = FFMIN(paths[idx - 1][i].min_val, q);
 426                         maxv = FFMAX(paths[idx - 1][i].max_val, q);
 427                         if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
 428                             paths[idx][q].cost    = cost;
 429                             paths[idx][q].prev    = i;
 430                             paths[idx][q].min_val = minv;
 431                             paths[idx][q].max_val = maxv;
 432                         }
 433                     }
 434                 }
 435             } else {
 436                 for (q = 0; q < TRELLIS_STATES; q++) {
 437                     if (!isinf(paths[idx - 1][q].cost)) {
 438                         paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 439                         paths[idx][q].prev = q;
 440                         paths[idx][q].min_val = FFMIN(paths[idx - 1][q].min_val, q);
 441                         paths[idx][q].max_val = FFMAX(paths[idx - 1][q].max_val, q);
 442                         continue;
 443                     }
 444                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, TRELLIS_STATES); i++) {
 445                         float cost;
 446                         int minv, maxv;
 447                         if (isinf(paths[idx - 1][i].cost))
 448                             continue;
 449                         cost = paths[idx - 1][i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 450                         minv = FFMIN(paths[idx - 1][i].min_val, q);
 451                         maxv = FFMAX(paths[idx - 1][i].max_val, q);
 452                         if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
 453                             paths[idx][q].cost    = cost;
 454                             paths[idx][q].prev    = i;
 455                             paths[idx][q].min_val = minv;
 456                             paths[idx][q].max_val = maxv;
 457                         }
 458                     }
 459                 }
 460             }
 461             sce->zeroes[w*16+g] = !nz;
 462             start += sce->ics.swb_sizes[g];
 463             idx++;
 464         }
 465     }
 466     idx--;
 467     mincost = paths[idx][0].cost;
 468     minq    = 0;
 469     for (i = 1; i < TRELLIS_STATES; i++) {
 470         if (paths[idx][i].cost < mincost) {
 471             mincost = paths[idx][i].cost;
 472             minq = i;
 473         }
 474     }
 475     while (idx) {
 476         sce->sf_idx[bandaddr[idx]] = minq;
 477         minq = paths[idx][minq].prev;
 478         idx--;
 479     }
 480     //set the same quantizers inside window groups
 481     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 482         for (g = 0;  g < sce->ics.num_swb; g++)
 483             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 484                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 485 }
 486
 487 /**
 488  * two-loop quantizers search taken from ISO 13818-7 Appendix C
 489  */
 490 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
 491                                           AACEncContext *s,
 492                                           SingleChannelElement *sce,
 493                                           const float lambda)
 494 {
 495     int start = 0, i, w, w2, g;
 496     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels;
 497     float dists[128], uplims[128];
 498     int fflag, minscaler;
 499     int its  = 0;
 500     int allz = 0;
 501     float minthr = INFINITY;
 502
 503     //XXX: some heuristic to determine initial quantizers will reduce search time
 504     memset(dists, 0, sizeof(dists));
 505     //determine zero bands and upper limits
 506     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 507         for (g = 0;  g < sce->ics.num_swb; g++) {
 508             int nz = 0;
 509             float uplim = 0.0f;
 510             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 511                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 512                 uplim += band->threshold;
 513                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 514                     sce->zeroes[(w+w2)*16+g] = 1;
 515                     continue;
 516                 }
 517                 nz = 1;
 518             }
 519             uplims[w*16+g] = uplim *512;
 520             sce->zeroes[w*16+g] = !nz;
 521             if (nz)
 522                 minthr = FFMIN(minthr, uplim);
 523             allz = FFMAX(allz, nz);
 524         }
 525     }
 526     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 527         for (g = 0;  g < sce->ics.num_swb; g++) {
 528             if (sce->zeroes[w*16+g]) {
 529                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 530                 continue;
 531             }
 532             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2(uplims[w*16+g]/minthr)*4,59);
 533         }
 534     }
 535
 536     if (!allz)
 537         return;
 538     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 539     //perform two-loop search
 540     //outer loop - improve quality
 541     do {
 542         int tbits, qstep;
 543         minscaler = sce->sf_idx[0];
 544         //inner loop - quantize spectrum to fit into given number of bits
 545         qstep = its ? 1 : 32;
 546         do {
 547             int prev = -1;
 548             tbits = 0;
 549             fflag = 0;
 550             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 551                 start = w*128;
 552                 for (g = 0;  g < sce->ics.num_swb; g++) {
 553                     const float *coefs = sce->coeffs + start;
 554                     const float *scaled = s->scoefs + start;
 555                     int bits = 0;
 556                     int cb;
 557                     float mindist = INFINITY;
 558                     int minbits = 0;
 559
 560                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
 561                         start += sce->ics.swb_sizes[g];
 562                         continue;
 563                     }
 564                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 565                     {
 566                         float dist = 0.0f;
 567                         int bb = 0;
 568                         float maxval = 0.0f;
 569                         float Q = ff_aac_pow2sf_tab[200 - sce->sf_idx[w*16+g] + SCALE_ONE_POS - SCALE_DIV_512];
 570                         float Q34 = sqrtf(Q * sqrtf(Q));
 571                         int qmaxval;
 572                         for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 573                             for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 574                                 maxval = fmaxf(maxval, scaled[w2*128+i]);
 575                             }
 576                         }
 577                         qmaxval = maxval * Q34 + 0.4054;
 578                         if      (qmaxval ==  0) cb = 0;
 579                         else if (qmaxval ==  1) cb = 1;
 580                         else if (qmaxval ==  2) cb = 3;
 581                         else if (qmaxval <=  4) cb = 5;
 582                         else if (qmaxval <=  7) cb = 7;
 583                         else if (qmaxval <= 12) cb = 9;
 584                         else                    cb = 11;
 585                         for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 586                             int b;
 587                             dist += quantize_band_cost(s, coefs + w2*128,
 588                                                        scaled + w2*128,
 589                                                        sce->ics.swb_sizes[g],
 590                                                        sce->sf_idx[w*16+g],
 591                                                        cb,
 592                                                        lambda,
 593                                                        INFINITY,
 594                                                        &b);
 595                             bb += b;
 596                         }
 597                             mindist = dist;
 598                             minbits = bb;
 599                     }
 600                     dists[w*16+g] = (mindist - minbits) / lambda;
 601                     bits = minbits;
 602                     if (prev != -1) {
 603                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 604                     }
 605                     tbits += bits;
 606                     start += sce->ics.swb_sizes[g];
 607                     prev = sce->sf_idx[w*16+g];
 608                 }
 609             }
 610             if (tbits > destbits) {
 611                 for (i = 0; i < 128; i++)
 612                     if (sce->sf_idx[i] < 218 - qstep)
 613                         sce->sf_idx[i] += qstep;
 614             } else {
 615                 for (i = 0; i < 128; i++)
 616                     if (sce->sf_idx[i] > 60 - qstep)
 617                         sce->sf_idx[i] -= qstep;
 618             }
 619             qstep >>= 1;
 620             if (!qstep && tbits > destbits*1.02)
 621                 qstep = 1;
 622             if (sce->sf_idx[0] >= 217)
 623                 break;
 624         } while (qstep);
 625
 626         fflag = 0;
 627         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 628         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 629             start = w*128;
 630             for (g = 0; g < sce->ics.num_swb; g++) {
 631                 int prevsc = sce->sf_idx[w*16+g];
 632                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60)
 633                     sce->sf_idx[w*16+g]--;
 634                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 635                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 636                 if (sce->sf_idx[w*16+g] != prevsc)
 637                     fflag = 1;
 638             }
 639         }
 640         its++;
 641     } while (fflag && its < 10);
 642 }
 643
 644 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 645                                        SingleChannelElement *sce,
 646                                        const float lambda)
 647 {
 648     int start = 0, i, w, w2, g;
 649     float uplim[128], maxq[128];
 650     int minq, maxsf;
 651     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 652     int last = 0, lastband = 0, curband = 0;
 653     float avg_energy = 0.0;
 654     if (sce->ics.num_windows == 1) {
 655         start = 0;
 656         for (i = 0; i < 1024; i++) {
 657             if (i - start >= sce->ics.swb_sizes[curband]) {
 658                 start += sce->ics.swb_sizes[curband];
 659                 curband++;
 660             }
 661             if (sce->coeffs[i]) {
 662                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 663                 last = i;
 664                 lastband = curband;
 665             }
 666         }
 667     } else {
 668         for (w = 0; w < 8; w++) {
 669             const float *coeffs = sce->coeffs + w*128;
 670             start = 0;
 671             for (i = 0; i < 128; i++) {
 672                 if (i - start >= sce->ics.swb_sizes[curband]) {
 673                     start += sce->ics.swb_sizes[curband];
 674                     curband++;
 675                 }
 676                 if (coeffs[i]) {
 677                     avg_energy += coeffs[i] * coeffs[i];
 678                     last = FFMAX(last, i);
 679                     lastband = FFMAX(lastband, curband);
 680                 }
 681             }
 682         }
 683     }
 684     last++;
 685     avg_energy /= last;
 686     if (avg_energy == 0.0f) {
 687         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
 688             sce->sf_idx[i] = SCALE_ONE_POS;
 689         return;
 690     }
 691     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 692         start = w*128;
 693         for (g = 0; g < sce->ics.num_swb; g++) {
 694             float *coefs   = sce->coeffs + start;
 695             const int size = sce->ics.swb_sizes[g];
 696             int start2 = start, end2 = start + size, peakpos = start;
 697             float maxval = -1, thr = 0.0f, t;
 698             maxq[w*16+g] = 0.0f;
 699             if (g > lastband) {
 700                 maxq[w*16+g] = 0.0f;
 701                 start += size;
 702                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
 703                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
 704                 continue;
 705             }
 706             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 707                 for (i = 0; i < size; i++) {
 708                     float t = coefs[w2*128+i]*coefs[w2*128+i];
 709                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
 710                     thr += t;
 711                     if (sce->ics.num_windows == 1 && maxval < t) {
 712                         maxval  = t;
 713                         peakpos = start+i;
 714                     }
 715                 }
 716             }
 717             if (sce->ics.num_windows == 1) {
 718                 start2 = FFMAX(peakpos - 2, start2);
 719                 end2   = FFMIN(peakpos + 3, end2);
 720             } else {
 721                 start2 -= start;
 722                 end2   -= start;
 723             }
 724             start += size;
 725             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
 726             t   = 1.0 - (1.0 * start2 / last);
 727             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
 728         }
 729     }
 730     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 731     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 732     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 733         start = w*128;
 734         for (g = 0;  g < sce->ics.num_swb; g++) {
 735             const float *coefs  = sce->coeffs + start;
 736             const float *scaled = s->scoefs   + start;
 737             const int size      = sce->ics.swb_sizes[g];
 738             int scf, prev_scf, step;
 739             int min_scf = -1, max_scf = 256;
 740             float curdiff;
 741             if (maxq[w*16+g] < 21.544) {
 742                 sce->zeroes[w*16+g] = 1;
 743                 start += size;
 744                 continue;
 745             }
 746             sce->zeroes[w*16+g] = 0;
 747             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2(1/maxq[w*16+g])*16/3, 60, 218);
 748             step = 16;
 749             for (;;) {
 750                 float dist = 0.0f;
 751                 int quant_max;
 752
 753                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 754                     int b;
 755                     dist += quantize_band_cost(s, coefs + w2*128,
 756                                                scaled + w2*128,
 757                                                sce->ics.swb_sizes[g],
 758                                                scf,
 759                                                ESC_BT,
 760                                                lambda,
 761                                                INFINITY,
 762                                                &b);
 763                     dist -= b;
 764                 }
 765                 dist *= 1.0f / 512.0f / lambda;
 766                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[200 - scf + SCALE_ONE_POS - SCALE_DIV_512]);
 767                 if (quant_max >= 8191) { // too much, return to the previous quantizer
 768                     sce->sf_idx[w*16+g] = prev_scf;
 769                     break;
 770                 }
 771                 prev_scf = scf;
 772                 curdiff = fabsf(dist - uplim[w*16+g]);
 773                 if (curdiff <= 1.0f)
 774                     step = 0;
 775                 else
 776                     step = log2(curdiff);
 777                 if (dist > uplim[w*16+g])
 778                     step = -step;
 779                 scf += step;
 780                 scf = av_clip_uint8(scf);
 781                 step = scf - prev_scf;
 782                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
 783                     sce->sf_idx[w*16+g] = av_clip(scf, min_scf, max_scf);
 784                     break;
 785                 }
 786                 if (step > 0)
 787                     min_scf = prev_scf;
 788                 else
 789                     max_scf = prev_scf;
 790             }
 791             start += size;
 792         }
 793     }
 794     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
 795     for (i = 1; i < 128; i++) {
 796         if (!sce->sf_idx[i])
 797             sce->sf_idx[i] = sce->sf_idx[i-1];
 798         else
 799             minq = FFMIN(minq, sce->sf_idx[i]);
 800     }
 801     if (minq == INT_MAX)
 802         minq = 0;
 803     minq = FFMIN(minq, SCALE_MAX_POS);
 804     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
 805     for (i = 126; i >= 0; i--) {
 806         if (!sce->sf_idx[i])
 807             sce->sf_idx[i] = sce->sf_idx[i+1];
 808         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
 809     }
 810 }
 811
 812 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
 813                                        SingleChannelElement *sce,
 814                                        const float lambda)
 815 {
 816     int start = 0, i, w, w2, g;
 817     int minq = 255;
 818
 819     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 820     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 821         start = w*128;
 822         for (g = 0; g < sce->ics.num_swb; g++) {
 823             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 824                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 825                 if (band->energy <= band->threshold) {
 826                     sce->sf_idx[(w+w2)*16+g] = 218;
 827                     sce->zeroes[(w+w2)*16+g] = 1;
 828                 } else {
 829                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2(band->threshold), 80, 218);
 830                     sce->zeroes[(w+w2)*16+g] = 0;
 831                 }
 832                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
 833             }
 834         }
 835     }
 836     for (i = 0; i < 128; i++) {
 837         sce->sf_idx[i] = 140;
 838         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
 839     }
 840     //set the same quantizers inside window groups
 841     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 842         for (g = 0;  g < sce->ics.num_swb; g++)
 843             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 844                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 845 }
 846
 847 static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
 848                           const float lambda)
 849 {
 850     int start = 0, i, w, w2, g;
 851     float M[128], S[128];
 852     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
 853     SingleChannelElement *sce0 = &cpe->ch[0];
 854     SingleChannelElement *sce1 = &cpe->ch[1];
 855     if (!cpe->common_window)
 856         return;
 857     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 858         for (g = 0;  g < sce0->ics.num_swb; g++) {
 859             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
 860                 float dist1 = 0.0f, dist2 = 0.0f;
 861                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 862                     FFPsyBand *band0 = &s->psy.psy_bands[(s->cur_channel+0)*PSY_MAX_BANDS+(w+w2)*16+g];
 863                     FFPsyBand *band1 = &s->psy.psy_bands[(s->cur_channel+1)*PSY_MAX_BANDS+(w+w2)*16+g];
 864                     float minthr = FFMIN(band0->threshold, band1->threshold);
 865                     float maxthr = FFMAX(band0->threshold, band1->threshold);
 866                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 867                         M[i] = (sce0->coeffs[start+w2*128+i]
 868                               + sce1->coeffs[start+w2*128+i]) * 0.5;
 869                         S[i] =  sce0->coeffs[start+w2*128+i]
 870                               - sce1->coeffs[start+w2*128+i];
 871                     }
 872                     abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 873                     abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 874                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
 875                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
 876                     dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
 877                                                 L34,
 878                                                 sce0->ics.swb_sizes[g],
 879                                                 sce0->sf_idx[(w+w2)*16+g],
 880                                                 sce0->band_type[(w+w2)*16+g],
 881                                                 lambda / band0->threshold, INFINITY, NULL);
 882                     dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
 883                                                 R34,
 884                                                 sce1->ics.swb_sizes[g],
 885                                                 sce1->sf_idx[(w+w2)*16+g],
 886                                                 sce1->band_type[(w+w2)*16+g],
 887                                                 lambda / band1->threshold, INFINITY, NULL);
 888                     dist2 += quantize_band_cost(s, M,
 889                                                 M34,
 890                                                 sce0->ics.swb_sizes[g],
 891                                                 sce0->sf_idx[(w+w2)*16+g],
 892                                                 sce0->band_type[(w+w2)*16+g],
 893                                                 lambda / maxthr, INFINITY, NULL);
 894                     dist2 += quantize_band_cost(s, S,
 895                                                 S34,
 896                                                 sce1->ics.swb_sizes[g],
 897                                                 sce1->sf_idx[(w+w2)*16+g],
 898                                                 sce1->band_type[(w+w2)*16+g],
 899                                                 lambda / minthr, INFINITY, NULL);
 900                 }
 901                 cpe->ms_mask[w*16+g] = dist2 < dist1;
 902             }
 903             start += sce0->ics.swb_sizes[g];
 904         }
 905     }
 906 }
 907
 908 AACCoefficientsEncoder ff_aac_coders[] = {
 909     {
 910         search_for_quantizers_faac,
 911         encode_window_bands_info,
 912         quantize_and_encode_band,
 913         search_for_ms,
 914     },
 915     {
 916         search_for_quantizers_anmr,
 917         encode_window_bands_info,
 918         quantize_and_encode_band,
 919         search_for_ms,
 920     },
 921     {
 922         search_for_quantizers_twoloop,
 923         encode_window_bands_info,
 924         quantize_and_encode_band,
 925         search_for_ms,
 926     },
 927     {
 928         search_for_quantizers_fast,
 929         encode_window_bands_info,
 930         quantize_and_encode_band,
 931         search_for_ms,
 932     },
 933 };