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)[2], 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][0] = (int)FFMIN(qc,          (double)maxval);
  76         out[i][1] = (int)FFMIN(qc + 0.4054, (double)maxval);
  77         if (is_signed && in[i] < 0.0f) {
  78             out[i][0] = -out[i][0];
  79             out[i][1] = -out[i][1];
  80         }
  81     }
  82 }
  83
  84 static void abs_pow34_v(float *out, const float *in, const int size)
  85 {
  86 #ifndef USE_REALLY_FULL_SEARCH
  87     int i;
  88     for (i = 0; i < size; i++) {
  89         float a = fabsf(in[i]);
  90         out[i] = sqrtf(a * sqrtf(a));
  91     }
  92 #endif /* USE_REALLY_FULL_SEARCH */
  93 }
  94
  95 static const uint8_t aac_cb_range [12] = {0, 3, 3, 3, 3, 9, 9, 8, 8, 13, 13, 17};
  96 static const uint8_t aac_cb_maxval[12] = {0, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 16};
  97
  98 /**
  99  * Calculate rate distortion cost for quantizing with given codebook
 100  *
 101  * @return quantization distortion
 102  */
 103 static float quantize_and_encode_band_cost(struct AACEncContext *s,
 104                                 PutBitContext *pb, const float *in,
 105                                 const float *scaled, int size, int scale_idx,
 106                                 int cb, const float lambda, const float uplim,
 107                                 int *bits)
 108 {
 109     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 110     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
 111     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 112     int i, j, k;
 113     float cost = 0;
 114     const int dim = cb < FIRST_PAIR_BT ? 4 : 2;
 115     int resbits = 0;
 116 #ifndef USE_REALLY_FULL_SEARCH
 117     const float  Q34 = sqrtf(Q * sqrtf(Q));
 118     const int range  = aac_cb_range[cb];
 119     const int maxval = aac_cb_maxval[cb];
 120     int offs[4];
 121 #endif /* USE_REALLY_FULL_SEARCH */
 122
 123     if (!cb) {
 124         for (i = 0; i < size; i++)
 125             cost += in[i]*in[i];
 126         if (bits)
 127             *bits = 0;
 128         return cost * lambda;
 129     }
 130 #ifndef USE_REALLY_FULL_SEARCH
 131     offs[0] = 1;
 132     for (i = 1; i < dim; i++)
 133         offs[i] = offs[i-1]*range;
 134     if (!scaled) {
 135         abs_pow34_v(s->scoefs, in, size);
 136         scaled = s->scoefs;
 137     }
 138     quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
 139 #endif /* USE_REALLY_FULL_SEARCH */
 140     for (i = 0; i < size; i += dim) {
 141         float mincost;
 142         int minidx  = 0;
 143         int minbits = 0;
 144         const float *vec;
 145 #ifndef USE_REALLY_FULL_SEARCH
 146         int (*quants)[2] = &s->qcoefs[i];
 147         mincost = 0.0f;
 148         for (j = 0; j < dim; j++)
 149             mincost += in[i+j]*in[i+j];
 150         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 151         minbits = ff_aac_spectral_bits[cb-1][minidx];
 152         mincost = mincost * lambda + minbits;
 153         for (j = 0; j < (1<<dim); j++) {
 154             float rd = 0.0f;
 155             int curbits;
 156             int curidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 157             int same   = 0;
 158             for (k = 0; k < dim; k++) {
 159                 if ((j & (1 << k)) && quants[k][0] == quants[k][1]) {
 160                     same = 1;
 161                     break;
 162                 }
 163             }
 164             if (same)
 165                 continue;
 166             for (k = 0; k < dim; k++)
 167                 curidx += quants[k][!!(j & (1 << k))] * offs[dim - 1 - k];
 168             curbits =  ff_aac_spectral_bits[cb-1][curidx];
 169             vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 170 #else
 171         mincost = INFINITY;
 172         vec = ff_aac_codebook_vectors[cb-1];
 173         for (j = 0; j < ff_aac_spectral_sizes[cb-1]; j++, vec += dim) {
 174             float rd = 0.0f;
 175             int curbits = ff_aac_spectral_bits[cb-1][j];
 176             int curidx = j;
 177 #endif /* USE_REALLY_FULL_SEARCH */
 178             if (IS_CODEBOOK_UNSIGNED(cb)) {
 179                 for (k = 0; k < dim; k++) {
 180                     float t = fabsf(in[i+k]);
 181                     float di;
 182                     if (vec[k] == 64.0f) { //FIXME: slow
 183                         //do not code with escape sequence small values
 184                         if (t < 39.0f*IQ) {
 185                             rd = INFINITY;
 186                             break;
 187                         }
 188                         if (t >= CLIPPED_ESCAPE) {
 189                             di = t - CLIPPED_ESCAPE;
 190                             curbits += 21;
 191                         } else {
 192                             int c = av_clip(quant(t, Q), 0, 8191);
 193                             di = t - c*cbrtf(c)*IQ;
 194                             curbits += av_log2(c)*2 - 4 + 1;
 195                         }
 196                     } else {
 197                         di = t - vec[k]*IQ;
 198                     }
 199                     if (vec[k] != 0.0f)
 200                         curbits++;
 201                     rd += di*di;
 202                 }
 203             } else {
 204                 for (k = 0; k < dim; k++) {
 205                     float di = in[i+k] - vec[k]*IQ;
 206                     rd += di*di;
 207                 }
 208             }
 209             rd = rd * lambda + curbits;
 210             if (rd < mincost) {
 211                 mincost = rd;
 212                 minidx  = curidx;
 213                 minbits = curbits;
 214             }
 215         }
 216         cost    += mincost;
 217         resbits += minbits;
 218         if (cost >= uplim)
 219             return uplim;
 220         if (pb) {
 221         put_bits(pb, ff_aac_spectral_bits[cb-1][minidx], ff_aac_spectral_codes[cb-1][minidx]);
 222         if (IS_CODEBOOK_UNSIGNED(cb))
 223             for (j = 0; j < dim; j++)
 224                 if (ff_aac_codebook_vectors[cb-1][minidx*dim+j] != 0.0f)
 225                     put_bits(pb, 1, in[i+j] < 0.0f);
 226         if (cb == ESC_BT) {
 227             for (j = 0; j < 2; j++) {
 228                 if (ff_aac_codebook_vectors[cb-1][minidx*2+j] == 64.0f) {
 229                     int coef = av_clip(quant(fabsf(in[i+j]), Q), 0, 8191);
 230                     int len = av_log2(coef);
 231
 232                     put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
 233                     put_bits(pb, len, coef & ((1 << len) - 1));
 234                 }
 235             }
 236         }
 237         }
 238     }
 239
 240     if (bits)
 241         *bits = resbits;
 242     return cost;
 243 }
 244 static float quantize_band_cost(struct AACEncContext *s, const float *in,
 245                                 const float *scaled, int size, int scale_idx,
 246                                 int cb, const float lambda, const float uplim,
 247                                 int *bits)
 248 {
 249     return quantize_and_encode_band_cost(s, NULL, in, scaled, size, scale_idx,
 250                                          cb, lambda, uplim, bits);
 251 }
 252
 253 static void quantize_and_encode_band(struct AACEncContext *s, PutBitContext *pb,
 254                                      const float *in, int size, int scale_idx,
 255                                      int cb, const float lambda)
 256 {
 257     quantize_and_encode_band_cost(s, pb, in, NULL, size, scale_idx, cb, lambda,
 258                                   INFINITY, NULL);
 259 }
 260
 261 /**
 262  * structure used in optimal codebook search
 263  */
 264 typedef struct BandCodingPath {
 265     int prev_idx; ///< pointer to the previous path point
 266     float cost;   ///< path cost
 267     int run;
 268 } BandCodingPath;
 269
 270 /**
 271  * Encode band info for single window group bands.
 272  */
 273 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
 274                                      int win, int group_len, const float lambda)
 275 {
 276     BandCodingPath path[120][12];
 277     int w, swb, cb, start, start2, size;
 278     int i, j;
 279     const int max_sfb  = sce->ics.max_sfb;
 280     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 281     const int run_esc  = (1 << run_bits) - 1;
 282     int idx, ppos, count;
 283     int stackrun[120], stackcb[120], stack_len;
 284     float next_minrd = INFINITY;
 285     int next_mincb = 0;
 286
 287     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 288     start = win*128;
 289     for (cb = 0; cb < 12; cb++) {
 290         path[0][cb].cost     = 0.0f;
 291         path[0][cb].prev_idx = -1;
 292         path[0][cb].run      = 0;
 293     }
 294     for (swb = 0; swb < max_sfb; swb++) {
 295         start2 = start;
 296         size = sce->ics.swb_sizes[swb];
 297         if (sce->zeroes[win*16 + swb]) {
 298             for (cb = 0; cb < 12; cb++) {
 299                 path[swb+1][cb].prev_idx = cb;
 300                 path[swb+1][cb].cost     = path[swb][cb].cost;
 301                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 302             }
 303         } else {
 304             float minrd = next_minrd;
 305             int mincb = next_mincb;
 306             next_minrd = INFINITY;
 307             next_mincb = 0;
 308             for (cb = 0; cb < 12; cb++) {
 309                 float cost_stay_here, cost_get_here;
 310                 float rd = 0.0f;
 311                 for (w = 0; w < group_len; w++) {
 312                     FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(win+w)*16+swb];
 313                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
 314                                              s->scoefs + start + w*128, size,
 315                                              sce->sf_idx[(win+w)*16+swb], cb,
 316                                              lambda / band->threshold, INFINITY, NULL);
 317                 }
 318                 cost_stay_here = path[swb][cb].cost + rd;
 319                 cost_get_here  = minrd              + rd + run_bits + 4;
 320                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 321                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 322                     cost_stay_here += run_bits;
 323                 if (cost_get_here < cost_stay_here) {
 324                     path[swb+1][cb].prev_idx = mincb;
 325                     path[swb+1][cb].cost     = cost_get_here;
 326                     path[swb+1][cb].run      = 1;
 327                 } else {
 328                     path[swb+1][cb].prev_idx = cb;
 329                     path[swb+1][cb].cost     = cost_stay_here;
 330                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 331                 }
 332                 if (path[swb+1][cb].cost < next_minrd) {
 333                     next_minrd = path[swb+1][cb].cost;
 334                     next_mincb = cb;
 335                 }
 336             }
 337         }
 338         start += sce->ics.swb_sizes[swb];
 339     }
 340
 341     //convert resulting path from backward-linked list
 342     stack_len = 0;
 343     idx       = 0;
 344     for (cb = 1; cb < 12; cb++)
 345         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 346             idx = cb;
 347     ppos = max_sfb;
 348     while (ppos > 0) {
 349         cb = idx;
 350         stackrun[stack_len] = path[ppos][cb].run;
 351         stackcb [stack_len] = cb;
 352         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 353         ppos -= path[ppos][cb].run;
 354         stack_len++;
 355     }
 356     //perform actual band info encoding
 357     start = 0;
 358     for (i = stack_len - 1; i >= 0; i--) {
 359         put_bits(&s->pb, 4, stackcb[i]);
 360         count = stackrun[i];
 361         memset(sce->zeroes + win*16 + start, !stackcb[i], count);
 362         //XXX: memset when band_type is also uint8_t
 363         for (j = 0; j < count; j++) {
 364             sce->band_type[win*16 + start] =  stackcb[i];
 365             start++;
 366         }
 367         while (count >= run_esc) {
 368             put_bits(&s->pb, run_bits, run_esc);
 369             count -= run_esc;
 370         }
 371         put_bits(&s->pb, run_bits, count);
 372     }
 373 }
 374
 375 typedef struct TrellisPath {
 376     float cost;
 377     int prev;
 378     int min_val;
 379     int max_val;
 380 } TrellisPath;
 381
 382 #define TRELLIS_STAGES 121
 383 #define TRELLIS_STATES 256
 384
 385 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 386                                        SingleChannelElement *sce,
 387                                        const float lambda)
 388 {
 389     int q, w, w2, g, start = 0;
 390     int i, j;
 391     int idx;
 392     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];
 393     int bandaddr[TRELLIS_STAGES];
 394     int minq;
 395     float mincost;
 396
 397     for (i = 0; i < TRELLIS_STATES; i++) {
 398         paths[0][i].cost    = 0.0f;
 399         paths[0][i].prev    = -1;
 400         paths[0][i].min_val = i;
 401         paths[0][i].max_val = i;
 402     }
 403     for (j = 1; j < TRELLIS_STAGES; j++) {
 404         for (i = 0; i < TRELLIS_STATES; i++) {
 405             paths[j][i].cost    = INFINITY;
 406             paths[j][i].prev    = -2;
 407             paths[j][i].min_val = INT_MAX;
 408             paths[j][i].max_val = 0;
 409         }
 410     }
 411     idx = 1;
 412     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 413     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 414         start = w*128;
 415         for (g = 0; g < sce->ics.num_swb; g++) {
 416             const float *coefs = sce->coeffs + start;
 417             float qmin, qmax;
 418             int nz = 0;
 419
 420             bandaddr[idx] = w * 16 + g;
 421             qmin = INT_MAX;
 422             qmax = 0.0f;
 423             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 424                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 425                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 426                     sce->zeroes[(w+w2)*16+g] = 1;
 427                     continue;
 428                 }
 429                 sce->zeroes[(w+w2)*16+g] = 0;
 430                 nz = 1;
 431                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 432                     float t = fabsf(coefs[w2*128+i]);
 433                     if (t > 0.0f)
 434                         qmin = FFMIN(qmin, t);
 435                     qmax = FFMAX(qmax, t);
 436                 }
 437             }
 438             if (nz) {
 439                 int minscale, maxscale;
 440                 float minrd = INFINITY;
 441                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 442                 minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 443                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 444                 maxscale = av_clip_uint8(log2(qmax)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 445                 for (q = minscale; q < maxscale; q++) {
 446                     float dists[12], dist;
 447                     memset(dists, 0, sizeof(dists));
 448                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 449                         FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 450                         int cb;
 451                         for (cb = 0; cb <= ESC_BT; cb++)
 452                             dists[cb] += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 453                                                             q, cb, lambda / band->threshold, INFINITY, NULL);
 454                     }
 455                     dist = dists[0];
 456                     for (i = 1; i <= ESC_BT; i++)
 457                         dist = FFMIN(dist, dists[i]);
 458                     minrd = FFMIN(minrd, dist);
 459
 460                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, TRELLIS_STATES); i++) {
 461                         float cost;
 462                         int minv, maxv;
 463                         if (isinf(paths[idx - 1][i].cost))
 464                             continue;
 465                         cost = paths[idx - 1][i].cost + dist
 466                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 467                         minv = FFMIN(paths[idx - 1][i].min_val, q);
 468                         maxv = FFMAX(paths[idx - 1][i].max_val, q);
 469                         if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
 470                             paths[idx][q].cost    = cost;
 471                             paths[idx][q].prev    = i;
 472                             paths[idx][q].min_val = minv;
 473                             paths[idx][q].max_val = maxv;
 474                         }
 475                     }
 476                 }
 477             } else {
 478                 for (q = 0; q < TRELLIS_STATES; q++) {
 479                     if (!isinf(paths[idx - 1][q].cost)) {
 480                         paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 481                         paths[idx][q].prev = q;
 482                         paths[idx][q].min_val = FFMIN(paths[idx - 1][q].min_val, q);
 483                         paths[idx][q].max_val = FFMAX(paths[idx - 1][q].max_val, q);
 484                         continue;
 485                     }
 486                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, TRELLIS_STATES); i++) {
 487                         float cost;
 488                         int minv, maxv;
 489                         if (isinf(paths[idx - 1][i].cost))
 490                             continue;
 491                         cost = paths[idx - 1][i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 492                         minv = FFMIN(paths[idx - 1][i].min_val, q);
 493                         maxv = FFMAX(paths[idx - 1][i].max_val, q);
 494                         if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
 495                             paths[idx][q].cost    = cost;
 496                             paths[idx][q].prev    = i;
 497                             paths[idx][q].min_val = minv;
 498                             paths[idx][q].max_val = maxv;
 499                         }
 500                     }
 501                 }
 502             }
 503             sce->zeroes[w*16+g] = !nz;
 504             start += sce->ics.swb_sizes[g];
 505             idx++;
 506         }
 507     }
 508     idx--;
 509     mincost = paths[idx][0].cost;
 510     minq    = 0;
 511     for (i = 1; i < TRELLIS_STATES; i++) {
 512         if (paths[idx][i].cost < mincost) {
 513             mincost = paths[idx][i].cost;
 514             minq = i;
 515         }
 516     }
 517     while (idx) {
 518         sce->sf_idx[bandaddr[idx]] = minq;
 519         minq = paths[idx][minq].prev;
 520         idx--;
 521     }
 522     //set the same quantizers inside window groups
 523     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 524         for (g = 0;  g < sce->ics.num_swb; g++)
 525             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 526                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 527 }
 528
 529 /**
 530  * two-loop quantizers search taken from ISO 13818-7 Appendix C
 531  */
 532 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
 533                                           AACEncContext *s,
 534                                           SingleChannelElement *sce,
 535                                           const float lambda)
 536 {
 537     int start = 0, i, w, w2, g;
 538     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels;
 539     float dists[128], uplims[128];
 540     int fflag, minscaler;
 541     int its  = 0;
 542     int allz = 0;
 543     float minthr = INFINITY;
 544
 545     //XXX: some heuristic to determine initial quantizers will reduce search time
 546     memset(dists, 0, sizeof(dists));
 547     //determine zero bands and upper limits
 548     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 549         for (g = 0;  g < sce->ics.num_swb; g++) {
 550             int nz = 0;
 551             float uplim = 0.0f;
 552             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 553                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 554                 uplim += band->threshold;
 555                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 556                     sce->zeroes[(w+w2)*16+g] = 1;
 557                     continue;
 558                 }
 559                 nz = 1;
 560             }
 561             uplims[w*16+g] = uplim *512;
 562             sce->zeroes[w*16+g] = !nz;
 563             if (nz)
 564                 minthr = FFMIN(minthr, uplim);
 565             allz = FFMAX(allz, nz);
 566         }
 567     }
 568     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 569         for (g = 0;  g < sce->ics.num_swb; g++) {
 570             if (sce->zeroes[w*16+g]) {
 571                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 572                 continue;
 573             }
 574             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2(uplims[w*16+g]/minthr)*4,59);
 575         }
 576     }
 577
 578     if (!allz)
 579         return;
 580     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 581     //perform two-loop search
 582     //outer loop - improve quality
 583     do {
 584         int tbits, qstep;
 585         minscaler = sce->sf_idx[0];
 586         //inner loop - quantize spectrum to fit into given number of bits
 587         qstep = its ? 1 : 32;
 588         do {
 589             int prev = -1;
 590             tbits = 0;
 591             fflag = 0;
 592             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 593                 start = w*128;
 594                 for (g = 0;  g < sce->ics.num_swb; g++) {
 595                     const float *coefs = sce->coeffs + start;
 596                     const float *scaled = s->scoefs + start;
 597                     int bits = 0;
 598                     int cb;
 599                     float mindist = INFINITY;
 600                     int minbits = 0;
 601
 602                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
 603                         start += sce->ics.swb_sizes[g];
 604                         continue;
 605                     }
 606                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 607                     for (cb = 0; cb <= ESC_BT; cb++) {
 608                         float dist = 0.0f;
 609                         int bb = 0;
 610                         for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 611                             int b;
 612                             dist += quantize_band_cost(s, coefs + w2*128,
 613                                                        scaled + w2*128,
 614                                                        sce->ics.swb_sizes[g],
 615                                                        sce->sf_idx[w*16+g],
 616                                                        cb,
 617                                                        lambda,
 618                                                        INFINITY,
 619                                                        &b);
 620                             bb += b;
 621                         }
 622                         if (dist < mindist) {
 623                             mindist = dist;
 624                             minbits = bb;
 625                         }
 626                     }
 627                     dists[w*16+g] = (mindist - minbits) / lambda;
 628                     bits = minbits;
 629                     if (prev != -1) {
 630                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 631                     }
 632                     tbits += bits;
 633                     start += sce->ics.swb_sizes[g];
 634                     prev = sce->sf_idx[w*16+g];
 635                 }
 636             }
 637             if (tbits > destbits) {
 638                 for (i = 0; i < 128; i++)
 639                     if (sce->sf_idx[i] < 218 - qstep)
 640                         sce->sf_idx[i] += qstep;
 641             } else {
 642                 for (i = 0; i < 128; i++)
 643                     if (sce->sf_idx[i] > 60 - qstep)
 644                         sce->sf_idx[i] -= qstep;
 645             }
 646             qstep >>= 1;
 647             if (!qstep && tbits > destbits*1.02)
 648                 qstep = 1;
 649             if (sce->sf_idx[0] >= 217)
 650                 break;
 651         } while (qstep);
 652
 653         fflag = 0;
 654         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 655         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 656             start = w*128;
 657             for (g = 0; g < sce->ics.num_swb; g++) {
 658                 int prevsc = sce->sf_idx[w*16+g];
 659                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60)
 660                     sce->sf_idx[w*16+g]--;
 661                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 662                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 663                 if (sce->sf_idx[w*16+g] != prevsc)
 664                     fflag = 1;
 665             }
 666         }
 667         its++;
 668     } while (fflag && its < 10);
 669 }
 670
 671 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 672                                        SingleChannelElement *sce,
 673                                        const float lambda)
 674 {
 675     int start = 0, i, w, w2, g;
 676     float uplim[128], maxq[128];
 677     int minq, maxsf;
 678     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 679     int last = 0, lastband = 0, curband = 0;
 680     float avg_energy = 0.0;
 681     if (sce->ics.num_windows == 1) {
 682         start = 0;
 683         for (i = 0; i < 1024; i++) {
 684             if (i - start >= sce->ics.swb_sizes[curband]) {
 685                 start += sce->ics.swb_sizes[curband];
 686                 curband++;
 687             }
 688             if (sce->coeffs[i]) {
 689                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 690                 last = i;
 691                 lastband = curband;
 692             }
 693         }
 694     } else {
 695         for (w = 0; w < 8; w++) {
 696             const float *coeffs = sce->coeffs + w*128;
 697             start = 0;
 698             for (i = 0; i < 128; i++) {
 699                 if (i - start >= sce->ics.swb_sizes[curband]) {
 700                     start += sce->ics.swb_sizes[curband];
 701                     curband++;
 702                 }
 703                 if (coeffs[i]) {
 704                     avg_energy += coeffs[i] * coeffs[i];
 705                     last = FFMAX(last, i);
 706                     lastband = FFMAX(lastband, curband);
 707                 }
 708             }
 709         }
 710     }
 711     last++;
 712     avg_energy /= last;
 713     if (avg_energy == 0.0f) {
 714         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
 715             sce->sf_idx[i] = SCALE_ONE_POS;
 716         return;
 717     }
 718     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 719         start = w*128;
 720         for (g = 0; g < sce->ics.num_swb; g++) {
 721             float *coefs   = sce->coeffs + start;
 722             const int size = sce->ics.swb_sizes[g];
 723             int start2 = start, end2 = start + size, peakpos = start;
 724             float maxval = -1, thr = 0.0f, t;
 725             maxq[w*16+g] = 0.0f;
 726             if (g > lastband) {
 727                 maxq[w*16+g] = 0.0f;
 728                 start += size;
 729                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
 730                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
 731                 continue;
 732             }
 733             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 734                 for (i = 0; i < size; i++) {
 735                     float t = coefs[w2*128+i]*coefs[w2*128+i];
 736                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
 737                     thr += t;
 738                     if (sce->ics.num_windows == 1 && maxval < t) {
 739                         maxval  = t;
 740                         peakpos = start+i;
 741                     }
 742                 }
 743             }
 744             if (sce->ics.num_windows == 1) {
 745                 start2 = FFMAX(peakpos - 2, start2);
 746                 end2   = FFMIN(peakpos + 3, end2);
 747             } else {
 748                 start2 -= start;
 749                 end2   -= start;
 750             }
 751             start += size;
 752             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
 753             t   = 1.0 - (1.0 * start2 / last);
 754             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
 755         }
 756     }
 757     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 758     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 759     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 760         start = w*128;
 761         for (g = 0;  g < sce->ics.num_swb; g++) {
 762             const float *coefs  = sce->coeffs + start;
 763             const float *scaled = s->scoefs   + start;
 764             const int size      = sce->ics.swb_sizes[g];
 765             int scf, prev_scf, step;
 766             int min_scf = 0, max_scf = 255;
 767             float curdiff;
 768             if (maxq[w*16+g] < 21.544) {
 769                 sce->zeroes[w*16+g] = 1;
 770                 start += size;
 771                 continue;
 772             }
 773             sce->zeroes[w*16+g] = 0;
 774             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2(1/maxq[w*16+g])*16/3, 60, 218);
 775             step = 16;
 776             for (;;) {
 777                 float dist = 0.0f;
 778                 int quant_max;
 779
 780                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 781                     int b;
 782                     dist += quantize_band_cost(s, coefs + w2*128,
 783                                                scaled + w2*128,
 784                                                sce->ics.swb_sizes[g],
 785                                                scf,
 786                                                ESC_BT,
 787                                                lambda,
 788                                                INFINITY,
 789                                                &b);
 790                     dist -= b;
 791                 }
 792                 dist *= 1.0f / 512.0f / lambda;
 793                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[200 - scf + SCALE_ONE_POS - SCALE_DIV_512]);
 794                 if (quant_max >= 8191) { // too much, return to the previous quantizer
 795                     sce->sf_idx[w*16+g] = prev_scf;
 796                     break;
 797                 }
 798                 prev_scf = scf;
 799                 curdiff = fabsf(dist - uplim[w*16+g]);
 800                 if (curdiff == 0.0f)
 801                     step = 0;
 802                 else
 803                     step = fabsf(log2(curdiff));
 804                 if (dist > uplim[w*16+g])
 805                     step = -step;
 806                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
 807                     sce->sf_idx[w*16+g] = scf;
 808                     break;
 809                 }
 810                 scf += step;
 811                 if (step > 0)
 812                     min_scf = scf;
 813                 else
 814                     max_scf = scf;
 815             }
 816             start += size;
 817         }
 818     }
 819     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
 820     for (i = 1; i < 128; i++) {
 821         if (!sce->sf_idx[i])
 822             sce->sf_idx[i] = sce->sf_idx[i-1];
 823         else
 824             minq = FFMIN(minq, sce->sf_idx[i]);
 825     }
 826     if (minq == INT_MAX)
 827         minq = 0;
 828     minq = FFMIN(minq, SCALE_MAX_POS);
 829     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
 830     for (i = 126; i >= 0; i--) {
 831         if (!sce->sf_idx[i])
 832             sce->sf_idx[i] = sce->sf_idx[i+1];
 833         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
 834     }
 835 }
 836
 837 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
 838                                        SingleChannelElement *sce,
 839                                        const float lambda)
 840 {
 841     int start = 0, i, w, w2, g;
 842     int minq = 255;
 843
 844     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 845     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 846         start = w*128;
 847         for (g = 0; g < sce->ics.num_swb; g++) {
 848             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 849                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 850                 if (band->energy <= band->threshold) {
 851                     sce->sf_idx[(w+w2)*16+g] = 218;
 852                     sce->zeroes[(w+w2)*16+g] = 1;
 853                 } else {
 854                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2(band->threshold), 80, 218);
 855                     sce->zeroes[(w+w2)*16+g] = 0;
 856                 }
 857                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
 858             }
 859         }
 860     }
 861     for (i = 0; i < 128; i++) {
 862         sce->sf_idx[i] = 140;
 863         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
 864     }
 865     //set the same quantizers inside window groups
 866     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 867         for (g = 0;  g < sce->ics.num_swb; g++)
 868             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 869                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 870 }
 871
 872 static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
 873                           const float lambda)
 874 {
 875     int start = 0, i, w, w2, g;
 876     float M[128], S[128];
 877     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
 878     SingleChannelElement *sce0 = &cpe->ch[0];
 879     SingleChannelElement *sce1 = &cpe->ch[1];
 880     if (!cpe->common_window)
 881         return;
 882     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 883         for (g = 0;  g < sce0->ics.num_swb; g++) {
 884             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
 885                 float dist1 = 0.0f, dist2 = 0.0f;
 886                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 887                     FFPsyBand *band0 = &s->psy.psy_bands[(s->cur_channel+0)*PSY_MAX_BANDS+(w+w2)*16+g];
 888                     FFPsyBand *band1 = &s->psy.psy_bands[(s->cur_channel+1)*PSY_MAX_BANDS+(w+w2)*16+g];
 889                     float minthr = FFMIN(band0->threshold, band1->threshold);
 890                     float maxthr = FFMAX(band0->threshold, band1->threshold);
 891                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 892                         M[i] = (sce0->coeffs[start+w2*128+i]
 893                               + sce1->coeffs[start+w2*128+i]) * 0.5;
 894                         S[i] =  sce0->coeffs[start+w2*128+i]
 895                               - sce1->coeffs[start+w2*128+i];
 896                     }
 897                     abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 898                     abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 899                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
 900                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
 901                     dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
 902                                                 L34,
 903                                                 sce0->ics.swb_sizes[g],
 904                                                 sce0->sf_idx[(w+w2)*16+g],
 905                                                 sce0->band_type[(w+w2)*16+g],
 906                                                 lambda / band0->threshold, INFINITY, NULL);
 907                     dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
 908                                                 R34,
 909                                                 sce1->ics.swb_sizes[g],
 910                                                 sce1->sf_idx[(w+w2)*16+g],
 911                                                 sce1->band_type[(w+w2)*16+g],
 912                                                 lambda / band1->threshold, INFINITY, NULL);
 913                     dist2 += quantize_band_cost(s, M,
 914                                                 M34,
 915                                                 sce0->ics.swb_sizes[g],
 916                                                 sce0->sf_idx[(w+w2)*16+g],
 917                                                 sce0->band_type[(w+w2)*16+g],
 918                                                 lambda / maxthr, INFINITY, NULL);
 919                     dist2 += quantize_band_cost(s, S,
 920                                                 S34,
 921                                                 sce1->ics.swb_sizes[g],
 922                                                 sce1->sf_idx[(w+w2)*16+g],
 923                                                 sce1->band_type[(w+w2)*16+g],
 924                                                 lambda / minthr, INFINITY, NULL);
 925                 }
 926                 cpe->ms_mask[w*16+g] = dist2 < dist1;
 927             }
 928             start += sce0->ics.swb_sizes[g];
 929         }
 930     }
 931 }
 932
 933 AACCoefficientsEncoder ff_aac_coders[] = {
 934     {
 935         search_for_quantizers_faac,
 936         encode_window_bands_info,
 937         quantize_and_encode_band,
 938         search_for_ms,
 939     },
 940     {
 941         search_for_quantizers_anmr,
 942         encode_window_bands_info,
 943         quantize_and_encode_band,
 944         search_for_ms,
 945     },
 946     {
 947         search_for_quantizers_twoloop,
 948         encode_window_bands_info,
 949         quantize_and_encode_band,
 950         search_for_ms,
 951     },
 952     {
 953         search_for_quantizers_fast,
 954         encode_window_bands_info,
 955         quantize_and_encode_band,
 956         search_for_ms,
 957     },
 958 };