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   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 libavcodec/aaccoder.c
  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     return pow(coef * Q, 0.75) + 0.4054;
  65 }
  66
  67 static void quantize_bands(int (*out)[2], const float *in, const float *scaled,
  68                            int size, float Q34, int is_signed, int maxval)
  69 {
  70     int i;
  71     double qc;
  72     for (i = 0; i < size; i++) {
  73         qc = scaled[i] * Q34;
  74         out[i][0] = (int)FFMIN((int)qc,            maxval);
  75         out[i][1] = (int)FFMIN((int)(qc + 0.4054), maxval);
  76         if (is_signed && in[i] < 0.0f) {
  77             out[i][0] = -out[i][0];
  78             out[i][1] = -out[i][1];
  79         }
  80     }
  81 }
  82
  83 static void abs_pow34_v(float *out, const float *in, const int size)
  84 {
  85 #ifndef USE_REALLY_FULL_SEARCH
  86     int i;
  87     for (i = 0; i < size; i++)
  88         out[i] = pow(fabsf(in[i]), 0.75);
  89 #endif /* USE_REALLY_FULL_SEARCH */
  90 }
  91
  92 static av_always_inline int quant2(float coef, const float Q)
  93 {
  94     return pow(coef * Q, 0.75);
  95 }
  96
  97 static const uint8_t aac_cb_range [12] = {0, 3, 3, 3, 3, 9, 9, 8, 8, 13, 13, 17};
  98 static const uint8_t aac_cb_maxval[12] = {0, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 16};
  99
 100 /**
 101  * Calculate rate distortion cost for quantizing with given codebook
 102  *
 103  * @return quantization distortion
 104  */
 105 static float quantize_band_cost(struct AACEncContext *s, const float *in,
 106                                 const float *scaled, int size, int scale_idx,
 107                                 int cb, const float lambda, const float uplim,
 108                                 int *bits)
 109 {
 110     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 111     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
 112     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 113     int i, j, k;
 114     float cost = 0;
 115     const int dim = cb < FIRST_PAIR_BT ? 4 : 2;
 116     int resbits = 0;
 117 #ifndef USE_REALLY_FULL_SEARCH
 118     const float  Q34 = pow(Q, 0.75);
 119     const int range  = aac_cb_range[cb];
 120     const int maxval = aac_cb_maxval[cb];
 121     int offs[4];
 122 #endif /* USE_REALLY_FULL_SEARCH */
 123
 124     if (!cb) {
 125         for (i = 0; i < size; i++)
 126             cost += in[i]*in[i]*lambda;
 127         return cost;
 128     }
 129 #ifndef USE_REALLY_FULL_SEARCH
 130     offs[0] = 1;
 131     for (i = 1; i < dim; i++)
 132         offs[i] = offs[i-1]*range;
 133     quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
 134 #endif /* USE_REALLY_FULL_SEARCH */
 135     for (i = 0; i < size; i += dim) {
 136         float mincost;
 137         int minidx  = 0;
 138         int minbits = 0;
 139         const float *vec;
 140 #ifndef USE_REALLY_FULL_SEARCH
 141         int (*quants)[2] = &s->qcoefs[i];
 142         mincost = 0.0f;
 143         for (j = 0; j < dim; j++)
 144             mincost += in[i+j]*in[i+j]*lambda;
 145         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 146         minbits = ff_aac_spectral_bits[cb-1][minidx];
 147         mincost += minbits;
 148         for (j = 0; j < (1<<dim); j++) {
 149             float rd = 0.0f;
 150             int curbits;
 151             int curidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 152             int same   = 0;
 153             for (k = 0; k < dim; k++) {
 154                 if ((j & (1 << k)) && quants[k][0] == quants[k][1]) {
 155                     same = 1;
 156                     break;
 157                 }
 158             }
 159             if (same)
 160                 continue;
 161             for (k = 0; k < dim; k++)
 162                 curidx += quants[k][!!(j & (1 << k))] * offs[dim - 1 - k];
 163             curbits =  ff_aac_spectral_bits[cb-1][curidx];
 164             vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 165 #else
 166         mincost = INFINITY;
 167         vec = ff_aac_codebook_vectors[cb-1];
 168         for (j = 0; j < ff_aac_spectral_sizes[cb-1]; j++, vec += dim) {
 169             float rd = 0.0f;
 170             int curbits = ff_aac_spectral_bits[cb-1][j];
 171 #endif /* USE_REALLY_FULL_SEARCH */
 172             if (IS_CODEBOOK_UNSIGNED(cb)) {
 173                 for (k = 0; k < dim; k++) {
 174                     float t = fabsf(in[i+k]);
 175                     float di;
 176                     //do not code with escape sequence small values
 177                     if (vec[k] == 64.0f && t < 39.0f*IQ) {
 178                         rd = INFINITY;
 179                         break;
 180                     }
 181                     if (vec[k] == 64.0f) { //FIXME: slow
 182                         if (t >= CLIPPED_ESCAPE) {
 183                             di = t - CLIPPED_ESCAPE;
 184                             curbits += 21;
 185                         } else {
 186                             int c = av_clip(quant(t, Q), 0, 8191);
 187                             di = t - c*cbrt(c)*IQ;
 188                             curbits += av_log2(c)*2 - 4 + 1;
 189                         }
 190                     } else {
 191                         di = t - vec[k]*IQ;
 192                     }
 193                     if (vec[k] != 0.0f)
 194                         curbits++;
 195                     rd += di*di*lambda;
 196                 }
 197             } else {
 198                 for (k = 0; k < dim; k++) {
 199                     float di = in[i+k] - vec[k]*IQ;
 200                     rd += di*di*lambda;
 201                 }
 202             }
 203             rd += curbits;
 204             if (rd < mincost) {
 205                 mincost = rd;
 206                 minidx  = j;
 207                 minbits = curbits;
 208             }
 209         }
 210         cost    += mincost;
 211         resbits += minbits;
 212         if (cost >= uplim)
 213             return uplim;
 214     }
 215
 216     if (bits)
 217         *bits = resbits;
 218     return cost;
 219 }
 220
 221 static void quantize_and_encode_band(struct AACEncContext *s, PutBitContext *pb,
 222                                      const float *in, int size, int scale_idx,
 223                                      int cb, const float lambda)
 224 {
 225     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 226     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
 227     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 228     const int dim = (cb < FIRST_PAIR_BT) ? 4 : 2;
 229     int i, j, k;
 230 #ifndef USE_REALLY_FULL_SEARCH
 231     const float  Q34 = pow(Q, 0.75);
 232     const int range  = aac_cb_range[cb];
 233     const int maxval = aac_cb_maxval[cb];
 234     int offs[4];
 235     float *scaled = s->scoefs;
 236 #endif /* USE_REALLY_FULL_SEARCH */
 237
 238 //START_TIMER
 239     if (!cb)
 240         return;
 241
 242 #ifndef USE_REALLY_FULL_SEARCH
 243     offs[0] = 1;
 244     for (i = 1; i < dim; i++)
 245         offs[i] = offs[i-1]*range;
 246     abs_pow34_v(scaled, in, size);
 247     quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
 248 #endif /* USE_REALLY_FULL_SEARCH */
 249     for (i = 0; i < size; i += dim) {
 250         float mincost;
 251         int minidx  = 0;
 252         int minbits = 0;
 253         const float *vec;
 254 #ifndef USE_REALLY_FULL_SEARCH
 255         int (*quants)[2] = &s->qcoefs[i];
 256         mincost = 0.0f;
 257         for (j = 0; j < dim; j++)
 258             mincost += in[i+j]*in[i+j]*lambda;
 259         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 260         minbits = ff_aac_spectral_bits[cb-1][minidx];
 261         mincost += minbits;
 262         for (j = 0; j < (1<<dim); j++) {
 263             float rd = 0.0f;
 264             int curbits;
 265             int curidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 266             int same   = 0;
 267             for (k = 0; k < dim; k++) {
 268                 if ((j & (1 << k)) && quants[k][0] == quants[k][1]) {
 269                     same = 1;
 270                     break;
 271                 }
 272             }
 273             if (same)
 274                 continue;
 275             for (k = 0; k < dim; k++)
 276                 curidx += quants[k][!!(j & (1 << k))] * offs[dim - 1 - k];
 277             curbits =  ff_aac_spectral_bits[cb-1][curidx];
 278             vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 279 #else
 280         vec = ff_aac_codebook_vectors[cb-1];
 281         mincost = INFINITY;
 282         for (j = 0; j < ff_aac_spectral_sizes[cb-1]; j++, vec += dim) {
 283             float rd = 0.0f;
 284             int curbits = ff_aac_spectral_bits[cb-1][j];
 285             int curidx  = j;
 286 #endif /* USE_REALLY_FULL_SEARCH */
 287             if (IS_CODEBOOK_UNSIGNED(cb)) {
 288                 for (k = 0; k < dim; k++) {
 289                     float t = fabsf(in[i+k]);
 290                     float di;
 291                     //do not code with escape sequence small values
 292                     if (vec[k] == 64.0f && t < 39.0f*IQ) {
 293                         rd = INFINITY;
 294                         break;
 295                     }
 296                     if (vec[k] == 64.0f) { //FIXME: slow
 297                         if (t >= CLIPPED_ESCAPE) {
 298                             di = t - CLIPPED_ESCAPE;
 299                             curbits += 21;
 300                         } else {
 301                             int c = av_clip(quant(t, Q), 0, 8191);
 302                             di = t - c*cbrt(c)*IQ;
 303                             curbits += av_log2(c)*2 - 4 + 1;
 304                         }
 305                     } else {
 306                         di = t - vec[k]*IQ;
 307                     }
 308                     if (vec[k] != 0.0f)
 309                         curbits++;
 310                     rd += di*di*lambda;
 311                 }
 312             } else {
 313                 for (k = 0; k < dim; k++) {
 314                     float di = in[i+k] - vec[k]*IQ;
 315                     rd += di*di*lambda;
 316                 }
 317             }
 318             rd += curbits;
 319             if (rd < mincost) {
 320                 mincost = rd;
 321                 minidx  = curidx;
 322                 minbits = curbits;
 323             }
 324         }
 325         put_bits(pb, ff_aac_spectral_bits[cb-1][minidx], ff_aac_spectral_codes[cb-1][minidx]);
 326         if (IS_CODEBOOK_UNSIGNED(cb))
 327             for (j = 0; j < dim; j++)
 328                 if (ff_aac_codebook_vectors[cb-1][minidx*dim+j] != 0.0f)
 329                     put_bits(pb, 1, in[i+j] < 0.0f);
 330         if (cb == ESC_BT) {
 331             for (j = 0; j < 2; j++) {
 332                 if (ff_aac_codebook_vectors[cb-1][minidx*2+j] == 64.0f) {
 333                     int coef = av_clip(quant(fabsf(in[i+j]), Q), 0, 8191);
 334                     int len = av_log2(coef);
 335
 336                     put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
 337                     put_bits(pb, len, coef & ((1 << len) - 1));
 338                 }
 339             }
 340         }
 341     }
 342 //STOP_TIMER("quantize_and_encode")
 343 }
 344
 345 /**
 346  * structure used in optimal codebook search
 347  */
 348 typedef struct BandCodingPath {
 349     int prev_idx; ///< pointer to the previous path point
 350     int codebook; ///< codebook for coding band run
 351     float cost;   ///< path cost
 352     int run;
 353 } BandCodingPath;
 354
 355 /**
 356  * Encode band info for single window group bands.
 357  */
 358 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
 359                                      int win, int group_len, const float lambda)
 360 {
 361     BandCodingPath path[120][12];
 362     int w, swb, cb, start, start2, size;
 363     int i, j;
 364     const int max_sfb  = sce->ics.max_sfb;
 365     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 366     const int run_esc  = (1 << run_bits) - 1;
 367     int idx, ppos, count;
 368     int stackrun[120], stackcb[120], stack_len;
 369     float next_minrd = INFINITY;
 370     int next_mincb = 0;
 371
 372     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 373     start = win*128;
 374     for (cb = 0; cb < 12; cb++) {
 375         path[0][cb].cost     = 0.0f;
 376         path[0][cb].prev_idx = -1;
 377         path[0][cb].run      = 0;
 378     }
 379     for (swb = 0; swb < max_sfb; swb++) {
 380         start2 = start;
 381         size = sce->ics.swb_sizes[swb];
 382         if (sce->zeroes[win*16 + swb]) {
 383             for (cb = 0; cb < 12; cb++) {
 384                 path[swb+1][cb].prev_idx = cb;
 385                 path[swb+1][cb].cost     = path[swb][cb].cost;
 386                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 387             }
 388         } else {
 389             float minrd = next_minrd;
 390             int mincb = next_mincb;
 391             next_minrd = INFINITY;
 392             next_mincb = 0;
 393             for (cb = 0; cb < 12; cb++) {
 394                 float cost_stay_here, cost_get_here;
 395                 float rd = 0.0f;
 396                 for (w = 0; w < group_len; w++) {
 397                     FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(win+w)*16+swb];
 398                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
 399                                              s->scoefs + start + w*128, size,
 400                                              sce->sf_idx[(win+w)*16+swb], cb,
 401                                              lambda / band->threshold, INFINITY, NULL);
 402                 }
 403                 cost_stay_here = path[swb][cb].cost + rd;
 404                 cost_get_here  = minrd              + rd + run_bits + 4;
 405                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 406                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 407                     cost_stay_here += run_bits;
 408                 if (cost_get_here < cost_stay_here) {
 409                     path[swb+1][cb].prev_idx = mincb;
 410                     path[swb+1][cb].cost     = cost_get_here;
 411                     path[swb+1][cb].run      = 1;
 412                 } else {
 413                     path[swb+1][cb].prev_idx = cb;
 414                     path[swb+1][cb].cost     = cost_stay_here;
 415                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 416                 }
 417                 if (path[swb+1][cb].cost < next_minrd) {
 418                     next_minrd = path[swb+1][cb].cost;
 419                     next_mincb = cb;
 420                 }
 421             }
 422         }
 423         start += sce->ics.swb_sizes[swb];
 424     }
 425
 426     //convert resulting path from backward-linked list
 427     stack_len = 0;
 428     idx       = 0;
 429     for (cb = 1; cb < 12; cb++)
 430         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 431             idx = cb;
 432     ppos = max_sfb;
 433     while (ppos > 0) {
 434         cb = idx;
 435         stackrun[stack_len] = path[ppos][cb].run;
 436         stackcb [stack_len] = cb;
 437         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 438         ppos -= path[ppos][cb].run;
 439         stack_len++;
 440     }
 441     //perform actual band info encoding
 442     start = 0;
 443     for (i = stack_len - 1; i >= 0; i--) {
 444         put_bits(&s->pb, 4, stackcb[i]);
 445         count = stackrun[i];
 446         memset(sce->zeroes + win*16 + start, !stackcb[i], count);
 447         //XXX: memset when band_type is also uint8_t
 448         for (j = 0; j < count; j++) {
 449             sce->band_type[win*16 + start] =  stackcb[i];
 450             start++;
 451         }
 452         while (count >= run_esc) {
 453             put_bits(&s->pb, run_bits, run_esc);
 454             count -= run_esc;
 455         }
 456         put_bits(&s->pb, run_bits, count);
 457     }
 458 }
 459
 460 typedef struct TrellisPath {
 461     float cost;
 462     int prev;
 463     int min_val;
 464     int max_val;
 465 } TrellisPath;
 466
 467 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 468                                        SingleChannelElement *sce,
 469                                        const float lambda)
 470 {
 471     int q, w, w2, g, start = 0;
 472     int i;
 473     int idx;
 474     TrellisPath paths[256*121];
 475     int bandaddr[121];
 476     int minq;
 477     float mincost;
 478
 479     for (i = 0; i < 256; i++) {
 480         paths[i].cost    = 0.0f;
 481         paths[i].prev    = -1;
 482         paths[i].min_val = i;
 483         paths[i].max_val = i;
 484     }
 485     for (i = 256; i < 256*121; i++) {
 486         paths[i].cost    = INFINITY;
 487         paths[i].prev    = -2;
 488         paths[i].min_val = INT_MAX;
 489         paths[i].max_val = 0;
 490     }
 491     idx = 256;
 492     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 493     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 494         start = w*128;
 495         for (g = 0; g < sce->ics.num_swb; g++) {
 496             const float *coefs = sce->coeffs + start;
 497             float qmin, qmax;
 498             int nz = 0;
 499
 500             bandaddr[idx >> 8] = w * 16 + g;
 501             qmin = INT_MAX;
 502             qmax = 0.0f;
 503             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 504                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 505                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 506                     sce->zeroes[(w+w2)*16+g] = 1;
 507                     continue;
 508                 }
 509                 sce->zeroes[(w+w2)*16+g] = 0;
 510                 nz = 1;
 511                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 512                     float t = fabsf(coefs[w2*128+i]);
 513                     if (t > 0.0f)
 514                         qmin = FFMIN(qmin, t);
 515                     qmax = FFMAX(qmax, t);
 516                 }
 517             }
 518             if (nz) {
 519                 int minscale, maxscale;
 520                 float minrd = INFINITY;
 521                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 522                 minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 523                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 524                 maxscale = av_clip_uint8(log2(qmax)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 525                 for (q = minscale; q < maxscale; q++) {
 526                     float dists[12], dist;
 527                     memset(dists, 0, sizeof(dists));
 528                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 529                         FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 530                         int cb;
 531                         for (cb = 0; cb <= ESC_BT; cb++)
 532                             dists[cb] += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 533                                                             q, cb, lambda / band->threshold, INFINITY, NULL);
 534                     }
 535                     dist = dists[0];
 536                     for (i = 1; i <= ESC_BT; i++)
 537                         dist = FFMIN(dist, dists[i]);
 538                     minrd = FFMIN(minrd, dist);
 539
 540                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++) {
 541                         float cost;
 542                         int minv, maxv;
 543                         if (isinf(paths[idx - 256 + i].cost))
 544                             continue;
 545                         cost = paths[idx - 256 + i].cost + dist
 546                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 547                         minv = FFMIN(paths[idx - 256 + i].min_val, q);
 548                         maxv = FFMAX(paths[idx - 256 + i].max_val, q);
 549                         if (cost < paths[idx + q].cost && maxv-minv < SCALE_MAX_DIFF) {
 550                             paths[idx + q].cost    = cost;
 551                             paths[idx + q].prev    = idx - 256 + i;
 552                             paths[idx + q].min_val = minv;
 553                             paths[idx + q].max_val = maxv;
 554                         }
 555                     }
 556                 }
 557             } else {
 558                 for (q = 0; q < 256; q++) {
 559                     if (!isinf(paths[idx - 256 + q].cost)) {
 560                         paths[idx + q].cost = paths[idx - 256 + q].cost + 1;
 561                         paths[idx + q].prev = idx - 256 + q;
 562                         paths[idx + q].min_val = FFMIN(paths[idx - 256 + q].min_val, q);
 563                         paths[idx + q].max_val = FFMAX(paths[idx - 256 + q].max_val, q);
 564                         continue;
 565                     }
 566                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++) {
 567                         float cost;
 568                         int minv, maxv;
 569                         if (isinf(paths[idx - 256 + i].cost))
 570                             continue;
 571                         cost = paths[idx - 256 + i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 572                         minv = FFMIN(paths[idx - 256 + i].min_val, q);
 573                         maxv = FFMAX(paths[idx - 256 + i].max_val, q);
 574                         if (cost < paths[idx + q].cost && maxv-minv < SCALE_MAX_DIFF) {
 575                             paths[idx + q].cost    = cost;
 576                             paths[idx + q].prev    = idx - 256 + i;
 577                             paths[idx + q].min_val = minv;
 578                             paths[idx + q].max_val = maxv;
 579                         }
 580                     }
 581                 }
 582             }
 583             sce->zeroes[w*16+g] = !nz;
 584             start += sce->ics.swb_sizes[g];
 585             idx   += 256;
 586         }
 587     }
 588     idx -= 256;
 589     mincost = paths[idx].cost;
 590     minq    = idx;
 591     for (i = 1; i < 256; i++) {
 592         if (paths[idx + i].cost < mincost) {
 593             mincost = paths[idx + i].cost;
 594             minq = idx + i;
 595         }
 596     }
 597     while (minq >= 256) {
 598         sce->sf_idx[bandaddr[minq>>8]] = minq & 0xFF;
 599         minq = paths[minq].prev;
 600     }
 601     //set the same quantizers inside window groups
 602     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 603         for (g = 0;  g < sce->ics.num_swb; g++)
 604             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 605                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 606 }
 607
 608 /**
 609  * two-loop quantizers search taken from ISO 13818-7 Appendix C
 610  */
 611 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
 612                                           AACEncContext *s,
 613                                           SingleChannelElement *sce,
 614                                           const float lambda)
 615 {
 616     int start = 0, i, w, w2, g;
 617     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels;
 618     float dists[128], uplims[128];
 619     int fflag, minscaler;
 620     int its  = 0;
 621     int allz = 0;
 622     float minthr = INFINITY;
 623
 624     //XXX: some heuristic to determine initial quantizers will reduce search time
 625     memset(dists, 0, sizeof(dists));
 626     //determine zero bands and upper limits
 627     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 628         for (g = 0;  g < sce->ics.num_swb; g++) {
 629             int nz = 0;
 630             float uplim = 0.0f;
 631             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 632                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 633                 uplim += band->threshold;
 634                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 635                     sce->zeroes[(w+w2)*16+g] = 1;
 636                     continue;
 637                 }
 638                 nz = 1;
 639             }
 640             uplims[w*16+g] = uplim *512;
 641             sce->zeroes[w*16+g] = !nz;
 642             if (nz)
 643                 minthr = FFMIN(minthr, uplim);
 644             allz = FFMAX(allz, nz);
 645         }
 646     }
 647     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 648         for (g = 0;  g < sce->ics.num_swb; g++) {
 649             if (sce->zeroes[w*16+g]) {
 650                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 651                 continue;
 652             }
 653             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2(uplims[w*16+g]/minthr)*4,59);
 654         }
 655     }
 656
 657     if (!allz)
 658         return;
 659     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 660     //perform two-loop search
 661     //outer loop - improve quality
 662     do {
 663         int tbits, qstep;
 664         minscaler = sce->sf_idx[0];
 665         //inner loop - quantize spectrum to fit into given number of bits
 666         qstep = its ? 1 : 32;
 667         do {
 668             int prev = -1;
 669             tbits = 0;
 670             fflag = 0;
 671             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 672                 start = w*128;
 673                 for (g = 0;  g < sce->ics.num_swb; g++) {
 674                     const float *coefs = sce->coeffs + start;
 675                     const float *scaled = s->scoefs + start;
 676                     int bits = 0;
 677                     int cb;
 678                     float mindist = INFINITY;
 679                     int minbits = 0;
 680
 681                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218)
 682                         continue;
 683                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 684                     for (cb = 0; cb <= ESC_BT; cb++) {
 685                         float dist = 0.0f;
 686                         int bb = 0;
 687                         for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 688                             int b;
 689                             dist += quantize_band_cost(s, coefs + w2*128,
 690                                                        scaled + w2*128,
 691                                                        sce->ics.swb_sizes[g],
 692                                                        sce->sf_idx[w*16+g],
 693                                                        ESC_BT,
 694                                                        lambda,
 695                                                        INFINITY,
 696                                                        &b);
 697                             bb += b;
 698                         }
 699                         if (dist < mindist) {
 700                             mindist = dist;
 701                             minbits = bb;
 702                         }
 703                     }
 704                     dists[w*16+g] = (mindist - minbits) / lambda;
 705                     bits = minbits;
 706                     if (prev != -1) {
 707                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 708                     }
 709                     tbits += bits;
 710                     start += sce->ics.swb_sizes[g];
 711                     prev = sce->sf_idx[w*16+g];
 712                 }
 713             }
 714             if (tbits > destbits) {
 715                 for (i = 0; i < 128; i++)
 716                     if (sce->sf_idx[i] < 218 - qstep)
 717                         sce->sf_idx[i] += qstep;
 718             } else {
 719                 for (i = 0; i < 128; i++)
 720                     if (sce->sf_idx[i] > 60 - qstep)
 721                         sce->sf_idx[i] -= qstep;
 722             }
 723             qstep >>= 1;
 724             if (!qstep && tbits > destbits*1.02)
 725                 qstep = 1;
 726             if (sce->sf_idx[0] >= 217)
 727                 break;
 728         } while (qstep);
 729
 730         fflag = 0;
 731         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 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                 int prevsc = sce->sf_idx[w*16+g];
 736                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60)
 737                     sce->sf_idx[w*16+g]--;
 738                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 739                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 740                 if (sce->sf_idx[w*16+g] != prevsc)
 741                     fflag = 1;
 742             }
 743         }
 744         its++;
 745     } while (fflag && its < 10);
 746 }
 747
 748 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 749                                        SingleChannelElement *sce,
 750                                        const float lambda)
 751 {
 752     int start = 0, i, w, w2, g;
 753     float uplim[128], maxq[128];
 754     int minq, maxsf;
 755     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 756     int last = 0, lastband = 0, curband = 0;
 757     float avg_energy = 0.0;
 758     if (sce->ics.num_windows == 1) {
 759         start = 0;
 760         for (i = 0; i < 1024; i++) {
 761             if (i - start >= sce->ics.swb_sizes[curband]) {
 762                 start += sce->ics.swb_sizes[curband];
 763                 curband++;
 764             }
 765             if (sce->coeffs[i]) {
 766                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 767                 last = i;
 768                 lastband = curband;
 769             }
 770         }
 771     } else {
 772         for (w = 0; w < 8; w++) {
 773             const float *coeffs = sce->coeffs + w*128;
 774             start = 0;
 775             for (i = 0; i < 128; i++) {
 776                 if (i - start >= sce->ics.swb_sizes[curband]) {
 777                     start += sce->ics.swb_sizes[curband];
 778                     curband++;
 779                 }
 780                 if (coeffs[i]) {
 781                     avg_energy += coeffs[i] * coeffs[i];
 782                     last = FFMAX(last, i);
 783                     lastband = FFMAX(lastband, curband);
 784                 }
 785             }
 786         }
 787     }
 788     last++;
 789     avg_energy /= last;
 790     if (avg_energy == 0.0f) {
 791         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
 792             sce->sf_idx[i] = SCALE_ONE_POS;
 793         return;
 794     }
 795     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 796         start = w*128;
 797         for (g = 0; g < sce->ics.num_swb; g++) {
 798             float *coefs   = sce->coeffs + start;
 799             const int size = sce->ics.swb_sizes[g];
 800             int start2 = start, end2 = start + size, peakpos = start;
 801             float maxval = -1, thr = 0.0f, t;
 802             maxq[w*16+g] = 0.0f;
 803             if (g > lastband) {
 804                 maxq[w*16+g] = 0.0f;
 805                 start += size;
 806                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
 807                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
 808                 continue;
 809             }
 810             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 811                 for (i = 0; i < size; i++) {
 812                     float t = coefs[w2*128+i]*coefs[w2*128+i];
 813                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
 814                     thr += t;
 815                     if (sce->ics.num_windows == 1 && maxval < t) {
 816                         maxval  = t;
 817                         peakpos = start+i;
 818                     }
 819                 }
 820             }
 821             if (sce->ics.num_windows == 1) {
 822                 start2 = FFMAX(peakpos - 2, start2);
 823                 end2   = FFMIN(peakpos + 3, end2);
 824             } else {
 825                 start2 -= start;
 826                 end2   -= start;
 827             }
 828             start += size;
 829             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
 830             t   = 1.0 - (1.0 * start2 / last);
 831             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
 832         }
 833     }
 834     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 835     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 836     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 837         start = w*128;
 838         for (g = 0;  g < sce->ics.num_swb; g++) {
 839             const float *coefs  = sce->coeffs + start;
 840             const float *scaled = s->scoefs   + start;
 841             const int size      = sce->ics.swb_sizes[g];
 842             int scf, prev_scf, step;
 843             int min_scf = 0, max_scf = 255;
 844             float curdiff;
 845             if (maxq[w*16+g] < 21.544) {
 846                 sce->zeroes[w*16+g] = 1;
 847                 start += size;
 848                 continue;
 849             }
 850             sce->zeroes[w*16+g] = 0;
 851             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2(1/maxq[w*16+g])*16/3, 60, 218);
 852             step = 16;
 853             for (;;) {
 854                 float dist = 0.0f;
 855                 int quant_max;
 856
 857                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 858                     int b;
 859                     dist += quantize_band_cost(s, coefs + w2*128,
 860                                                scaled + w2*128,
 861                                                sce->ics.swb_sizes[g],
 862                                                scf,
 863                                                ESC_BT,
 864                                                lambda,
 865                                                INFINITY,
 866                                                &b);
 867                     dist -= b;
 868                 }
 869                 dist *= 1.0f / 512.0f / lambda;
 870                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[200 - scf + SCALE_ONE_POS - SCALE_DIV_512]);
 871                 if (quant_max >= 8191) { // too much, return to the previous quantizer
 872                     sce->sf_idx[w*16+g] = prev_scf;
 873                     break;
 874                 }
 875                 prev_scf = scf;
 876                 curdiff = fabsf(dist - uplim[w*16+g]);
 877                 if (curdiff == 0.0f)
 878                     step = 0;
 879                 else
 880                     step = fabsf(log2(curdiff));
 881                 if (dist > uplim[w*16+g])
 882                     step = -step;
 883                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
 884                     sce->sf_idx[w*16+g] = scf;
 885                     break;
 886                 }
 887                 scf += step;
 888                 if (step > 0)
 889                     min_scf = scf;
 890                 else
 891                     max_scf = scf;
 892             }
 893             start += size;
 894         }
 895     }
 896     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
 897     for (i = 1; i < 128; i++) {
 898         if (!sce->sf_idx[i])
 899             sce->sf_idx[i] = sce->sf_idx[i-1];
 900         else
 901             minq = FFMIN(minq, sce->sf_idx[i]);
 902     }
 903     if (minq == INT_MAX)
 904         minq = 0;
 905     minq = FFMIN(minq, SCALE_MAX_POS);
 906     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
 907     for (i = 126; i >= 0; i--) {
 908         if (!sce->sf_idx[i])
 909             sce->sf_idx[i] = sce->sf_idx[i+1];
 910         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
 911     }
 912 }
 913
 914 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
 915                                        SingleChannelElement *sce,
 916                                        const float lambda)
 917 {
 918     int start = 0, i, w, w2, g;
 919     int minq = 255;
 920
 921     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 922     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 923         start = w*128;
 924         for (g = 0; g < sce->ics.num_swb; g++) {
 925             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 926                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 927                 if (band->energy <= band->threshold) {
 928                     sce->sf_idx[(w+w2)*16+g] = 218;
 929                     sce->zeroes[(w+w2)*16+g] = 1;
 930                 } else {
 931                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2(band->threshold), 80, 218);
 932                     sce->zeroes[(w+w2)*16+g] = 0;
 933                 }
 934                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
 935             }
 936         }
 937     }
 938     for (i = 0; i < 128; i++) {
 939         sce->sf_idx[i] = 140;
 940         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
 941     }
 942     //set the same quantizers inside window groups
 943     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 944         for (g = 0;  g < sce->ics.num_swb; g++)
 945             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 946                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 947 }
 948
 949 static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
 950                           const float lambda)
 951 {
 952     int start = 0, i, w, w2, g;
 953     float M[128], S[128];
 954     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
 955     SingleChannelElement *sce0 = &cpe->ch[0];
 956     SingleChannelElement *sce1 = &cpe->ch[1];
 957     if (!cpe->common_window)
 958         return;
 959     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 960         for (g = 0;  g < sce0->ics.num_swb; g++) {
 961             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
 962                 float dist1 = 0.0f, dist2 = 0.0f;
 963                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 964                     FFPsyBand *band0 = &s->psy.psy_bands[(s->cur_channel+0)*PSY_MAX_BANDS+(w+w2)*16+g];
 965                     FFPsyBand *band1 = &s->psy.psy_bands[(s->cur_channel+1)*PSY_MAX_BANDS+(w+w2)*16+g];
 966                     float minthr = FFMIN(band0->threshold, band1->threshold);
 967                     float maxthr = FFMAX(band0->threshold, band1->threshold);
 968                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 969                         M[i] = (sce0->coeffs[start+w2*128+i]
 970                               + sce1->coeffs[start+w2*128+i]) * 0.5;
 971                         S[i] =  sce0->coeffs[start+w2*128+i]
 972                               - sce1->coeffs[start+w2*128+i];
 973                     }
 974                     abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 975                     abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 976                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
 977                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
 978                     dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
 979                                                 L34,
 980                                                 sce0->ics.swb_sizes[g],
 981                                                 sce0->sf_idx[(w+w2)*16+g],
 982                                                 sce0->band_type[(w+w2)*16+g],
 983                                                 lambda / band0->threshold, INFINITY, NULL);
 984                     dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
 985                                                 R34,
 986                                                 sce1->ics.swb_sizes[g],
 987                                                 sce1->sf_idx[(w+w2)*16+g],
 988                                                 sce1->band_type[(w+w2)*16+g],
 989                                                 lambda / band1->threshold, INFINITY, NULL);
 990                     dist2 += quantize_band_cost(s, M,
 991                                                 M34,
 992                                                 sce0->ics.swb_sizes[g],
 993                                                 sce0->sf_idx[(w+w2)*16+g],
 994                                                 sce0->band_type[(w+w2)*16+g],
 995                                                 lambda / maxthr, INFINITY, NULL);
 996                     dist2 += quantize_band_cost(s, S,
 997                                                 S34,
 998                                                 sce1->ics.swb_sizes[g],
 999                                                 sce1->sf_idx[(w+w2)*16+g],
1000                                                 sce1->band_type[(w+w2)*16+g],
1001                                                 lambda / minthr, INFINITY, NULL);
1002                 }
1003                 cpe->ms_mask[w*16+g] = dist2 < dist1;
1004             }
1005             start += sce0->ics.swb_sizes[g];
1006         }
1007     }
1008 }
1009
1010 AACCoefficientsEncoder ff_aac_coders[] = {
1011     {
1012         search_for_quantizers_faac,
1013         encode_window_bands_info,
1014         quantize_and_encode_band,
1015 //        search_for_ms,
1016     },
1017     {
1018         search_for_quantizers_anmr,
1019         encode_window_bands_info,
1020         quantize_and_encode_band,
1021 //        search_for_ms,
1022     },
1023     {
1024         search_for_quantizers_twoloop,
1025         encode_window_bands_info,
1026         quantize_and_encode_band,
1027 //        search_for_ms,
1028     },
1029     {
1030         search_for_quantizers_fast,
1031         encode_window_bands_info,
1032         quantize_and_encode_band,
1033 //        search_for_ms,
1034     },
1035 };