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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     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_band_cost(struct AACEncContext *s, const float *in,
 104                                 const float *scaled, int size, int scale_idx,
 105                                 int cb, const float lambda, const float uplim,
 106                                 int *bits)
 107 {
 108     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 109     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
 110     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 111     int i, j, k;
 112     float cost = 0;
 113     const int dim = cb < FIRST_PAIR_BT ? 4 : 2;
 114     int resbits = 0;
 115 #ifndef USE_REALLY_FULL_SEARCH
 116     const float  Q34 = sqrtf(Q * sqrtf(Q));
 117     const int range  = aac_cb_range[cb];
 118     const int maxval = aac_cb_maxval[cb];
 119     int offs[4];
 120 #endif /* USE_REALLY_FULL_SEARCH */
 121
 122     if (!cb) {
 123         for (i = 0; i < size; i++)
 124             cost += in[i]*in[i];
 125         if (bits)
 126             *bits = 0;
 127         return cost * lambda;
 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];
 145         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 146         minbits = ff_aac_spectral_bits[cb-1][minidx];
 147         mincost = mincost * lambda + 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                     if (vec[k] == 64.0f) { //FIXME: slow
 177                         //do not code with escape sequence small values
 178                         if (t < 39.0f*IQ) {
 179                             rd = INFINITY;
 180                             break;
 181                         }
 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*cbrtf(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;
 196                 }
 197             } else {
 198                 for (k = 0; k < dim; k++) {
 199                     float di = in[i+k] - vec[k]*IQ;
 200                     rd += di*di;
 201                 }
 202             }
 203             rd = rd * lambda + 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 = sqrtf(Q * sqrtf(Q));
 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];
 259         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 260         minbits = ff_aac_spectral_bits[cb-1][minidx];
 261         mincost = mincost * lambda + 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                     if (vec[k] == 64.0f) { //FIXME: slow
 292                         //do not code with escape sequence small values
 293                         if (t < 39.0f*IQ) {
 294                             rd = INFINITY;
 295                             break;
 296                         }
 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*cbrtf(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;
 311                 }
 312             } else {
 313                 for (k = 0; k < dim; k++) {
 314                     float di = in[i+k] - vec[k]*IQ;
 315                     rd += di*di;
 316                 }
 317             }
 318             rd = rd * lambda + 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     float cost;   ///< path cost
 351     int run;
 352 } BandCodingPath;
 353
 354 /**
 355  * Encode band info for single window group bands.
 356  */
 357 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
 358                                      int win, int group_len, const float lambda)
 359 {
 360     BandCodingPath path[120][12];
 361     int w, swb, cb, start, start2, size;
 362     int i, j;
 363     const int max_sfb  = sce->ics.max_sfb;
 364     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 365     const int run_esc  = (1 << run_bits) - 1;
 366     int idx, ppos, count;
 367     int stackrun[120], stackcb[120], stack_len;
 368     float next_minrd = INFINITY;
 369     int next_mincb = 0;
 370
 371     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 372     start = win*128;
 373     for (cb = 0; cb < 12; cb++) {
 374         path[0][cb].cost     = 0.0f;
 375         path[0][cb].prev_idx = -1;
 376         path[0][cb].run      = 0;
 377     }
 378     for (swb = 0; swb < max_sfb; swb++) {
 379         start2 = start;
 380         size = sce->ics.swb_sizes[swb];
 381         if (sce->zeroes[win*16 + swb]) {
 382             for (cb = 0; cb < 12; cb++) {
 383                 path[swb+1][cb].prev_idx = cb;
 384                 path[swb+1][cb].cost     = path[swb][cb].cost;
 385                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 386             }
 387         } else {
 388             float minrd = next_minrd;
 389             int mincb = next_mincb;
 390             next_minrd = INFINITY;
 391             next_mincb = 0;
 392             for (cb = 0; cb < 12; cb++) {
 393                 float cost_stay_here, cost_get_here;
 394                 float rd = 0.0f;
 395                 for (w = 0; w < group_len; w++) {
 396                     FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(win+w)*16+swb];
 397                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
 398                                              s->scoefs + start + w*128, size,
 399                                              sce->sf_idx[(win+w)*16+swb], cb,
 400                                              lambda / band->threshold, INFINITY, NULL);
 401                 }
 402                 cost_stay_here = path[swb][cb].cost + rd;
 403                 cost_get_here  = minrd              + rd + run_bits + 4;
 404                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 405                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 406                     cost_stay_here += run_bits;
 407                 if (cost_get_here < cost_stay_here) {
 408                     path[swb+1][cb].prev_idx = mincb;
 409                     path[swb+1][cb].cost     = cost_get_here;
 410                     path[swb+1][cb].run      = 1;
 411                 } else {
 412                     path[swb+1][cb].prev_idx = cb;
 413                     path[swb+1][cb].cost     = cost_stay_here;
 414                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 415                 }
 416                 if (path[swb+1][cb].cost < next_minrd) {
 417                     next_minrd = path[swb+1][cb].cost;
 418                     next_mincb = cb;
 419                 }
 420             }
 421         }
 422         start += sce->ics.swb_sizes[swb];
 423     }
 424
 425     //convert resulting path from backward-linked list
 426     stack_len = 0;
 427     idx       = 0;
 428     for (cb = 1; cb < 12; cb++)
 429         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 430             idx = cb;
 431     ppos = max_sfb;
 432     while (ppos > 0) {
 433         cb = idx;
 434         stackrun[stack_len] = path[ppos][cb].run;
 435         stackcb [stack_len] = cb;
 436         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 437         ppos -= path[ppos][cb].run;
 438         stack_len++;
 439     }
 440     //perform actual band info encoding
 441     start = 0;
 442     for (i = stack_len - 1; i >= 0; i--) {
 443         put_bits(&s->pb, 4, stackcb[i]);
 444         count = stackrun[i];
 445         memset(sce->zeroes + win*16 + start, !stackcb[i], count);
 446         //XXX: memset when band_type is also uint8_t
 447         for (j = 0; j < count; j++) {
 448             sce->band_type[win*16 + start] =  stackcb[i];
 449             start++;
 450         }
 451         while (count >= run_esc) {
 452             put_bits(&s->pb, run_bits, run_esc);
 453             count -= run_esc;
 454         }
 455         put_bits(&s->pb, run_bits, count);
 456     }
 457 }
 458
 459 typedef struct TrellisPath {
 460     float cost;
 461     int prev;
 462     int min_val;
 463     int max_val;
 464 } TrellisPath;
 465
 466 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 467                                        SingleChannelElement *sce,
 468                                        const float lambda)
 469 {
 470     int q, w, w2, g, start = 0;
 471     int i, j;
 472     int idx;
 473     TrellisPath paths[121][256];
 474     int bandaddr[121];
 475     int minq;
 476     float mincost;
 477
 478     for (i = 0; i < 256; i++) {
 479         paths[0][i].cost    = 0.0f;
 480         paths[0][i].prev    = -1;
 481         paths[0][i].min_val = i;
 482         paths[0][i].max_val = i;
 483     }
 484     for (j = 1; j < 121; j++) {
 485         for (i = 0; i < 256; i++) {
 486             paths[j][i].cost    = INFINITY;
 487             paths[j][i].prev    = -2;
 488             paths[j][i].min_val = INT_MAX;
 489             paths[j][i].max_val = 0;
 490         }
 491     }
 492     idx = 1;
 493     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 494     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 495         start = w*128;
 496         for (g = 0; g < sce->ics.num_swb; g++) {
 497             const float *coefs = sce->coeffs + start;
 498             float qmin, qmax;
 499             int nz = 0;
 500
 501             bandaddr[idx] = w * 16 + g;
 502             qmin = INT_MAX;
 503             qmax = 0.0f;
 504             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 505                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 506                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 507                     sce->zeroes[(w+w2)*16+g] = 1;
 508                     continue;
 509                 }
 510                 sce->zeroes[(w+w2)*16+g] = 0;
 511                 nz = 1;
 512                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 513                     float t = fabsf(coefs[w2*128+i]);
 514                     if (t > 0.0f)
 515                         qmin = FFMIN(qmin, t);
 516                     qmax = FFMAX(qmax, t);
 517                 }
 518             }
 519             if (nz) {
 520                 int minscale, maxscale;
 521                 float minrd = INFINITY;
 522                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 523                 minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 524                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 525                 maxscale = av_clip_uint8(log2(qmax)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 526                 for (q = minscale; q < maxscale; q++) {
 527                     float dists[12], dist;
 528                     memset(dists, 0, sizeof(dists));
 529                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 530                         FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 531                         int cb;
 532                         for (cb = 0; cb <= ESC_BT; cb++)
 533                             dists[cb] += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 534                                                             q, cb, lambda / band->threshold, INFINITY, NULL);
 535                     }
 536                     dist = dists[0];
 537                     for (i = 1; i <= ESC_BT; i++)
 538                         dist = FFMIN(dist, dists[i]);
 539                     minrd = FFMIN(minrd, dist);
 540
 541                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++) {
 542                         float cost;
 543                         int minv, maxv;
 544                         if (isinf(paths[idx - 1][i].cost))
 545                             continue;
 546                         cost = paths[idx - 1][i].cost + dist
 547                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 548                         minv = FFMIN(paths[idx - 1][i].min_val, q);
 549                         maxv = FFMAX(paths[idx - 1][i].max_val, q);
 550                         if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
 551                             paths[idx][q].cost    = cost;
 552                             paths[idx][q].prev    = i;
 553                             paths[idx][q].min_val = minv;
 554                             paths[idx][q].max_val = maxv;
 555                         }
 556                     }
 557                 }
 558             } else {
 559                 for (q = 0; q < 256; q++) {
 560                     if (!isinf(paths[idx - 1][q].cost)) {
 561                         paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 562                         paths[idx][q].prev = q;
 563                         paths[idx][q].min_val = FFMIN(paths[idx - 1][q].min_val, q);
 564                         paths[idx][q].max_val = FFMAX(paths[idx - 1][q].max_val, q);
 565                         continue;
 566                     }
 567                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++) {
 568                         float cost;
 569                         int minv, maxv;
 570                         if (isinf(paths[idx - 1][i].cost))
 571                             continue;
 572                         cost = paths[idx - 1][i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 573                         minv = FFMIN(paths[idx - 1][i].min_val, q);
 574                         maxv = FFMAX(paths[idx - 1][i].max_val, q);
 575                         if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
 576                             paths[idx][q].cost    = cost;
 577                             paths[idx][q].prev    = i;
 578                             paths[idx][q].min_val = minv;
 579                             paths[idx][q].max_val = maxv;
 580                         }
 581                     }
 582                 }
 583             }
 584             sce->zeroes[w*16+g] = !nz;
 585             start += sce->ics.swb_sizes[g];
 586             idx++;
 587         }
 588     }
 589     idx--;
 590     mincost = paths[idx][0].cost;
 591     minq    = 0;
 592     for (i = 1; i < 256; i++) {
 593         if (paths[idx][i].cost < mincost) {
 594             mincost = paths[idx][i].cost;
 595             minq = i;
 596         }
 597     }
 598     while (idx) {
 599         sce->sf_idx[bandaddr[idx]] = minq;
 600         minq = paths[idx][minq].prev;
 601         idx--;
 602     }
 603     //set the same quantizers inside window groups
 604     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 605         for (g = 0;  g < sce->ics.num_swb; g++)
 606             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 607                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 608 }
 609
 610 /**
 611  * two-loop quantizers search taken from ISO 13818-7 Appendix C
 612  */
 613 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
 614                                           AACEncContext *s,
 615                                           SingleChannelElement *sce,
 616                                           const float lambda)
 617 {
 618     int start = 0, i, w, w2, g;
 619     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels;
 620     float dists[128], uplims[128];
 621     int fflag, minscaler;
 622     int its  = 0;
 623     int allz = 0;
 624     float minthr = INFINITY;
 625
 626     //XXX: some heuristic to determine initial quantizers will reduce search time
 627     memset(dists, 0, sizeof(dists));
 628     //determine zero bands and upper limits
 629     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 630         for (g = 0;  g < sce->ics.num_swb; g++) {
 631             int nz = 0;
 632             float uplim = 0.0f;
 633             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 634                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 635                 uplim += band->threshold;
 636                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 637                     sce->zeroes[(w+w2)*16+g] = 1;
 638                     continue;
 639                 }
 640                 nz = 1;
 641             }
 642             uplims[w*16+g] = uplim *512;
 643             sce->zeroes[w*16+g] = !nz;
 644             if (nz)
 645                 minthr = FFMIN(minthr, uplim);
 646             allz = FFMAX(allz, nz);
 647         }
 648     }
 649     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 650         for (g = 0;  g < sce->ics.num_swb; g++) {
 651             if (sce->zeroes[w*16+g]) {
 652                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 653                 continue;
 654             }
 655             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2(uplims[w*16+g]/minthr)*4,59);
 656         }
 657     }
 658
 659     if (!allz)
 660         return;
 661     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 662     //perform two-loop search
 663     //outer loop - improve quality
 664     do {
 665         int tbits, qstep;
 666         minscaler = sce->sf_idx[0];
 667         //inner loop - quantize spectrum to fit into given number of bits
 668         qstep = its ? 1 : 32;
 669         do {
 670             int prev = -1;
 671             tbits = 0;
 672             fflag = 0;
 673             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 674                 start = w*128;
 675                 for (g = 0;  g < sce->ics.num_swb; g++) {
 676                     const float *coefs = sce->coeffs + start;
 677                     const float *scaled = s->scoefs + start;
 678                     int bits = 0;
 679                     int cb;
 680                     float mindist = INFINITY;
 681                     int minbits = 0;
 682
 683                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
 684                         start += sce->ics.swb_sizes[g];
 685                         continue;
 686                     }
 687                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 688                     for (cb = 0; cb <= ESC_BT; cb++) {
 689                         float dist = 0.0f;
 690                         int bb = 0;
 691                         for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 692                             int b;
 693                             dist += quantize_band_cost(s, coefs + w2*128,
 694                                                        scaled + w2*128,
 695                                                        sce->ics.swb_sizes[g],
 696                                                        sce->sf_idx[w*16+g],
 697                                                        cb,
 698                                                        lambda,
 699                                                        INFINITY,
 700                                                        &b);
 701                             bb += b;
 702                         }
 703                         if (dist < mindist) {
 704                             mindist = dist;
 705                             minbits = bb;
 706                         }
 707                     }
 708                     dists[w*16+g] = (mindist - minbits) / lambda;
 709                     bits = minbits;
 710                     if (prev != -1) {
 711                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 712                     }
 713                     tbits += bits;
 714                     start += sce->ics.swb_sizes[g];
 715                     prev = sce->sf_idx[w*16+g];
 716                 }
 717             }
 718             if (tbits > destbits) {
 719                 for (i = 0; i < 128; i++)
 720                     if (sce->sf_idx[i] < 218 - qstep)
 721                         sce->sf_idx[i] += qstep;
 722             } else {
 723                 for (i = 0; i < 128; i++)
 724                     if (sce->sf_idx[i] > 60 - qstep)
 725                         sce->sf_idx[i] -= qstep;
 726             }
 727             qstep >>= 1;
 728             if (!qstep && tbits > destbits*1.02)
 729                 qstep = 1;
 730             if (sce->sf_idx[0] >= 217)
 731                 break;
 732         } while (qstep);
 733
 734         fflag = 0;
 735         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 736         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 737             start = w*128;
 738             for (g = 0; g < sce->ics.num_swb; g++) {
 739                 int prevsc = sce->sf_idx[w*16+g];
 740                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60)
 741                     sce->sf_idx[w*16+g]--;
 742                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 743                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 744                 if (sce->sf_idx[w*16+g] != prevsc)
 745                     fflag = 1;
 746             }
 747         }
 748         its++;
 749     } while (fflag && its < 10);
 750 }
 751
 752 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 753                                        SingleChannelElement *sce,
 754                                        const float lambda)
 755 {
 756     int start = 0, i, w, w2, g;
 757     float uplim[128], maxq[128];
 758     int minq, maxsf;
 759     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 760     int last = 0, lastband = 0, curband = 0;
 761     float avg_energy = 0.0;
 762     if (sce->ics.num_windows == 1) {
 763         start = 0;
 764         for (i = 0; i < 1024; i++) {
 765             if (i - start >= sce->ics.swb_sizes[curband]) {
 766                 start += sce->ics.swb_sizes[curband];
 767                 curband++;
 768             }
 769             if (sce->coeffs[i]) {
 770                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 771                 last = i;
 772                 lastband = curband;
 773             }
 774         }
 775     } else {
 776         for (w = 0; w < 8; w++) {
 777             const float *coeffs = sce->coeffs + w*128;
 778             start = 0;
 779             for (i = 0; i < 128; i++) {
 780                 if (i - start >= sce->ics.swb_sizes[curband]) {
 781                     start += sce->ics.swb_sizes[curband];
 782                     curband++;
 783                 }
 784                 if (coeffs[i]) {
 785                     avg_energy += coeffs[i] * coeffs[i];
 786                     last = FFMAX(last, i);
 787                     lastband = FFMAX(lastband, curband);
 788                 }
 789             }
 790         }
 791     }
 792     last++;
 793     avg_energy /= last;
 794     if (avg_energy == 0.0f) {
 795         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
 796             sce->sf_idx[i] = SCALE_ONE_POS;
 797         return;
 798     }
 799     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 800         start = w*128;
 801         for (g = 0; g < sce->ics.num_swb; g++) {
 802             float *coefs   = sce->coeffs + start;
 803             const int size = sce->ics.swb_sizes[g];
 804             int start2 = start, end2 = start + size, peakpos = start;
 805             float maxval = -1, thr = 0.0f, t;
 806             maxq[w*16+g] = 0.0f;
 807             if (g > lastband) {
 808                 maxq[w*16+g] = 0.0f;
 809                 start += size;
 810                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
 811                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
 812                 continue;
 813             }
 814             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 815                 for (i = 0; i < size; i++) {
 816                     float t = coefs[w2*128+i]*coefs[w2*128+i];
 817                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
 818                     thr += t;
 819                     if (sce->ics.num_windows == 1 && maxval < t) {
 820                         maxval  = t;
 821                         peakpos = start+i;
 822                     }
 823                 }
 824             }
 825             if (sce->ics.num_windows == 1) {
 826                 start2 = FFMAX(peakpos - 2, start2);
 827                 end2   = FFMIN(peakpos + 3, end2);
 828             } else {
 829                 start2 -= start;
 830                 end2   -= start;
 831             }
 832             start += size;
 833             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
 834             t   = 1.0 - (1.0 * start2 / last);
 835             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
 836         }
 837     }
 838     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 839     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 840     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 841         start = w*128;
 842         for (g = 0;  g < sce->ics.num_swb; g++) {
 843             const float *coefs  = sce->coeffs + start;
 844             const float *scaled = s->scoefs   + start;
 845             const int size      = sce->ics.swb_sizes[g];
 846             int scf, prev_scf, step;
 847             int min_scf = 0, max_scf = 255;
 848             float curdiff;
 849             if (maxq[w*16+g] < 21.544) {
 850                 sce->zeroes[w*16+g] = 1;
 851                 start += size;
 852                 continue;
 853             }
 854             sce->zeroes[w*16+g] = 0;
 855             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2(1/maxq[w*16+g])*16/3, 60, 218);
 856             step = 16;
 857             for (;;) {
 858                 float dist = 0.0f;
 859                 int quant_max;
 860
 861                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 862                     int b;
 863                     dist += quantize_band_cost(s, coefs + w2*128,
 864                                                scaled + w2*128,
 865                                                sce->ics.swb_sizes[g],
 866                                                scf,
 867                                                ESC_BT,
 868                                                lambda,
 869                                                INFINITY,
 870                                                &b);
 871                     dist -= b;
 872                 }
 873                 dist *= 1.0f / 512.0f / lambda;
 874                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[200 - scf + SCALE_ONE_POS - SCALE_DIV_512]);
 875                 if (quant_max >= 8191) { // too much, return to the previous quantizer
 876                     sce->sf_idx[w*16+g] = prev_scf;
 877                     break;
 878                 }
 879                 prev_scf = scf;
 880                 curdiff = fabsf(dist - uplim[w*16+g]);
 881                 if (curdiff == 0.0f)
 882                     step = 0;
 883                 else
 884                     step = fabsf(log2(curdiff));
 885                 if (dist > uplim[w*16+g])
 886                     step = -step;
 887                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
 888                     sce->sf_idx[w*16+g] = scf;
 889                     break;
 890                 }
 891                 scf += step;
 892                 if (step > 0)
 893                     min_scf = scf;
 894                 else
 895                     max_scf = scf;
 896             }
 897             start += size;
 898         }
 899     }
 900     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
 901     for (i = 1; i < 128; i++) {
 902         if (!sce->sf_idx[i])
 903             sce->sf_idx[i] = sce->sf_idx[i-1];
 904         else
 905             minq = FFMIN(minq, sce->sf_idx[i]);
 906     }
 907     if (minq == INT_MAX)
 908         minq = 0;
 909     minq = FFMIN(minq, SCALE_MAX_POS);
 910     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
 911     for (i = 126; i >= 0; i--) {
 912         if (!sce->sf_idx[i])
 913             sce->sf_idx[i] = sce->sf_idx[i+1];
 914         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
 915     }
 916 }
 917
 918 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
 919                                        SingleChannelElement *sce,
 920                                        const float lambda)
 921 {
 922     int start = 0, i, w, w2, g;
 923     int minq = 255;
 924
 925     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 926     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 927         start = w*128;
 928         for (g = 0; g < sce->ics.num_swb; g++) {
 929             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 930                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 931                 if (band->energy <= band->threshold) {
 932                     sce->sf_idx[(w+w2)*16+g] = 218;
 933                     sce->zeroes[(w+w2)*16+g] = 1;
 934                 } else {
 935                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2(band->threshold), 80, 218);
 936                     sce->zeroes[(w+w2)*16+g] = 0;
 937                 }
 938                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
 939             }
 940         }
 941     }
 942     for (i = 0; i < 128; i++) {
 943         sce->sf_idx[i] = 140;
 944         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
 945     }
 946     //set the same quantizers inside window groups
 947     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 948         for (g = 0;  g < sce->ics.num_swb; g++)
 949             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 950                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 951 }
 952
 953 static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
 954                           const float lambda)
 955 {
 956     int start = 0, i, w, w2, g;
 957     float M[128], S[128];
 958     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
 959     SingleChannelElement *sce0 = &cpe->ch[0];
 960     SingleChannelElement *sce1 = &cpe->ch[1];
 961     if (!cpe->common_window)
 962         return;
 963     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 964         for (g = 0;  g < sce0->ics.num_swb; g++) {
 965             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
 966                 float dist1 = 0.0f, dist2 = 0.0f;
 967                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 968                     FFPsyBand *band0 = &s->psy.psy_bands[(s->cur_channel+0)*PSY_MAX_BANDS+(w+w2)*16+g];
 969                     FFPsyBand *band1 = &s->psy.psy_bands[(s->cur_channel+1)*PSY_MAX_BANDS+(w+w2)*16+g];
 970                     float minthr = FFMIN(band0->threshold, band1->threshold);
 971                     float maxthr = FFMAX(band0->threshold, band1->threshold);
 972                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 973                         M[i] = (sce0->coeffs[start+w2*128+i]
 974                               + sce1->coeffs[start+w2*128+i]) * 0.5;
 975                         S[i] =  sce0->coeffs[start+w2*128+i]
 976                               - sce1->coeffs[start+w2*128+i];
 977                     }
 978                     abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 979                     abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 980                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
 981                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
 982                     dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
 983                                                 L34,
 984                                                 sce0->ics.swb_sizes[g],
 985                                                 sce0->sf_idx[(w+w2)*16+g],
 986                                                 sce0->band_type[(w+w2)*16+g],
 987                                                 lambda / band0->threshold, INFINITY, NULL);
 988                     dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
 989                                                 R34,
 990                                                 sce1->ics.swb_sizes[g],
 991                                                 sce1->sf_idx[(w+w2)*16+g],
 992                                                 sce1->band_type[(w+w2)*16+g],
 993                                                 lambda / band1->threshold, INFINITY, NULL);
 994                     dist2 += quantize_band_cost(s, M,
 995                                                 M34,
 996                                                 sce0->ics.swb_sizes[g],
 997                                                 sce0->sf_idx[(w+w2)*16+g],
 998                                                 sce0->band_type[(w+w2)*16+g],
 999                                                 lambda / maxthr, INFINITY, NULL);
1000                     dist2 += quantize_band_cost(s, S,
1001                                                 S34,
1002                                                 sce1->ics.swb_sizes[g],
1003                                                 sce1->sf_idx[(w+w2)*16+g],
1004                                                 sce1->band_type[(w+w2)*16+g],
1005                                                 lambda / minthr, INFINITY, NULL);
1006                 }
1007                 cpe->ms_mask[w*16+g] = dist2 < dist1;
1008             }
1009             start += sce0->ics.swb_sizes[g];
1010         }
1011     }
1012 }
1013
1014 AACCoefficientsEncoder ff_aac_coders[] = {
1015     {
1016         search_for_quantizers_faac,
1017         encode_window_bands_info,
1018         quantize_and_encode_band,
1019         search_for_ms,
1020     },
1021     {
1022         search_for_quantizers_anmr,
1023         encode_window_bands_info,
1024         quantize_and_encode_band,
1025         search_for_ms,
1026     },
1027     {
1028         search_for_quantizers_twoloop,
1029         encode_window_bands_info,
1030         quantize_and_encode_band,
1031         search_for_ms,
1032     },
1033     {
1034         search_for_quantizers_fast,
1035         encode_window_bands_info,
1036         quantize_and_encode_band,
1037         search_for_ms,
1038     },
1039 };