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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
  24  * AAC coefficients encoder
  25  */
  26
  27 /***********************************
  28  *              TODOs:
  29  * speedup quantizer selection
  30  * add sane pulse detection
  31  ***********************************/
  32
  33 #include "libavutil/libm.h" // brought forward to work around cygwin header breakage
  34
  35 #include <float.h>
  36 #include "libavutil/mathematics.h"
  37 #include "avcodec.h"
  38 #include "put_bits.h"
  39 #include "aac.h"
  40 #include "aacenc.h"
  41 #include "aactab.h"
  42 #include "aacenctab.h"
  43 #include "aac_tablegen_decl.h"
  44
  45 /** Frequency in Hz for lower limit of noise substitution **/
  46 #define NOISE_LOW_LIMIT 4500
  47
  48 /* Energy spread threshold value below which no PNS is used, this corresponds to
  49  * typically around 17Khz, after which PNS usage decays ending at 19Khz */
  50 #define NOISE_SPREAD_THRESHOLD 0.5f
  51
  52 /* This constant gets divided by lambda to return ~1.65 which when multiplied
  53  * by the band->threshold and compared to band->energy is the boundary between
  54  * excessive PNS and little PNS usage. */
  55 #define NOISE_LAMBDA_NUMERATOR 252.1f
  56
  57 /** Frequency in Hz for lower limit of intensity stereo   **/
  58 #define INT_STEREO_LOW_LIMIT 6100
  59
  60 #define ROUND_STANDARD 0.4054f
  61 #define ROUND_TO_ZERO 0.1054f
  62
  63 /**
  64  * Quantize one coefficient.
  65  * @return absolute value of the quantized coefficient
  66  * @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
  67  */
  68 static av_always_inline int quant(float coef, const float Q, const float rounding)
  69 {
  70     float a = coef * Q;
  71     return sqrtf(a * sqrtf(a)) + rounding;
  72 }
  73
  74 static void quantize_bands(int *out, const float *in, const float *scaled,
  75                            int size, float Q34, int is_signed, int maxval, const float rounding)
  76 {
  77     int i;
  78     double qc;
  79     for (i = 0; i < size; i++) {
  80         qc = scaled[i] * Q34;
  81         out[i] = (int)FFMIN(qc + rounding, (double)maxval);
  82         if (is_signed && in[i] < 0.0f) {
  83             out[i] = -out[i];
  84         }
  85     }
  86 }
  87
  88 static void abs_pow34_v(float *out, const float *in, const int size)
  89 {
  90 #ifndef USE_REALLY_FULL_SEARCH
  91     int i;
  92     for (i = 0; i < size; i++) {
  93         float a = fabsf(in[i]);
  94         out[i] = sqrtf(a * sqrtf(a));
  95     }
  96 #endif /* USE_REALLY_FULL_SEARCH */
  97 }
  98
  99 /**
 100  * Calculate rate distortion cost for quantizing with given codebook
 101  *
 102  * @return quantization distortion
 103  */
 104 static av_always_inline float quantize_and_encode_band_cost_template(
 105                                 struct AACEncContext *s,
 106                                 PutBitContext *pb, const float *in,
 107                                 const float *scaled, int size, int scale_idx,
 108                                 int cb, const float lambda, const float uplim,
 109                                 int *bits, int BT_ZERO, int BT_UNSIGNED,
 110                                 int BT_PAIR, int BT_ESC, int BT_NOISE, int BT_STEREO,
 111                                 const float ROUNDING)
 112 {
 113     const int q_idx = POW_SF2_ZERO - scale_idx + SCALE_ONE_POS - SCALE_DIV_512;
 114     const float Q   = ff_aac_pow2sf_tab [q_idx];
 115     const float Q34 = ff_aac_pow34sf_tab[q_idx];
 116     const float IQ  = ff_aac_pow2sf_tab [POW_SF2_ZERO + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 117     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 118     int i, j;
 119     float cost = 0;
 120     const int dim = BT_PAIR ? 2 : 4;
 121     int resbits = 0;
 122     int off;
 123
 124     if (BT_ZERO || BT_NOISE || BT_STEREO) {
 125         for (i = 0; i < size; i++)
 126             cost += in[i]*in[i];
 127         if (bits)
 128             *bits = 0;
 129         return cost * lambda;
 130     }
 131     if (!scaled) {
 132         abs_pow34_v(s->scoefs, in, size);
 133         scaled = s->scoefs;
 134     }
 135     quantize_bands(s->qcoefs, in, scaled, size, Q34, !BT_UNSIGNED, aac_cb_maxval[cb], ROUNDING);
 136     if (BT_UNSIGNED) {
 137         off = 0;
 138     } else {
 139         off = aac_cb_maxval[cb];
 140     }
 141     for (i = 0; i < size; i += dim) {
 142         const float *vec;
 143         int *quants = s->qcoefs + i;
 144         int curidx = 0;
 145         int curbits;
 146         float rd = 0.0f;
 147         for (j = 0; j < dim; j++) {
 148             curidx *= aac_cb_range[cb];
 149             curidx += quants[j] + off;
 150         }
 151         curbits =  ff_aac_spectral_bits[cb-1][curidx];
 152         vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 153         if (BT_UNSIGNED) {
 154             for (j = 0; j < dim; j++) {
 155                 float t = fabsf(in[i+j]);
 156                 float di;
 157                 if (BT_ESC && vec[j] == 64.0f) { //FIXME: slow
 158                     if (t >= CLIPPED_ESCAPE) {
 159                         di = t - CLIPPED_ESCAPE;
 160                         curbits += 21;
 161                     } else {
 162                         int c = av_clip_uintp2(quant(t, Q, ROUNDING), 13);
 163                         di = t - c*cbrtf(c)*IQ;
 164                         curbits += av_log2(c)*2 - 4 + 1;
 165                     }
 166                 } else {
 167                     di = t - vec[j]*IQ;
 168                 }
 169                 if (vec[j] != 0.0f)
 170                     curbits++;
 171                 rd += di*di;
 172             }
 173         } else {
 174             for (j = 0; j < dim; j++) {
 175                 float di = in[i+j] - vec[j]*IQ;
 176                 rd += di*di;
 177             }
 178         }
 179         cost    += rd * lambda + curbits;
 180         resbits += curbits;
 181         if (cost >= uplim)
 182             return uplim;
 183         if (pb) {
 184             put_bits(pb, ff_aac_spectral_bits[cb-1][curidx], ff_aac_spectral_codes[cb-1][curidx]);
 185             if (BT_UNSIGNED)
 186                 for (j = 0; j < dim; j++)
 187                     if (ff_aac_codebook_vectors[cb-1][curidx*dim+j] != 0.0f)
 188                         put_bits(pb, 1, in[i+j] < 0.0f);
 189             if (BT_ESC) {
 190                 for (j = 0; j < 2; j++) {
 191                     if (ff_aac_codebook_vectors[cb-1][curidx*2+j] == 64.0f) {
 192                         int coef = av_clip_uintp2(quant(fabsf(in[i+j]), Q, ROUNDING), 13);
 193                         int len = av_log2(coef);
 194
 195                         put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
 196                         put_sbits(pb, len, coef);
 197                     }
 198                 }
 199             }
 200         }
 201     }
 202
 203     if (bits)
 204         *bits = resbits;
 205     return cost;
 206 }
 207
 208 static float quantize_and_encode_band_cost_NONE(struct AACEncContext *s, PutBitContext *pb,
 209                                                 const float *in, const float *scaled,
 210                                                 int size, int scale_idx, int cb,
 211                                                 const float lambda, const float uplim,
 212                                                 int *bits) {
 213     av_assert0(0);
 214     return 0.0f;
 215 }
 216
 217 #define QUANTIZE_AND_ENCODE_BAND_COST_FUNC(NAME, BT_ZERO, BT_UNSIGNED, BT_PAIR, BT_ESC, BT_NOISE, BT_STEREO, ROUNDING) \
 218 static float quantize_and_encode_band_cost_ ## NAME(                                         \
 219                                 struct AACEncContext *s,                                     \
 220                                 PutBitContext *pb, const float *in,                          \
 221                                 const float *scaled, int size, int scale_idx,                \
 222                                 int cb, const float lambda, const float uplim,               \
 223                                 int *bits) {                                                 \
 224     return quantize_and_encode_band_cost_template(                                           \
 225                                 s, pb, in, scaled, size, scale_idx,                          \
 226                                 BT_ESC ? ESC_BT : cb, lambda, uplim, bits,                   \
 227                                 BT_ZERO, BT_UNSIGNED, BT_PAIR, BT_ESC, BT_NOISE, BT_STEREO,  \
 228                                 ROUNDING);                                                   \
 229 }
 230
 231 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(ZERO,  1, 0, 0, 0, 0, 0, ROUND_STANDARD)
 232 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(SQUAD, 0, 0, 0, 0, 0, 0, ROUND_STANDARD)
 233 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(UQUAD, 0, 1, 0, 0, 0, 0, ROUND_STANDARD)
 234 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(SPAIR, 0, 0, 1, 0, 0, 0, ROUND_STANDARD)
 235 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(UPAIR, 0, 1, 1, 0, 0, 0, ROUND_STANDARD)
 236 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(ESC,   0, 1, 1, 1, 0, 0, ROUND_STANDARD)
 237 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(ESC_RTZ, 0, 1, 1, 1, 0, 0, ROUND_TO_ZERO)
 238 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(NOISE, 0, 0, 0, 0, 1, 0, ROUND_STANDARD)
 239 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(STEREO,0, 0, 0, 0, 0, 1, ROUND_STANDARD)
 240
 241 static float (*const quantize_and_encode_band_cost_arr[])(
 242                                 struct AACEncContext *s,
 243                                 PutBitContext *pb, const float *in,
 244                                 const float *scaled, int size, int scale_idx,
 245                                 int cb, const float lambda, const float uplim,
 246                                 int *bits) = {
 247     quantize_and_encode_band_cost_ZERO,
 248     quantize_and_encode_band_cost_SQUAD,
 249     quantize_and_encode_band_cost_SQUAD,
 250     quantize_and_encode_band_cost_UQUAD,
 251     quantize_and_encode_band_cost_UQUAD,
 252     quantize_and_encode_band_cost_SPAIR,
 253     quantize_and_encode_band_cost_SPAIR,
 254     quantize_and_encode_band_cost_UPAIR,
 255     quantize_and_encode_band_cost_UPAIR,
 256     quantize_and_encode_band_cost_UPAIR,
 257     quantize_and_encode_band_cost_UPAIR,
 258     quantize_and_encode_band_cost_ESC,
 259     quantize_and_encode_band_cost_NONE,     /* CB 12 doesn't exist */
 260     quantize_and_encode_band_cost_NOISE,
 261     quantize_and_encode_band_cost_STEREO,
 262     quantize_and_encode_band_cost_STEREO,
 263 };
 264
 265 static float (*const quantize_and_encode_band_cost_rtz_arr[])(
 266                                 struct AACEncContext *s,
 267                                 PutBitContext *pb, const float *in,
 268                                 const float *scaled, int size, int scale_idx,
 269                                 int cb, const float lambda, const float uplim,
 270                                 int *bits) = {
 271     quantize_and_encode_band_cost_ZERO,
 272     quantize_and_encode_band_cost_SQUAD,
 273     quantize_and_encode_band_cost_SQUAD,
 274     quantize_and_encode_band_cost_UQUAD,
 275     quantize_and_encode_band_cost_UQUAD,
 276     quantize_and_encode_band_cost_SPAIR,
 277     quantize_and_encode_band_cost_SPAIR,
 278     quantize_and_encode_band_cost_UPAIR,
 279     quantize_and_encode_band_cost_UPAIR,
 280     quantize_and_encode_band_cost_UPAIR,
 281     quantize_and_encode_band_cost_UPAIR,
 282     quantize_and_encode_band_cost_ESC_RTZ,
 283     quantize_and_encode_band_cost_NONE,     /* CB 12 doesn't exist */
 284     quantize_and_encode_band_cost_NOISE,
 285     quantize_and_encode_band_cost_STEREO,
 286     quantize_and_encode_band_cost_STEREO,
 287 };
 288
 289 #define quantize_and_encode_band_cost(                                  \
 290                                 s, pb, in, scaled, size, scale_idx, cb, \
 291                                 lambda, uplim, bits, rtz)               \
 292     ((rtz) ? quantize_and_encode_band_cost_rtz_arr : quantize_and_encode_band_cost_arr)[cb]( \
 293                                 s, pb, in, scaled, size, scale_idx, cb, \
 294                                 lambda, uplim, bits)
 295
 296 static float quantize_band_cost(struct AACEncContext *s, const float *in,
 297                                 const float *scaled, int size, int scale_idx,
 298                                 int cb, const float lambda, const float uplim,
 299                                 int *bits, int rtz)
 300 {
 301     return quantize_and_encode_band_cost(s, NULL, in, scaled, size, scale_idx,
 302                                          cb, lambda, uplim, bits, rtz);
 303 }
 304
 305 static void quantize_and_encode_band(struct AACEncContext *s, PutBitContext *pb,
 306                                      const float *in, int size, int scale_idx,
 307                                      int cb, const float lambda, int rtz)
 308 {
 309     quantize_and_encode_band_cost(s, pb, in, NULL, size, scale_idx, cb, lambda,
 310                                   INFINITY, NULL, rtz);
 311 }
 312
 313 static float find_max_val(int group_len, int swb_size, const float *scaled) {
 314     float maxval = 0.0f;
 315     int w2, i;
 316     for (w2 = 0; w2 < group_len; w2++) {
 317         for (i = 0; i < swb_size; i++) {
 318             maxval = FFMAX(maxval, scaled[w2*128+i]);
 319         }
 320     }
 321     return maxval;
 322 }
 323
 324 static int find_min_book(float maxval, int sf) {
 325     float Q = ff_aac_pow2sf_tab[POW_SF2_ZERO - sf + SCALE_ONE_POS - SCALE_DIV_512];
 326     float Q34 = sqrtf(Q * sqrtf(Q));
 327     int qmaxval, cb;
 328     qmaxval = maxval * Q34 + 0.4054f;
 329     if      (qmaxval ==  0) cb = 0;
 330     else if (qmaxval ==  1) cb = 1;
 331     else if (qmaxval ==  2) cb = 3;
 332     else if (qmaxval <=  4) cb = 5;
 333     else if (qmaxval <=  7) cb = 7;
 334     else if (qmaxval <= 12) cb = 9;
 335     else                    cb = 11;
 336     return cb;
 337 }
 338
 339 /**
 340  * structure used in optimal codebook search
 341  */
 342 typedef struct BandCodingPath {
 343     int prev_idx; ///< pointer to the previous path point
 344     float cost;   ///< path cost
 345     int run;
 346 } BandCodingPath;
 347
 348 /**
 349  * Encode band info for single window group bands.
 350  */
 351 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
 352                                      int win, int group_len, const float lambda)
 353 {
 354     BandCodingPath path[120][CB_TOT_ALL];
 355     int w, swb, cb, start, size;
 356     int i, j;
 357     const int max_sfb  = sce->ics.max_sfb;
 358     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 359     const int run_esc  = (1 << run_bits) - 1;
 360     int idx, ppos, count;
 361     int stackrun[120], stackcb[120], stack_len;
 362     float next_minrd = INFINITY;
 363     int next_mincb = 0;
 364
 365     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 366     start = win*128;
 367     for (cb = 0; cb < CB_TOT_ALL; cb++) {
 368         path[0][cb].cost     = 0.0f;
 369         path[0][cb].prev_idx = -1;
 370         path[0][cb].run      = 0;
 371     }
 372     for (swb = 0; swb < max_sfb; swb++) {
 373         size = sce->ics.swb_sizes[swb];
 374         if (sce->zeroes[win*16 + swb]) {
 375             for (cb = 0; cb < CB_TOT_ALL; cb++) {
 376                 path[swb+1][cb].prev_idx = cb;
 377                 path[swb+1][cb].cost     = path[swb][cb].cost;
 378                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 379             }
 380         } else {
 381             float minrd = next_minrd;
 382             int mincb = next_mincb;
 383             next_minrd = INFINITY;
 384             next_mincb = 0;
 385             for (cb = 0; cb < CB_TOT_ALL; cb++) {
 386                 float cost_stay_here, cost_get_here;
 387                 float rd = 0.0f;
 388                 if (cb >= 12 && sce->band_type[win*16+swb] < aac_cb_out_map[cb] ||
 389                     cb  < aac_cb_in_map[sce->band_type[win*16+swb]] && sce->band_type[win*16+swb] > aac_cb_out_map[cb]) {
 390                     path[swb+1][cb].prev_idx = -1;
 391                     path[swb+1][cb].cost     = INFINITY;
 392                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 393                     continue;
 394                 }
 395                 for (w = 0; w < group_len; w++) {
 396                     FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_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], aac_cb_out_map[cb],
 400                                              lambda / band->threshold, INFINITY, NULL, 0);
 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 < CB_TOT_ALL; 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         av_assert1(idx >= 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         cb = aac_cb_out_map[stackcb[i]];
 445         put_bits(&s->pb, 4, cb);
 446         count = stackrun[i];
 447         memset(sce->zeroes + win*16 + start, !cb, count);
 448         //XXX: memset when band_type is also uint8_t
 449         for (j = 0; j < count; j++) {
 450             sce->band_type[win*16 + start] = cb;
 451             start++;
 452         }
 453         while (count >= run_esc) {
 454             put_bits(&s->pb, run_bits, run_esc);
 455             count -= run_esc;
 456         }
 457         put_bits(&s->pb, run_bits, count);
 458     }
 459 }
 460
 461 static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,
 462                                   int win, int group_len, const float lambda)
 463 {
 464     BandCodingPath path[120][CB_TOT_ALL];
 465     int w, swb, cb, start, size;
 466     int i, j;
 467     const int max_sfb  = sce->ics.max_sfb;
 468     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 469     const int run_esc  = (1 << run_bits) - 1;
 470     int idx, ppos, count;
 471     int stackrun[120], stackcb[120], stack_len;
 472     float next_minbits = INFINITY;
 473     int next_mincb = 0;
 474
 475     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 476     start = win*128;
 477     for (cb = 0; cb < CB_TOT_ALL; cb++) {
 478         path[0][cb].cost     = run_bits+4;
 479         path[0][cb].prev_idx = -1;
 480         path[0][cb].run      = 0;
 481     }
 482     for (swb = 0; swb < max_sfb; swb++) {
 483         size = sce->ics.swb_sizes[swb];
 484         if (sce->zeroes[win*16 + swb]) {
 485             float cost_stay_here = path[swb][0].cost;
 486             float cost_get_here  = next_minbits + run_bits + 4;
 487             if (   run_value_bits[sce->ics.num_windows == 8][path[swb][0].run]
 488                 != run_value_bits[sce->ics.num_windows == 8][path[swb][0].run+1])
 489                 cost_stay_here += run_bits;
 490             if (cost_get_here < cost_stay_here) {
 491                 path[swb+1][0].prev_idx = next_mincb;
 492                 path[swb+1][0].cost     = cost_get_here;
 493                 path[swb+1][0].run      = 1;
 494             } else {
 495                 path[swb+1][0].prev_idx = 0;
 496                 path[swb+1][0].cost     = cost_stay_here;
 497                 path[swb+1][0].run      = path[swb][0].run + 1;
 498             }
 499             next_minbits = path[swb+1][0].cost;
 500             next_mincb = 0;
 501             for (cb = 1; cb < CB_TOT_ALL; cb++) {
 502                 path[swb+1][cb].cost = 61450;
 503                 path[swb+1][cb].prev_idx = -1;
 504                 path[swb+1][cb].run = 0;
 505             }
 506         } else {
 507             float minbits = next_minbits;
 508             int mincb = next_mincb;
 509             int startcb = sce->band_type[win*16+swb];
 510             startcb = aac_cb_in_map[startcb];
 511             next_minbits = INFINITY;
 512             next_mincb = 0;
 513             for (cb = 0; cb < startcb; cb++) {
 514                 path[swb+1][cb].cost = 61450;
 515                 path[swb+1][cb].prev_idx = -1;
 516                 path[swb+1][cb].run = 0;
 517             }
 518             for (cb = startcb; cb < CB_TOT_ALL; cb++) {
 519                 float cost_stay_here, cost_get_here;
 520                 float bits = 0.0f;
 521                 if (cb >= 12 && sce->band_type[win*16+swb] != aac_cb_out_map[cb]) {
 522                     path[swb+1][cb].cost = 61450;
 523                     path[swb+1][cb].prev_idx = -1;
 524                     path[swb+1][cb].run = 0;
 525                     continue;
 526                 }
 527                 for (w = 0; w < group_len; w++) {
 528                     bits += quantize_band_cost(s, sce->coeffs + start + w*128,
 529                                                s->scoefs + start + w*128, size,
 530                                                sce->sf_idx[win*16+swb],
 531                                                aac_cb_out_map[cb],
 532                                                0, INFINITY, NULL, 0);
 533                 }
 534                 cost_stay_here = path[swb][cb].cost + bits;
 535                 cost_get_here  = minbits            + bits + run_bits + 4;
 536                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 537                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 538                     cost_stay_here += run_bits;
 539                 if (cost_get_here < cost_stay_here) {
 540                     path[swb+1][cb].prev_idx = mincb;
 541                     path[swb+1][cb].cost     = cost_get_here;
 542                     path[swb+1][cb].run      = 1;
 543                 } else {
 544                     path[swb+1][cb].prev_idx = cb;
 545                     path[swb+1][cb].cost     = cost_stay_here;
 546                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 547                 }
 548                 if (path[swb+1][cb].cost < next_minbits) {
 549                     next_minbits = path[swb+1][cb].cost;
 550                     next_mincb = cb;
 551                 }
 552             }
 553         }
 554         start += sce->ics.swb_sizes[swb];
 555     }
 556
 557     //convert resulting path from backward-linked list
 558     stack_len = 0;
 559     idx       = 0;
 560     for (cb = 1; cb < CB_TOT_ALL; cb++)
 561         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 562             idx = cb;
 563     ppos = max_sfb;
 564     while (ppos > 0) {
 565         av_assert1(idx >= 0);
 566         cb = idx;
 567         stackrun[stack_len] = path[ppos][cb].run;
 568         stackcb [stack_len] = cb;
 569         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 570         ppos -= path[ppos][cb].run;
 571         stack_len++;
 572     }
 573     //perform actual band info encoding
 574     start = 0;
 575     for (i = stack_len - 1; i >= 0; i--) {
 576         cb = aac_cb_out_map[stackcb[i]];
 577         put_bits(&s->pb, 4, cb);
 578         count = stackrun[i];
 579         memset(sce->zeroes + win*16 + start, !cb, count);
 580         //XXX: memset when band_type is also uint8_t
 581         for (j = 0; j < count; j++) {
 582             sce->band_type[win*16 + start] = cb;
 583             start++;
 584         }
 585         while (count >= run_esc) {
 586             put_bits(&s->pb, run_bits, run_esc);
 587             count -= run_esc;
 588         }
 589         put_bits(&s->pb, run_bits, count);
 590     }
 591 }
 592
 593 /** Return the minimum scalefactor where the quantized coef does not clip. */
 594 static av_always_inline uint8_t coef2minsf(float coef) {
 595     return av_clip_uint8(log2f(coef)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 596 }
 597
 598 /** Return the maximum scalefactor where the quantized coef is not zero. */
 599 static av_always_inline uint8_t coef2maxsf(float coef) {
 600     return av_clip_uint8(log2f(coef)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 601 }
 602
 603 typedef struct TrellisPath {
 604     float cost;
 605     int prev;
 606 } TrellisPath;
 607
 608 #define TRELLIS_STAGES 121
 609 #define TRELLIS_STATES (SCALE_MAX_DIFF+1)
 610
 611 static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement *sce)
 612 {
 613     int w, g, start = 0;
 614     int minscaler_n = sce->sf_idx[0], minscaler_i = sce->sf_idx[0];
 615     int bands = 0;
 616
 617     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 618         start = 0;
 619         for (g = 0;  g < sce->ics.num_swb; g++) {
 620             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
 621                 sce->sf_idx[w*16+g] = av_clip(ceilf(log2f(sce->is_ener[w*16+g])*2), -155, 100);
 622                 minscaler_i = FFMIN(minscaler_i, sce->sf_idx[w*16+g]);
 623                 bands++;
 624             } else if (sce->band_type[w*16+g] == NOISE_BT) {
 625                 sce->sf_idx[w*16+g] = av_clip(4+log2f(sce->pns_ener[w*16+g])*2, -100, 155);
 626                 minscaler_n = FFMIN(minscaler_n, sce->sf_idx[w*16+g]);
 627                 bands++;
 628             }
 629             start += sce->ics.swb_sizes[g];
 630         }
 631     }
 632
 633     if (!bands)
 634         return;
 635
 636     /* Clip the scalefactor indices */
 637     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 638         for (g = 0;  g < sce->ics.num_swb; g++) {
 639             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
 640                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_i, minscaler_i + SCALE_MAX_DIFF);
 641             } else if (sce->band_type[w*16+g] == NOISE_BT) {
 642                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_n, minscaler_n + SCALE_MAX_DIFF);
 643             }
 644         }
 645     }
 646 }
 647
 648 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 649                                        SingleChannelElement *sce,
 650                                        const float lambda)
 651 {
 652     int q, w, w2, g, start = 0;
 653     int i, j;
 654     int idx;
 655     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];
 656     int bandaddr[TRELLIS_STAGES];
 657     int minq;
 658     float mincost;
 659     float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f;
 660     int q0, q1, qcnt = 0;
 661
 662     for (i = 0; i < 1024; i++) {
 663         float t = fabsf(sce->coeffs[i]);
 664         if (t > 0.0f) {
 665             q0f = FFMIN(q0f, t);
 666             q1f = FFMAX(q1f, t);
 667             qnrgf += t*t;
 668             qcnt++;
 669         }
 670     }
 671
 672     if (!qcnt) {
 673         memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 674         memset(sce->zeroes, 1, sizeof(sce->zeroes));
 675         return;
 676     }
 677
 678     //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 679     q0 = coef2minsf(q0f);
 680     //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 681     q1 = coef2maxsf(q1f);
 682     if (q1 - q0 > 60) {
 683         int q0low  = q0;
 684         int q1high = q1;
 685         //minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped
 686         int qnrg = av_clip_uint8(log2f(sqrtf(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512);
 687         q1 = qnrg + 30;
 688         q0 = qnrg - 30;
 689         if (q0 < q0low) {
 690             q1 += q0low - q0;
 691             q0  = q0low;
 692         } else if (q1 > q1high) {
 693             q0 -= q1 - q1high;
 694             q1  = q1high;
 695         }
 696     }
 697
 698     for (i = 0; i < TRELLIS_STATES; i++) {
 699         paths[0][i].cost    = 0.0f;
 700         paths[0][i].prev    = -1;
 701     }
 702     for (j = 1; j < TRELLIS_STAGES; j++) {
 703         for (i = 0; i < TRELLIS_STATES; i++) {
 704             paths[j][i].cost    = INFINITY;
 705             paths[j][i].prev    = -2;
 706         }
 707     }
 708     idx = 1;
 709     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 710     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 711         start = w*128;
 712         for (g = 0; g < sce->ics.num_swb; g++) {
 713             const float *coefs = sce->coeffs + start;
 714             float qmin, qmax;
 715             int nz = 0;
 716
 717             bandaddr[idx] = w * 16 + g;
 718             qmin = INT_MAX;
 719             qmax = 0.0f;
 720             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 721                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 722                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 723                     sce->zeroes[(w+w2)*16+g] = 1;
 724                     continue;
 725                 }
 726                 sce->zeroes[(w+w2)*16+g] = 0;
 727                 nz = 1;
 728                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 729                     float t = fabsf(coefs[w2*128+i]);
 730                     if (t > 0.0f)
 731                         qmin = FFMIN(qmin, t);
 732                     qmax = FFMAX(qmax, t);
 733                 }
 734             }
 735             if (nz) {
 736                 int minscale, maxscale;
 737                 float minrd = INFINITY;
 738                 float maxval;
 739                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 740                 minscale = coef2minsf(qmin);
 741                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 742                 maxscale = coef2maxsf(qmax);
 743                 minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);
 744                 maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);
 745                 maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start);
 746                 for (q = minscale; q < maxscale; q++) {
 747                     float dist = 0;
 748                     int cb = find_min_book(maxval, sce->sf_idx[w*16+g]);
 749                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 750                         FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 751                         dist += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 752                                                    q + q0, cb, lambda / band->threshold, INFINITY, NULL, 0);
 753                     }
 754                     minrd = FFMIN(minrd, dist);
 755
 756                     for (i = 0; i < q1 - q0; i++) {
 757                         float cost;
 758                         cost = paths[idx - 1][i].cost + dist
 759                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 760                         if (cost < paths[idx][q].cost) {
 761                             paths[idx][q].cost    = cost;
 762                             paths[idx][q].prev    = i;
 763                         }
 764                     }
 765                 }
 766             } else {
 767                 for (q = 0; q < q1 - q0; q++) {
 768                     paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 769                     paths[idx][q].prev = q;
 770                 }
 771             }
 772             sce->zeroes[w*16+g] = !nz;
 773             start += sce->ics.swb_sizes[g];
 774             idx++;
 775         }
 776     }
 777     idx--;
 778     mincost = paths[idx][0].cost;
 779     minq    = 0;
 780     for (i = 1; i < TRELLIS_STATES; i++) {
 781         if (paths[idx][i].cost < mincost) {
 782             mincost = paths[idx][i].cost;
 783             minq = i;
 784         }
 785     }
 786     while (idx) {
 787         sce->sf_idx[bandaddr[idx]] = minq + q0;
 788         minq = paths[idx][minq].prev;
 789         idx--;
 790     }
 791     //set the same quantizers inside window groups
 792     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 793         for (g = 0;  g < sce->ics.num_swb; g++)
 794             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 795                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 796 }
 797
 798 /**
 799  * two-loop quantizers search taken from ISO 13818-7 Appendix C
 800  */
 801 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
 802                                           AACEncContext *s,
 803                                           SingleChannelElement *sce,
 804                                           const float lambda)
 805 {
 806     int start = 0, i, w, w2, g;
 807     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels * (lambda / 120.f);
 808     float dists[128] = { 0 }, uplims[128] = { 0 };
 809     float maxvals[128];
 810     int fflag, minscaler;
 811     int its  = 0;
 812     int allz = 0;
 813     float minthr = INFINITY;
 814
 815     // for values above this the decoder might end up in an endless loop
 816     // due to always having more bits than what can be encoded.
 817     destbits = FFMIN(destbits, 5800);
 818     //XXX: some heuristic to determine initial quantizers will reduce search time
 819     //determine zero bands and upper limits
 820     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 821         for (g = 0;  g < sce->ics.num_swb; g++) {
 822             int nz = 0;
 823             float uplim = 0.0f, energy = 0.0f;
 824             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 825                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 826                 uplim  += band->threshold;
 827                 energy += band->energy;
 828                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 829                     sce->zeroes[(w+w2)*16+g] = 1;
 830                     continue;
 831                 }
 832                 nz = 1;
 833             }
 834             uplims[w*16+g] = uplim *512;
 835             sce->zeroes[w*16+g] = !nz;
 836             if (nz)
 837                 minthr = FFMIN(minthr, uplim);
 838             allz |= nz;
 839         }
 840     }
 841     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 842         for (g = 0;  g < sce->ics.num_swb; g++) {
 843             if (sce->zeroes[w*16+g]) {
 844                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 845                 continue;
 846             }
 847             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2f(uplims[w*16+g]/minthr)*4,59);
 848         }
 849     }
 850
 851     if (!allz)
 852         return;
 853     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 854
 855     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 856         start = w*128;
 857         for (g = 0;  g < sce->ics.num_swb; g++) {
 858             const float *scaled = s->scoefs + start;
 859             maxvals[w*16+g] = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled);
 860             start += sce->ics.swb_sizes[g];
 861         }
 862     }
 863
 864     //perform two-loop search
 865     //outer loop - improve quality
 866     do {
 867         int tbits, qstep;
 868         minscaler = sce->sf_idx[0];
 869         //inner loop - quantize spectrum to fit into given number of bits
 870         qstep = its ? 1 : 32;
 871         do {
 872             int prev = -1;
 873             tbits = 0;
 874             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 875                 start = w*128;
 876                 for (g = 0;  g < sce->ics.num_swb; g++) {
 877                     const float *coefs = sce->coeffs + start;
 878                     const float *scaled = s->scoefs + start;
 879                     int bits = 0;
 880                     int cb;
 881                     float dist = 0.0f;
 882
 883                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
 884                         start += sce->ics.swb_sizes[g];
 885                         continue;
 886                     }
 887                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 888                     cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
 889                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 890                         int b;
 891                         dist += quantize_band_cost(s, coefs + w2*128,
 892                                                    scaled + w2*128,
 893                                                    sce->ics.swb_sizes[g],
 894                                                    sce->sf_idx[w*16+g],
 895                                                    cb,
 896                                                    1.0f,
 897                                                    INFINITY,
 898                                                    &b,
 899                                                    0);
 900                         bits += b;
 901                     }
 902                     dists[w*16+g] = dist - bits;
 903                     if (prev != -1) {
 904                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 905                     }
 906                     tbits += bits;
 907                     start += sce->ics.swb_sizes[g];
 908                     prev = sce->sf_idx[w*16+g];
 909                 }
 910             }
 911             if (tbits > destbits) {
 912                 for (i = 0; i < 128; i++)
 913                     if (sce->sf_idx[i] < 218 - qstep)
 914                         sce->sf_idx[i] += qstep;
 915             } else {
 916                 for (i = 0; i < 128; i++)
 917                     if (sce->sf_idx[i] > 60 - qstep)
 918                         sce->sf_idx[i] -= qstep;
 919             }
 920             qstep >>= 1;
 921             if (!qstep && tbits > destbits*1.02 && sce->sf_idx[0] < 217)
 922                 qstep = 1;
 923         } while (qstep);
 924
 925         fflag = 0;
 926         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 927
 928         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 929             for (g = 0; g < sce->ics.num_swb; g++) {
 930                 int prevsc = sce->sf_idx[w*16+g];
 931                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60) {
 932                     if (find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]-1))
 933                         sce->sf_idx[w*16+g]--;
 934                     else //Try to make sure there is some energy in every band
 935                         sce->sf_idx[w*16+g]-=2;
 936                 }
 937                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 938                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 939                 if (sce->sf_idx[w*16+g] != prevsc)
 940                     fflag = 1;
 941                 sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
 942             }
 943         }
 944         its++;
 945     } while (fflag && its < 10);
 946 }
 947
 948 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 949                                        SingleChannelElement *sce,
 950                                        const float lambda)
 951 {
 952     int start = 0, i, w, w2, g;
 953     float uplim[128], maxq[128];
 954     int minq, maxsf;
 955     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 956     int last = 0, lastband = 0, curband = 0;
 957     float avg_energy = 0.0;
 958     if (sce->ics.num_windows == 1) {
 959         start = 0;
 960         for (i = 0; i < 1024; i++) {
 961             if (i - start >= sce->ics.swb_sizes[curband]) {
 962                 start += sce->ics.swb_sizes[curband];
 963                 curband++;
 964             }
 965             if (sce->coeffs[i]) {
 966                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 967                 last = i;
 968                 lastband = curband;
 969             }
 970         }
 971     } else {
 972         for (w = 0; w < 8; w++) {
 973             const float *coeffs = sce->coeffs + w*128;
 974             curband = start = 0;
 975             for (i = 0; i < 128; i++) {
 976                 if (i - start >= sce->ics.swb_sizes[curband]) {
 977                     start += sce->ics.swb_sizes[curband];
 978                     curband++;
 979                 }
 980                 if (coeffs[i]) {
 981                     avg_energy += coeffs[i] * coeffs[i];
 982                     last = FFMAX(last, i);
 983                     lastband = FFMAX(lastband, curband);
 984                 }
 985             }
 986         }
 987     }
 988     last++;
 989     avg_energy /= last;
 990     if (avg_energy == 0.0f) {
 991         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
 992             sce->sf_idx[i] = SCALE_ONE_POS;
 993         return;
 994     }
 995     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 996         start = w*128;
 997         for (g = 0; g < sce->ics.num_swb; g++) {
 998             float *coefs   = sce->coeffs + start;
 999             const int size = sce->ics.swb_sizes[g];
1000             int start2 = start, end2 = start + size, peakpos = start;
1001             float maxval = -1, thr = 0.0f, t;
1002             maxq[w*16+g] = 0.0f;
1003             if (g > lastband) {
1004                 maxq[w*16+g] = 0.0f;
1005                 start += size;
1006                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
1007                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
1008                 continue;
1009             }
1010             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
1011                 for (i = 0; i < size; i++) {
1012                     float t = coefs[w2*128+i]*coefs[w2*128+i];
1013                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
1014                     thr += t;
1015                     if (sce->ics.num_windows == 1 && maxval < t) {
1016                         maxval  = t;
1017                         peakpos = start+i;
1018                     }
1019                 }
1020             }
1021             if (sce->ics.num_windows == 1) {
1022                 start2 = FFMAX(peakpos - 2, start2);
1023                 end2   = FFMIN(peakpos + 3, end2);
1024             } else {
1025                 start2 -= start;
1026                 end2   -= start;
1027             }
1028             start += size;
1029             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
1030             t   = 1.0 - (1.0 * start2 / last);
1031             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
1032         }
1033     }
1034     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
1035     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
1036     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
1037         start = w*128;
1038         for (g = 0;  g < sce->ics.num_swb; g++) {
1039             const float *coefs  = sce->coeffs + start;
1040             const float *scaled = s->scoefs   + start;
1041             const int size      = sce->ics.swb_sizes[g];
1042             int scf, prev_scf, step;
1043             int min_scf = -1, max_scf = 256;
1044             float curdiff;
1045             if (maxq[w*16+g] < 21.544) {
1046                 sce->zeroes[w*16+g] = 1;
1047                 start += size;
1048                 continue;
1049             }
1050             sce->zeroes[w*16+g] = 0;
1051             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2f(1/maxq[w*16+g])*16/3, 60, 218);
1052             for (;;) {
1053                 float dist = 0.0f;
1054                 int quant_max;
1055
1056                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
1057                     int b;
1058                     dist += quantize_band_cost(s, coefs + w2*128,
1059                                                scaled + w2*128,
1060                                                sce->ics.swb_sizes[g],
1061                                                scf,
1062                                                ESC_BT,
1063                                                lambda,
1064                                                INFINITY,
1065                                                &b,
1066                                                0);
1067                     dist -= b;
1068                 }
1069                 dist *= 1.0f / 512.0f / lambda;
1070                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[POW_SF2_ZERO - scf + SCALE_ONE_POS - SCALE_DIV_512], ROUND_STANDARD);
1071                 if (quant_max >= 8191) { // too much, return to the previous quantizer
1072                     sce->sf_idx[w*16+g] = prev_scf;
1073                     break;
1074                 }
1075                 prev_scf = scf;
1076                 curdiff = fabsf(dist - uplim[w*16+g]);
1077                 if (curdiff <= 1.0f)
1078                     step = 0;
1079                 else
1080                     step = log2f(curdiff);
1081                 if (dist > uplim[w*16+g])
1082                     step = -step;
1083                 scf += step;
1084                 scf = av_clip_uint8(scf);
1085                 step = scf - prev_scf;
1086                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
1087                     sce->sf_idx[w*16+g] = av_clip(scf, min_scf, max_scf);
1088                     break;
1089                 }
1090                 if (step > 0)
1091                     min_scf = prev_scf;
1092                 else
1093                     max_scf = prev_scf;
1094             }
1095             start += size;
1096         }
1097     }
1098     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
1099     for (i = 1; i < 128; i++) {
1100         if (!sce->sf_idx[i])
1101             sce->sf_idx[i] = sce->sf_idx[i-1];
1102         else
1103             minq = FFMIN(minq, sce->sf_idx[i]);
1104     }
1105     if (minq == INT_MAX)
1106         minq = 0;
1107     minq = FFMIN(minq, SCALE_MAX_POS);
1108     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
1109     for (i = 126; i >= 0; i--) {
1110         if (!sce->sf_idx[i])
1111             sce->sf_idx[i] = sce->sf_idx[i+1];
1112         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
1113     }
1114 }
1115
1116 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
1117                                        SingleChannelElement *sce,
1118                                        const float lambda)
1119 {
1120     int i, w, w2, g;
1121     int minq = 255;
1122
1123     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
1124     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
1125         for (g = 0; g < sce->ics.num_swb; g++) {
1126             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
1127                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
1128                 if (band->energy <= band->threshold) {
1129                     sce->sf_idx[(w+w2)*16+g] = 218;
1130                     sce->zeroes[(w+w2)*16+g] = 1;
1131                 } else {
1132                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2f(band->threshold), 80, 218);
1133                     sce->zeroes[(w+w2)*16+g] = 0;
1134                 }
1135                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
1136             }
1137         }
1138     }
1139     for (i = 0; i < 128; i++) {
1140         sce->sf_idx[i] = 140;
1141         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
1142     }
1143     //set the same quantizers inside window groups
1144     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
1145         for (g = 0;  g < sce->ics.num_swb; g++)
1146             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
1147                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
1148 }
1149
1150 static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)
1151 {
1152     int start = 0, w, w2, g;
1153     const float lambda = s->lambda;
1154     const float freq_mult = avctx->sample_rate/(1024.0f/sce->ics.num_windows)/2.0f;
1155     const float spread_threshold = NOISE_SPREAD_THRESHOLD*(lambda/120.f);
1156     const float thr_mult = NOISE_LAMBDA_NUMERATOR/lambda;
1157
1158     /* Coders !twoloop don't reset the band_types */
1159     for (w = 0; w < 128; w++)
1160         if (sce->band_type[w] == NOISE_BT)
1161             sce->band_type[w] = 0;
1162
1163     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
1164         start = 0;
1165         for (g = 0;  g < sce->ics.num_swb; g++) {
1166             if (start*freq_mult > NOISE_LOW_LIMIT*(lambda/170.0f)) {
1167                 float energy = 0.0f, threshold = 0.0f, spread = 0.0f;
1168                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
1169                     FFPsyBand *band = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
1170                     energy += band->energy;
1171                     threshold += band->threshold;
1172                     spread += band->spread;
1173                 }
1174                 if (spread > spread_threshold*sce->ics.group_len[w] &&
1175                     ((sce->zeroes[w*16+g] && energy >= threshold) ||
1176                     energy < threshold*thr_mult*sce->ics.group_len[w])) {
1177                     sce->band_type[w*16+g] = NOISE_BT;
1178                     sce->pns_ener[w*16+g] = energy / sce->ics.group_len[w];
1179                     sce->zeroes[w*16+g] = 0;
1180                 }
1181             }
1182             start += sce->ics.swb_sizes[g];
1183         }
1184     }
1185 }
1186
1187 static void search_for_is(AACEncContext *s, AVCodecContext *avctx, ChannelElement *cpe)
1188 {
1189     float IS[128];
1190     float *L34  = s->scoefs + 128*0, *R34  = s->scoefs + 128*1;
1191     float *I34  = s->scoefs + 128*2;
1192     SingleChannelElement *sce0 = &cpe->ch[0];
1193     SingleChannelElement *sce1 = &cpe->ch[1];
1194     int start = 0, count = 0, i, w, w2, g;
1195     const float freq_mult = avctx->sample_rate/(1024.0f/sce0->ics.num_windows)/2.0f;
1196     const float lambda = s->lambda;
1197
1198     for (w = 0; w < 128; w++)
1199         if (sce1->band_type[w] >= INTENSITY_BT2)
1200             sce1->band_type[w] = 0;
1201
1202     if (!cpe->common_window)
1203         return;
1204     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
1205         start = 0;
1206         for (g = 0;  g < sce0->ics.num_swb; g++) {
1207             if (start*freq_mult > INT_STEREO_LOW_LIMIT*(lambda/170.0f) &&
1208                 cpe->ch[0].band_type[w*16+g] != NOISE_BT && !cpe->ch[0].zeroes[w*16+g] &&
1209                 cpe->ch[1].band_type[w*16+g] != NOISE_BT && !cpe->ch[1].zeroes[w*16+g]) {
1210                 int phase = 0;
1211                 float ener0 = 0.0f, ener1 = 0.0f, ener01 = 0.0f;
1212                 float dist1 = 0.0f, dist2 = 0.0f;
1213                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
1214                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
1215                         float coef0 = sce0->pcoeffs[start+(w+w2)*128+i];
1216                         float coef1 = sce1->pcoeffs[start+(w+w2)*128+i];
1217                         phase += coef0*coef1 >= 0.0f ? 1 : -1;
1218                         ener0 += coef0*coef0;
1219                         ener1 += coef1*coef1;
1220                         ener01 += (coef0 + coef1)*(coef0 + coef1);
1221                     }
1222                 }
1223                 if (!phase) { /* Too much phase difference between channels */
1224                     start += sce0->ics.swb_sizes[g];
1225                     continue;
1226                 }
1227                 phase = av_clip(phase, -1, 1);
1228                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
1229                     FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
1230                     FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];
1231                     int is_band_type, is_sf_idx = FFMAX(1, sce0->sf_idx[(w+w2)*16+g]-4);
1232                     float e01_34 = phase*pow(sqrt(ener1/ener0), 3.0/4.0);
1233                     float maxval, dist_spec_err = 0.0f;
1234                     float minthr = FFMIN(band0->threshold, band1->threshold);
1235                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++)
1236                         IS[i] = (sce0->pcoeffs[start+(w+w2)*128+i] + phase*sce1->pcoeffs[start+(w+w2)*128+i]) * sqrt(ener0/ener01);
1237                     abs_pow34_v(L34, sce0->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
1238                     abs_pow34_v(R34, sce1->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
1239                     abs_pow34_v(I34, IS,                            sce0->ics.swb_sizes[g]);
1240                     maxval = find_max_val(1, sce0->ics.swb_sizes[g], I34);
1241                     is_band_type = find_min_book(maxval, is_sf_idx);
1242                     dist1 += quantize_band_cost(s, sce0->coeffs + start + (w+w2)*128,
1243                                                 L34,
1244                                                 sce0->ics.swb_sizes[g],
1245                                                 sce0->sf_idx[(w+w2)*16+g],
1246                                                 sce0->band_type[(w+w2)*16+g],
1247                                                 lambda / band0->threshold, INFINITY, NULL, 0);
1248                     dist1 += quantize_band_cost(s, sce1->coeffs + start + (w+w2)*128,
1249                                                 R34,
1250                                                 sce1->ics.swb_sizes[g],
1251                                                 sce1->sf_idx[(w+w2)*16+g],
1252                                                 sce1->band_type[(w+w2)*16+g],
1253                                                 lambda / band1->threshold, INFINITY, NULL, 0);
1254                     dist2 += quantize_band_cost(s, IS,
1255                                                 I34,
1256                                                 sce0->ics.swb_sizes[g],
1257                                                 is_sf_idx,
1258                                                 is_band_type,
1259                                                 lambda / minthr, INFINITY, NULL, 0);
1260                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
1261                         dist_spec_err += (L34[i] - I34[i])*(L34[i] - I34[i]);
1262                         dist_spec_err += (R34[i] - I34[i]*e01_34)*(R34[i] - I34[i]*e01_34);
1263                     }
1264                     dist_spec_err *= lambda / minthr;
1265                     dist2 += dist_spec_err;
1266                 }
1267                 if (dist2 <= dist1) {
1268                     cpe->is_mask[w*16+g] = 1;
1269                     cpe->ms_mask[w*16+g] = 0;
1270                     cpe->ch[0].is_ener[w*16+g] = sqrt(ener0/ener01);
1271                     cpe->ch[1].is_ener[w*16+g] = ener0/ener1;
1272                     if (phase)
1273                         cpe->ch[1].band_type[w*16+g] = INTENSITY_BT;
1274                     else
1275                         cpe->ch[1].band_type[w*16+g] = INTENSITY_BT2;
1276                     count++;
1277                 }
1278             }
1279             start += sce0->ics.swb_sizes[g];
1280         }
1281     }
1282     cpe->is_mode = !!count;
1283 }
1284
1285 static void search_for_ms(AACEncContext *s, ChannelElement *cpe)
1286 {
1287     int start = 0, i, w, w2, g;
1288     float M[128], S[128];
1289     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
1290     const float lambda = s->lambda;
1291     SingleChannelElement *sce0 = &cpe->ch[0];
1292     SingleChannelElement *sce1 = &cpe->ch[1];
1293     if (!cpe->common_window)
1294         return;
1295     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
1296         start = 0;
1297         for (g = 0;  g < sce0->ics.num_swb; g++) {
1298             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g] && !cpe->is_mask[w*16+g]) {
1299                 float dist1 = 0.0f, dist2 = 0.0f;
1300                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
1301                     FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
1302                     FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];
1303                     float minthr = FFMIN(band0->threshold, band1->threshold);
1304                     float maxthr = FFMAX(band0->threshold, band1->threshold);
1305                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
1306                         M[i] = (sce0->pcoeffs[start+(w+w2)*128+i]
1307                               + sce1->pcoeffs[start+(w+w2)*128+i]) * 0.5;
1308                         S[i] =  M[i]
1309                               - sce1->pcoeffs[start+(w+w2)*128+i];
1310                     }
1311                     abs_pow34_v(L34, sce0->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
1312                     abs_pow34_v(R34, sce1->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
1313                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
1314                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
1315                     dist1 += quantize_band_cost(s, sce0->coeffs + start + (w+w2)*128,
1316                                                 L34,
1317                                                 sce0->ics.swb_sizes[g],
1318                                                 sce0->sf_idx[(w+w2)*16+g],
1319                                                 sce0->band_type[(w+w2)*16+g],
1320                                                 lambda / band0->threshold, INFINITY, NULL, 0);
1321                     dist1 += quantize_band_cost(s, sce1->coeffs + start + (w+w2)*128,
1322                                                 R34,
1323                                                 sce1->ics.swb_sizes[g],
1324                                                 sce1->sf_idx[(w+w2)*16+g],
1325                                                 sce1->band_type[(w+w2)*16+g],
1326                                                 lambda / band1->threshold, INFINITY, NULL, 0);
1327                     dist2 += quantize_band_cost(s, M,
1328                                                 M34,
1329                                                 sce0->ics.swb_sizes[g],
1330                                                 sce0->sf_idx[(w+w2)*16+g],
1331                                                 sce0->band_type[(w+w2)*16+g],
1332                                                 lambda / maxthr, INFINITY, NULL, 0);
1333                     dist2 += quantize_band_cost(s, S,
1334                                                 S34,
1335                                                 sce1->ics.swb_sizes[g],
1336                                                 sce1->sf_idx[(w+w2)*16+g],
1337                                                 sce1->band_type[(w+w2)*16+g],
1338                                                 lambda / minthr, INFINITY, NULL, 0);
1339                 }
1340                 cpe->ms_mask[w*16+g] = dist2 < dist1;
1341             }
1342             start += sce0->ics.swb_sizes[g];
1343         }
1344     }
1345 }
1346
1347 AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = {
1348     [AAC_CODER_FAAC] = {
1349         search_for_quantizers_faac,
1350         encode_window_bands_info,
1351         quantize_and_encode_band,
1352         set_special_band_scalefactors,
1353         search_for_pns,
1354         search_for_ms,
1355         search_for_is,
1356     },
1357     [AAC_CODER_ANMR] = {
1358         search_for_quantizers_anmr,
1359         encode_window_bands_info,
1360         quantize_and_encode_band,
1361         set_special_band_scalefactors,
1362         search_for_pns,
1363         search_for_ms,
1364         search_for_is,
1365     },
1366     [AAC_CODER_TWOLOOP] = {
1367         search_for_quantizers_twoloop,
1368         codebook_trellis_rate,
1369         quantize_and_encode_band,
1370         set_special_band_scalefactors,
1371         search_for_pns,
1372         search_for_ms,
1373         search_for_is,
1374     },
1375     [AAC_CODER_FAST] = {
1376         search_for_quantizers_fast,
1377         encode_window_bands_info,
1378         quantize_and_encode_band,
1379         set_special_band_scalefactors,
1380         search_for_pns,
1381         search_for_ms,
1382         search_for_is,
1383     },
1384 };