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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
  43 /** Frequency in Hz for lower limit of noise substitution **/
  44 #define NOISE_LOW_LIMIT 4000
  45
  46 /** Total number of usable codebooks **/
  47 #define CB_TOT 12
  48
  49 /** Total number of codebooks, including special ones **/
  50 #define CB_TOT_ALL 15
  51
  52 /** bits needed to code codebook run value for long windows */
  53 static const uint8_t run_value_bits_long[64] = {
  54      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,
  55      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5, 10,
  56     10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
  57     10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 15
  58 };
  59
  60 /** bits needed to code codebook run value for short windows */
  61 static const uint8_t run_value_bits_short[16] = {
  62     3, 3, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6, 6, 6, 9
  63 };
  64
  65 static const uint8_t * const run_value_bits[2] = {
  66     run_value_bits_long, run_value_bits_short
  67 };
  68
  69 /** Map to convert values from BandCodingPath index to a codebook index **/
  70 static const uint8_t aac_cb_out_map[CB_TOT_ALL]  = {0,1,2,3,4,5,6,7,8,9,10,11,13,14,15};
  71 /** Inverse map to convert from codebooks to BandCodingPath indices **/
  72 static const uint8_t aac_cb_in_map[CB_TOT_ALL+1] = {0,1,2,3,4,5,6,7,8,9,10,11,0,12,13,14};
  73
  74 /**
  75  * Quantize one coefficient.
  76  * @return absolute value of the quantized coefficient
  77  * @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
  78  */
  79 static av_always_inline int quant(float coef, const float Q)
  80 {
  81     float a = coef * Q;
  82     return sqrtf(a * sqrtf(a)) + 0.4054;
  83 }
  84
  85 static void quantize_bands(int *out, const float *in, const float *scaled,
  86                            int size, float Q34, int is_signed, int maxval)
  87 {
  88     int i;
  89     double qc;
  90     for (i = 0; i < size; i++) {
  91         qc = scaled[i] * Q34;
  92         out[i] = (int)FFMIN(qc + 0.4054, (double)maxval);
  93         if (is_signed && in[i] < 0.0f) {
  94             out[i] = -out[i];
  95         }
  96     }
  97 }
  98
  99 static void abs_pow34_v(float *out, const float *in, const int size)
 100 {
 101 #ifndef USE_REALLY_FULL_SEARCH
 102     int i;
 103     for (i = 0; i < size; i++) {
 104         float a = fabsf(in[i]);
 105         out[i] = sqrtf(a * sqrtf(a));
 106     }
 107 #endif /* USE_REALLY_FULL_SEARCH */
 108 }
 109
 110 static const uint8_t aac_cb_range [12] = {0, 3, 3, 3, 3, 9, 9, 8, 8, 13, 13, 17};
 111 static const uint8_t aac_cb_maxval[12] = {0, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 16};
 112
 113 /**
 114  * Calculate rate distortion cost for quantizing with given codebook
 115  *
 116  * @return quantization distortion
 117  */
 118 static av_always_inline float quantize_and_encode_band_cost_template(
 119                                 struct AACEncContext *s,
 120                                 PutBitContext *pb, const float *in,
 121                                 const float *scaled, int size, int scale_idx,
 122                                 int cb, const float lambda, const float uplim,
 123                                 int *bits, int BT_ZERO, int BT_UNSIGNED,
 124                                 int BT_PAIR, int BT_ESC, int BT_NOISE, int BT_STEREO)
 125 {
 126     const int q_idx = POW_SF2_ZERO - scale_idx + SCALE_ONE_POS - SCALE_DIV_512;
 127     const float Q   = ff_aac_pow2sf_tab [q_idx];
 128     const float Q34 = ff_aac_pow34sf_tab[q_idx];
 129     const float IQ  = ff_aac_pow2sf_tab [POW_SF2_ZERO + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 130     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 131     int i, j;
 132     float cost = 0;
 133     const int dim = BT_PAIR ? 2 : 4;
 134     int resbits = 0;
 135     int off;
 136
 137     if (BT_ZERO || BT_NOISE || BT_STEREO) {
 138         for (i = 0; i < size; i++)
 139             cost += in[i]*in[i];
 140         if (bits)
 141             *bits = 0;
 142         return cost * lambda;
 143     }
 144     if (!scaled) {
 145         abs_pow34_v(s->scoefs, in, size);
 146         scaled = s->scoefs;
 147     }
 148     quantize_bands(s->qcoefs, in, scaled, size, Q34, !BT_UNSIGNED, aac_cb_maxval[cb]);
 149     if (BT_UNSIGNED) {
 150         off = 0;
 151     } else {
 152         off = aac_cb_maxval[cb];
 153     }
 154     for (i = 0; i < size; i += dim) {
 155         const float *vec;
 156         int *quants = s->qcoefs + i;
 157         int curidx = 0;
 158         int curbits;
 159         float rd = 0.0f;
 160         for (j = 0; j < dim; j++) {
 161             curidx *= aac_cb_range[cb];
 162             curidx += quants[j] + off;
 163         }
 164         curbits =  ff_aac_spectral_bits[cb-1][curidx];
 165         vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 166         if (BT_UNSIGNED) {
 167             for (j = 0; j < dim; j++) {
 168                 float t = fabsf(in[i+j]);
 169                 float di;
 170                 if (BT_ESC && vec[j] == 64.0f) { //FIXME: slow
 171                     if (t >= CLIPPED_ESCAPE) {
 172                         di = t - CLIPPED_ESCAPE;
 173                         curbits += 21;
 174                     } else {
 175                         int c = av_clip_uintp2(quant(t, Q), 13);
 176                         di = t - c*cbrtf(c)*IQ;
 177                         curbits += av_log2(c)*2 - 4 + 1;
 178                     }
 179                 } else {
 180                     di = t - vec[j]*IQ;
 181                 }
 182                 if (vec[j] != 0.0f)
 183                     curbits++;
 184                 rd += di*di;
 185             }
 186         } else {
 187             for (j = 0; j < dim; j++) {
 188                 float di = in[i+j] - vec[j]*IQ;
 189                 rd += di*di;
 190             }
 191         }
 192         cost    += rd * lambda + curbits;
 193         resbits += curbits;
 194         if (cost >= uplim)
 195             return uplim;
 196         if (pb) {
 197             put_bits(pb, ff_aac_spectral_bits[cb-1][curidx], ff_aac_spectral_codes[cb-1][curidx]);
 198             if (BT_UNSIGNED)
 199                 for (j = 0; j < dim; j++)
 200                     if (ff_aac_codebook_vectors[cb-1][curidx*dim+j] != 0.0f)
 201                         put_bits(pb, 1, in[i+j] < 0.0f);
 202             if (BT_ESC) {
 203                 for (j = 0; j < 2; j++) {
 204                     if (ff_aac_codebook_vectors[cb-1][curidx*2+j] == 64.0f) {
 205                         int coef = av_clip_uintp2(quant(fabsf(in[i+j]), Q), 13);
 206                         int len = av_log2(coef);
 207
 208                         put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
 209                         put_sbits(pb, len, coef);
 210                     }
 211                 }
 212             }
 213         }
 214     }
 215
 216     if (bits)
 217         *bits = resbits;
 218     return cost;
 219 }
 220
 221 static float quantize_and_encode_band_cost_NONE(struct AACEncContext *s, PutBitContext *pb,
 222                                                 const float *in, const float *scaled,
 223                                                 int size, int scale_idx, int cb,
 224                                                 const float lambda, const float uplim,
 225                                                 int *bits) {
 226     av_assert0(0);
 227     return 0.0f;
 228 }
 229
 230 #define QUANTIZE_AND_ENCODE_BAND_COST_FUNC(NAME, BT_ZERO, BT_UNSIGNED, BT_PAIR, BT_ESC, BT_NOISE, BT_STEREO) \
 231 static float quantize_and_encode_band_cost_ ## NAME(                                         \
 232                                 struct AACEncContext *s,                                     \
 233                                 PutBitContext *pb, const float *in,                          \
 234                                 const float *scaled, int size, int scale_idx,                \
 235                                 int cb, const float lambda, const float uplim,               \
 236                                 int *bits) {                                                 \
 237     return quantize_and_encode_band_cost_template(                                           \
 238                                 s, pb, in, scaled, size, scale_idx,                          \
 239                                 BT_ESC ? ESC_BT : cb, lambda, uplim, bits,                   \
 240                                 BT_ZERO, BT_UNSIGNED, BT_PAIR, BT_ESC, BT_NOISE, BT_STEREO); \
 241 }
 242
 243 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(ZERO,  1, 0, 0, 0, 0, 0)
 244 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(SQUAD, 0, 0, 0, 0, 0, 0)
 245 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(UQUAD, 0, 1, 0, 0, 0, 0)
 246 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(SPAIR, 0, 0, 1, 0, 0, 0)
 247 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(UPAIR, 0, 1, 1, 0, 0, 0)
 248 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(ESC,   0, 1, 1, 1, 0, 0)
 249 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(NOISE, 0, 0, 0, 0, 1, 0)
 250 QUANTIZE_AND_ENCODE_BAND_COST_FUNC(STEREO,0, 0, 0, 0, 0, 1)
 251
 252 static float (*const quantize_and_encode_band_cost_arr[])(
 253                                 struct AACEncContext *s,
 254                                 PutBitContext *pb, const float *in,
 255                                 const float *scaled, int size, int scale_idx,
 256                                 int cb, const float lambda, const float uplim,
 257                                 int *bits) = {
 258     quantize_and_encode_band_cost_ZERO,
 259     quantize_and_encode_band_cost_SQUAD,
 260     quantize_and_encode_band_cost_SQUAD,
 261     quantize_and_encode_band_cost_UQUAD,
 262     quantize_and_encode_band_cost_UQUAD,
 263     quantize_and_encode_band_cost_SPAIR,
 264     quantize_and_encode_band_cost_SPAIR,
 265     quantize_and_encode_band_cost_UPAIR,
 266     quantize_and_encode_band_cost_UPAIR,
 267     quantize_and_encode_band_cost_UPAIR,
 268     quantize_and_encode_band_cost_UPAIR,
 269     quantize_and_encode_band_cost_ESC,
 270     quantize_and_encode_band_cost_NONE,     /* CB 12 doesn't exist */
 271     quantize_and_encode_band_cost_NOISE,
 272     quantize_and_encode_band_cost_STEREO,
 273     quantize_and_encode_band_cost_STEREO,
 274 };
 275
 276 #define quantize_and_encode_band_cost(                                  \
 277                                 s, pb, in, scaled, size, scale_idx, cb, \
 278                                 lambda, uplim, bits)                    \
 279     quantize_and_encode_band_cost_arr[cb](                              \
 280                                 s, pb, in, scaled, size, scale_idx, cb, \
 281                                 lambda, uplim, bits)
 282
 283 static float quantize_band_cost(struct AACEncContext *s, const float *in,
 284                                 const float *scaled, int size, int scale_idx,
 285                                 int cb, const float lambda, const float uplim,
 286                                 int *bits)
 287 {
 288     return quantize_and_encode_band_cost(s, NULL, in, scaled, size, scale_idx,
 289                                          cb, lambda, uplim, bits);
 290 }
 291
 292 static void quantize_and_encode_band(struct AACEncContext *s, PutBitContext *pb,
 293                                      const float *in, int size, int scale_idx,
 294                                      int cb, const float lambda)
 295 {
 296     quantize_and_encode_band_cost(s, pb, in, NULL, size, scale_idx, cb, lambda,
 297                                   INFINITY, NULL);
 298 }
 299
 300 static float find_max_val(int group_len, int swb_size, const float *scaled) {
 301     float maxval = 0.0f;
 302     int w2, i;
 303     for (w2 = 0; w2 < group_len; w2++) {
 304         for (i = 0; i < swb_size; i++) {
 305             maxval = FFMAX(maxval, scaled[w2*128+i]);
 306         }
 307     }
 308     return maxval;
 309 }
 310
 311 static int find_min_book(float maxval, int sf) {
 312     float Q = ff_aac_pow2sf_tab[POW_SF2_ZERO - sf + SCALE_ONE_POS - SCALE_DIV_512];
 313     float Q34 = sqrtf(Q * sqrtf(Q));
 314     int qmaxval, cb;
 315     qmaxval = maxval * Q34 + 0.4054f;
 316     if      (qmaxval ==  0) cb = 0;
 317     else if (qmaxval ==  1) cb = 1;
 318     else if (qmaxval ==  2) cb = 3;
 319     else if (qmaxval <=  4) cb = 5;
 320     else if (qmaxval <=  7) cb = 7;
 321     else if (qmaxval <= 12) cb = 9;
 322     else                    cb = 11;
 323     return cb;
 324 }
 325
 326 /**
 327  * structure used in optimal codebook search
 328  */
 329 typedef struct BandCodingPath {
 330     int prev_idx; ///< pointer to the previous path point
 331     float cost;   ///< path cost
 332     int run;
 333 } BandCodingPath;
 334
 335 /**
 336  * Encode band info for single window group bands.
 337  */
 338 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
 339                                      int win, int group_len, const float lambda)
 340 {
 341     BandCodingPath path[120][CB_TOT_ALL];
 342     int w, swb, cb, start, size;
 343     int i, j;
 344     const int max_sfb  = sce->ics.max_sfb;
 345     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 346     const int run_esc  = (1 << run_bits) - 1;
 347     int idx, ppos, count;
 348     int stackrun[120], stackcb[120], stack_len;
 349     float next_minrd = INFINITY;
 350     int next_mincb = 0;
 351
 352     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 353     start = win*128;
 354     for (cb = 0; cb < CB_TOT_ALL; cb++) {
 355         path[0][cb].cost     = 0.0f;
 356         path[0][cb].prev_idx = -1;
 357         path[0][cb].run      = 0;
 358     }
 359     for (swb = 0; swb < max_sfb; swb++) {
 360         size = sce->ics.swb_sizes[swb];
 361         if (sce->zeroes[win*16 + swb]) {
 362             for (cb = 0; cb < CB_TOT_ALL; cb++) {
 363                 path[swb+1][cb].prev_idx = cb;
 364                 path[swb+1][cb].cost     = path[swb][cb].cost;
 365                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 366             }
 367         } else {
 368             float minrd = next_minrd;
 369             int mincb = next_mincb;
 370             next_minrd = INFINITY;
 371             next_mincb = 0;
 372             for (cb = 0; cb < CB_TOT_ALL; cb++) {
 373                 float cost_stay_here, cost_get_here;
 374                 float rd = 0.0f;
 375                 if (cb >= 12 && sce->band_type[win*16+swb] < aac_cb_out_map[cb] ||
 376                     cb  < aac_cb_in_map[sce->band_type[win*16+swb]] && sce->band_type[win*16+swb] > aac_cb_out_map[cb]) {
 377                     path[swb+1][cb].prev_idx = -1;
 378                     path[swb+1][cb].cost     = INFINITY;
 379                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 380                     continue;
 381                 }
 382                 for (w = 0; w < group_len; w++) {
 383                     FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(win+w)*16+swb];
 384                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
 385                                              s->scoefs + start + w*128, size,
 386                                              sce->sf_idx[(win+w)*16+swb], aac_cb_out_map[cb],
 387                                              lambda / band->threshold, INFINITY, NULL);
 388                 }
 389                 cost_stay_here = path[swb][cb].cost + rd;
 390                 cost_get_here  = minrd              + rd + run_bits + 4;
 391                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 392                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 393                     cost_stay_here += run_bits;
 394                 if (cost_get_here < cost_stay_here) {
 395                     path[swb+1][cb].prev_idx = mincb;
 396                     path[swb+1][cb].cost     = cost_get_here;
 397                     path[swb+1][cb].run      = 1;
 398                 } else {
 399                     path[swb+1][cb].prev_idx = cb;
 400                     path[swb+1][cb].cost     = cost_stay_here;
 401                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 402                 }
 403                 if (path[swb+1][cb].cost < next_minrd) {
 404                     next_minrd = path[swb+1][cb].cost;
 405                     next_mincb = cb;
 406                 }
 407             }
 408         }
 409         start += sce->ics.swb_sizes[swb];
 410     }
 411
 412     //convert resulting path from backward-linked list
 413     stack_len = 0;
 414     idx       = 0;
 415     for (cb = 1; cb < CB_TOT_ALL; cb++)
 416         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 417             idx = cb;
 418     ppos = max_sfb;
 419     while (ppos > 0) {
 420         av_assert1(idx >= 0);
 421         cb = idx;
 422         stackrun[stack_len] = path[ppos][cb].run;
 423         stackcb [stack_len] = cb;
 424         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 425         ppos -= path[ppos][cb].run;
 426         stack_len++;
 427     }
 428     //perform actual band info encoding
 429     start = 0;
 430     for (i = stack_len - 1; i >= 0; i--) {
 431         cb = aac_cb_out_map[stackcb[i]];
 432         put_bits(&s->pb, 4, cb);
 433         count = stackrun[i];
 434         memset(sce->zeroes + win*16 + start, !cb, count);
 435         //XXX: memset when band_type is also uint8_t
 436         for (j = 0; j < count; j++) {
 437             sce->band_type[win*16 + start] = cb;
 438             start++;
 439         }
 440         while (count >= run_esc) {
 441             put_bits(&s->pb, run_bits, run_esc);
 442             count -= run_esc;
 443         }
 444         put_bits(&s->pb, run_bits, count);
 445     }
 446 }
 447
 448 static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,
 449                                   int win, int group_len, const float lambda)
 450 {
 451     BandCodingPath path[120][CB_TOT_ALL];
 452     int w, swb, cb, start, size;
 453     int i, j;
 454     const int max_sfb  = sce->ics.max_sfb;
 455     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 456     const int run_esc  = (1 << run_bits) - 1;
 457     int idx, ppos, count;
 458     int stackrun[120], stackcb[120], stack_len;
 459     float next_minbits = INFINITY;
 460     int next_mincb = 0;
 461
 462     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 463     start = win*128;
 464     for (cb = 0; cb < CB_TOT_ALL; cb++) {
 465         path[0][cb].cost     = run_bits+4;
 466         path[0][cb].prev_idx = -1;
 467         path[0][cb].run      = 0;
 468     }
 469     for (swb = 0; swb < max_sfb; swb++) {
 470         size = sce->ics.swb_sizes[swb];
 471         if (sce->zeroes[win*16 + swb]) {
 472             float cost_stay_here = path[swb][0].cost;
 473             float cost_get_here  = next_minbits + run_bits + 4;
 474             if (   run_value_bits[sce->ics.num_windows == 8][path[swb][0].run]
 475                 != run_value_bits[sce->ics.num_windows == 8][path[swb][0].run+1])
 476                 cost_stay_here += run_bits;
 477             if (cost_get_here < cost_stay_here) {
 478                 path[swb+1][0].prev_idx = next_mincb;
 479                 path[swb+1][0].cost     = cost_get_here;
 480                 path[swb+1][0].run      = 1;
 481             } else {
 482                 path[swb+1][0].prev_idx = 0;
 483                 path[swb+1][0].cost     = cost_stay_here;
 484                 path[swb+1][0].run      = path[swb][0].run + 1;
 485             }
 486             next_minbits = path[swb+1][0].cost;
 487             next_mincb = 0;
 488             for (cb = 1; cb < CB_TOT_ALL; cb++) {
 489                 path[swb+1][cb].cost = 61450;
 490                 path[swb+1][cb].prev_idx = -1;
 491                 path[swb+1][cb].run = 0;
 492             }
 493         } else {
 494             float minbits = next_minbits;
 495             int mincb = next_mincb;
 496             int startcb = sce->band_type[win*16+swb];
 497             startcb = aac_cb_in_map[startcb];
 498             next_minbits = INFINITY;
 499             next_mincb = 0;
 500             for (cb = 0; cb < startcb; cb++) {
 501                 path[swb+1][cb].cost = 61450;
 502                 path[swb+1][cb].prev_idx = -1;
 503                 path[swb+1][cb].run = 0;
 504             }
 505             for (cb = startcb; cb < CB_TOT_ALL; cb++) {
 506                 float cost_stay_here, cost_get_here;
 507                 float bits = 0.0f;
 508                 if (cb >= 12 && sce->band_type[win*16+swb] != aac_cb_out_map[cb]) {
 509                     path[swb+1][cb].cost = 61450;
 510                     path[swb+1][cb].prev_idx = -1;
 511                     path[swb+1][cb].run = 0;
 512                     continue;
 513                 }
 514                 for (w = 0; w < group_len; w++) {
 515                     bits += quantize_band_cost(s, sce->coeffs + start + w*128,
 516                                                s->scoefs + start + w*128, size,
 517                                                sce->sf_idx[(win+w)*16+swb],
 518                                                aac_cb_out_map[cb],
 519                                                0, INFINITY, NULL);
 520                 }
 521                 cost_stay_here = path[swb][cb].cost + bits;
 522                 cost_get_here  = minbits            + bits + run_bits + 4;
 523                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 524                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 525                     cost_stay_here += run_bits;
 526                 if (cost_get_here < cost_stay_here) {
 527                     path[swb+1][cb].prev_idx = mincb;
 528                     path[swb+1][cb].cost     = cost_get_here;
 529                     path[swb+1][cb].run      = 1;
 530                 } else {
 531                     path[swb+1][cb].prev_idx = cb;
 532                     path[swb+1][cb].cost     = cost_stay_here;
 533                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 534                 }
 535                 if (path[swb+1][cb].cost < next_minbits) {
 536                     next_minbits = path[swb+1][cb].cost;
 537                     next_mincb = cb;
 538                 }
 539             }
 540         }
 541         start += sce->ics.swb_sizes[swb];
 542     }
 543
 544     //convert resulting path from backward-linked list
 545     stack_len = 0;
 546     idx       = 0;
 547     for (cb = 1; cb < CB_TOT_ALL; cb++)
 548         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 549             idx = cb;
 550     ppos = max_sfb;
 551     while (ppos > 0) {
 552         av_assert1(idx >= 0);
 553         cb = idx;
 554         stackrun[stack_len] = path[ppos][cb].run;
 555         stackcb [stack_len] = cb;
 556         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 557         ppos -= path[ppos][cb].run;
 558         stack_len++;
 559     }
 560     //perform actual band info encoding
 561     start = 0;
 562     for (i = stack_len - 1; i >= 0; i--) {
 563         cb = aac_cb_out_map[stackcb[i]];
 564         put_bits(&s->pb, 4, cb);
 565         count = stackrun[i];
 566         memset(sce->zeroes + win*16 + start, !cb, count);
 567         //XXX: memset when band_type is also uint8_t
 568         for (j = 0; j < count; j++) {
 569             sce->band_type[win*16 + start] = cb;
 570             start++;
 571         }
 572         while (count >= run_esc) {
 573             put_bits(&s->pb, run_bits, run_esc);
 574             count -= run_esc;
 575         }
 576         put_bits(&s->pb, run_bits, count);
 577     }
 578 }
 579
 580 /** Return the minimum scalefactor where the quantized coef does not clip. */
 581 static av_always_inline uint8_t coef2minsf(float coef) {
 582     return av_clip_uint8(log2f(coef)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 583 }
 584
 585 /** Return the maximum scalefactor where the quantized coef is not zero. */
 586 static av_always_inline uint8_t coef2maxsf(float coef) {
 587     return av_clip_uint8(log2f(coef)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 588 }
 589
 590 typedef struct TrellisPath {
 591     float cost;
 592     int prev;
 593 } TrellisPath;
 594
 595 #define TRELLIS_STAGES 121
 596 #define TRELLIS_STATES (SCALE_MAX_DIFF+1)
 597
 598 static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement *sce)
 599 {
 600     int w, g, start = 0;
 601     int minscaler_n = sce->sf_idx[0], minscaler_i = sce->sf_idx[0];
 602     int bands = 0;
 603
 604     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 605         start = 0;
 606         for (g = 0;  g < sce->ics.num_swb; g++) {
 607             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
 608                 sce->sf_idx[w*16+g] = av_clip(ceilf(log2f(sce->is_ener[w*16+g])*2), -155, 100);
 609                 minscaler_i = FFMIN(minscaler_i, sce->sf_idx[w*16+g]);
 610                 bands++;
 611             } else if (sce->band_type[w*16+g] == NOISE_BT) {
 612                 sce->sf_idx[w*16+g] = av_clip(4+log2f(sce->pns_ener[w*16+g])*2, -100, 155);
 613                 minscaler_n = FFMIN(minscaler_n, sce->sf_idx[w*16+g]);
 614                 bands++;
 615             }
 616             start += sce->ics.swb_sizes[g];
 617         }
 618     }
 619
 620     if (!bands)
 621         return;
 622
 623     /* Clip the scalefactor indices */
 624     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 625         for (g = 0;  g < sce->ics.num_swb; g++) {
 626             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
 627                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_i, minscaler_i + SCALE_MAX_DIFF);
 628             } else if (sce->band_type[w*16+g] == NOISE_BT) {
 629                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_n, minscaler_n + SCALE_MAX_DIFF);
 630             }
 631         }
 632     }
 633 }
 634
 635 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 636                                        SingleChannelElement *sce,
 637                                        const float lambda)
 638 {
 639     int q, w, w2, g, start = 0;
 640     int i, j;
 641     int idx;
 642     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];
 643     int bandaddr[TRELLIS_STAGES];
 644     int minq;
 645     float mincost;
 646     float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f;
 647     int q0, q1, qcnt = 0;
 648
 649     for (i = 0; i < 1024; i++) {
 650         float t = fabsf(sce->coeffs[i]);
 651         if (t > 0.0f) {
 652             q0f = FFMIN(q0f, t);
 653             q1f = FFMAX(q1f, t);
 654             qnrgf += t*t;
 655             qcnt++;
 656         }
 657     }
 658
 659     if (!qcnt) {
 660         memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 661         memset(sce->zeroes, 1, sizeof(sce->zeroes));
 662         return;
 663     }
 664
 665     //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 666     q0 = coef2minsf(q0f);
 667     //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 668     q1 = coef2maxsf(q1f);
 669     if (q1 - q0 > 60) {
 670         int q0low  = q0;
 671         int q1high = q1;
 672         //minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped
 673         int qnrg = av_clip_uint8(log2f(sqrtf(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512);
 674         q1 = qnrg + 30;
 675         q0 = qnrg - 30;
 676         if (q0 < q0low) {
 677             q1 += q0low - q0;
 678             q0  = q0low;
 679         } else if (q1 > q1high) {
 680             q0 -= q1 - q1high;
 681             q1  = q1high;
 682         }
 683     }
 684
 685     for (i = 0; i < TRELLIS_STATES; i++) {
 686         paths[0][i].cost    = 0.0f;
 687         paths[0][i].prev    = -1;
 688     }
 689     for (j = 1; j < TRELLIS_STAGES; j++) {
 690         for (i = 0; i < TRELLIS_STATES; i++) {
 691             paths[j][i].cost    = INFINITY;
 692             paths[j][i].prev    = -2;
 693         }
 694     }
 695     idx = 1;
 696     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 697     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 698         start = w*128;
 699         for (g = 0; g < sce->ics.num_swb; g++) {
 700             const float *coefs = sce->coeffs + start;
 701             float qmin, qmax;
 702             int nz = 0;
 703
 704             bandaddr[idx] = w * 16 + g;
 705             qmin = INT_MAX;
 706             qmax = 0.0f;
 707             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 708                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 709                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 710                     sce->zeroes[(w+w2)*16+g] = 1;
 711                     continue;
 712                 }
 713                 sce->zeroes[(w+w2)*16+g] = 0;
 714                 nz = 1;
 715                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 716                     float t = fabsf(coefs[w2*128+i]);
 717                     if (t > 0.0f)
 718                         qmin = FFMIN(qmin, t);
 719                     qmax = FFMAX(qmax, t);
 720                 }
 721             }
 722             if (nz) {
 723                 int minscale, maxscale;
 724                 float minrd = INFINITY;
 725                 float maxval;
 726                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 727                 minscale = coef2minsf(qmin);
 728                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 729                 maxscale = coef2maxsf(qmax);
 730                 minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);
 731                 maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);
 732                 maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start);
 733                 for (q = minscale; q < maxscale; q++) {
 734                     float dist = 0;
 735                     int cb = find_min_book(maxval, sce->sf_idx[w*16+g]);
 736                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 737                         FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 738                         dist += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 739                                                    q + q0, cb, lambda / band->threshold, INFINITY, NULL);
 740                     }
 741                     minrd = FFMIN(minrd, dist);
 742
 743                     for (i = 0; i < q1 - q0; i++) {
 744                         float cost;
 745                         cost = paths[idx - 1][i].cost + dist
 746                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 747                         if (cost < paths[idx][q].cost) {
 748                             paths[idx][q].cost    = cost;
 749                             paths[idx][q].prev    = i;
 750                         }
 751                     }
 752                 }
 753             } else {
 754                 for (q = 0; q < q1 - q0; q++) {
 755                     paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 756                     paths[idx][q].prev = q;
 757                 }
 758             }
 759             sce->zeroes[w*16+g] = !nz;
 760             start += sce->ics.swb_sizes[g];
 761             idx++;
 762         }
 763     }
 764     idx--;
 765     mincost = paths[idx][0].cost;
 766     minq    = 0;
 767     for (i = 1; i < TRELLIS_STATES; i++) {
 768         if (paths[idx][i].cost < mincost) {
 769             mincost = paths[idx][i].cost;
 770             minq = i;
 771         }
 772     }
 773     while (idx) {
 774         sce->sf_idx[bandaddr[idx]] = minq + q0;
 775         minq = paths[idx][minq].prev;
 776         idx--;
 777     }
 778     //set the same quantizers inside window groups
 779     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 780         for (g = 0;  g < sce->ics.num_swb; g++)
 781             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 782                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 783 }
 784
 785 /**
 786  * two-loop quantizers search taken from ISO 13818-7 Appendix C
 787  */
 788 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
 789                                           AACEncContext *s,
 790                                           SingleChannelElement *sce,
 791                                           const float lambda)
 792 {
 793     int start = 0, i, w, w2, g;
 794     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels * (lambda / 120.f);
 795     const float freq_mult = avctx->sample_rate/(1024.0f/sce->ics.num_windows)/2.0f;
 796     float dists[128] = { 0 }, uplims[128] = { 0 };
 797     float maxvals[128];
 798     int noise_sf[128] = { 0 };
 799     int fflag, minscaler, minscaler_n;
 800     int its  = 0;
 801     int allz = 0;
 802     float minthr = INFINITY;
 803
 804     // for values above this the decoder might end up in an endless loop
 805     // due to always having more bits than what can be encoded.
 806     destbits = FFMIN(destbits, 5800);
 807     //XXX: some heuristic to determine initial quantizers will reduce search time
 808     //determine zero bands and upper limits
 809     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 810         start = 0;
 811         for (g = 0;  g < sce->ics.num_swb; g++) {
 812             int nz = 0;
 813             float uplim = 0.0f, energy = 0.0f;
 814             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 815                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 816                 uplim += band->threshold;
 817                 energy += band->energy;
 818                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 819                     sce->zeroes[(w+w2)*16+g] = 1;
 820                     continue;
 821                 }
 822                 nz = 1;
 823             }
 824             uplims[w*16+g] = uplim *512;
 825             if (s->options.pns && start*freq_mult > NOISE_LOW_LIMIT && energy < uplim * 1.2f) {
 826                 noise_sf[w*16+g] = av_clip(4+FFMIN(log2f(energy)*2,255), -100, 155);
 827                 sce->band_type[w*16+g] = NOISE_BT;
 828                 nz= 1;
 829             } else { /** Band type will be determined by the twoloop algorithm */
 830                 sce->band_type[w*16+g] = 0;
 831             }
 832             sce->zeroes[w*16+g] = !nz;
 833             if (nz)
 834                 minthr = FFMIN(minthr, uplim);
 835             allz |= nz;
 836             start += sce->ics.swb_sizes[g];
 837         }
 838     }
 839     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 840         for (g = 0;  g < sce->ics.num_swb; g++) {
 841             if (sce->zeroes[w*16+g]) {
 842                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 843                 continue;
 844             }
 845             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2f(uplims[w*16+g]/minthr)*4,59);
 846         }
 847     }
 848
 849     if (!allz)
 850         return;
 851     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 852
 853     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 854         start = w*128;
 855         for (g = 0;  g < sce->ics.num_swb; g++) {
 856             const float *scaled = s->scoefs + start;
 857             maxvals[w*16+g] = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled);
 858             start += sce->ics.swb_sizes[g];
 859         }
 860     }
 861
 862     //perform two-loop search
 863     //outer loop - improve quality
 864     do {
 865         int tbits, qstep;
 866         minscaler = sce->sf_idx[0];
 867         minscaler_n = sce->sf_idx[0];
 868         //inner loop - quantize spectrum to fit into given number of bits
 869         qstep = its ? 1 : 32;
 870         do {
 871             int prev = -1;
 872             tbits = 0;
 873             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 874                 start = w*128;
 875                 for (g = 0;  g < sce->ics.num_swb; g++) {
 876                     const float *coefs = sce->coeffs + start;
 877                     const float *scaled = s->scoefs + start;
 878                     int bits = 0;
 879                     int cb;
 880                     float dist = 0.0f;
 881
 882                     if (sce->band_type[w*16+g] == NOISE_BT) {
 883                         minscaler_n = FFMIN(minscaler_n, noise_sf[w*16+g]);
 884                         start += sce->ics.swb_sizes[g];
 885                         continue;
 886                     } else if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
 887                         start += sce->ics.swb_sizes[g];
 888                         continue;
 889                     }
 890                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 891                     cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
 892                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 893                         int b;
 894                         dist += quantize_band_cost(s, coefs + w2*128,
 895                                                    scaled + w2*128,
 896                                                    sce->ics.swb_sizes[g],
 897                                                    sce->sf_idx[w*16+g],
 898                                                    cb,
 899                                                    1.0f,
 900                                                    INFINITY,
 901                                                    &b);
 902                         bits += b;
 903                     }
 904                     dists[w*16+g] = dist - bits;
 905                     if (prev != -1) {
 906                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 907                     }
 908                     tbits += bits;
 909                     start += sce->ics.swb_sizes[g];
 910                     prev = sce->sf_idx[w*16+g];
 911                 }
 912             }
 913             if (tbits > destbits) {
 914                 for (i = 0; i < 128; i++)
 915                     if (sce->sf_idx[i] < 218 - qstep)
 916                         sce->sf_idx[i] += qstep;
 917             } else {
 918                 for (i = 0; i < 128; i++)
 919                     if (sce->sf_idx[i] > 60 - qstep)
 920                         sce->sf_idx[i] -= qstep;
 921             }
 922             qstep >>= 1;
 923             if (!qstep && tbits > destbits*1.02 && sce->sf_idx[0] < 217)
 924                 qstep = 1;
 925         } while (qstep);
 926
 927         fflag = 0;
 928         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 929
 930         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 931             for (g = 0; g < sce->ics.num_swb; g++)
 932                 if (sce->band_type[w*16+g] == NOISE_BT)
 933                     sce->sf_idx[w*16+g] = av_clip(noise_sf[w*16+g], minscaler_n, minscaler_n + SCALE_MAX_DIFF);
 934
 935         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 936             for (g = 0; g < sce->ics.num_swb; g++) {
 937                 int prevsc = sce->sf_idx[w*16+g];
 938                 if (sce->band_type[w*16+g] == NOISE_BT)
 939                     continue;
 940                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60) {
 941                     if (find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]-1))
 942                         sce->sf_idx[w*16+g]--;
 943                     else //Try to make sure there is some energy in every band
 944                         sce->sf_idx[w*16+g]-=2;
 945                 }
 946                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 947                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 948                 if (sce->sf_idx[w*16+g] != prevsc)
 949                     fflag = 1;
 950                 sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
 951             }
 952         }
 953         its++;
 954     } while (fflag && its < 10);
 955 }
 956
 957 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 958                                        SingleChannelElement *sce,
 959                                        const float lambda)
 960 {
 961     int start = 0, i, w, w2, g;
 962     float uplim[128], maxq[128];
 963     int minq, maxsf;
 964     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 965     int last = 0, lastband = 0, curband = 0;
 966     float avg_energy = 0.0;
 967     if (sce->ics.num_windows == 1) {
 968         start = 0;
 969         for (i = 0; i < 1024; i++) {
 970             if (i - start >= sce->ics.swb_sizes[curband]) {
 971                 start += sce->ics.swb_sizes[curband];
 972                 curband++;
 973             }
 974             if (sce->coeffs[i]) {
 975                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 976                 last = i;
 977                 lastband = curband;
 978             }
 979         }
 980     } else {
 981         for (w = 0; w < 8; w++) {
 982             const float *coeffs = sce->coeffs + w*128;
 983             curband = start = 0;
 984             for (i = 0; i < 128; i++) {
 985                 if (i - start >= sce->ics.swb_sizes[curband]) {
 986                     start += sce->ics.swb_sizes[curband];
 987                     curband++;
 988                 }
 989                 if (coeffs[i]) {
 990                     avg_energy += coeffs[i] * coeffs[i];
 991                     last = FFMAX(last, i);
 992                     lastband = FFMAX(lastband, curband);
 993                 }
 994             }
 995         }
 996     }
 997     last++;
 998     avg_energy /= last;
 999     if (avg_energy == 0.0f) {
1000         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
1001             sce->sf_idx[i] = SCALE_ONE_POS;
1002         return;
1003     }
1004     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
1005         start = w*128;
1006         for (g = 0; g < sce->ics.num_swb; g++) {
1007             float *coefs   = sce->coeffs + start;
1008             const int size = sce->ics.swb_sizes[g];
1009             int start2 = start, end2 = start + size, peakpos = start;
1010             float maxval = -1, thr = 0.0f, t;
1011             maxq[w*16+g] = 0.0f;
1012             if (g > lastband) {
1013                 maxq[w*16+g] = 0.0f;
1014                 start += size;
1015                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
1016                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
1017                 continue;
1018             }
1019             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
1020                 for (i = 0; i < size; i++) {
1021                     float t = coefs[w2*128+i]*coefs[w2*128+i];
1022                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
1023                     thr += t;
1024                     if (sce->ics.num_windows == 1 && maxval < t) {
1025                         maxval  = t;
1026                         peakpos = start+i;
1027                     }
1028                 }
1029             }
1030             if (sce->ics.num_windows == 1) {
1031                 start2 = FFMAX(peakpos - 2, start2);
1032                 end2   = FFMIN(peakpos + 3, end2);
1033             } else {
1034                 start2 -= start;
1035                 end2   -= start;
1036             }
1037             start += size;
1038             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
1039             t   = 1.0 - (1.0 * start2 / last);
1040             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
1041         }
1042     }
1043     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
1044     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
1045     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
1046         start = w*128;
1047         for (g = 0;  g < sce->ics.num_swb; g++) {
1048             const float *coefs  = sce->coeffs + start;
1049             const float *scaled = s->scoefs   + start;
1050             const int size      = sce->ics.swb_sizes[g];
1051             int scf, prev_scf, step;
1052             int min_scf = -1, max_scf = 256;
1053             float curdiff;
1054             if (maxq[w*16+g] < 21.544) {
1055                 sce->zeroes[w*16+g] = 1;
1056                 start += size;
1057                 continue;
1058             }
1059             sce->zeroes[w*16+g] = 0;
1060             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2f(1/maxq[w*16+g])*16/3, 60, 218);
1061             for (;;) {
1062                 float dist = 0.0f;
1063                 int quant_max;
1064
1065                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
1066                     int b;
1067                     dist += quantize_band_cost(s, coefs + w2*128,
1068                                                scaled + w2*128,
1069                                                sce->ics.swb_sizes[g],
1070                                                scf,
1071                                                ESC_BT,
1072                                                lambda,
1073                                                INFINITY,
1074                                                &b);
1075                     dist -= b;
1076                 }
1077                 dist *= 1.0f / 512.0f / lambda;
1078                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[POW_SF2_ZERO - scf + SCALE_ONE_POS - SCALE_DIV_512]);
1079                 if (quant_max >= 8191) { // too much, return to the previous quantizer
1080                     sce->sf_idx[w*16+g] = prev_scf;
1081                     break;
1082                 }
1083                 prev_scf = scf;
1084                 curdiff = fabsf(dist - uplim[w*16+g]);
1085                 if (curdiff <= 1.0f)
1086                     step = 0;
1087                 else
1088                     step = log2f(curdiff);
1089                 if (dist > uplim[w*16+g])
1090                     step = -step;
1091                 scf += step;
1092                 scf = av_clip_uint8(scf);
1093                 step = scf - prev_scf;
1094                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
1095                     sce->sf_idx[w*16+g] = av_clip(scf, min_scf, max_scf);
1096                     break;
1097                 }
1098                 if (step > 0)
1099                     min_scf = prev_scf;
1100                 else
1101                     max_scf = prev_scf;
1102             }
1103             start += size;
1104         }
1105     }
1106     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
1107     for (i = 1; i < 128; i++) {
1108         if (!sce->sf_idx[i])
1109             sce->sf_idx[i] = sce->sf_idx[i-1];
1110         else
1111             minq = FFMIN(minq, sce->sf_idx[i]);
1112     }
1113     if (minq == INT_MAX)
1114         minq = 0;
1115     minq = FFMIN(minq, SCALE_MAX_POS);
1116     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
1117     for (i = 126; i >= 0; i--) {
1118         if (!sce->sf_idx[i])
1119             sce->sf_idx[i] = sce->sf_idx[i+1];
1120         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
1121     }
1122 }
1123
1124 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
1125                                        SingleChannelElement *sce,
1126                                        const float lambda)
1127 {
1128     int i, w, w2, g;
1129     int minq = 255;
1130
1131     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
1132     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
1133         for (g = 0; g < sce->ics.num_swb; g++) {
1134             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
1135                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
1136                 if (band->energy <= band->threshold) {
1137                     sce->sf_idx[(w+w2)*16+g] = 218;
1138                     sce->zeroes[(w+w2)*16+g] = 1;
1139                 } else {
1140                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2f(band->threshold), 80, 218);
1141                     sce->zeroes[(w+w2)*16+g] = 0;
1142                 }
1143                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
1144             }
1145         }
1146     }
1147     for (i = 0; i < 128; i++) {
1148         sce->sf_idx[i] = 140;
1149         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
1150     }
1151     //set the same quantizers inside window groups
1152     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
1153         for (g = 0;  g < sce->ics.num_swb; g++)
1154             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
1155                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
1156 }
1157
1158 static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
1159                           const float lambda)
1160 {
1161     int start = 0, i, w, w2, g;
1162     float M[128], S[128];
1163     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
1164     SingleChannelElement *sce0 = &cpe->ch[0];
1165     SingleChannelElement *sce1 = &cpe->ch[1];
1166     if (!cpe->common_window)
1167         return;
1168     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
1169         for (g = 0;  g < sce0->ics.num_swb; g++) {
1170             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
1171                 float dist1 = 0.0f, dist2 = 0.0f;
1172                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
1173                     FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
1174                     FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];
1175                     float minthr = FFMIN(band0->threshold, band1->threshold);
1176                     float maxthr = FFMAX(band0->threshold, band1->threshold);
1177                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
1178                         M[i] = (sce0->pcoeffs[start+w2*128+i]
1179                               + sce1->pcoeffs[start+w2*128+i]) * 0.5;
1180                         S[i] =  M[i]
1181                               - sce1->pcoeffs[start+w2*128+i];
1182                     }
1183                     abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
1184                     abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
1185                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
1186                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
1187                     dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
1188                                                 L34,
1189                                                 sce0->ics.swb_sizes[g],
1190                                                 sce0->sf_idx[(w+w2)*16+g],
1191                                                 sce0->band_type[(w+w2)*16+g],
1192                                                 lambda / band0->threshold, INFINITY, NULL);
1193                     dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
1194                                                 R34,
1195                                                 sce1->ics.swb_sizes[g],
1196                                                 sce1->sf_idx[(w+w2)*16+g],
1197                                                 sce1->band_type[(w+w2)*16+g],
1198                                                 lambda / band1->threshold, INFINITY, NULL);
1199                     dist2 += quantize_band_cost(s, M,
1200                                                 M34,
1201                                                 sce0->ics.swb_sizes[g],
1202                                                 sce0->sf_idx[(w+w2)*16+g],
1203                                                 sce0->band_type[(w+w2)*16+g],
1204                                                 lambda / maxthr, INFINITY, NULL);
1205                     dist2 += quantize_band_cost(s, S,
1206                                                 S34,
1207                                                 sce1->ics.swb_sizes[g],
1208                                                 sce1->sf_idx[(w+w2)*16+g],
1209                                                 sce1->band_type[(w+w2)*16+g],
1210                                                 lambda / minthr, INFINITY, NULL);
1211                 }
1212                 cpe->ms_mask[w*16+g] = dist2 < dist1;
1213             }
1214             start += sce0->ics.swb_sizes[g];
1215         }
1216     }
1217 }
1218
1219 AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = {
1220     [AAC_CODER_FAAC] = {
1221         search_for_quantizers_faac,
1222         encode_window_bands_info,
1223         quantize_and_encode_band,
1224         search_for_ms,
1225     },
1226     [AAC_CODER_ANMR] = {
1227         search_for_quantizers_anmr,
1228         encode_window_bands_info,
1229         quantize_and_encode_band,
1230         search_for_ms,
1231     },
1232     [AAC_CODER_TWOLOOP] = {
1233         search_for_quantizers_twoloop,
1234         codebook_trellis_rate,
1235         quantize_and_encode_band,
1236         search_for_ms,
1237     },
1238     [AAC_CODER_FAST] = {
1239         search_for_quantizers_fast,
1240         encode_window_bands_info,
1241         quantize_and_encode_band,
1242         search_for_ms,
1243     },
1244 };