git.sesse.net Git - ffmpeg/blob - libavcodec/aaccoder.c

   1 /*
   2  * AAC coefficients encoder
   3  * Copyright (C) 2008-2009 Konstantin Shishkov
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * AAC coefficients encoder
  25  */
  26
  27 /***********************************
  28  *              TODOs:
  29  * speedup quantizer selection
  30  * add sane pulse detection
  31  ***********************************/
  32
  33 #include <float.h>
  34 #include "avcodec.h"
  35 #include "put_bits.h"
  36 #include "aac.h"
  37 #include "aacenc.h"
  38 #include "aactab.h"
  39
  40 /** bits needed to code codebook run value for long windows */
  41 static const uint8_t run_value_bits_long[64] = {
  42      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,
  43      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5, 10,
  44     10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
  45     10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 15
  46 };
  47
  48 /** bits needed to code codebook run value for short windows */
  49 static const uint8_t run_value_bits_short[16] = {
  50     3, 3, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6, 6, 6, 9
  51 };
  52
  53 static const uint8_t *run_value_bits[2] = {
  54     run_value_bits_long, run_value_bits_short
  55 };
  56
  57
  58 /**
  59  * Quantize one coefficient.
  60  * @return absolute value of the quantized coefficient
  61  * @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
  62  */
  63 static av_always_inline int quant(float coef, const float Q)
  64 {
  65     float a = coef * Q;
  66     return sqrtf(a * sqrtf(a)) + 0.4054;
  67 }
  68
  69 static void quantize_bands(int *out, const float *in, const float *scaled,
  70                            int size, float Q34, int is_signed, int maxval)
  71 {
  72     int i;
  73     double qc;
  74     for (i = 0; i < size; i++) {
  75         qc = scaled[i] * Q34;
  76         out[i] = (int)FFMIN(qc + 0.4054, (double)maxval);
  77         if (is_signed && in[i] < 0.0f) {
  78             out[i] = -out[i];
  79         }
  80     }
  81 }
  82
  83 static void abs_pow34_v(float *out, const float *in, const int size)
  84 {
  85 #ifndef USE_REALLY_FULL_SEARCH
  86     int i;
  87     for (i = 0; i < size; i++) {
  88         float a = fabsf(in[i]);
  89         out[i] = sqrtf(a * sqrtf(a));
  90     }
  91 #endif /* USE_REALLY_FULL_SEARCH */
  92 }
  93
  94 static const uint8_t aac_cb_range [12] = {0, 3, 3, 3, 3, 9, 9, 8, 8, 13, 13, 17};
  95 static const uint8_t aac_cb_maxval[12] = {0, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 16};
  96
  97 /**
  98  * Calculate rate distortion cost for quantizing with given codebook
  99  *
 100  * @return quantization distortion
 101  */
 102 static float quantize_and_encode_band_cost(struct AACEncContext *s,
 103                                 PutBitContext *pb, const float *in,
 104                                 const float *scaled, int size, int scale_idx,
 105                                 int cb, const float lambda, const float uplim,
 106                                 int *bits)
 107 {
 108     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 109     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
 110     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 111     int i, j, k;
 112     float cost = 0;
 113     const int dim = cb < FIRST_PAIR_BT ? 4 : 2;
 114     int resbits = 0;
 115     const float  Q34 = sqrtf(Q * sqrtf(Q));
 116     const int range  = aac_cb_range[cb];
 117     const int maxval = aac_cb_maxval[cb];
 118     int off;
 119
 120     if (!cb) {
 121         for (i = 0; i < size; i++)
 122             cost += in[i]*in[i];
 123         if (bits)
 124             *bits = 0;
 125         return cost * lambda;
 126     }
 127     if (!scaled) {
 128         abs_pow34_v(s->scoefs, in, size);
 129         scaled = s->scoefs;
 130     }
 131     quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
 132     if (IS_CODEBOOK_UNSIGNED(cb)) {
 133         off = 0;
 134     } else {
 135         off = maxval;
 136     }
 137     for (i = 0; i < size; i += dim) {
 138         const float *vec;
 139         int *quants = s->qcoefs + i;
 140         int curidx = 0;
 141         int curbits;
 142         float rd = 0.0f;
 143         for (j = 0; j < dim; j++) {
 144             curidx *= range;
 145             curidx += quants[j] + off;
 146         }
 147             curbits =  ff_aac_spectral_bits[cb-1][curidx];
 148             vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 149             if (IS_CODEBOOK_UNSIGNED(cb)) {
 150                 for (k = 0; k < dim; k++) {
 151                     float t = fabsf(in[i+k]);
 152                     float di;
 153                     if (vec[k] == 64.0f) { //FIXME: slow
 154                         if (t >= CLIPPED_ESCAPE) {
 155                             di = t - CLIPPED_ESCAPE;
 156                             curbits += 21;
 157                         } else {
 158                             int c = av_clip(quant(t, Q), 0, 8191);
 159                             di = t - c*cbrtf(c)*IQ;
 160                             curbits += av_log2(c)*2 - 4 + 1;
 161                         }
 162                     } else {
 163                         di = t - vec[k]*IQ;
 164                     }
 165                     if (vec[k] != 0.0f)
 166                         curbits++;
 167                     rd += di*di;
 168                 }
 169             } else {
 170                 for (k = 0; k < dim; k++) {
 171                     float di = in[i+k] - vec[k]*IQ;
 172                     rd += di*di;
 173                 }
 174             }
 175         cost    += rd * lambda + curbits;
 176         resbits += curbits;
 177         if (cost >= uplim)
 178             return uplim;
 179         if (pb) {
 180         put_bits(pb, ff_aac_spectral_bits[cb-1][curidx], ff_aac_spectral_codes[cb-1][curidx]);
 181         if (IS_CODEBOOK_UNSIGNED(cb))
 182             for (j = 0; j < dim; j++)
 183                 if (ff_aac_codebook_vectors[cb-1][curidx*dim+j] != 0.0f)
 184                     put_bits(pb, 1, in[i+j] < 0.0f);
 185         if (cb == ESC_BT) {
 186             for (j = 0; j < 2; j++) {
 187                 if (ff_aac_codebook_vectors[cb-1][curidx*2+j] == 64.0f) {
 188                     int coef = av_clip(quant(fabsf(in[i+j]), Q), 0, 8191);
 189                     int len = av_log2(coef);
 190
 191                     put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
 192                     put_bits(pb, len, coef & ((1 << len) - 1));
 193                 }
 194             }
 195         }
 196         }
 197     }
 198
 199     if (bits)
 200         *bits = resbits;
 201     return cost;
 202 }
 203 static float quantize_band_cost(struct AACEncContext *s, const float *in,
 204                                 const float *scaled, int size, int scale_idx,
 205                                 int cb, const float lambda, const float uplim,
 206                                 int *bits)
 207 {
 208     return quantize_and_encode_band_cost(s, NULL, in, scaled, size, scale_idx,
 209                                          cb, lambda, uplim, bits);
 210 }
 211
 212 static void quantize_and_encode_band(struct AACEncContext *s, PutBitContext *pb,
 213                                      const float *in, int size, int scale_idx,
 214                                      int cb, const float lambda)
 215 {
 216     quantize_and_encode_band_cost(s, pb, in, NULL, size, scale_idx, cb, lambda,
 217                                   INFINITY, NULL);
 218 }
 219
 220 static float find_max_val(int group_len, int swb_size, const float *scaled) {
 221     float maxval = 0.0f;
 222     int w2, i;
 223     for (w2 = 0; w2 < group_len; w2++) {
 224         for (i = 0; i < swb_size; i++) {
 225             maxval = FFMAX(maxval, scaled[w2*128+i]);
 226         }
 227     }
 228     return maxval;
 229 }
 230
 231 static int find_min_book(float maxval, int sf) {
 232     float Q = ff_aac_pow2sf_tab[200 - sf + SCALE_ONE_POS - SCALE_DIV_512];
 233     float Q34 = sqrtf(Q * sqrtf(Q));
 234     int qmaxval, cb;
 235     qmaxval = maxval * Q34 + 0.4054f;
 236     if      (qmaxval ==  0) cb = 0;
 237     else if (qmaxval ==  1) cb = 1;
 238     else if (qmaxval ==  2) cb = 3;
 239     else if (qmaxval <=  4) cb = 5;
 240     else if (qmaxval <=  7) cb = 7;
 241     else if (qmaxval <= 12) cb = 9;
 242     else                    cb = 11;
 243     return cb;
 244 }
 245
 246 /**
 247  * structure used in optimal codebook search
 248  */
 249 typedef struct BandCodingPath {
 250     int prev_idx; ///< pointer to the previous path point
 251     float cost;   ///< path cost
 252     int run;
 253 } BandCodingPath;
 254
 255 /**
 256  * Encode band info for single window group bands.
 257  */
 258 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
 259                                      int win, int group_len, const float lambda)
 260 {
 261     BandCodingPath path[120][12];
 262     int w, swb, cb, start, start2, size;
 263     int i, j;
 264     const int max_sfb  = sce->ics.max_sfb;
 265     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 266     const int run_esc  = (1 << run_bits) - 1;
 267     int idx, ppos, count;
 268     int stackrun[120], stackcb[120], stack_len;
 269     float next_minrd = INFINITY;
 270     int next_mincb = 0;
 271
 272     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 273     start = win*128;
 274     for (cb = 0; cb < 12; cb++) {
 275         path[0][cb].cost     = 0.0f;
 276         path[0][cb].prev_idx = -1;
 277         path[0][cb].run      = 0;
 278     }
 279     for (swb = 0; swb < max_sfb; swb++) {
 280         start2 = start;
 281         size = sce->ics.swb_sizes[swb];
 282         if (sce->zeroes[win*16 + swb]) {
 283             for (cb = 0; cb < 12; cb++) {
 284                 path[swb+1][cb].prev_idx = cb;
 285                 path[swb+1][cb].cost     = path[swb][cb].cost;
 286                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 287             }
 288         } else {
 289             float minrd = next_minrd;
 290             int mincb = next_mincb;
 291             next_minrd = INFINITY;
 292             next_mincb = 0;
 293             for (cb = 0; cb < 12; cb++) {
 294                 float cost_stay_here, cost_get_here;
 295                 float rd = 0.0f;
 296                 for (w = 0; w < group_len; w++) {
 297                     FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(win+w)*16+swb];
 298                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
 299                                              s->scoefs + start + w*128, size,
 300                                              sce->sf_idx[(win+w)*16+swb], cb,
 301                                              lambda / band->threshold, INFINITY, NULL);
 302                 }
 303                 cost_stay_here = path[swb][cb].cost + rd;
 304                 cost_get_here  = minrd              + rd + run_bits + 4;
 305                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 306                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 307                     cost_stay_here += run_bits;
 308                 if (cost_get_here < cost_stay_here) {
 309                     path[swb+1][cb].prev_idx = mincb;
 310                     path[swb+1][cb].cost     = cost_get_here;
 311                     path[swb+1][cb].run      = 1;
 312                 } else {
 313                     path[swb+1][cb].prev_idx = cb;
 314                     path[swb+1][cb].cost     = cost_stay_here;
 315                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 316                 }
 317                 if (path[swb+1][cb].cost < next_minrd) {
 318                     next_minrd = path[swb+1][cb].cost;
 319                     next_mincb = cb;
 320                 }
 321             }
 322         }
 323         start += sce->ics.swb_sizes[swb];
 324     }
 325
 326     //convert resulting path from backward-linked list
 327     stack_len = 0;
 328     idx       = 0;
 329     for (cb = 1; cb < 12; cb++)
 330         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 331             idx = cb;
 332     ppos = max_sfb;
 333     while (ppos > 0) {
 334         cb = idx;
 335         stackrun[stack_len] = path[ppos][cb].run;
 336         stackcb [stack_len] = cb;
 337         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 338         ppos -= path[ppos][cb].run;
 339         stack_len++;
 340     }
 341     //perform actual band info encoding
 342     start = 0;
 343     for (i = stack_len - 1; i >= 0; i--) {
 344         put_bits(&s->pb, 4, stackcb[i]);
 345         count = stackrun[i];
 346         memset(sce->zeroes + win*16 + start, !stackcb[i], count);
 347         //XXX: memset when band_type is also uint8_t
 348         for (j = 0; j < count; j++) {
 349             sce->band_type[win*16 + start] =  stackcb[i];
 350             start++;
 351         }
 352         while (count >= run_esc) {
 353             put_bits(&s->pb, run_bits, run_esc);
 354             count -= run_esc;
 355         }
 356         put_bits(&s->pb, run_bits, count);
 357     }
 358 }
 359
 360 static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,
 361                                   int win, int group_len, const float lambda)
 362 {
 363     BandCodingPath path[120][12];
 364     int w, swb, cb, start, start2, size;
 365     int i, j;
 366     const int max_sfb  = sce->ics.max_sfb;
 367     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 368     const int run_esc  = (1 << run_bits) - 1;
 369     int idx, ppos, count;
 370     int stackrun[120], stackcb[120], stack_len;
 371     float next_minrd = INFINITY;
 372     int next_mincb = 0;
 373
 374     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 375     start = win*128;
 376     for (cb = 0; cb < 12; cb++) {
 377         path[0][cb].cost     = run_bits+4;
 378         path[0][cb].prev_idx = -1;
 379         path[0][cb].run      = 0;
 380     }
 381     for (swb = 0; swb < max_sfb; swb++) {
 382         start2 = start;
 383         size = sce->ics.swb_sizes[swb];
 384         if (sce->zeroes[win*16 + swb]) {
 385             for (cb = 0; cb < 12; cb++) {
 386                 path[swb+1][cb].prev_idx = cb;
 387                 path[swb+1][cb].cost     = path[swb][cb].cost;
 388                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 389             }
 390         } else {
 391             float minrd = next_minrd;
 392             int mincb = next_mincb;
 393             int startcb = sce->band_type[win*16+swb];
 394             next_minrd = INFINITY;
 395             next_mincb = 0;
 396             for (cb = 0; cb < startcb; cb++) {
 397                 path[swb+1][cb].cost = 61450;
 398                 path[swb+1][cb].prev_idx = -1;
 399                 path[swb+1][cb].run = 0;
 400             }
 401             for (cb = startcb; cb < 12; cb++) {
 402                 float cost_stay_here, cost_get_here;
 403                 float rd = 0.0f;
 404                 for (w = 0; w < group_len; w++) {
 405                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
 406                                              s->scoefs + start + w*128, size,
 407                                              sce->sf_idx[(win+w)*16+swb], cb,
 408                                              0, INFINITY, NULL);
 409                 }
 410                 cost_stay_here = path[swb][cb].cost + rd;
 411                 cost_get_here  = minrd              + rd + run_bits + 4;
 412                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 413                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 414                     cost_stay_here += run_bits;
 415                 if (cost_get_here < cost_stay_here) {
 416                     path[swb+1][cb].prev_idx = mincb;
 417                     path[swb+1][cb].cost     = cost_get_here;
 418                     path[swb+1][cb].run      = 1;
 419                 } else {
 420                     path[swb+1][cb].prev_idx = cb;
 421                     path[swb+1][cb].cost     = cost_stay_here;
 422                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 423                 }
 424                 if (path[swb+1][cb].cost < next_minrd) {
 425                     next_minrd = path[swb+1][cb].cost;
 426                     next_mincb = cb;
 427                 }
 428             }
 429         }
 430         start += sce->ics.swb_sizes[swb];
 431     }
 432
 433     //convert resulting path from backward-linked list
 434     stack_len = 0;
 435     idx       = 0;
 436     for (cb = 1; cb < 12; cb++)
 437         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 438             idx = cb;
 439     ppos = max_sfb;
 440     while (ppos > 0) {
 441         if (idx < 0) abort();
 442         cb = idx;
 443         stackrun[stack_len] = path[ppos][cb].run;
 444         stackcb [stack_len] = cb;
 445         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 446         ppos -= path[ppos][cb].run;
 447         stack_len++;
 448     }
 449     //perform actual band info encoding
 450     start = 0;
 451     for (i = stack_len - 1; i >= 0; i--) {
 452         put_bits(&s->pb, 4, stackcb[i]);
 453         count = stackrun[i];
 454         memset(sce->zeroes + win*16 + start, !stackcb[i], count);
 455         //XXX: memset when band_type is also uint8_t
 456         for (j = 0; j < count; j++) {
 457             sce->band_type[win*16 + start] =  stackcb[i];
 458             start++;
 459         }
 460         while (count >= run_esc) {
 461             put_bits(&s->pb, run_bits, run_esc);
 462             count -= run_esc;
 463         }
 464         put_bits(&s->pb, run_bits, count);
 465     }
 466 }
 467
 468 typedef struct TrellisPath {
 469     float cost;
 470     int prev;
 471 } TrellisPath;
 472
 473 #define TRELLIS_STAGES 121
 474 #define TRELLIS_STATES (SCALE_MAX_DIFF+1)
 475
 476 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 477                                        SingleChannelElement *sce,
 478                                        const float lambda)
 479 {
 480     int q, w, w2, g, start = 0;
 481     int i, j;
 482     int idx;
 483     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];
 484     int bandaddr[TRELLIS_STAGES];
 485     int minq;
 486     float mincost;
 487     float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f;
 488     int q0, q1, qcnt = 0;
 489
 490     for (i = 0; i < 1024; i++) {
 491         float t = fabsf(sce->coeffs[i]);
 492         if (t > 0.0f) {
 493             q0f = FFMIN(q0f, t);
 494             q1f = FFMAX(q1f, t);
 495             qnrgf += t*t;
 496             qcnt++;
 497         }
 498     }
 499
 500     if (!qcnt) {
 501         memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 502         memset(sce->zeroes, 1, sizeof(sce->zeroes));
 503         return;
 504     }
 505
 506     //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 507     q0 = av_clip_uint8(log2(q0f)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 508     //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 509     q1 = av_clip_uint8(log2(q1f)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 510     //av_log(NULL, AV_LOG_ERROR, "q0 %d, q1 %d\n", q0, q1);
 511     if (q1 - q0 > 60) {
 512         int q0low  = q0;
 513         int q1high = q1;
 514         //minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped
 515         int qnrg = av_clip_uint8(log2(sqrt(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512);
 516         q1 = qnrg + 30;
 517         q0 = qnrg - 30;
 518     //av_log(NULL, AV_LOG_ERROR, "q0 %d, q1 %d\n", q0, q1);
 519         if (q0 < q0low) {
 520             q1 += q0low - q0;
 521             q0  = q0low;
 522         } else if (q1 > q1high) {
 523             q0 -= q1 - q1high;
 524             q1  = q1high;
 525         }
 526     }
 527     //av_log(NULL, AV_LOG_ERROR, "q0 %d, q1 %d\n", q0, q1);
 528
 529     for (i = 0; i < TRELLIS_STATES; i++) {
 530         paths[0][i].cost    = 0.0f;
 531         paths[0][i].prev    = -1;
 532     }
 533     for (j = 1; j < TRELLIS_STAGES; j++) {
 534         for (i = 0; i < TRELLIS_STATES; i++) {
 535             paths[j][i].cost    = INFINITY;
 536             paths[j][i].prev    = -2;
 537         }
 538     }
 539     idx = 1;
 540     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 541     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 542         start = w*128;
 543         for (g = 0; g < sce->ics.num_swb; g++) {
 544             const float *coefs = sce->coeffs + start;
 545             float qmin, qmax;
 546             int nz = 0;
 547
 548             bandaddr[idx] = w * 16 + g;
 549             qmin = INT_MAX;
 550             qmax = 0.0f;
 551             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 552                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 553                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 554                     sce->zeroes[(w+w2)*16+g] = 1;
 555                     continue;
 556                 }
 557                 sce->zeroes[(w+w2)*16+g] = 0;
 558                 nz = 1;
 559                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 560                     float t = fabsf(coefs[w2*128+i]);
 561                     if (t > 0.0f)
 562                         qmin = FFMIN(qmin, t);
 563                     qmax = FFMAX(qmax, t);
 564                 }
 565             }
 566             if (nz) {
 567                 int minscale, maxscale;
 568                 float minrd = INFINITY;
 569                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 570                 minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 571                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 572                 maxscale = av_clip_uint8(log2(qmax)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 573                 minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);
 574                 maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);
 575                 float maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start);
 576                 for (q = minscale; q < maxscale; q++) {
 577                     float dist = 0;
 578                     int cb = find_min_book(maxval, sce->sf_idx[w*16+g]);
 579                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 580                         FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 581                         dist += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 582                                                             q + q0, cb, lambda / band->threshold, INFINITY, NULL);
 583                     }
 584                     minrd = FFMIN(minrd, dist);
 585
 586                     for (i = 0; i < q1 - q0; i++) {
 587                         float cost;
 588                         cost = paths[idx - 1][i].cost + dist
 589                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 590                         if (cost < paths[idx][q].cost) {
 591                             paths[idx][q].cost    = cost;
 592                             paths[idx][q].prev    = i;
 593                         }
 594                     }
 595                 }
 596             } else {
 597                 for (q = 0; q < q1 - q0; q++) {
 598                         paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 599                         paths[idx][q].prev = q;
 600                 }
 601             }
 602             sce->zeroes[w*16+g] = !nz;
 603             start += sce->ics.swb_sizes[g];
 604             idx++;
 605         }
 606     }
 607     idx--;
 608     mincost = paths[idx][0].cost;
 609     minq    = 0;
 610     for (i = 1; i < TRELLIS_STATES; i++) {
 611         if (paths[idx][i].cost < mincost) {
 612             mincost = paths[idx][i].cost;
 613             minq = i;
 614         }
 615     }
 616     while (idx) {
 617         sce->sf_idx[bandaddr[idx]] = minq + q0;
 618         minq = paths[idx][minq].prev;
 619         idx--;
 620     }
 621     //set the same quantizers inside window groups
 622     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 623         for (g = 0;  g < sce->ics.num_swb; g++)
 624             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 625                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 626 }
 627
 628 /**
 629  * two-loop quantizers search taken from ISO 13818-7 Appendix C
 630  */
 631 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
 632                                           AACEncContext *s,
 633                                           SingleChannelElement *sce,
 634                                           const float lambda)
 635 {
 636     int start = 0, i, w, w2, g;
 637     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels;
 638     float dists[128], uplims[128];
 639     int fflag, minscaler;
 640     int its  = 0;
 641     int allz = 0;
 642     float minthr = INFINITY;
 643
 644     //XXX: some heuristic to determine initial quantizers will reduce search time
 645     memset(dists, 0, sizeof(dists));
 646     //determine zero bands and upper limits
 647     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 648         for (g = 0;  g < sce->ics.num_swb; g++) {
 649             int nz = 0;
 650             float uplim = 0.0f;
 651             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 652                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 653                 uplim += band->threshold;
 654                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 655                     sce->zeroes[(w+w2)*16+g] = 1;
 656                     continue;
 657                 }
 658                 nz = 1;
 659             }
 660             uplims[w*16+g] = uplim *512;
 661             sce->zeroes[w*16+g] = !nz;
 662             if (nz)
 663                 minthr = FFMIN(minthr, uplim);
 664             allz = FFMAX(allz, nz);
 665         }
 666     }
 667     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 668         for (g = 0;  g < sce->ics.num_swb; g++) {
 669             if (sce->zeroes[w*16+g]) {
 670                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 671                 continue;
 672             }
 673             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2(uplims[w*16+g]/minthr)*4,59);
 674         }
 675     }
 676
 677     if (!allz)
 678         return;
 679     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 680     //perform two-loop search
 681     //outer loop - improve quality
 682     do {
 683         int tbits, qstep;
 684         minscaler = sce->sf_idx[0];
 685         //inner loop - quantize spectrum to fit into given number of bits
 686         qstep = its ? 1 : 32;
 687         do {
 688             int prev = -1;
 689             tbits = 0;
 690             fflag = 0;
 691             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 692                 start = w*128;
 693                 for (g = 0;  g < sce->ics.num_swb; g++) {
 694                     const float *coefs = sce->coeffs + start;
 695                     const float *scaled = s->scoefs + start;
 696                     int bits = 0;
 697                     int cb;
 698                     float mindist = INFINITY;
 699                     int minbits = 0;
 700
 701                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
 702                         start += sce->ics.swb_sizes[g];
 703                         continue;
 704                     }
 705                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 706                     {
 707                         float dist = 0.0f;
 708                         int bb = 0;
 709                         cb = find_min_book(find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled), sce->sf_idx[w*16+g]);
 710                         sce->band_type[w*16+g] = cb;
 711                         for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 712                             int b;
 713                             dist += quantize_band_cost(s, coefs + w2*128,
 714                                                        scaled + w2*128,
 715                                                        sce->ics.swb_sizes[g],
 716                                                        sce->sf_idx[w*16+g],
 717                                                        cb,
 718                                                        lambda,
 719                                                        INFINITY,
 720                                                        &b);
 721                             bb += b;
 722                         }
 723                             mindist = dist;
 724                             minbits = bb;
 725                     }
 726                     dists[w*16+g] = (mindist - minbits) / lambda;
 727                     bits = minbits;
 728                     if (prev != -1) {
 729                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 730                     }
 731                     tbits += bits;
 732                     start += sce->ics.swb_sizes[g];
 733                     prev = sce->sf_idx[w*16+g];
 734                 }
 735             }
 736             if (tbits > destbits) {
 737                 for (i = 0; i < 128; i++)
 738                     if (sce->sf_idx[i] < 218 - qstep)
 739                         sce->sf_idx[i] += qstep;
 740             } else {
 741                 for (i = 0; i < 128; i++)
 742                     if (sce->sf_idx[i] > 60 - qstep)
 743                         sce->sf_idx[i] -= qstep;
 744             }
 745             qstep >>= 1;
 746             if (!qstep && tbits > destbits*1.02)
 747                 qstep = 1;
 748             if (sce->sf_idx[0] >= 217)
 749                 break;
 750         } while (qstep);
 751
 752         fflag = 0;
 753         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 754         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 755             start = w*128;
 756             for (g = 0; g < sce->ics.num_swb; g++) {
 757                 int prevsc = sce->sf_idx[w*16+g];
 758                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60)
 759                     sce->sf_idx[w*16+g]--;
 760                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 761                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 762                 if (sce->sf_idx[w*16+g] != prevsc)
 763                     fflag = 1;
 764             }
 765         }
 766         its++;
 767     } while (fflag && its < 10);
 768 }
 769
 770 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 771                                        SingleChannelElement *sce,
 772                                        const float lambda)
 773 {
 774     int start = 0, i, w, w2, g;
 775     float uplim[128], maxq[128];
 776     int minq, maxsf;
 777     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 778     int last = 0, lastband = 0, curband = 0;
 779     float avg_energy = 0.0;
 780     if (sce->ics.num_windows == 1) {
 781         start = 0;
 782         for (i = 0; i < 1024; i++) {
 783             if (i - start >= sce->ics.swb_sizes[curband]) {
 784                 start += sce->ics.swb_sizes[curband];
 785                 curband++;
 786             }
 787             if (sce->coeffs[i]) {
 788                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 789                 last = i;
 790                 lastband = curband;
 791             }
 792         }
 793     } else {
 794         for (w = 0; w < 8; w++) {
 795             const float *coeffs = sce->coeffs + w*128;
 796             start = 0;
 797             for (i = 0; i < 128; i++) {
 798                 if (i - start >= sce->ics.swb_sizes[curband]) {
 799                     start += sce->ics.swb_sizes[curband];
 800                     curband++;
 801                 }
 802                 if (coeffs[i]) {
 803                     avg_energy += coeffs[i] * coeffs[i];
 804                     last = FFMAX(last, i);
 805                     lastband = FFMAX(lastband, curband);
 806                 }
 807             }
 808         }
 809     }
 810     last++;
 811     avg_energy /= last;
 812     if (avg_energy == 0.0f) {
 813         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
 814             sce->sf_idx[i] = SCALE_ONE_POS;
 815         return;
 816     }
 817     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 818         start = w*128;
 819         for (g = 0; g < sce->ics.num_swb; g++) {
 820             float *coefs   = sce->coeffs + start;
 821             const int size = sce->ics.swb_sizes[g];
 822             int start2 = start, end2 = start + size, peakpos = start;
 823             float maxval = -1, thr = 0.0f, t;
 824             maxq[w*16+g] = 0.0f;
 825             if (g > lastband) {
 826                 maxq[w*16+g] = 0.0f;
 827                 start += size;
 828                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
 829                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
 830                 continue;
 831             }
 832             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 833                 for (i = 0; i < size; i++) {
 834                     float t = coefs[w2*128+i]*coefs[w2*128+i];
 835                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
 836                     thr += t;
 837                     if (sce->ics.num_windows == 1 && maxval < t) {
 838                         maxval  = t;
 839                         peakpos = start+i;
 840                     }
 841                 }
 842             }
 843             if (sce->ics.num_windows == 1) {
 844                 start2 = FFMAX(peakpos - 2, start2);
 845                 end2   = FFMIN(peakpos + 3, end2);
 846             } else {
 847                 start2 -= start;
 848                 end2   -= start;
 849             }
 850             start += size;
 851             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
 852             t   = 1.0 - (1.0 * start2 / last);
 853             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
 854         }
 855     }
 856     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 857     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 858     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 859         start = w*128;
 860         for (g = 0;  g < sce->ics.num_swb; g++) {
 861             const float *coefs  = sce->coeffs + start;
 862             const float *scaled = s->scoefs   + start;
 863             const int size      = sce->ics.swb_sizes[g];
 864             int scf, prev_scf, step;
 865             int min_scf = -1, max_scf = 256;
 866             float curdiff;
 867             if (maxq[w*16+g] < 21.544) {
 868                 sce->zeroes[w*16+g] = 1;
 869                 start += size;
 870                 continue;
 871             }
 872             sce->zeroes[w*16+g] = 0;
 873             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2(1/maxq[w*16+g])*16/3, 60, 218);
 874             step = 16;
 875             for (;;) {
 876                 float dist = 0.0f;
 877                 int quant_max;
 878
 879                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 880                     int b;
 881                     dist += quantize_band_cost(s, coefs + w2*128,
 882                                                scaled + w2*128,
 883                                                sce->ics.swb_sizes[g],
 884                                                scf,
 885                                                ESC_BT,
 886                                                lambda,
 887                                                INFINITY,
 888                                                &b);
 889                     dist -= b;
 890                 }
 891                 dist *= 1.0f / 512.0f / lambda;
 892                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[200 - scf + SCALE_ONE_POS - SCALE_DIV_512]);
 893                 if (quant_max >= 8191) { // too much, return to the previous quantizer
 894                     sce->sf_idx[w*16+g] = prev_scf;
 895                     break;
 896                 }
 897                 prev_scf = scf;
 898                 curdiff = fabsf(dist - uplim[w*16+g]);
 899                 if (curdiff <= 1.0f)
 900                     step = 0;
 901                 else
 902                     step = log2(curdiff);
 903                 if (dist > uplim[w*16+g])
 904                     step = -step;
 905                 scf += step;
 906                 scf = av_clip_uint8(scf);
 907                 step = scf - prev_scf;
 908                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
 909                     sce->sf_idx[w*16+g] = av_clip(scf, min_scf, max_scf);
 910                     break;
 911                 }
 912                 if (step > 0)
 913                     min_scf = prev_scf;
 914                 else
 915                     max_scf = prev_scf;
 916             }
 917             start += size;
 918         }
 919     }
 920     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
 921     for (i = 1; i < 128; i++) {
 922         if (!sce->sf_idx[i])
 923             sce->sf_idx[i] = sce->sf_idx[i-1];
 924         else
 925             minq = FFMIN(minq, sce->sf_idx[i]);
 926     }
 927     if (minq == INT_MAX)
 928         minq = 0;
 929     minq = FFMIN(minq, SCALE_MAX_POS);
 930     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
 931     for (i = 126; i >= 0; i--) {
 932         if (!sce->sf_idx[i])
 933             sce->sf_idx[i] = sce->sf_idx[i+1];
 934         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
 935     }
 936 }
 937
 938 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
 939                                        SingleChannelElement *sce,
 940                                        const float lambda)
 941 {
 942     int start = 0, i, w, w2, g;
 943     int minq = 255;
 944
 945     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 946     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 947         start = w*128;
 948         for (g = 0; g < sce->ics.num_swb; g++) {
 949             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 950                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 951                 if (band->energy <= band->threshold) {
 952                     sce->sf_idx[(w+w2)*16+g] = 218;
 953                     sce->zeroes[(w+w2)*16+g] = 1;
 954                 } else {
 955                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2(band->threshold), 80, 218);
 956                     sce->zeroes[(w+w2)*16+g] = 0;
 957                 }
 958                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
 959             }
 960         }
 961     }
 962     for (i = 0; i < 128; i++) {
 963         sce->sf_idx[i] = 140;
 964         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
 965     }
 966     //set the same quantizers inside window groups
 967     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 968         for (g = 0;  g < sce->ics.num_swb; g++)
 969             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 970                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 971 }
 972
 973 static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
 974                           const float lambda)
 975 {
 976     int start = 0, i, w, w2, g;
 977     float M[128], S[128];
 978     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
 979     SingleChannelElement *sce0 = &cpe->ch[0];
 980     SingleChannelElement *sce1 = &cpe->ch[1];
 981     if (!cpe->common_window)
 982         return;
 983     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 984         for (g = 0;  g < sce0->ics.num_swb; g++) {
 985             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
 986                 float dist1 = 0.0f, dist2 = 0.0f;
 987                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 988                     FFPsyBand *band0 = &s->psy.psy_bands[(s->cur_channel+0)*PSY_MAX_BANDS+(w+w2)*16+g];
 989                     FFPsyBand *band1 = &s->psy.psy_bands[(s->cur_channel+1)*PSY_MAX_BANDS+(w+w2)*16+g];
 990                     float minthr = FFMIN(band0->threshold, band1->threshold);
 991                     float maxthr = FFMAX(band0->threshold, band1->threshold);
 992                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 993                         M[i] = (sce0->coeffs[start+w2*128+i]
 994                               + sce1->coeffs[start+w2*128+i]) * 0.5;
 995                         S[i] =  sce0->coeffs[start+w2*128+i]
 996                               - sce1->coeffs[start+w2*128+i];
 997                     }
 998                     abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 999                     abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
1000                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
1001                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
1002                     dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
1003                                                 L34,
1004                                                 sce0->ics.swb_sizes[g],
1005                                                 sce0->sf_idx[(w+w2)*16+g],
1006                                                 sce0->band_type[(w+w2)*16+g],
1007                                                 lambda / band0->threshold, INFINITY, NULL);
1008                     dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
1009                                                 R34,
1010                                                 sce1->ics.swb_sizes[g],
1011                                                 sce1->sf_idx[(w+w2)*16+g],
1012                                                 sce1->band_type[(w+w2)*16+g],
1013                                                 lambda / band1->threshold, INFINITY, NULL);
1014                     dist2 += quantize_band_cost(s, M,
1015                                                 M34,
1016                                                 sce0->ics.swb_sizes[g],
1017                                                 sce0->sf_idx[(w+w2)*16+g],
1018                                                 sce0->band_type[(w+w2)*16+g],
1019                                                 lambda / maxthr, INFINITY, NULL);
1020                     dist2 += quantize_band_cost(s, S,
1021                                                 S34,
1022                                                 sce1->ics.swb_sizes[g],
1023                                                 sce1->sf_idx[(w+w2)*16+g],
1024                                                 sce1->band_type[(w+w2)*16+g],
1025                                                 lambda / minthr, INFINITY, NULL);
1026                 }
1027                 cpe->ms_mask[w*16+g] = dist2 < dist1;
1028             }
1029             start += sce0->ics.swb_sizes[g];
1030         }
1031     }
1032 }
1033
1034 AACCoefficientsEncoder ff_aac_coders[] = {
1035     {
1036         search_for_quantizers_faac,
1037         encode_window_bands_info,
1038         quantize_and_encode_band,
1039         search_for_ms,
1040     },
1041     {
1042         search_for_quantizers_anmr,
1043         encode_window_bands_info,
1044         quantize_and_encode_band,
1045         search_for_ms,
1046     },
1047     {
1048         search_for_quantizers_twoloop,
1049         codebook_trellis_rate,
1050         quantize_and_encode_band,
1051         search_for_ms,
1052     },
1053     {
1054         search_for_quantizers_fast,
1055         encode_window_bands_info,
1056         quantize_and_encode_band,
1057         search_for_ms,
1058     },
1059 };