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 libavcodec/aaccoder.c
  24  * AAC coefficients encoder
  25  */
  26
  27 /***********************************
  28  *              TODOs:
  29  * speedup quantizer selection
  30  * add sane pulse detection
  31  ***********************************/
  32
  33 #include "avcodec.h"
  34 #include "put_bits.h"
  35 #include "aac.h"
  36 #include "aacenc.h"
  37 #include "aactab.h"
  38
  39 /** bits needed to code codebook run value for long windows */
  40 static const uint8_t run_value_bits_long[64] = {
  41      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,
  42      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5, 10,
  43     10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
  44     10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 15
  45 };
  46
  47 /** bits needed to code codebook run value for short windows */
  48 static const uint8_t run_value_bits_short[16] = {
  49     3, 3, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6, 6, 6, 9
  50 };
  51
  52 static const uint8_t *run_value_bits[2] = {
  53     run_value_bits_long, run_value_bits_short
  54 };
  55
  56
  57 /**
  58  * Quantize one coefficient.
  59  * @return absolute value of the quantized coefficient
  60  * @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
  61  */
  62 static av_always_inline int quant(float coef, const float Q)
  63 {
  64     float a = coef * Q;
  65     return sqrtf(a * sqrtf(a)) + 0.4054;
  66 }
  67
  68 static void quantize_bands(int (*out)[2], const float *in, const float *scaled,
  69                            int size, float Q34, int is_signed, int maxval)
  70 {
  71     int i;
  72     double qc;
  73     for (i = 0; i < size; i++) {
  74         qc = scaled[i] * Q34;
  75         out[i][0] = (int)FFMIN(qc,          (double)maxval);
  76         out[i][1] = (int)FFMIN(qc + 0.4054, (double)maxval);
  77         if (is_signed && in[i] < 0.0f) {
  78             out[i][0] = -out[i][0];
  79             out[i][1] = -out[i][1];
  80         }
  81     }
  82 }
  83
  84 static void abs_pow34_v(float *out, const float *in, const int size)
  85 {
  86 #ifndef USE_REALLY_FULL_SEARCH
  87     int i;
  88     for (i = 0; i < size; i++) {
  89         float a = fabsf(in[i]);
  90         out[i] = sqrtf(a * sqrtf(a));
  91     }
  92 #endif /* USE_REALLY_FULL_SEARCH */
  93 }
  94
  95 static const uint8_t aac_cb_range [12] = {0, 3, 3, 3, 3, 9, 9, 8, 8, 13, 13, 17};
  96 static const uint8_t aac_cb_maxval[12] = {0, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 16};
  97
  98 /**
  99  * Calculate rate distortion cost for quantizing with given codebook
 100  *
 101  * @return quantization distortion
 102  */
 103 static float quantize_band_cost(struct AACEncContext *s, const float *in,
 104                                 const float *scaled, int size, int scale_idx,
 105                                 int cb, const float lambda, const float uplim,
 106                                 int *bits)
 107 {
 108     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 109     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
 110     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 111     int i, j, k;
 112     float cost = 0;
 113     const int dim = cb < FIRST_PAIR_BT ? 4 : 2;
 114     int resbits = 0;
 115 #ifndef USE_REALLY_FULL_SEARCH
 116     const float  Q34 = sqrtf(Q * sqrtf(Q));
 117     const int range  = aac_cb_range[cb];
 118     const int maxval = aac_cb_maxval[cb];
 119     int offs[4];
 120 #endif /* USE_REALLY_FULL_SEARCH */
 121
 122     if (!cb) {
 123         for (i = 0; i < size; i++)
 124             cost += in[i]*in[i];
 125         if (bits)
 126             *bits = 0;
 127         return cost * lambda;
 128     }
 129 #ifndef USE_REALLY_FULL_SEARCH
 130     offs[0] = 1;
 131     for (i = 1; i < dim; i++)
 132         offs[i] = offs[i-1]*range;
 133     quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
 134 #endif /* USE_REALLY_FULL_SEARCH */
 135     for (i = 0; i < size; i += dim) {
 136         float mincost;
 137         int minidx  = 0;
 138         int minbits = 0;
 139         const float *vec;
 140 #ifndef USE_REALLY_FULL_SEARCH
 141         int (*quants)[2] = &s->qcoefs[i];
 142         mincost = 0.0f;
 143         for (j = 0; j < dim; j++)
 144             mincost += in[i+j]*in[i+j];
 145         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 146         minbits = ff_aac_spectral_bits[cb-1][minidx];
 147         mincost = mincost * lambda + minbits;
 148         for (j = 0; j < (1<<dim); j++) {
 149             float rd = 0.0f;
 150             int curbits;
 151             int curidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 152             int same   = 0;
 153             for (k = 0; k < dim; k++) {
 154                 if ((j & (1 << k)) && quants[k][0] == quants[k][1]) {
 155                     same = 1;
 156                     break;
 157                 }
 158             }
 159             if (same)
 160                 continue;
 161             for (k = 0; k < dim; k++)
 162                 curidx += quants[k][!!(j & (1 << k))] * offs[dim - 1 - k];
 163             curbits =  ff_aac_spectral_bits[cb-1][curidx];
 164             vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 165 #else
 166         mincost = INFINITY;
 167         vec = ff_aac_codebook_vectors[cb-1];
 168         for (j = 0; j < ff_aac_spectral_sizes[cb-1]; j++, vec += dim) {
 169             float rd = 0.0f;
 170             int curbits = ff_aac_spectral_bits[cb-1][j];
 171 #endif /* USE_REALLY_FULL_SEARCH */
 172             if (IS_CODEBOOK_UNSIGNED(cb)) {
 173                 for (k = 0; k < dim; k++) {
 174                     float t = fabsf(in[i+k]);
 175                     float di;
 176                     if (vec[k] == 64.0f) { //FIXME: slow
 177                         //do not code with escape sequence small values
 178                         if (t < 39.0f*IQ) {
 179                             rd = INFINITY;
 180                             break;
 181                         }
 182                         if (t >= CLIPPED_ESCAPE) {
 183                             di = t - CLIPPED_ESCAPE;
 184                             curbits += 21;
 185                         } else {
 186                             int c = av_clip(quant(t, Q), 0, 8191);
 187                             di = t - c*cbrtf(c)*IQ;
 188                             curbits += av_log2(c)*2 - 4 + 1;
 189                         }
 190                     } else {
 191                         di = t - vec[k]*IQ;
 192                     }
 193                     if (vec[k] != 0.0f)
 194                         curbits++;
 195                     rd += di*di;
 196                 }
 197             } else {
 198                 for (k = 0; k < dim; k++) {
 199                     float di = in[i+k] - vec[k]*IQ;
 200                     rd += di*di;
 201                 }
 202             }
 203             rd = rd * lambda + curbits;
 204             if (rd < mincost) {
 205                 mincost = rd;
 206                 minidx  = j;
 207                 minbits = curbits;
 208             }
 209         }
 210         cost    += mincost;
 211         resbits += minbits;
 212         if (cost >= uplim)
 213             return uplim;
 214     }
 215
 216     if (bits)
 217         *bits = resbits;
 218     return cost;
 219 }
 220
 221 static void quantize_and_encode_band(struct AACEncContext *s, PutBitContext *pb,
 222                                      const float *in, int size, int scale_idx,
 223                                      int cb, const float lambda)
 224 {
 225     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
 226     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
 227     const float CLIPPED_ESCAPE = 165140.0f*IQ;
 228     const int dim = (cb < FIRST_PAIR_BT) ? 4 : 2;
 229     int i, j, k;
 230 #ifndef USE_REALLY_FULL_SEARCH
 231     const float  Q34 = sqrtf(Q * sqrtf(Q));
 232     const int range  = aac_cb_range[cb];
 233     const int maxval = aac_cb_maxval[cb];
 234     int offs[4];
 235     float *scaled = s->scoefs;
 236 #endif /* USE_REALLY_FULL_SEARCH */
 237
 238 //START_TIMER
 239     if (!cb)
 240         return;
 241
 242 #ifndef USE_REALLY_FULL_SEARCH
 243     offs[0] = 1;
 244     for (i = 1; i < dim; i++)
 245         offs[i] = offs[i-1]*range;
 246     abs_pow34_v(scaled, in, size);
 247     quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
 248 #endif /* USE_REALLY_FULL_SEARCH */
 249     for (i = 0; i < size; i += dim) {
 250         float mincost;
 251         int minidx  = 0;
 252         int minbits = 0;
 253         const float *vec;
 254 #ifndef USE_REALLY_FULL_SEARCH
 255         int (*quants)[2] = &s->qcoefs[i];
 256         mincost = 0.0f;
 257         for (j = 0; j < dim; j++)
 258             mincost += in[i+j]*in[i+j];
 259         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 260         minbits = ff_aac_spectral_bits[cb-1][minidx];
 261         mincost = mincost * lambda + minbits;
 262         for (j = 0; j < (1<<dim); j++) {
 263             float rd = 0.0f;
 264             int curbits;
 265             int curidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
 266             int same   = 0;
 267             for (k = 0; k < dim; k++) {
 268                 if ((j & (1 << k)) && quants[k][0] == quants[k][1]) {
 269                     same = 1;
 270                     break;
 271                 }
 272             }
 273             if (same)
 274                 continue;
 275             for (k = 0; k < dim; k++)
 276                 curidx += quants[k][!!(j & (1 << k))] * offs[dim - 1 - k];
 277             curbits =  ff_aac_spectral_bits[cb-1][curidx];
 278             vec     = &ff_aac_codebook_vectors[cb-1][curidx*dim];
 279 #else
 280         vec = ff_aac_codebook_vectors[cb-1];
 281         mincost = INFINITY;
 282         for (j = 0; j < ff_aac_spectral_sizes[cb-1]; j++, vec += dim) {
 283             float rd = 0.0f;
 284             int curbits = ff_aac_spectral_bits[cb-1][j];
 285             int curidx  = j;
 286 #endif /* USE_REALLY_FULL_SEARCH */
 287             if (IS_CODEBOOK_UNSIGNED(cb)) {
 288                 for (k = 0; k < dim; k++) {
 289                     float t = fabsf(in[i+k]);
 290                     float di;
 291                     if (vec[k] == 64.0f) { //FIXME: slow
 292                         //do not code with escape sequence small values
 293                         if (t < 39.0f*IQ) {
 294                             rd = INFINITY;
 295                             break;
 296                         }
 297                         if (t >= CLIPPED_ESCAPE) {
 298                             di = t - CLIPPED_ESCAPE;
 299                             curbits += 21;
 300                         } else {
 301                             int c = av_clip(quant(t, Q), 0, 8191);
 302                             di = t - c*cbrtf(c)*IQ;
 303                             curbits += av_log2(c)*2 - 4 + 1;
 304                         }
 305                     } else {
 306                         di = t - vec[k]*IQ;
 307                     }
 308                     if (vec[k] != 0.0f)
 309                         curbits++;
 310                     rd += di*di;
 311                 }
 312             } else {
 313                 for (k = 0; k < dim; k++) {
 314                     float di = in[i+k] - vec[k]*IQ;
 315                     rd += di*di;
 316                 }
 317             }
 318             rd = rd * lambda + curbits;
 319             if (rd < mincost) {
 320                 mincost = rd;
 321                 minidx  = curidx;
 322                 minbits = curbits;
 323             }
 324         }
 325         put_bits(pb, ff_aac_spectral_bits[cb-1][minidx], ff_aac_spectral_codes[cb-1][minidx]);
 326         if (IS_CODEBOOK_UNSIGNED(cb))
 327             for (j = 0; j < dim; j++)
 328                 if (ff_aac_codebook_vectors[cb-1][minidx*dim+j] != 0.0f)
 329                     put_bits(pb, 1, in[i+j] < 0.0f);
 330         if (cb == ESC_BT) {
 331             for (j = 0; j < 2; j++) {
 332                 if (ff_aac_codebook_vectors[cb-1][minidx*2+j] == 64.0f) {
 333                     int coef = av_clip(quant(fabsf(in[i+j]), Q), 0, 8191);
 334                     int len = av_log2(coef);
 335
 336                     put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
 337                     put_bits(pb, len, coef & ((1 << len) - 1));
 338                 }
 339             }
 340         }
 341     }
 342 //STOP_TIMER("quantize_and_encode")
 343 }
 344
 345 /**
 346  * structure used in optimal codebook search
 347  */
 348 typedef struct BandCodingPath {
 349     int prev_idx; ///< pointer to the previous path point
 350     float cost;   ///< path cost
 351     int run;
 352 } BandCodingPath;
 353
 354 /**
 355  * Encode band info for single window group bands.
 356  */
 357 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
 358                                      int win, int group_len, const float lambda)
 359 {
 360     BandCodingPath path[120][12];
 361     int w, swb, cb, start, start2, size;
 362     int i, j;
 363     const int max_sfb  = sce->ics.max_sfb;
 364     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
 365     const int run_esc  = (1 << run_bits) - 1;
 366     int idx, ppos, count;
 367     int stackrun[120], stackcb[120], stack_len;
 368     float next_minrd = INFINITY;
 369     int next_mincb = 0;
 370
 371     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 372     start = win*128;
 373     for (cb = 0; cb < 12; cb++) {
 374         path[0][cb].cost     = 0.0f;
 375         path[0][cb].prev_idx = -1;
 376         path[0][cb].run      = 0;
 377     }
 378     for (swb = 0; swb < max_sfb; swb++) {
 379         start2 = start;
 380         size = sce->ics.swb_sizes[swb];
 381         if (sce->zeroes[win*16 + swb]) {
 382             for (cb = 0; cb < 12; cb++) {
 383                 path[swb+1][cb].prev_idx = cb;
 384                 path[swb+1][cb].cost     = path[swb][cb].cost;
 385                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 386             }
 387         } else {
 388             float minrd = next_minrd;
 389             int mincb = next_mincb;
 390             next_minrd = INFINITY;
 391             next_mincb = 0;
 392             for (cb = 0; cb < 12; cb++) {
 393                 float cost_stay_here, cost_get_here;
 394                 float rd = 0.0f;
 395                 for (w = 0; w < group_len; w++) {
 396                     FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(win+w)*16+swb];
 397                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
 398                                              s->scoefs + start + w*128, size,
 399                                              sce->sf_idx[(win+w)*16+swb], cb,
 400                                              lambda / band->threshold, INFINITY, NULL);
 401                 }
 402                 cost_stay_here = path[swb][cb].cost + rd;
 403                 cost_get_here  = minrd              + rd + run_bits + 4;
 404                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 405                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 406                     cost_stay_here += run_bits;
 407                 if (cost_get_here < cost_stay_here) {
 408                     path[swb+1][cb].prev_idx = mincb;
 409                     path[swb+1][cb].cost     = cost_get_here;
 410                     path[swb+1][cb].run      = 1;
 411                 } else {
 412                     path[swb+1][cb].prev_idx = cb;
 413                     path[swb+1][cb].cost     = cost_stay_here;
 414                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 415                 }
 416                 if (path[swb+1][cb].cost < next_minrd) {
 417                     next_minrd = path[swb+1][cb].cost;
 418                     next_mincb = cb;
 419                 }
 420             }
 421         }
 422         start += sce->ics.swb_sizes[swb];
 423     }
 424
 425     //convert resulting path from backward-linked list
 426     stack_len = 0;
 427     idx       = 0;
 428     for (cb = 1; cb < 12; cb++)
 429         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 430             idx = cb;
 431     ppos = max_sfb;
 432     while (ppos > 0) {
 433         cb = idx;
 434         stackrun[stack_len] = path[ppos][cb].run;
 435         stackcb [stack_len] = cb;
 436         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 437         ppos -= path[ppos][cb].run;
 438         stack_len++;
 439     }
 440     //perform actual band info encoding
 441     start = 0;
 442     for (i = stack_len - 1; i >= 0; i--) {
 443         put_bits(&s->pb, 4, stackcb[i]);
 444         count = stackrun[i];
 445         memset(sce->zeroes + win*16 + start, !stackcb[i], count);
 446         //XXX: memset when band_type is also uint8_t
 447         for (j = 0; j < count; j++) {
 448             sce->band_type[win*16 + start] =  stackcb[i];
 449             start++;
 450         }
 451         while (count >= run_esc) {
 452             put_bits(&s->pb, run_bits, run_esc);
 453             count -= run_esc;
 454         }
 455         put_bits(&s->pb, run_bits, count);
 456     }
 457 }
 458
 459 typedef struct TrellisPath {
 460     float cost;
 461     int prev;
 462     int min_val;
 463     int max_val;
 464 } TrellisPath;
 465
 466 #define TRELLIS_STAGES 121
 467 #define TRELLIS_STATES 256
 468
 469 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 470                                        SingleChannelElement *sce,
 471                                        const float lambda)
 472 {
 473     int q, w, w2, g, start = 0;
 474     int i, j;
 475     int idx;
 476     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];
 477     int bandaddr[TRELLIS_STAGES];
 478     int minq;
 479     float mincost;
 480
 481     for (i = 0; i < TRELLIS_STATES; i++) {
 482         paths[0][i].cost    = 0.0f;
 483         paths[0][i].prev    = -1;
 484         paths[0][i].min_val = i;
 485         paths[0][i].max_val = i;
 486     }
 487     for (j = 1; j < TRELLIS_STAGES; j++) {
 488         for (i = 0; i < TRELLIS_STATES; i++) {
 489             paths[j][i].cost    = INFINITY;
 490             paths[j][i].prev    = -2;
 491             paths[j][i].min_val = INT_MAX;
 492             paths[j][i].max_val = 0;
 493         }
 494     }
 495     idx = 1;
 496     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 497     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 498         start = w*128;
 499         for (g = 0; g < sce->ics.num_swb; g++) {
 500             const float *coefs = sce->coeffs + start;
 501             float qmin, qmax;
 502             int nz = 0;
 503
 504             bandaddr[idx] = w * 16 + g;
 505             qmin = INT_MAX;
 506             qmax = 0.0f;
 507             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 508                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 509                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 510                     sce->zeroes[(w+w2)*16+g] = 1;
 511                     continue;
 512                 }
 513                 sce->zeroes[(w+w2)*16+g] = 0;
 514                 nz = 1;
 515                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 516                     float t = fabsf(coefs[w2*128+i]);
 517                     if (t > 0.0f)
 518                         qmin = FFMIN(qmin, t);
 519                     qmax = FFMAX(qmax, t);
 520                 }
 521             }
 522             if (nz) {
 523                 int minscale, maxscale;
 524                 float minrd = INFINITY;
 525                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 526                 minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
 527                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 528                 maxscale = av_clip_uint8(log2(qmax)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
 529                 for (q = minscale; q < maxscale; q++) {
 530                     float dists[12], dist;
 531                     memset(dists, 0, sizeof(dists));
 532                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 533                         FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 534                         int cb;
 535                         for (cb = 0; cb <= ESC_BT; cb++)
 536                             dists[cb] += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 537                                                             q, cb, lambda / band->threshold, INFINITY, NULL);
 538                     }
 539                     dist = dists[0];
 540                     for (i = 1; i <= ESC_BT; i++)
 541                         dist = FFMIN(dist, dists[i]);
 542                     minrd = FFMIN(minrd, dist);
 543
 544                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, TRELLIS_STATES); i++) {
 545                         float cost;
 546                         int minv, maxv;
 547                         if (isinf(paths[idx - 1][i].cost))
 548                             continue;
 549                         cost = paths[idx - 1][i].cost + dist
 550                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 551                         minv = FFMIN(paths[idx - 1][i].min_val, q);
 552                         maxv = FFMAX(paths[idx - 1][i].max_val, q);
 553                         if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
 554                             paths[idx][q].cost    = cost;
 555                             paths[idx][q].prev    = i;
 556                             paths[idx][q].min_val = minv;
 557                             paths[idx][q].max_val = maxv;
 558                         }
 559                     }
 560                 }
 561             } else {
 562                 for (q = 0; q < TRELLIS_STATES; q++) {
 563                     if (!isinf(paths[idx - 1][q].cost)) {
 564                         paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 565                         paths[idx][q].prev = q;
 566                         paths[idx][q].min_val = FFMIN(paths[idx - 1][q].min_val, q);
 567                         paths[idx][q].max_val = FFMAX(paths[idx - 1][q].max_val, q);
 568                         continue;
 569                     }
 570                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, TRELLIS_STATES); i++) {
 571                         float cost;
 572                         int minv, maxv;
 573                         if (isinf(paths[idx - 1][i].cost))
 574                             continue;
 575                         cost = paths[idx - 1][i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 576                         minv = FFMIN(paths[idx - 1][i].min_val, q);
 577                         maxv = FFMAX(paths[idx - 1][i].max_val, q);
 578                         if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
 579                             paths[idx][q].cost    = cost;
 580                             paths[idx][q].prev    = i;
 581                             paths[idx][q].min_val = minv;
 582                             paths[idx][q].max_val = maxv;
 583                         }
 584                     }
 585                 }
 586             }
 587             sce->zeroes[w*16+g] = !nz;
 588             start += sce->ics.swb_sizes[g];
 589             idx++;
 590         }
 591     }
 592     idx--;
 593     mincost = paths[idx][0].cost;
 594     minq    = 0;
 595     for (i = 1; i < TRELLIS_STATES; i++) {
 596         if (paths[idx][i].cost < mincost) {
 597             mincost = paths[idx][i].cost;
 598             minq = i;
 599         }
 600     }
 601     while (idx) {
 602         sce->sf_idx[bandaddr[idx]] = minq;
 603         minq = paths[idx][minq].prev;
 604         idx--;
 605     }
 606     //set the same quantizers inside window groups
 607     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 608         for (g = 0;  g < sce->ics.num_swb; g++)
 609             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 610                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 611 }
 612
 613 /**
 614  * two-loop quantizers search taken from ISO 13818-7 Appendix C
 615  */
 616 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
 617                                           AACEncContext *s,
 618                                           SingleChannelElement *sce,
 619                                           const float lambda)
 620 {
 621     int start = 0, i, w, w2, g;
 622     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels;
 623     float dists[128], uplims[128];
 624     int fflag, minscaler;
 625     int its  = 0;
 626     int allz = 0;
 627     float minthr = INFINITY;
 628
 629     //XXX: some heuristic to determine initial quantizers will reduce search time
 630     memset(dists, 0, sizeof(dists));
 631     //determine zero bands and upper limits
 632     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 633         for (g = 0;  g < sce->ics.num_swb; g++) {
 634             int nz = 0;
 635             float uplim = 0.0f;
 636             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 637                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 638                 uplim += band->threshold;
 639                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 640                     sce->zeroes[(w+w2)*16+g] = 1;
 641                     continue;
 642                 }
 643                 nz = 1;
 644             }
 645             uplims[w*16+g] = uplim *512;
 646             sce->zeroes[w*16+g] = !nz;
 647             if (nz)
 648                 minthr = FFMIN(minthr, uplim);
 649             allz = FFMAX(allz, nz);
 650         }
 651     }
 652     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 653         for (g = 0;  g < sce->ics.num_swb; g++) {
 654             if (sce->zeroes[w*16+g]) {
 655                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 656                 continue;
 657             }
 658             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2(uplims[w*16+g]/minthr)*4,59);
 659         }
 660     }
 661
 662     if (!allz)
 663         return;
 664     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 665     //perform two-loop search
 666     //outer loop - improve quality
 667     do {
 668         int tbits, qstep;
 669         minscaler = sce->sf_idx[0];
 670         //inner loop - quantize spectrum to fit into given number of bits
 671         qstep = its ? 1 : 32;
 672         do {
 673             int prev = -1;
 674             tbits = 0;
 675             fflag = 0;
 676             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 677                 start = w*128;
 678                 for (g = 0;  g < sce->ics.num_swb; g++) {
 679                     const float *coefs = sce->coeffs + start;
 680                     const float *scaled = s->scoefs + start;
 681                     int bits = 0;
 682                     int cb;
 683                     float mindist = INFINITY;
 684                     int minbits = 0;
 685
 686                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
 687                         start += sce->ics.swb_sizes[g];
 688                         continue;
 689                     }
 690                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 691                     for (cb = 0; cb <= ESC_BT; cb++) {
 692                         float dist = 0.0f;
 693                         int bb = 0;
 694                         for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 695                             int b;
 696                             dist += quantize_band_cost(s, coefs + w2*128,
 697                                                        scaled + w2*128,
 698                                                        sce->ics.swb_sizes[g],
 699                                                        sce->sf_idx[w*16+g],
 700                                                        cb,
 701                                                        lambda,
 702                                                        INFINITY,
 703                                                        &b);
 704                             bb += b;
 705                         }
 706                         if (dist < mindist) {
 707                             mindist = dist;
 708                             minbits = bb;
 709                         }
 710                     }
 711                     dists[w*16+g] = (mindist - minbits) / lambda;
 712                     bits = minbits;
 713                     if (prev != -1) {
 714                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 715                     }
 716                     tbits += bits;
 717                     start += sce->ics.swb_sizes[g];
 718                     prev = sce->sf_idx[w*16+g];
 719                 }
 720             }
 721             if (tbits > destbits) {
 722                 for (i = 0; i < 128; i++)
 723                     if (sce->sf_idx[i] < 218 - qstep)
 724                         sce->sf_idx[i] += qstep;
 725             } else {
 726                 for (i = 0; i < 128; i++)
 727                     if (sce->sf_idx[i] > 60 - qstep)
 728                         sce->sf_idx[i] -= qstep;
 729             }
 730             qstep >>= 1;
 731             if (!qstep && tbits > destbits*1.02)
 732                 qstep = 1;
 733             if (sce->sf_idx[0] >= 217)
 734                 break;
 735         } while (qstep);
 736
 737         fflag = 0;
 738         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 739         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 740             start = w*128;
 741             for (g = 0; g < sce->ics.num_swb; g++) {
 742                 int prevsc = sce->sf_idx[w*16+g];
 743                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60)
 744                     sce->sf_idx[w*16+g]--;
 745                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 746                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 747                 if (sce->sf_idx[w*16+g] != prevsc)
 748                     fflag = 1;
 749             }
 750         }
 751         its++;
 752     } while (fflag && its < 10);
 753 }
 754
 755 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 756                                        SingleChannelElement *sce,
 757                                        const float lambda)
 758 {
 759     int start = 0, i, w, w2, g;
 760     float uplim[128], maxq[128];
 761     int minq, maxsf;
 762     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 763     int last = 0, lastband = 0, curband = 0;
 764     float avg_energy = 0.0;
 765     if (sce->ics.num_windows == 1) {
 766         start = 0;
 767         for (i = 0; i < 1024; i++) {
 768             if (i - start >= sce->ics.swb_sizes[curband]) {
 769                 start += sce->ics.swb_sizes[curband];
 770                 curband++;
 771             }
 772             if (sce->coeffs[i]) {
 773                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 774                 last = i;
 775                 lastband = curband;
 776             }
 777         }
 778     } else {
 779         for (w = 0; w < 8; w++) {
 780             const float *coeffs = sce->coeffs + w*128;
 781             start = 0;
 782             for (i = 0; i < 128; i++) {
 783                 if (i - start >= sce->ics.swb_sizes[curband]) {
 784                     start += sce->ics.swb_sizes[curband];
 785                     curband++;
 786                 }
 787                 if (coeffs[i]) {
 788                     avg_energy += coeffs[i] * coeffs[i];
 789                     last = FFMAX(last, i);
 790                     lastband = FFMAX(lastband, curband);
 791                 }
 792             }
 793         }
 794     }
 795     last++;
 796     avg_energy /= last;
 797     if (avg_energy == 0.0f) {
 798         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
 799             sce->sf_idx[i] = SCALE_ONE_POS;
 800         return;
 801     }
 802     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 803         start = w*128;
 804         for (g = 0; g < sce->ics.num_swb; g++) {
 805             float *coefs   = sce->coeffs + start;
 806             const int size = sce->ics.swb_sizes[g];
 807             int start2 = start, end2 = start + size, peakpos = start;
 808             float maxval = -1, thr = 0.0f, t;
 809             maxq[w*16+g] = 0.0f;
 810             if (g > lastband) {
 811                 maxq[w*16+g] = 0.0f;
 812                 start += size;
 813                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
 814                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
 815                 continue;
 816             }
 817             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 818                 for (i = 0; i < size; i++) {
 819                     float t = coefs[w2*128+i]*coefs[w2*128+i];
 820                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
 821                     thr += t;
 822                     if (sce->ics.num_windows == 1 && maxval < t) {
 823                         maxval  = t;
 824                         peakpos = start+i;
 825                     }
 826                 }
 827             }
 828             if (sce->ics.num_windows == 1) {
 829                 start2 = FFMAX(peakpos - 2, start2);
 830                 end2   = FFMIN(peakpos + 3, end2);
 831             } else {
 832                 start2 -= start;
 833                 end2   -= start;
 834             }
 835             start += size;
 836             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
 837             t   = 1.0 - (1.0 * start2 / last);
 838             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
 839         }
 840     }
 841     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 842     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 843     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 844         start = w*128;
 845         for (g = 0;  g < sce->ics.num_swb; g++) {
 846             const float *coefs  = sce->coeffs + start;
 847             const float *scaled = s->scoefs   + start;
 848             const int size      = sce->ics.swb_sizes[g];
 849             int scf, prev_scf, step;
 850             int min_scf = 0, max_scf = 255;
 851             float curdiff;
 852             if (maxq[w*16+g] < 21.544) {
 853                 sce->zeroes[w*16+g] = 1;
 854                 start += size;
 855                 continue;
 856             }
 857             sce->zeroes[w*16+g] = 0;
 858             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2(1/maxq[w*16+g])*16/3, 60, 218);
 859             step = 16;
 860             for (;;) {
 861                 float dist = 0.0f;
 862                 int quant_max;
 863
 864                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 865                     int b;
 866                     dist += quantize_band_cost(s, coefs + w2*128,
 867                                                scaled + w2*128,
 868                                                sce->ics.swb_sizes[g],
 869                                                scf,
 870                                                ESC_BT,
 871                                                lambda,
 872                                                INFINITY,
 873                                                &b);
 874                     dist -= b;
 875                 }
 876                 dist *= 1.0f / 512.0f / lambda;
 877                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[200 - scf + SCALE_ONE_POS - SCALE_DIV_512]);
 878                 if (quant_max >= 8191) { // too much, return to the previous quantizer
 879                     sce->sf_idx[w*16+g] = prev_scf;
 880                     break;
 881                 }
 882                 prev_scf = scf;
 883                 curdiff = fabsf(dist - uplim[w*16+g]);
 884                 if (curdiff == 0.0f)
 885                     step = 0;
 886                 else
 887                     step = fabsf(log2(curdiff));
 888                 if (dist > uplim[w*16+g])
 889                     step = -step;
 890                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
 891                     sce->sf_idx[w*16+g] = scf;
 892                     break;
 893                 }
 894                 scf += step;
 895                 if (step > 0)
 896                     min_scf = scf;
 897                 else
 898                     max_scf = scf;
 899             }
 900             start += size;
 901         }
 902     }
 903     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
 904     for (i = 1; i < 128; i++) {
 905         if (!sce->sf_idx[i])
 906             sce->sf_idx[i] = sce->sf_idx[i-1];
 907         else
 908             minq = FFMIN(minq, sce->sf_idx[i]);
 909     }
 910     if (minq == INT_MAX)
 911         minq = 0;
 912     minq = FFMIN(minq, SCALE_MAX_POS);
 913     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
 914     for (i = 126; i >= 0; i--) {
 915         if (!sce->sf_idx[i])
 916             sce->sf_idx[i] = sce->sf_idx[i+1];
 917         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
 918     }
 919 }
 920
 921 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
 922                                        SingleChannelElement *sce,
 923                                        const float lambda)
 924 {
 925     int start = 0, i, w, w2, g;
 926     int minq = 255;
 927
 928     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 929     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 930         start = w*128;
 931         for (g = 0; g < sce->ics.num_swb; g++) {
 932             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 933                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
 934                 if (band->energy <= band->threshold) {
 935                     sce->sf_idx[(w+w2)*16+g] = 218;
 936                     sce->zeroes[(w+w2)*16+g] = 1;
 937                 } else {
 938                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2(band->threshold), 80, 218);
 939                     sce->zeroes[(w+w2)*16+g] = 0;
 940                 }
 941                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
 942             }
 943         }
 944     }
 945     for (i = 0; i < 128; i++) {
 946         sce->sf_idx[i] = 140;
 947         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
 948     }
 949     //set the same quantizers inside window groups
 950     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 951         for (g = 0;  g < sce->ics.num_swb; g++)
 952             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 953                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 954 }
 955
 956 static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
 957                           const float lambda)
 958 {
 959     int start = 0, i, w, w2, g;
 960     float M[128], S[128];
 961     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
 962     SingleChannelElement *sce0 = &cpe->ch[0];
 963     SingleChannelElement *sce1 = &cpe->ch[1];
 964     if (!cpe->common_window)
 965         return;
 966     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 967         for (g = 0;  g < sce0->ics.num_swb; g++) {
 968             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
 969                 float dist1 = 0.0f, dist2 = 0.0f;
 970                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 971                     FFPsyBand *band0 = &s->psy.psy_bands[(s->cur_channel+0)*PSY_MAX_BANDS+(w+w2)*16+g];
 972                     FFPsyBand *band1 = &s->psy.psy_bands[(s->cur_channel+1)*PSY_MAX_BANDS+(w+w2)*16+g];
 973                     float minthr = FFMIN(band0->threshold, band1->threshold);
 974                     float maxthr = FFMAX(band0->threshold, band1->threshold);
 975                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 976                         M[i] = (sce0->coeffs[start+w2*128+i]
 977                               + sce1->coeffs[start+w2*128+i]) * 0.5;
 978                         S[i] =  sce0->coeffs[start+w2*128+i]
 979                               - sce1->coeffs[start+w2*128+i];
 980                     }
 981                     abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 982                     abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
 983                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
 984                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
 985                     dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
 986                                                 L34,
 987                                                 sce0->ics.swb_sizes[g],
 988                                                 sce0->sf_idx[(w+w2)*16+g],
 989                                                 sce0->band_type[(w+w2)*16+g],
 990                                                 lambda / band0->threshold, INFINITY, NULL);
 991                     dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
 992                                                 R34,
 993                                                 sce1->ics.swb_sizes[g],
 994                                                 sce1->sf_idx[(w+w2)*16+g],
 995                                                 sce1->band_type[(w+w2)*16+g],
 996                                                 lambda / band1->threshold, INFINITY, NULL);
 997                     dist2 += quantize_band_cost(s, M,
 998                                                 M34,
 999                                                 sce0->ics.swb_sizes[g],
1000                                                 sce0->sf_idx[(w+w2)*16+g],
1001                                                 sce0->band_type[(w+w2)*16+g],
1002                                                 lambda / maxthr, INFINITY, NULL);
1003                     dist2 += quantize_band_cost(s, S,
1004                                                 S34,
1005                                                 sce1->ics.swb_sizes[g],
1006                                                 sce1->sf_idx[(w+w2)*16+g],
1007                                                 sce1->band_type[(w+w2)*16+g],
1008                                                 lambda / minthr, INFINITY, NULL);
1009                 }
1010                 cpe->ms_mask[w*16+g] = dist2 < dist1;
1011             }
1012             start += sce0->ics.swb_sizes[g];
1013         }
1014     }
1015 }
1016
1017 AACCoefficientsEncoder ff_aac_coders[] = {
1018     {
1019         search_for_quantizers_faac,
1020         encode_window_bands_info,
1021         quantize_and_encode_band,
1022         search_for_ms,
1023     },
1024     {
1025         search_for_quantizers_anmr,
1026         encode_window_bands_info,
1027         quantize_and_encode_band,
1028         search_for_ms,
1029     },
1030     {
1031         search_for_quantizers_twoloop,
1032         encode_window_bands_info,
1033         quantize_and_encode_band,
1034         search_for_ms,
1035     },
1036     {
1037         search_for_quantizers_fast,
1038         encode_window_bands_info,
1039         quantize_and_encode_band,
1040         search_for_ms,
1041     },
1042 };