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 "libavutil/libm.h" // brought forward to work around cygwin header breakage
  34
  35 #include <float.h>
  36
  37 #include "libavutil/mathematics.h"
  38 #include "mathops.h"
  39 #include "avcodec.h"
  40 #include "put_bits.h"
  41 #include "aac.h"
  42 #include "aacenc.h"
  43 #include "aactab.h"
  44 #include "aacenctab.h"
  45 #include "aacenc_utils.h"
  46 #include "aacenc_quantization.h"
  47 #include "aac_tablegen_decl.h"
  48
  49 #include "aacenc_is.h"
  50 #include "aacenc_tns.h"
  51 #include "aacenc_pred.h"
  52
  53 #include "libavcodec/aaccoder_twoloop.h"
  54
  55 /* Parameter of f(x) = a*(lambda/100), defines the maximum fourier spread
  56  * beyond which no PNS is used (since the SFBs contain tone rather than noise) */
  57 #define NOISE_SPREAD_THRESHOLD 0.5073f
  58
  59 /* Parameter of f(x) = a*(100/lambda), defines how much PNS is allowed to
  60  * replace low energy non zero bands */
  61 #define NOISE_LAMBDA_REPLACE 1.948f
  62
  63 #include "libavcodec/aaccoder_trellis.h"
  64
  65 /**
  66  * structure used in optimal codebook search
  67  */
  68 typedef struct BandCodingPath {
  69     int prev_idx; ///< pointer to the previous path point
  70     float cost;   ///< path cost
  71     int run;
  72 } BandCodingPath;
  73
  74 /**
  75  * Encode band info for single window group bands.
  76  */
  77 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
  78                                      int win, int group_len, const float lambda)
  79 {
  80     BandCodingPath path[120][CB_TOT_ALL];
  81     int w, swb, cb, start, size;
  82     int i, j;
  83     const int max_sfb  = sce->ics.max_sfb;
  84     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
  85     const int run_esc  = (1 << run_bits) - 1;
  86     int idx, ppos, count;
  87     int stackrun[120], stackcb[120], stack_len;
  88     float next_minrd = INFINITY;
  89     int next_mincb = 0;
  90
  91     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
  92     start = win*128;
  93     for (cb = 0; cb < CB_TOT_ALL; cb++) {
  94         path[0][cb].cost     = 0.0f;
  95         path[0][cb].prev_idx = -1;
  96         path[0][cb].run      = 0;
  97     }
  98     for (swb = 0; swb < max_sfb; swb++) {
  99         size = sce->ics.swb_sizes[swb];
 100         if (sce->zeroes[win*16 + swb]) {
 101             for (cb = 0; cb < CB_TOT_ALL; cb++) {
 102                 path[swb+1][cb].prev_idx = cb;
 103                 path[swb+1][cb].cost     = path[swb][cb].cost;
 104                 path[swb+1][cb].run      = path[swb][cb].run + 1;
 105             }
 106         } else {
 107             float minrd = next_minrd;
 108             int mincb = next_mincb;
 109             next_minrd = INFINITY;
 110             next_mincb = 0;
 111             for (cb = 0; cb < CB_TOT_ALL; cb++) {
 112                 float cost_stay_here, cost_get_here;
 113                 float rd = 0.0f;
 114                 if (cb >= 12 && sce->band_type[win*16+swb] < aac_cb_out_map[cb] ||
 115                     cb  < aac_cb_in_map[sce->band_type[win*16+swb]] && sce->band_type[win*16+swb] > aac_cb_out_map[cb]) {
 116                     path[swb+1][cb].prev_idx = -1;
 117                     path[swb+1][cb].cost     = INFINITY;
 118                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 119                     continue;
 120                 }
 121                 for (w = 0; w < group_len; w++) {
 122                     FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(win+w)*16+swb];
 123                     rd += quantize_band_cost(s, &sce->coeffs[start + w*128],
 124                                              &s->scoefs[start + w*128], size,
 125                                              sce->sf_idx[(win+w)*16+swb], aac_cb_out_map[cb],
 126                                              lambda / band->threshold, INFINITY, NULL, NULL, 0);
 127                 }
 128                 cost_stay_here = path[swb][cb].cost + rd;
 129                 cost_get_here  = minrd              + rd + run_bits + 4;
 130                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
 131                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
 132                     cost_stay_here += run_bits;
 133                 if (cost_get_here < cost_stay_here) {
 134                     path[swb+1][cb].prev_idx = mincb;
 135                     path[swb+1][cb].cost     = cost_get_here;
 136                     path[swb+1][cb].run      = 1;
 137                 } else {
 138                     path[swb+1][cb].prev_idx = cb;
 139                     path[swb+1][cb].cost     = cost_stay_here;
 140                     path[swb+1][cb].run      = path[swb][cb].run + 1;
 141                 }
 142                 if (path[swb+1][cb].cost < next_minrd) {
 143                     next_minrd = path[swb+1][cb].cost;
 144                     next_mincb = cb;
 145                 }
 146             }
 147         }
 148         start += sce->ics.swb_sizes[swb];
 149     }
 150
 151     //convert resulting path from backward-linked list
 152     stack_len = 0;
 153     idx       = 0;
 154     for (cb = 1; cb < CB_TOT_ALL; cb++)
 155         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
 156             idx = cb;
 157     ppos = max_sfb;
 158     while (ppos > 0) {
 159         av_assert1(idx >= 0);
 160         cb = idx;
 161         stackrun[stack_len] = path[ppos][cb].run;
 162         stackcb [stack_len] = cb;
 163         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
 164         ppos -= path[ppos][cb].run;
 165         stack_len++;
 166     }
 167     //perform actual band info encoding
 168     start = 0;
 169     for (i = stack_len - 1; i >= 0; i--) {
 170         cb = aac_cb_out_map[stackcb[i]];
 171         put_bits(&s->pb, 4, cb);
 172         count = stackrun[i];
 173         memset(sce->zeroes + win*16 + start, !cb, count);
 174         //XXX: memset when band_type is also uint8_t
 175         for (j = 0; j < count; j++) {
 176             sce->band_type[win*16 + start] = cb;
 177             start++;
 178         }
 179         while (count >= run_esc) {
 180             put_bits(&s->pb, run_bits, run_esc);
 181             count -= run_esc;
 182         }
 183         put_bits(&s->pb, run_bits, count);
 184     }
 185 }
 186
 187
 188 typedef struct TrellisPath {
 189     float cost;
 190     int prev;
 191 } TrellisPath;
 192
 193 #define TRELLIS_STAGES 121
 194 #define TRELLIS_STATES (SCALE_MAX_DIFF+1)
 195
 196 static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement *sce)
 197 {
 198     int w, g, start = 0;
 199     int minscaler_n = sce->sf_idx[0], minscaler_i = sce->sf_idx[0];
 200     int bands = 0;
 201
 202     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 203         start = 0;
 204         for (g = 0;  g < sce->ics.num_swb; g++) {
 205             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
 206                 sce->sf_idx[w*16+g] = av_clip(roundf(log2f(sce->is_ener[w*16+g])*2), -155, 100);
 207                 minscaler_i = FFMIN(minscaler_i, sce->sf_idx[w*16+g]);
 208                 bands++;
 209             } else if (sce->band_type[w*16+g] == NOISE_BT) {
 210                 sce->sf_idx[w*16+g] = av_clip(3+ceilf(log2f(sce->pns_ener[w*16+g])*2), -100, 155);
 211                 minscaler_n = FFMIN(minscaler_n, sce->sf_idx[w*16+g]);
 212                 bands++;
 213             }
 214             start += sce->ics.swb_sizes[g];
 215         }
 216     }
 217
 218     if (!bands)
 219         return;
 220
 221     /* Clip the scalefactor indices */
 222     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 223         for (g = 0;  g < sce->ics.num_swb; g++) {
 224             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
 225                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_i, minscaler_i + SCALE_MAX_DIFF);
 226             } else if (sce->band_type[w*16+g] == NOISE_BT) {
 227                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_n, minscaler_n + SCALE_MAX_DIFF);
 228             }
 229         }
 230     }
 231 }
 232
 233 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 234                                        SingleChannelElement *sce,
 235                                        const float lambda)
 236 {
 237     int q, w, w2, g, start = 0;
 238     int i, j;
 239     int idx;
 240     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];
 241     int bandaddr[TRELLIS_STAGES];
 242     int minq;
 243     float mincost;
 244     float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f;
 245     int q0, q1, qcnt = 0;
 246
 247     for (i = 0; i < 1024; i++) {
 248         float t = fabsf(sce->coeffs[i]);
 249         if (t > 0.0f) {
 250             q0f = FFMIN(q0f, t);
 251             q1f = FFMAX(q1f, t);
 252             qnrgf += t*t;
 253             qcnt++;
 254         }
 255     }
 256
 257     if (!qcnt) {
 258         memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 259         memset(sce->zeroes, 1, sizeof(sce->zeroes));
 260         return;
 261     }
 262
 263     //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 264     q0 = coef2minsf(q0f);
 265     //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 266     q1 = coef2maxsf(q1f);
 267     if (q1 - q0 > 60) {
 268         int q0low  = q0;
 269         int q1high = q1;
 270         //minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped
 271         int qnrg = av_clip_uint8(log2f(sqrtf(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512);
 272         q1 = qnrg + 30;
 273         q0 = qnrg - 30;
 274         if (q0 < q0low) {
 275             q1 += q0low - q0;
 276             q0  = q0low;
 277         } else if (q1 > q1high) {
 278             q0 -= q1 - q1high;
 279             q1  = q1high;
 280         }
 281     }
 282
 283     for (i = 0; i < TRELLIS_STATES; i++) {
 284         paths[0][i].cost    = 0.0f;
 285         paths[0][i].prev    = -1;
 286     }
 287     for (j = 1; j < TRELLIS_STAGES; j++) {
 288         for (i = 0; i < TRELLIS_STATES; i++) {
 289             paths[j][i].cost    = INFINITY;
 290             paths[j][i].prev    = -2;
 291         }
 292     }
 293     idx = 1;
 294     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 295     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 296         start = w*128;
 297         for (g = 0; g < sce->ics.num_swb; g++) {
 298             const float *coefs = &sce->coeffs[start];
 299             float qmin, qmax;
 300             int nz = 0;
 301
 302             bandaddr[idx] = w * 16 + g;
 303             qmin = INT_MAX;
 304             qmax = 0.0f;
 305             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 306                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 307                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 308                     sce->zeroes[(w+w2)*16+g] = 1;
 309                     continue;
 310                 }
 311                 sce->zeroes[(w+w2)*16+g] = 0;
 312                 nz = 1;
 313                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 314                     float t = fabsf(coefs[w2*128+i]);
 315                     if (t > 0.0f)
 316                         qmin = FFMIN(qmin, t);
 317                     qmax = FFMAX(qmax, t);
 318                 }
 319             }
 320             if (nz) {
 321                 int minscale, maxscale;
 322                 float minrd = INFINITY;
 323                 float maxval;
 324                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 325                 minscale = coef2minsf(qmin);
 326                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 327                 maxscale = coef2maxsf(qmax);
 328                 minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);
 329                 maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);
 330                 maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start);
 331                 for (q = minscale; q < maxscale; q++) {
 332                     float dist = 0;
 333                     int cb = find_min_book(maxval, sce->sf_idx[w*16+g]);
 334                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 335                         FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 336                         dist += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 337                                                    q + q0, cb, lambda / band->threshold, INFINITY, NULL, NULL, 0);
 338                     }
 339                     minrd = FFMIN(minrd, dist);
 340
 341                     for (i = 0; i < q1 - q0; i++) {
 342                         float cost;
 343                         cost = paths[idx - 1][i].cost + dist
 344                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 345                         if (cost < paths[idx][q].cost) {
 346                             paths[idx][q].cost    = cost;
 347                             paths[idx][q].prev    = i;
 348                         }
 349                     }
 350                 }
 351             } else {
 352                 for (q = 0; q < q1 - q0; q++) {
 353                     paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 354                     paths[idx][q].prev = q;
 355                 }
 356             }
 357             sce->zeroes[w*16+g] = !nz;
 358             start += sce->ics.swb_sizes[g];
 359             idx++;
 360         }
 361     }
 362     idx--;
 363     mincost = paths[idx][0].cost;
 364     minq    = 0;
 365     for (i = 1; i < TRELLIS_STATES; i++) {
 366         if (paths[idx][i].cost < mincost) {
 367             mincost = paths[idx][i].cost;
 368             minq = i;
 369         }
 370     }
 371     while (idx) {
 372         sce->sf_idx[bandaddr[idx]] = minq + q0;
 373         minq = paths[idx][minq].prev;
 374         idx--;
 375     }
 376     //set the same quantizers inside window groups
 377     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 378         for (g = 0;  g < sce->ics.num_swb; g++)
 379             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 380                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 381 }
 382
 383
 384 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
 385                                        SingleChannelElement *sce,
 386                                        const float lambda)
 387 {
 388     int start = 0, i, w, w2, g;
 389     float uplim[128], maxq[128];
 390     int minq, maxsf;
 391     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
 392     int last = 0, lastband = 0, curband = 0;
 393     float avg_energy = 0.0;
 394     if (sce->ics.num_windows == 1) {
 395         start = 0;
 396         for (i = 0; i < 1024; i++) {
 397             if (i - start >= sce->ics.swb_sizes[curband]) {
 398                 start += sce->ics.swb_sizes[curband];
 399                 curband++;
 400             }
 401             if (sce->coeffs[i]) {
 402                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
 403                 last = i;
 404                 lastband = curband;
 405             }
 406         }
 407     } else {
 408         for (w = 0; w < 8; w++) {
 409             const float *coeffs = &sce->coeffs[w*128];
 410             curband = start = 0;
 411             for (i = 0; i < 128; i++) {
 412                 if (i - start >= sce->ics.swb_sizes[curband]) {
 413                     start += sce->ics.swb_sizes[curband];
 414                     curband++;
 415                 }
 416                 if (coeffs[i]) {
 417                     avg_energy += coeffs[i] * coeffs[i];
 418                     last = FFMAX(last, i);
 419                     lastband = FFMAX(lastband, curband);
 420                 }
 421             }
 422         }
 423     }
 424     last++;
 425     avg_energy /= last;
 426     if (avg_energy == 0.0f) {
 427         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
 428             sce->sf_idx[i] = SCALE_ONE_POS;
 429         return;
 430     }
 431     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 432         start = w*128;
 433         for (g = 0; g < sce->ics.num_swb; g++) {
 434             float *coefs   = &sce->coeffs[start];
 435             const int size = sce->ics.swb_sizes[g];
 436             int start2 = start, end2 = start + size, peakpos = start;
 437             float maxval = -1, thr = 0.0f, t;
 438             maxq[w*16+g] = 0.0f;
 439             if (g > lastband) {
 440                 maxq[w*16+g] = 0.0f;
 441                 start += size;
 442                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
 443                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
 444                 continue;
 445             }
 446             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 447                 for (i = 0; i < size; i++) {
 448                     float t = coefs[w2*128+i]*coefs[w2*128+i];
 449                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
 450                     thr += t;
 451                     if (sce->ics.num_windows == 1 && maxval < t) {
 452                         maxval  = t;
 453                         peakpos = start+i;
 454                     }
 455                 }
 456             }
 457             if (sce->ics.num_windows == 1) {
 458                 start2 = FFMAX(peakpos - 2, start2);
 459                 end2   = FFMIN(peakpos + 3, end2);
 460             } else {
 461                 start2 -= start;
 462                 end2   -= start;
 463             }
 464             start += size;
 465             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
 466             t   = 1.0 - (1.0 * start2 / last);
 467             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
 468         }
 469     }
 470     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 471     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
 472     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 473         start = w*128;
 474         for (g = 0;  g < sce->ics.num_swb; g++) {
 475             const float *coefs  = &sce->coeffs[start];
 476             const float *scaled = &s->scoefs[start];
 477             const int size      = sce->ics.swb_sizes[g];
 478             int scf, prev_scf, step;
 479             int min_scf = -1, max_scf = 256;
 480             float curdiff;
 481             if (maxq[w*16+g] < 21.544) {
 482                 sce->zeroes[w*16+g] = 1;
 483                 start += size;
 484                 continue;
 485             }
 486             sce->zeroes[w*16+g] = 0;
 487             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2f(1/maxq[w*16+g])*16/3, 60, 218);
 488             for (;;) {
 489                 float dist = 0.0f;
 490                 int quant_max;
 491
 492                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 493                     int b;
 494                     dist += quantize_band_cost(s, coefs + w2*128,
 495                                                scaled + w2*128,
 496                                                sce->ics.swb_sizes[g],
 497                                                scf,
 498                                                ESC_BT,
 499                                                lambda,
 500                                                INFINITY,
 501                                                &b, NULL,
 502                                                0);
 503                     dist -= b;
 504                 }
 505                 dist *= 1.0f / 512.0f / lambda;
 506                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[POW_SF2_ZERO - scf + SCALE_ONE_POS - SCALE_DIV_512], ROUND_STANDARD);
 507                 if (quant_max >= 8191) { // too much, return to the previous quantizer
 508                     sce->sf_idx[w*16+g] = prev_scf;
 509                     break;
 510                 }
 511                 prev_scf = scf;
 512                 curdiff = fabsf(dist - uplim[w*16+g]);
 513                 if (curdiff <= 1.0f)
 514                     step = 0;
 515                 else
 516                     step = log2f(curdiff);
 517                 if (dist > uplim[w*16+g])
 518                     step = -step;
 519                 scf += step;
 520                 scf = av_clip_uint8(scf);
 521                 step = scf - prev_scf;
 522                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
 523                     sce->sf_idx[w*16+g] = av_clip(scf, min_scf, max_scf);
 524                     break;
 525                 }
 526                 if (step > 0)
 527                     min_scf = prev_scf;
 528                 else
 529                     max_scf = prev_scf;
 530             }
 531             start += size;
 532         }
 533     }
 534     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
 535     for (i = 1; i < 128; i++) {
 536         if (!sce->sf_idx[i])
 537             sce->sf_idx[i] = sce->sf_idx[i-1];
 538         else
 539             minq = FFMIN(minq, sce->sf_idx[i]);
 540     }
 541     if (minq == INT_MAX)
 542         minq = 0;
 543     minq = FFMIN(minq, SCALE_MAX_POS);
 544     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
 545     for (i = 126; i >= 0; i--) {
 546         if (!sce->sf_idx[i])
 547             sce->sf_idx[i] = sce->sf_idx[i+1];
 548         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
 549     }
 550 }
 551
 552 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
 553                                        SingleChannelElement *sce,
 554                                        const float lambda)
 555 {
 556     int i, w, w2, g;
 557     int minq = 255;
 558
 559     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 560     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 561         for (g = 0; g < sce->ics.num_swb; g++) {
 562             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 563                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 564                 if (band->energy <= band->threshold) {
 565                     sce->sf_idx[(w+w2)*16+g] = 218;
 566                     sce->zeroes[(w+w2)*16+g] = 1;
 567                 } else {
 568                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2f(band->threshold), 80, 218);
 569                     sce->zeroes[(w+w2)*16+g] = 0;
 570                 }
 571                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
 572             }
 573         }
 574     }
 575     for (i = 0; i < 128; i++) {
 576         sce->sf_idx[i] = 140;
 577         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
 578     }
 579     //set the same quantizers inside window groups
 580     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 581         for (g = 0;  g < sce->ics.num_swb; g++)
 582             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 583                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 584 }
 585
 586 static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)
 587 {
 588     FFPsyBand *band;
 589     int w, g, w2, i;
 590     int wlen = 1024 / sce->ics.num_windows;
 591     int bandwidth, cutoff;
 592     float *PNS = &s->scoefs[0*128], *PNS34 = &s->scoefs[1*128];
 593     float *NOR34 = &s->scoefs[3*128];
 594     const float lambda = s->lambda;
 595     const float freq_mult = avctx->sample_rate*0.5f/wlen;
 596     const float thr_mult = NOISE_LAMBDA_REPLACE*(100.0f/lambda);
 597     const float spread_threshold = FFMIN(0.75f, NOISE_SPREAD_THRESHOLD*FFMAX(0.5f, lambda/100.f));
 598     const float dist_bias = av_clipf(4.f * 120 / lambda, 0.25f, 4.0f);
 599     const float pns_transient_energy_r = FFMIN(0.7f, lambda / 140.f);
 600
 601     int refbits = avctx->bit_rate * 1024.0 / avctx->sample_rate
 602         / ((avctx->flags & CODEC_FLAG_QSCALE) ? 2.0f : avctx->channels)
 603         * (lambda / 120.f);
 604
 605     /** Keep this in sync with twoloop's cutoff selection */
 606     float rate_bandwidth_multiplier = 1.5f;
 607     int frame_bit_rate = (avctx->flags & CODEC_FLAG_QSCALE)
 608         ? (refbits * rate_bandwidth_multiplier * avctx->sample_rate / 1024)
 609         : (avctx->bit_rate / avctx->channels);
 610
 611     frame_bit_rate *= 1.15f;
 612
 613     if (avctx->cutoff > 0) {
 614         bandwidth = avctx->cutoff;
 615     } else {
 616         bandwidth = FFMAX(3000, AAC_CUTOFF_FROM_BITRATE(frame_bit_rate, 1, avctx->sample_rate));
 617     }
 618
 619     cutoff = bandwidth * 2 * wlen / avctx->sample_rate;
 620
 621     memcpy(sce->band_alt, sce->band_type, sizeof(sce->band_type));
 622     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 623         int wstart = w*128;
 624         for (g = 0;  g < sce->ics.num_swb; g++) {
 625             int noise_sfi;
 626             float dist1 = 0.0f, dist2 = 0.0f, noise_amp;
 627             float pns_energy = 0.0f, pns_tgt_energy, energy_ratio, dist_thresh;
 628             float sfb_energy = 0.0f, threshold = 0.0f, spread = 2.0f;
 629             float min_energy = -1.0f, max_energy = 0.0f;
 630             const int start = wstart+sce->ics.swb_offset[g];
 631             const float freq = (start-wstart)*freq_mult;
 632             const float freq_boost = FFMAX(0.88f*freq/NOISE_LOW_LIMIT, 1.0f);
 633             if (freq < NOISE_LOW_LIMIT || (start-wstart) >= cutoff)
 634                 continue;
 635             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 636                 band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 637                 sfb_energy += band->energy;
 638                 spread     = FFMIN(spread, band->spread);
 639                 threshold  += band->threshold;
 640                 if (!w2) {
 641                     min_energy = max_energy = band->energy;
 642                 } else {
 643                     min_energy = FFMIN(min_energy, band->energy);
 644                     max_energy = FFMAX(max_energy, band->energy);
 645                 }
 646             }
 647
 648             /* Ramps down at ~8000Hz and loosens the dist threshold */
 649             dist_thresh = av_clipf(2.5f*NOISE_LOW_LIMIT/freq, 0.5f, 2.5f) * dist_bias;
 650
 651             /* PNS is acceptable when all of these are true:
 652              * 1. high spread energy (noise-like band)
 653              * 2. near-threshold energy (high PE means the random nature of PNS content will be noticed)
 654              * 3. on short window groups, all windows have similar energy (variations in energy would be destroyed by PNS)
 655              *
 656              * At this stage, point 2 is relaxed for zeroed bands near the noise threshold (hole avoidance is more important)
 657              */
 658             if (((sce->zeroes[w*16+g] || !sce->band_alt[w*16+g]) && sfb_energy < threshold*sqrtf(1.5f/freq_boost)) || spread < spread_threshold ||
 659                 (!sce->zeroes[w*16+g] && sce->band_alt[w*16+g] && sfb_energy > threshold*thr_mult*freq_boost) ||
 660                 min_energy < pns_transient_energy_r * max_energy ) {
 661                 sce->pns_ener[w*16+g] = sfb_energy;
 662                 continue;
 663             }
 664
 665             pns_tgt_energy = sfb_energy*FFMIN(1.0f, spread*spread);
 666             noise_sfi = av_clip(roundf(log2f(pns_tgt_energy)*2), -100, 155); /* Quantize */
 667             noise_amp = -ff_aac_pow2sf_tab[noise_sfi + POW_SF2_ZERO];    /* Dequantize */
 668             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 669                 float band_energy, scale, pns_senergy;
 670                 const int start_c = (w+w2)*128+sce->ics.swb_offset[g];
 671                 band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 672                 for (i = 0; i < sce->ics.swb_sizes[g]; i++)
 673                     PNS[i] = s->random_state = lcg_random(s->random_state);
 674                 band_energy = s->fdsp->scalarproduct_float(PNS, PNS, sce->ics.swb_sizes[g]);
 675                 scale = noise_amp/sqrtf(band_energy);
 676                 s->fdsp->vector_fmul_scalar(PNS, PNS, scale, sce->ics.swb_sizes[g]);
 677                 pns_senergy = s->fdsp->scalarproduct_float(PNS, PNS, sce->ics.swb_sizes[g]);
 678                 pns_energy += pns_senergy;
 679                 abs_pow34_v(NOR34, &sce->coeffs[start_c], sce->ics.swb_sizes[g]);
 680                 abs_pow34_v(PNS34, PNS, sce->ics.swb_sizes[g]);
 681                 dist1 += quantize_band_cost(s, &sce->coeffs[start_c],
 682                                             NOR34,
 683                                             sce->ics.swb_sizes[g],
 684                                             sce->sf_idx[(w+w2)*16+g],
 685                                             sce->band_alt[(w+w2)*16+g],
 686                                             lambda/band->threshold, INFINITY, NULL, NULL, 0);
 687                 /* Estimate rd on average as 5 bits for SF, 4 for the CB, plus spread energy * lambda/thr */
 688                 dist2 += band->energy/(band->spread*band->spread)*lambda*dist_thresh/band->threshold;
 689             }
 690             if (g && sce->sf_idx[(w+w2)*16+g-1] == NOISE_BT) {
 691                 dist2 += 5;
 692             } else {
 693                 dist2 += 9;
 694             }
 695             energy_ratio = pns_tgt_energy/pns_energy; /* Compensates for quantization error */
 696             sce->pns_ener[w*16+g] = energy_ratio*pns_tgt_energy;
 697             if (sce->zeroes[w*16+g] || !sce->band_alt[w*16+g] || (energy_ratio > 0.85f && energy_ratio < 1.25f && dist2 < dist1)) {
 698                 sce->band_type[w*16+g] = NOISE_BT;
 699                 sce->zeroes[w*16+g] = 0;
 700             }
 701         }
 702     }
 703 }
 704
 705 static void mark_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)
 706 {
 707     FFPsyBand *band;
 708     int w, g, w2;
 709     int wlen = 1024 / sce->ics.num_windows;
 710     int bandwidth, cutoff;
 711     const float lambda = s->lambda;
 712     const float freq_mult = avctx->sample_rate*0.5f/wlen;
 713     const float spread_threshold = FFMIN(0.75f, NOISE_SPREAD_THRESHOLD*FFMAX(0.5f, lambda/100.f));
 714     const float pns_transient_energy_r = FFMIN(0.7f, lambda / 140.f);
 715
 716     int refbits = avctx->bit_rate * 1024.0 / avctx->sample_rate
 717         / ((avctx->flags & CODEC_FLAG_QSCALE) ? 2.0f : avctx->channels)
 718         * (lambda / 120.f);
 719
 720     /** Keep this in sync with twoloop's cutoff selection */
 721     float rate_bandwidth_multiplier = 1.5f;
 722     int frame_bit_rate = (avctx->flags & CODEC_FLAG_QSCALE)
 723         ? (refbits * rate_bandwidth_multiplier * avctx->sample_rate / 1024)
 724         : (avctx->bit_rate / avctx->channels);
 725
 726     frame_bit_rate *= 1.15f;
 727
 728     if (avctx->cutoff > 0) {
 729         bandwidth = avctx->cutoff;
 730     } else {
 731         bandwidth = FFMAX(3000, AAC_CUTOFF_FROM_BITRATE(frame_bit_rate, 1, avctx->sample_rate));
 732     }
 733
 734     cutoff = bandwidth * 2 * wlen / avctx->sample_rate;
 735
 736     memcpy(sce->band_alt, sce->band_type, sizeof(sce->band_type));
 737     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 738         for (g = 0;  g < sce->ics.num_swb; g++) {
 739             float sfb_energy = 0.0f, threshold = 0.0f, spread = 2.0f;
 740             float min_energy = -1.0f, max_energy = 0.0f;
 741             const int start = sce->ics.swb_offset[g];
 742             const float freq = start*freq_mult;
 743             const float freq_boost = FFMAX(0.88f*freq/NOISE_LOW_LIMIT, 1.0f);
 744             if (freq < NOISE_LOW_LIMIT || start >= cutoff) {
 745                 sce->can_pns[w*16+g] = 0;
 746                 continue;
 747             }
 748             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 749                 band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 750                 sfb_energy += band->energy;
 751                 spread     = FFMIN(spread, band->spread);
 752                 threshold  += band->threshold;
 753                 if (!w2) {
 754                     min_energy = max_energy = band->energy;
 755                 } else {
 756                     min_energy = FFMIN(min_energy, band->energy);
 757                     max_energy = FFMAX(max_energy, band->energy);
 758                 }
 759             }
 760
 761             /* PNS is acceptable when all of these are true:
 762              * 1. high spread energy (noise-like band)
 763              * 2. near-threshold energy (high PE means the random nature of PNS content will be noticed)
 764              * 3. on short window groups, all windows have similar energy (variations in energy would be destroyed by PNS)
 765              */
 766             sce->pns_ener[w*16+g] = sfb_energy;
 767             if (sfb_energy < threshold*sqrtf(1.5f/freq_boost) || spread < spread_threshold || min_energy < pns_transient_energy_r * max_energy) {
 768                 sce->can_pns[w*16+g] = 0;
 769             } else {
 770                 sce->can_pns[w*16+g] = 1;
 771             }
 772         }
 773     }
 774 }
 775
 776 static void search_for_ms(AACEncContext *s, ChannelElement *cpe)
 777 {
 778     int start = 0, i, w, w2, g, sid_sf_boost;
 779     float M[128], S[128];
 780     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
 781     const float lambda = s->lambda;
 782     const float mslambda = FFMIN(1.0f, lambda / 120.f);
 783     SingleChannelElement *sce0 = &cpe->ch[0];
 784     SingleChannelElement *sce1 = &cpe->ch[1];
 785     if (!cpe->common_window)
 786         return;
 787     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 788         int min_sf_idx_mid = SCALE_MAX_POS;
 789         int min_sf_idx_side = SCALE_MAX_POS;
 790         for (g = 0; g < sce0->ics.num_swb; g++) {
 791             if (!sce0->zeroes[w*16+g] && sce0->band_type[w*16+g] < RESERVED_BT)
 792                 min_sf_idx_mid = FFMIN(min_sf_idx_mid, sce0->sf_idx[w*16+g]);
 793             if (!sce1->zeroes[w*16+g] && sce1->band_type[w*16+g] < RESERVED_BT)
 794                 min_sf_idx_side = FFMIN(min_sf_idx_side, sce1->sf_idx[w*16+g]);
 795         }
 796
 797         start = 0;
 798         for (g = 0;  g < sce0->ics.num_swb; g++) {
 799             float bmax = bval2bmax(g * 17.0f / sce0->ics.num_swb) / 0.0045f;
 800             cpe->ms_mask[w*16+g] = 0;
 801             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
 802                 float Mmax = 0.0f, Smax = 0.0f;
 803
 804                 /* Must compute mid/side SF and book for the whole window group */
 805                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 806                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 807                         M[i] = (sce0->coeffs[start+(w+w2)*128+i]
 808                               + sce1->coeffs[start+(w+w2)*128+i]) * 0.5;
 809                         S[i] =  M[i]
 810                               - sce1->coeffs[start+(w+w2)*128+i];
 811                     }
 812                     abs_pow34_v(M34, M, sce0->ics.swb_sizes[g]);
 813                     abs_pow34_v(S34, S, sce0->ics.swb_sizes[g]);
 814                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++ ) {
 815                         Mmax = FFMAX(Mmax, M34[i]);
 816                         Smax = FFMAX(Smax, S34[i]);
 817                     }
 818                 }
 819
 820                 for (sid_sf_boost = 0; sid_sf_boost < 4; sid_sf_boost++) {
 821                     float dist1 = 0.0f, dist2 = 0.0f;
 822                     int B0 = 0, B1 = 0;
 823                     int minidx;
 824                     int mididx, sididx;
 825                     int midcb, sidcb;
 826
 827                     minidx = FFMIN(sce0->sf_idx[w*16+g], sce1->sf_idx[w*16+g]);
 828                     mididx = av_clip(minidx, min_sf_idx_mid, min_sf_idx_mid + SCALE_MAX_DIFF);
 829                     sididx = av_clip(minidx - sid_sf_boost * 3, min_sf_idx_side, min_sf_idx_side + SCALE_MAX_DIFF);
 830                     midcb = find_min_book(Mmax, mididx);
 831                     sidcb = find_min_book(Smax, sididx);
 832
 833                     if ((mididx > minidx) || (sididx > minidx)) {
 834                         /* scalefactor range violation, bad stuff, will decrease quality unacceptably */
 835                         continue;
 836                     }
 837
 838                     /* No CB can be zero */
 839                     midcb = FFMAX(1,midcb);
 840                     sidcb = FFMAX(1,sidcb);
 841
 842                     for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 843                         FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
 844                         FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];
 845                         float minthr = FFMIN(band0->threshold, band1->threshold);
 846                         int b1,b2,b3,b4;
 847                         for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 848                             M[i] = (sce0->coeffs[start+(w+w2)*128+i]
 849                                   + sce1->coeffs[start+(w+w2)*128+i]) * 0.5;
 850                             S[i] =  M[i]
 851                                   - sce1->coeffs[start+(w+w2)*128+i];
 852                         }
 853
 854                         abs_pow34_v(L34, sce0->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
 855                         abs_pow34_v(R34, sce1->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
 856                         abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
 857                         abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
 858                         dist1 += quantize_band_cost(s, &sce0->coeffs[start + (w+w2)*128],
 859                                                     L34,
 860                                                     sce0->ics.swb_sizes[g],
 861                                                     sce0->sf_idx[(w+w2)*16+g],
 862                                                     sce0->band_type[(w+w2)*16+g],
 863                                                     lambda / band0->threshold, INFINITY, &b1, NULL, 0);
 864                         dist1 += quantize_band_cost(s, &sce1->coeffs[start + (w+w2)*128],
 865                                                     R34,
 866                                                     sce1->ics.swb_sizes[g],
 867                                                     sce1->sf_idx[(w+w2)*16+g],
 868                                                     sce1->band_type[(w+w2)*16+g],
 869                                                     lambda / band1->threshold, INFINITY, &b2, NULL, 0);
 870                         dist2 += quantize_band_cost(s, M,
 871                                                     M34,
 872                                                     sce0->ics.swb_sizes[g],
 873                                                     sce0->sf_idx[(w+w2)*16+g],
 874                                                     sce0->band_type[(w+w2)*16+g],
 875                                                     lambda / minthr, INFINITY, &b3, NULL, 0);
 876                         dist2 += quantize_band_cost(s, S,
 877                                                     S34,
 878                                                     sce1->ics.swb_sizes[g],
 879                                                     sce1->sf_idx[(w+w2)*16+g],
 880                                                     sce1->band_type[(w+w2)*16+g],
 881                                                     mslambda / (minthr * bmax), INFINITY, &b4, NULL, 0);
 882                         B0 += b1+b2;
 883                         B1 += b3+b4;
 884                         dist1 -= B0;
 885                         dist2 -= B1;
 886                     }
 887                     cpe->ms_mask[w*16+g] = dist2 <= dist1 && B1 < B0;
 888                     if (cpe->ms_mask[w*16+g]) {
 889                         /* Setting the M/S mask is useful with I/S, but only the flag */
 890                         if (!cpe->is_mask[w*16+g]) {
 891                             sce0->sf_idx[w*16+g] = mididx;
 892                             sce1->sf_idx[w*16+g] = sididx;
 893                             sce0->band_type[w*16+g] = midcb;
 894                             sce1->band_type[w*16+g] = sidcb;
 895                         }
 896                         break;
 897                     } else if (B1 > B0) {
 898                         /* More boost won't fix this */
 899                         break;
 900                     }
 901                 }
 902             }
 903             start += sce0->ics.swb_sizes[g];
 904         }
 905     }
 906 }
 907
 908 AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = {
 909     [AAC_CODER_FAAC] = {
 910         search_for_quantizers_faac,
 911         encode_window_bands_info,
 912         quantize_and_encode_band,
 913         ff_aac_encode_tns_info,
 914         ff_aac_encode_main_pred,
 915         ff_aac_adjust_common_pred,
 916         ff_aac_apply_main_pred,
 917         ff_aac_apply_tns,
 918         set_special_band_scalefactors,
 919         search_for_pns,
 920         mark_pns,
 921         ff_aac_search_for_tns,
 922         search_for_ms,
 923         ff_aac_search_for_is,
 924         ff_aac_search_for_pred,
 925     },
 926     [AAC_CODER_ANMR] = {
 927         search_for_quantizers_anmr,
 928         encode_window_bands_info,
 929         quantize_and_encode_band,
 930         ff_aac_encode_tns_info,
 931         ff_aac_encode_main_pred,
 932         ff_aac_adjust_common_pred,
 933         ff_aac_apply_main_pred,
 934         ff_aac_apply_tns,
 935         set_special_band_scalefactors,
 936         search_for_pns,
 937         mark_pns,
 938         ff_aac_search_for_tns,
 939         search_for_ms,
 940         ff_aac_search_for_is,
 941         ff_aac_search_for_pred,
 942     },
 943     [AAC_CODER_TWOLOOP] = {
 944         search_for_quantizers_twoloop,
 945         codebook_trellis_rate,
 946         quantize_and_encode_band,
 947         ff_aac_encode_tns_info,
 948         ff_aac_encode_main_pred,
 949         ff_aac_adjust_common_pred,
 950         ff_aac_apply_main_pred,
 951         ff_aac_apply_tns,
 952         set_special_band_scalefactors,
 953         search_for_pns,
 954         mark_pns,
 955         ff_aac_search_for_tns,
 956         search_for_ms,
 957         ff_aac_search_for_is,
 958         ff_aac_search_for_pred,
 959     },
 960     [AAC_CODER_FAST] = {
 961         search_for_quantizers_fast,
 962         encode_window_bands_info,
 963         quantize_and_encode_band,
 964         ff_aac_encode_tns_info,
 965         ff_aac_encode_main_pred,
 966         ff_aac_adjust_common_pred,
 967         ff_aac_apply_main_pred,
 968         ff_aac_apply_tns,
 969         set_special_band_scalefactors,
 970         search_for_pns,
 971         mark_pns,
 972         ff_aac_search_for_tns,
 973         search_for_ms,
 974         ff_aac_search_for_is,
 975         ff_aac_search_for_pred,
 976     },
 977 };