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
  48 #include "aacenc_is.h"
  49 #include "aacenc_tns.h"
  50 #include "aacenc_ltp.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 0.9f
  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     s->abs_pow34(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;
 199     int prevscaler_n = -255, prevscaler_i = 0;
 200     int bands = 0;
 201
 202     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 203         for (g = 0; g < sce->ics.num_swb; g++) {
 204             if (sce->zeroes[w*16+g])
 205                 continue;
 206             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
 207                 sce->sf_idx[w*16+g] = av_clip(roundf(log2f(sce->is_ener[w*16+g])*2), -155, 100);
 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                 if (prevscaler_n == -255)
 212                     prevscaler_n = sce->sf_idx[w*16+g];
 213                 bands++;
 214             }
 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->zeroes[w*16+g])
 225                 continue;
 226             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
 227                 sce->sf_idx[w*16+g] = prevscaler_i = av_clip(sce->sf_idx[w*16+g], prevscaler_i - SCALE_MAX_DIFF, prevscaler_i + SCALE_MAX_DIFF);
 228             } else if (sce->band_type[w*16+g] == NOISE_BT) {
 229                 sce->sf_idx[w*16+g] = prevscaler_n = av_clip(sce->sf_idx[w*16+g], prevscaler_n - SCALE_MAX_DIFF, prevscaler_n + SCALE_MAX_DIFF);
 230             }
 231         }
 232     }
 233 }
 234
 235 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
 236                                        SingleChannelElement *sce,
 237                                        const float lambda)
 238 {
 239     int q, w, w2, g, start = 0;
 240     int i, j;
 241     int idx;
 242     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];
 243     int bandaddr[TRELLIS_STAGES];
 244     int minq;
 245     float mincost;
 246     float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f;
 247     int q0, q1, qcnt = 0;
 248
 249     for (i = 0; i < 1024; i++) {
 250         float t = fabsf(sce->coeffs[i]);
 251         if (t > 0.0f) {
 252             q0f = FFMIN(q0f, t);
 253             q1f = FFMAX(q1f, t);
 254             qnrgf += t*t;
 255             qcnt++;
 256         }
 257     }
 258
 259     if (!qcnt) {
 260         memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
 261         memset(sce->zeroes, 1, sizeof(sce->zeroes));
 262         return;
 263     }
 264
 265     //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 266     q0 = av_clip(coef2minsf(q0f), 0, SCALE_MAX_POS-1);
 267     //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 268     q1 = av_clip(coef2maxsf(q1f), 1, SCALE_MAX_POS);
 269     if (q1 - q0 > 60) {
 270         int q0low  = q0;
 271         int q1high = q1;
 272         //minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped
 273         int qnrg = av_clip_uint8(log2f(sqrtf(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512);
 274         q1 = qnrg + 30;
 275         q0 = qnrg - 30;
 276         if (q0 < q0low) {
 277             q1 += q0low - q0;
 278             q0  = q0low;
 279         } else if (q1 > q1high) {
 280             q0 -= q1 - q1high;
 281             q1  = q1high;
 282         }
 283     }
 284     // q0 == q1 isn't really a legal situation
 285     if (q0 == q1) {
 286         // the following is indirect but guarantees q1 != q0 && q1 near q0
 287         q1 = av_clip(q0+1, 1, SCALE_MAX_POS);
 288         q0 = av_clip(q1-1, 0, SCALE_MAX_POS - 1);
 289     }
 290
 291     for (i = 0; i < TRELLIS_STATES; i++) {
 292         paths[0][i].cost    = 0.0f;
 293         paths[0][i].prev    = -1;
 294     }
 295     for (j = 1; j < TRELLIS_STAGES; j++) {
 296         for (i = 0; i < TRELLIS_STATES; i++) {
 297             paths[j][i].cost    = INFINITY;
 298             paths[j][i].prev    = -2;
 299         }
 300     }
 301     idx = 1;
 302     s->abs_pow34(s->scoefs, sce->coeffs, 1024);
 303     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 304         start = w*128;
 305         for (g = 0; g < sce->ics.num_swb; g++) {
 306             const float *coefs = &sce->coeffs[start];
 307             float qmin, qmax;
 308             int nz = 0;
 309
 310             bandaddr[idx] = w * 16 + g;
 311             qmin = INT_MAX;
 312             qmax = 0.0f;
 313             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 314                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 315                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 316                     sce->zeroes[(w+w2)*16+g] = 1;
 317                     continue;
 318                 }
 319                 sce->zeroes[(w+w2)*16+g] = 0;
 320                 nz = 1;
 321                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 322                     float t = fabsf(coefs[w2*128+i]);
 323                     if (t > 0.0f)
 324                         qmin = FFMIN(qmin, t);
 325                     qmax = FFMAX(qmax, t);
 326                 }
 327             }
 328             if (nz) {
 329                 int minscale, maxscale;
 330                 float minrd = INFINITY;
 331                 float maxval;
 332                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
 333                 minscale = coef2minsf(qmin);
 334                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
 335                 maxscale = coef2maxsf(qmax);
 336                 minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);
 337                 maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);
 338                 if (minscale == maxscale) {
 339                     maxscale = av_clip(minscale+1, 1, TRELLIS_STATES);
 340                     minscale = av_clip(maxscale-1, 0, TRELLIS_STATES - 1);
 341                 }
 342                 maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start);
 343                 for (q = minscale; q < maxscale; q++) {
 344                     float dist = 0;
 345                     int cb = find_min_book(maxval, sce->sf_idx[w*16+g]);
 346                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 347                         FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 348                         dist += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
 349                                                    q + q0, cb, lambda / band->threshold, INFINITY, NULL, NULL, 0);
 350                     }
 351                     minrd = FFMIN(minrd, dist);
 352
 353                     for (i = 0; i < q1 - q0; i++) {
 354                         float cost;
 355                         cost = paths[idx - 1][i].cost + dist
 356                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
 357                         if (cost < paths[idx][q].cost) {
 358                             paths[idx][q].cost    = cost;
 359                             paths[idx][q].prev    = i;
 360                         }
 361                     }
 362                 }
 363             } else {
 364                 for (q = 0; q < q1 - q0; q++) {
 365                     paths[idx][q].cost = paths[idx - 1][q].cost + 1;
 366                     paths[idx][q].prev = q;
 367                 }
 368             }
 369             sce->zeroes[w*16+g] = !nz;
 370             start += sce->ics.swb_sizes[g];
 371             idx++;
 372         }
 373     }
 374     idx--;
 375     mincost = paths[idx][0].cost;
 376     minq    = 0;
 377     for (i = 1; i < TRELLIS_STATES; i++) {
 378         if (paths[idx][i].cost < mincost) {
 379             mincost = paths[idx][i].cost;
 380             minq = i;
 381         }
 382     }
 383     while (idx) {
 384         sce->sf_idx[bandaddr[idx]] = minq + q0;
 385         minq = FFMAX(paths[idx][minq].prev, 0);
 386         idx--;
 387     }
 388     //set the same quantizers inside window groups
 389     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
 390         for (g = 0; g < sce->ics.num_swb; g++)
 391             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
 392                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
 393 }
 394
 395 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
 396                                        SingleChannelElement *sce,
 397                                        const float lambda)
 398 {
 399     int start = 0, i, w, w2, g;
 400     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels * (lambda / 120.f);
 401     float dists[128] = { 0 }, uplims[128] = { 0 };
 402     float maxvals[128];
 403     int fflag, minscaler;
 404     int its  = 0;
 405     int allz = 0;
 406     float minthr = INFINITY;
 407
 408     // for values above this the decoder might end up in an endless loop
 409     // due to always having more bits than what can be encoded.
 410     destbits = FFMIN(destbits, 5800);
 411     //some heuristic to determine initial quantizers will reduce search time
 412     //determine zero bands and upper limits
 413     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 414         start = 0;
 415         for (g = 0; g < sce->ics.num_swb; g++) {
 416             int nz = 0;
 417             float uplim = 0.0f, energy = 0.0f;
 418             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 419                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 420                 uplim += band->threshold;
 421                 energy += band->energy;
 422                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
 423                     sce->zeroes[(w+w2)*16+g] = 1;
 424                     continue;
 425                 }
 426                 nz = 1;
 427             }
 428             uplims[w*16+g] = uplim *512;
 429             sce->band_type[w*16+g] = 0;
 430             sce->zeroes[w*16+g] = !nz;
 431             if (nz)
 432                 minthr = FFMIN(minthr, uplim);
 433             allz |= nz;
 434             start += sce->ics.swb_sizes[g];
 435         }
 436     }
 437     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 438         for (g = 0; g < sce->ics.num_swb; g++) {
 439             if (sce->zeroes[w*16+g]) {
 440                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
 441                 continue;
 442             }
 443             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2f(uplims[w*16+g]/minthr)*4,59);
 444         }
 445     }
 446
 447     if (!allz)
 448         return;
 449     s->abs_pow34(s->scoefs, sce->coeffs, 1024);
 450     ff_quantize_band_cost_cache_init(s);
 451
 452     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 453         start = w*128;
 454         for (g = 0; g < sce->ics.num_swb; g++) {
 455             const float *scaled = s->scoefs + start;
 456             maxvals[w*16+g] = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled);
 457             start += sce->ics.swb_sizes[g];
 458         }
 459     }
 460
 461     //perform two-loop search
 462     //outer loop - improve quality
 463     do {
 464         int tbits, qstep;
 465         minscaler = sce->sf_idx[0];
 466         //inner loop - quantize spectrum to fit into given number of bits
 467         qstep = its ? 1 : 32;
 468         do {
 469             int prev = -1;
 470             tbits = 0;
 471             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 472                 start = w*128;
 473                 for (g = 0; g < sce->ics.num_swb; g++) {
 474                     const float *coefs = sce->coeffs + start;
 475                     const float *scaled = s->scoefs + start;
 476                     int bits = 0;
 477                     int cb;
 478                     float dist = 0.0f;
 479
 480                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
 481                         start += sce->ics.swb_sizes[g];
 482                         continue;
 483                     }
 484                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
 485                     cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
 486                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 487                         int b;
 488                         dist += quantize_band_cost_cached(s, w + w2, g,
 489                                                           coefs + w2*128,
 490                                                           scaled + w2*128,
 491                                                           sce->ics.swb_sizes[g],
 492                                                           sce->sf_idx[w*16+g],
 493                                                           cb, 1.0f, INFINITY,
 494                                                           &b, NULL, 0);
 495                         bits += b;
 496                     }
 497                     dists[w*16+g] = dist - bits;
 498                     if (prev != -1) {
 499                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
 500                     }
 501                     tbits += bits;
 502                     start += sce->ics.swb_sizes[g];
 503                     prev = sce->sf_idx[w*16+g];
 504                 }
 505             }
 506             if (tbits > destbits) {
 507                 for (i = 0; i < 128; i++)
 508                     if (sce->sf_idx[i] < 218 - qstep)
 509                         sce->sf_idx[i] += qstep;
 510             } else {
 511                 for (i = 0; i < 128; i++)
 512                     if (sce->sf_idx[i] > 60 - qstep)
 513                         sce->sf_idx[i] -= qstep;
 514             }
 515             qstep >>= 1;
 516             if (!qstep && tbits > destbits*1.02 && sce->sf_idx[0] < 217)
 517                 qstep = 1;
 518         } while (qstep);
 519
 520         fflag = 0;
 521         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
 522
 523         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 524             for (g = 0; g < sce->ics.num_swb; g++) {
 525                 int prevsc = sce->sf_idx[w*16+g];
 526                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60) {
 527                     if (find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]-1))
 528                         sce->sf_idx[w*16+g]--;
 529                     else //Try to make sure there is some energy in every band
 530                         sce->sf_idx[w*16+g]-=2;
 531                 }
 532                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
 533                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
 534                 if (sce->sf_idx[w*16+g] != prevsc)
 535                     fflag = 1;
 536                 sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
 537             }
 538         }
 539         its++;
 540     } while (fflag && its < 10);
 541 }
 542
 543 static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)
 544 {
 545     FFPsyBand *band;
 546     int w, g, w2, i;
 547     int wlen = 1024 / sce->ics.num_windows;
 548     int bandwidth, cutoff;
 549     float *PNS = &s->scoefs[0*128], *PNS34 = &s->scoefs[1*128];
 550     float *NOR34 = &s->scoefs[3*128];
 551     uint8_t nextband[128];
 552     const float lambda = s->lambda;
 553     const float freq_mult = avctx->sample_rate*0.5f/wlen;
 554     const float thr_mult = NOISE_LAMBDA_REPLACE*(100.0f/lambda);
 555     const float spread_threshold = FFMIN(0.75f, NOISE_SPREAD_THRESHOLD*FFMAX(0.5f, lambda/100.f));
 556     const float dist_bias = av_clipf(4.f * 120 / lambda, 0.25f, 4.0f);
 557     const float pns_transient_energy_r = FFMIN(0.7f, lambda / 140.f);
 558
 559     int refbits = avctx->bit_rate * 1024.0 / avctx->sample_rate
 560         / ((avctx->flags & AV_CODEC_FLAG_QSCALE) ? 2.0f : avctx->channels)
 561         * (lambda / 120.f);
 562
 563     /** Keep this in sync with twoloop's cutoff selection */
 564     float rate_bandwidth_multiplier = 1.5f;
 565     int prev = -1000, prev_sf = -1;
 566     int frame_bit_rate = (avctx->flags & AV_CODEC_FLAG_QSCALE)
 567         ? (refbits * rate_bandwidth_multiplier * avctx->sample_rate / 1024)
 568         : (avctx->bit_rate / avctx->channels);
 569
 570     frame_bit_rate *= 1.15f;
 571
 572     if (avctx->cutoff > 0) {
 573         bandwidth = avctx->cutoff;
 574     } else {
 575         bandwidth = FFMAX(3000, AAC_CUTOFF_FROM_BITRATE(frame_bit_rate, 1, avctx->sample_rate));
 576     }
 577
 578     cutoff = bandwidth * 2 * wlen / avctx->sample_rate;
 579
 580     memcpy(sce->band_alt, sce->band_type, sizeof(sce->band_type));
 581     ff_init_nextband_map(sce, nextband);
 582     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 583         int wstart = w*128;
 584         for (g = 0; g < sce->ics.num_swb; g++) {
 585             int noise_sfi;
 586             float dist1 = 0.0f, dist2 = 0.0f, noise_amp;
 587             float pns_energy = 0.0f, pns_tgt_energy, energy_ratio, dist_thresh;
 588             float sfb_energy = 0.0f, threshold = 0.0f, spread = 2.0f;
 589             float min_energy = -1.0f, max_energy = 0.0f;
 590             const int start = wstart+sce->ics.swb_offset[g];
 591             const float freq = (start-wstart)*freq_mult;
 592             const float freq_boost = FFMAX(0.88f*freq/NOISE_LOW_LIMIT, 1.0f);
 593             if (freq < NOISE_LOW_LIMIT || (start-wstart) >= cutoff) {
 594                 if (!sce->zeroes[w*16+g])
 595                     prev_sf = sce->sf_idx[w*16+g];
 596                 continue;
 597             }
 598             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 599                 band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 600                 sfb_energy += band->energy;
 601                 spread     = FFMIN(spread, band->spread);
 602                 threshold  += band->threshold;
 603                 if (!w2) {
 604                     min_energy = max_energy = band->energy;
 605                 } else {
 606                     min_energy = FFMIN(min_energy, band->energy);
 607                     max_energy = FFMAX(max_energy, band->energy);
 608                 }
 609             }
 610
 611             /* Ramps down at ~8000Hz and loosens the dist threshold */
 612             dist_thresh = av_clipf(2.5f*NOISE_LOW_LIMIT/freq, 0.5f, 2.5f) * dist_bias;
 613
 614             /* PNS is acceptable when all of these are true:
 615              * 1. high spread energy (noise-like band)
 616              * 2. near-threshold energy (high PE means the random nature of PNS content will be noticed)
 617              * 3. on short window groups, all windows have similar energy (variations in energy would be destroyed by PNS)
 618              *
 619              * At this stage, point 2 is relaxed for zeroed bands near the noise threshold (hole avoidance is more important)
 620              */
 621             if ((!sce->zeroes[w*16+g] && !ff_sfdelta_can_remove_band(sce, nextband, prev_sf, w*16+g)) ||
 622                 ((sce->zeroes[w*16+g] || !sce->band_alt[w*16+g]) && sfb_energy < threshold*sqrtf(1.0f/freq_boost)) || spread < spread_threshold ||
 623                 (!sce->zeroes[w*16+g] && sce->band_alt[w*16+g] && sfb_energy > threshold*thr_mult*freq_boost) ||
 624                 min_energy < pns_transient_energy_r * max_energy ) {
 625                 sce->pns_ener[w*16+g] = sfb_energy;
 626                 if (!sce->zeroes[w*16+g])
 627                     prev_sf = sce->sf_idx[w*16+g];
 628                 continue;
 629             }
 630
 631             pns_tgt_energy = sfb_energy*FFMIN(1.0f, spread*spread);
 632             noise_sfi = av_clip(roundf(log2f(pns_tgt_energy)*2), -100, 155); /* Quantize */
 633             noise_amp = -ff_aac_pow2sf_tab[noise_sfi + POW_SF2_ZERO];    /* Dequantize */
 634             if (prev != -1000) {
 635                 int noise_sfdiff = noise_sfi - prev + SCALE_DIFF_ZERO;
 636                 if (noise_sfdiff < 0 || noise_sfdiff > 2*SCALE_MAX_DIFF) {
 637                     if (!sce->zeroes[w*16+g])
 638                         prev_sf = sce->sf_idx[w*16+g];
 639                     continue;
 640                 }
 641             }
 642             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 643                 float band_energy, scale, pns_senergy;
 644                 const int start_c = (w+w2)*128+sce->ics.swb_offset[g];
 645                 band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 646                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
 647                     s->random_state  = lcg_random(s->random_state);
 648                     PNS[i] = s->random_state;
 649                 }
 650                 band_energy = s->fdsp->scalarproduct_float(PNS, PNS, sce->ics.swb_sizes[g]);
 651                 scale = noise_amp/sqrtf(band_energy);
 652                 s->fdsp->vector_fmul_scalar(PNS, PNS, scale, sce->ics.swb_sizes[g]);
 653                 pns_senergy = s->fdsp->scalarproduct_float(PNS, PNS, sce->ics.swb_sizes[g]);
 654                 pns_energy += pns_senergy;
 655                 s->abs_pow34(NOR34, &sce->coeffs[start_c], sce->ics.swb_sizes[g]);
 656                 s->abs_pow34(PNS34, PNS, sce->ics.swb_sizes[g]);
 657                 dist1 += quantize_band_cost(s, &sce->coeffs[start_c],
 658                                             NOR34,
 659                                             sce->ics.swb_sizes[g],
 660                                             sce->sf_idx[(w+w2)*16+g],
 661                                             sce->band_alt[(w+w2)*16+g],
 662                                             lambda/band->threshold, INFINITY, NULL, NULL, 0);
 663                 /* Estimate rd on average as 5 bits for SF, 4 for the CB, plus spread energy * lambda/thr */
 664                 dist2 += band->energy/(band->spread*band->spread)*lambda*dist_thresh/band->threshold;
 665             }
 666             if (g && sce->band_type[w*16+g-1] == NOISE_BT) {
 667                 dist2 += 5;
 668             } else {
 669                 dist2 += 9;
 670             }
 671             energy_ratio = pns_tgt_energy/pns_energy; /* Compensates for quantization error */
 672             sce->pns_ener[w*16+g] = energy_ratio*pns_tgt_energy;
 673             if (sce->zeroes[w*16+g] || !sce->band_alt[w*16+g] || (energy_ratio > 0.85f && energy_ratio < 1.25f && dist2 < dist1)) {
 674                 sce->band_type[w*16+g] = NOISE_BT;
 675                 sce->zeroes[w*16+g] = 0;
 676                 prev = noise_sfi;
 677             } else {
 678                 if (!sce->zeroes[w*16+g])
 679                     prev_sf = sce->sf_idx[w*16+g];
 680             }
 681         }
 682     }
 683 }
 684
 685 static void mark_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)
 686 {
 687     FFPsyBand *band;
 688     int w, g, w2;
 689     int wlen = 1024 / sce->ics.num_windows;
 690     int bandwidth, cutoff;
 691     const float lambda = s->lambda;
 692     const float freq_mult = avctx->sample_rate*0.5f/wlen;
 693     const float spread_threshold = FFMIN(0.75f, NOISE_SPREAD_THRESHOLD*FFMAX(0.5f, lambda/100.f));
 694     const float pns_transient_energy_r = FFMIN(0.7f, lambda / 140.f);
 695
 696     int refbits = avctx->bit_rate * 1024.0 / avctx->sample_rate
 697         / ((avctx->flags & AV_CODEC_FLAG_QSCALE) ? 2.0f : avctx->channels)
 698         * (lambda / 120.f);
 699
 700     /** Keep this in sync with twoloop's cutoff selection */
 701     float rate_bandwidth_multiplier = 1.5f;
 702     int frame_bit_rate = (avctx->flags & AV_CODEC_FLAG_QSCALE)
 703         ? (refbits * rate_bandwidth_multiplier * avctx->sample_rate / 1024)
 704         : (avctx->bit_rate / avctx->channels);
 705
 706     frame_bit_rate *= 1.15f;
 707
 708     if (avctx->cutoff > 0) {
 709         bandwidth = avctx->cutoff;
 710     } else {
 711         bandwidth = FFMAX(3000, AAC_CUTOFF_FROM_BITRATE(frame_bit_rate, 1, avctx->sample_rate));
 712     }
 713
 714     cutoff = bandwidth * 2 * wlen / avctx->sample_rate;
 715
 716     memcpy(sce->band_alt, sce->band_type, sizeof(sce->band_type));
 717     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
 718         for (g = 0; g < sce->ics.num_swb; g++) {
 719             float sfb_energy = 0.0f, threshold = 0.0f, spread = 2.0f;
 720             float min_energy = -1.0f, max_energy = 0.0f;
 721             const int start = sce->ics.swb_offset[g];
 722             const float freq = start*freq_mult;
 723             const float freq_boost = FFMAX(0.88f*freq/NOISE_LOW_LIMIT, 1.0f);
 724             if (freq < NOISE_LOW_LIMIT || start >= cutoff) {
 725                 sce->can_pns[w*16+g] = 0;
 726                 continue;
 727             }
 728             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
 729                 band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
 730                 sfb_energy += band->energy;
 731                 spread     = FFMIN(spread, band->spread);
 732                 threshold  += band->threshold;
 733                 if (!w2) {
 734                     min_energy = max_energy = band->energy;
 735                 } else {
 736                     min_energy = FFMIN(min_energy, band->energy);
 737                     max_energy = FFMAX(max_energy, band->energy);
 738                 }
 739             }
 740
 741             /* PNS is acceptable when all of these are true:
 742              * 1. high spread energy (noise-like band)
 743              * 2. near-threshold energy (high PE means the random nature of PNS content will be noticed)
 744              * 3. on short window groups, all windows have similar energy (variations in energy would be destroyed by PNS)
 745              */
 746             sce->pns_ener[w*16+g] = sfb_energy;
 747             if (sfb_energy < threshold*sqrtf(1.5f/freq_boost) || spread < spread_threshold || min_energy < pns_transient_energy_r * max_energy) {
 748                 sce->can_pns[w*16+g] = 0;
 749             } else {
 750                 sce->can_pns[w*16+g] = 1;
 751             }
 752         }
 753     }
 754 }
 755
 756 static void search_for_ms(AACEncContext *s, ChannelElement *cpe)
 757 {
 758     int start = 0, i, w, w2, g, sid_sf_boost, prev_mid, prev_side;
 759     uint8_t nextband0[128], nextband1[128];
 760     float *M   = s->scoefs + 128*0, *S   = s->scoefs + 128*1;
 761     float *L34 = s->scoefs + 128*2, *R34 = s->scoefs + 128*3;
 762     float *M34 = s->scoefs + 128*4, *S34 = s->scoefs + 128*5;
 763     const float lambda = s->lambda;
 764     const float mslambda = FFMIN(1.0f, lambda / 120.f);
 765     SingleChannelElement *sce0 = &cpe->ch[0];
 766     SingleChannelElement *sce1 = &cpe->ch[1];
 767     if (!cpe->common_window)
 768         return;
 769
 770     /** Scout out next nonzero bands */
 771     ff_init_nextband_map(sce0, nextband0);
 772     ff_init_nextband_map(sce1, nextband1);
 773
 774     prev_mid = sce0->sf_idx[0];
 775     prev_side = sce1->sf_idx[0];
 776     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 777         start = 0;
 778         for (g = 0; g < sce0->ics.num_swb; g++) {
 779             float bmax = bval2bmax(g * 17.0f / sce0->ics.num_swb) / 0.0045f;
 780             if (!cpe->is_mask[w*16+g])
 781                 cpe->ms_mask[w*16+g] = 0;
 782             if (!sce0->zeroes[w*16+g] && !sce1->zeroes[w*16+g] && !cpe->is_mask[w*16+g]) {
 783                 float Mmax = 0.0f, Smax = 0.0f;
 784
 785                 /* Must compute mid/side SF and book for the whole window group */
 786                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 787                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 788                         M[i] = (sce0->coeffs[start+(w+w2)*128+i]
 789                               + sce1->coeffs[start+(w+w2)*128+i]) * 0.5;
 790                         S[i] =  M[i]
 791                               - sce1->coeffs[start+(w+w2)*128+i];
 792                     }
 793                     s->abs_pow34(M34, M, sce0->ics.swb_sizes[g]);
 794                     s->abs_pow34(S34, S, sce0->ics.swb_sizes[g]);
 795                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++ ) {
 796                         Mmax = FFMAX(Mmax, M34[i]);
 797                         Smax = FFMAX(Smax, S34[i]);
 798                     }
 799                 }
 800
 801                 for (sid_sf_boost = 0; sid_sf_boost < 4; sid_sf_boost++) {
 802                     float dist1 = 0.0f, dist2 = 0.0f;
 803                     int B0 = 0, B1 = 0;
 804                     int minidx;
 805                     int mididx, sididx;
 806                     int midcb, sidcb;
 807
 808                     minidx = FFMIN(sce0->sf_idx[w*16+g], sce1->sf_idx[w*16+g]);
 809                     mididx = av_clip(minidx, 0, SCALE_MAX_POS - SCALE_DIV_512);
 810                     sididx = av_clip(minidx - sid_sf_boost * 3, 0, SCALE_MAX_POS - SCALE_DIV_512);
 811                     if (sce0->band_type[w*16+g] != NOISE_BT && sce1->band_type[w*16+g] != NOISE_BT
 812                         && (   !ff_sfdelta_can_replace(sce0, nextband0, prev_mid, mididx, w*16+g)
 813                             || !ff_sfdelta_can_replace(sce1, nextband1, prev_side, sididx, w*16+g))) {
 814                         /* scalefactor range violation, bad stuff, will decrease quality unacceptably */
 815                         continue;
 816                     }
 817
 818                     midcb = find_min_book(Mmax, mididx);
 819                     sidcb = find_min_book(Smax, sididx);
 820
 821                     /* No CB can be zero */
 822                     midcb = FFMAX(1,midcb);
 823                     sidcb = FFMAX(1,sidcb);
 824
 825                     for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 826                         FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
 827                         FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];
 828                         float minthr = FFMIN(band0->threshold, band1->threshold);
 829                         int b1,b2,b3,b4;
 830                         for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 831                             M[i] = (sce0->coeffs[start+(w+w2)*128+i]
 832                                   + sce1->coeffs[start+(w+w2)*128+i]) * 0.5;
 833                             S[i] =  M[i]
 834                                   - sce1->coeffs[start+(w+w2)*128+i];
 835                         }
 836
 837                         s->abs_pow34(L34, sce0->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
 838                         s->abs_pow34(R34, sce1->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
 839                         s->abs_pow34(M34, M,                         sce0->ics.swb_sizes[g]);
 840                         s->abs_pow34(S34, S,                         sce0->ics.swb_sizes[g]);
 841                         dist1 += quantize_band_cost(s, &sce0->coeffs[start + (w+w2)*128],
 842                                                     L34,
 843                                                     sce0->ics.swb_sizes[g],
 844                                                     sce0->sf_idx[w*16+g],
 845                                                     sce0->band_type[w*16+g],
 846                                                     lambda / band0->threshold, INFINITY, &b1, NULL, 0);
 847                         dist1 += quantize_band_cost(s, &sce1->coeffs[start + (w+w2)*128],
 848                                                     R34,
 849                                                     sce1->ics.swb_sizes[g],
 850                                                     sce1->sf_idx[w*16+g],
 851                                                     sce1->band_type[w*16+g],
 852                                                     lambda / band1->threshold, INFINITY, &b2, NULL, 0);
 853                         dist2 += quantize_band_cost(s, M,
 854                                                     M34,
 855                                                     sce0->ics.swb_sizes[g],
 856                                                     mididx,
 857                                                     midcb,
 858                                                     lambda / minthr, INFINITY, &b3, NULL, 0);
 859                         dist2 += quantize_band_cost(s, S,
 860                                                     S34,
 861                                                     sce1->ics.swb_sizes[g],
 862                                                     sididx,
 863                                                     sidcb,
 864                                                     mslambda / (minthr * bmax), INFINITY, &b4, NULL, 0);
 865                         B0 += b1+b2;
 866                         B1 += b3+b4;
 867                         dist1 -= b1+b2;
 868                         dist2 -= b3+b4;
 869                     }
 870                     cpe->ms_mask[w*16+g] = dist2 <= dist1 && B1 < B0;
 871                     if (cpe->ms_mask[w*16+g]) {
 872                         if (sce0->band_type[w*16+g] != NOISE_BT && sce1->band_type[w*16+g] != NOISE_BT) {
 873                             sce0->sf_idx[w*16+g] = mididx;
 874                             sce1->sf_idx[w*16+g] = sididx;
 875                             sce0->band_type[w*16+g] = midcb;
 876                             sce1->band_type[w*16+g] = sidcb;
 877                         } else if ((sce0->band_type[w*16+g] != NOISE_BT) ^ (sce1->band_type[w*16+g] != NOISE_BT)) {
 878                             /* ms_mask unneeded, and it confuses some decoders */
 879                             cpe->ms_mask[w*16+g] = 0;
 880                         }
 881                         break;
 882                     } else if (B1 > B0) {
 883                         /* More boost won't fix this */
 884                         break;
 885                     }
 886                 }
 887             }
 888             if (!sce0->zeroes[w*16+g] && sce0->band_type[w*16+g] < RESERVED_BT)
 889                 prev_mid = sce0->sf_idx[w*16+g];
 890             if (!sce1->zeroes[w*16+g] && !cpe->is_mask[w*16+g] && sce1->band_type[w*16+g] < RESERVED_BT)
 891                 prev_side = sce1->sf_idx[w*16+g];
 892             start += sce0->ics.swb_sizes[g];
 893         }
 894     }
 895 }
 896
 897 const AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = {
 898     [AAC_CODER_ANMR] = {
 899         search_for_quantizers_anmr,
 900         encode_window_bands_info,
 901         quantize_and_encode_band,
 902         ff_aac_encode_tns_info,
 903         ff_aac_encode_ltp_info,
 904         ff_aac_encode_main_pred,
 905         ff_aac_adjust_common_pred,
 906         ff_aac_adjust_common_ltp,
 907         ff_aac_apply_main_pred,
 908         ff_aac_apply_tns,
 909         ff_aac_update_ltp,
 910         ff_aac_ltp_insert_new_frame,
 911         set_special_band_scalefactors,
 912         search_for_pns,
 913         mark_pns,
 914         ff_aac_search_for_tns,
 915         ff_aac_search_for_ltp,
 916         search_for_ms,
 917         ff_aac_search_for_is,
 918         ff_aac_search_for_pred,
 919     },
 920     [AAC_CODER_TWOLOOP] = {
 921         search_for_quantizers_twoloop,
 922         codebook_trellis_rate,
 923         quantize_and_encode_band,
 924         ff_aac_encode_tns_info,
 925         ff_aac_encode_ltp_info,
 926         ff_aac_encode_main_pred,
 927         ff_aac_adjust_common_pred,
 928         ff_aac_adjust_common_ltp,
 929         ff_aac_apply_main_pred,
 930         ff_aac_apply_tns,
 931         ff_aac_update_ltp,
 932         ff_aac_ltp_insert_new_frame,
 933         set_special_band_scalefactors,
 934         search_for_pns,
 935         mark_pns,
 936         ff_aac_search_for_tns,
 937         ff_aac_search_for_ltp,
 938         search_for_ms,
 939         ff_aac_search_for_is,
 940         ff_aac_search_for_pred,
 941     },
 942     [AAC_CODER_FAST] = {
 943         search_for_quantizers_fast,
 944         codebook_trellis_rate,
 945         quantize_and_encode_band,
 946         ff_aac_encode_tns_info,
 947         ff_aac_encode_ltp_info,
 948         ff_aac_encode_main_pred,
 949         ff_aac_adjust_common_pred,
 950         ff_aac_adjust_common_ltp,
 951         ff_aac_apply_main_pred,
 952         ff_aac_apply_tns,
 953         ff_aac_update_ltp,
 954         ff_aac_ltp_insert_new_frame,
 955         set_special_band_scalefactors,
 956         search_for_pns,
 957         mark_pns,
 958         ff_aac_search_for_tns,
 959         ff_aac_search_for_ltp,
 960         search_for_ms,
 961         ff_aac_search_for_is,
 962         ff_aac_search_for_pred,
 963     },
 964 };