3e90880feb5ced9efde043c6d31f90612406a688
[ffmpeg.git] / 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     return pow(coef * Q, 0.75) + 0.4054;
65 }
66
67 static void quantize_bands(int (*out)[2], const float *in, const float *scaled,
68                            int size, float Q34, int is_signed, int maxval)
69 {
70     int i;
71     double qc;
72     for (i = 0; i < size; i++) {
73         qc = scaled[i] * Q34;
74         out[i][0] = (int)FFMIN((int)qc,            maxval);
75         out[i][1] = (int)FFMIN((int)(qc + 0.4054), maxval);
76         if (is_signed && in[i] < 0.0f) {
77             out[i][0] = -out[i][0];
78             out[i][1] = -out[i][1];
79         }
80     }
81 }
82
83 static void abs_pow34_v(float *out, const float *in, const int size)
84 {
85 #ifndef USE_REALLY_FULL_SEARCH
86     int i;
87     for (i = 0; i < size; i++)
88         out[i] = pow(fabsf(in[i]), 0.75);
89 #endif /* USE_REALLY_FULL_SEARCH */
90 }
91
92 static av_always_inline int quant2(float coef, const float Q)
93 {
94     return pow(coef * Q, 0.75);
95 }
96
97 static const uint8_t aac_cb_range [12] = {0, 3, 3, 3, 3, 9, 9, 8, 8, 13, 13, 17};
98 static const uint8_t aac_cb_maxval[12] = {0, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 16};
99
100 /**
101  * Calculate rate distortion cost for quantizing with given codebook
102  *
103  * @return quantization distortion
104  */
105 static float quantize_band_cost(struct AACEncContext *s, const float *in,
106                                 const float *scaled, int size, int scale_idx,
107                                 int cb, const float lambda, const float uplim,
108                                 int *bits)
109 {
110     const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
111     const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
112     const float CLIPPED_ESCAPE = 165140.0f*IQ;
113     int i, j, k;
114     float cost = 0;
115     const int dim = cb < FIRST_PAIR_BT ? 4 : 2;
116     int resbits = 0;
117 #ifndef USE_REALLY_FULL_SEARCH
118     const float  Q34 = pow(Q, 0.75);
119     const int range  = aac_cb_range[cb];
120     const int maxval = aac_cb_maxval[cb];
121     int offs[4];
122 #endif /* USE_REALLY_FULL_SEARCH */
123
124     if (!cb) {
125         for (i = 0; i < size; i++)
126             cost += in[i]*in[i]*lambda;
127         return cost;
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]*lambda;
145         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
146         minbits = ff_aac_spectral_bits[cb-1][minidx];
147         mincost += 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                     //do not code with escape sequence small values
177                     if (vec[k] == 64.0f && t < 39.0f*IQ) {
178                         rd = INFINITY;
179                         break;
180                     }
181                     if (vec[k] == 64.0f) { //FIXME: slow
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*cbrt(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*lambda;
196                 }
197             } else {
198                 for (k = 0; k < dim; k++) {
199                     float di = in[i+k] - vec[k]*IQ;
200                     rd += di*di*lambda;
201                 }
202             }
203             rd += 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 = pow(Q, 0.75);
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]*lambda;
259         minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
260         minbits = ff_aac_spectral_bits[cb-1][minidx];
261         mincost += 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                     //do not code with escape sequence small values
292                     if (vec[k] == 64.0f && t < 39.0f*IQ) {
293                         rd = INFINITY;
294                         break;
295                     }
296                     if (vec[k] == 64.0f) { //FIXME: slow
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*cbrt(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*lambda;
311                 }
312             } else {
313                 for (k = 0; k < dim; k++) {
314                     float di = in[i+k] - vec[k]*IQ;
315                     rd += di*di*lambda;
316                 }
317             }
318             rd += 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     int codebook; ///< codebook for coding band run
351     float cost;   ///< path cost
352     int run;
353 } BandCodingPath;
354
355 /**
356  * Encode band info for single window group bands.
357  */
358 static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,
359                                      int win, int group_len, const float lambda)
360 {
361     BandCodingPath path[120][12];
362     int w, swb, cb, start, start2, size;
363     int i, j;
364     const int max_sfb  = sce->ics.max_sfb;
365     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
366     const int run_esc  = (1 << run_bits) - 1;
367     int idx, ppos, count;
368     int stackrun[120], stackcb[120], stack_len;
369     float next_minrd = INFINITY;
370     int next_mincb = 0;
371
372     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
373     start = win*128;
374     for (cb = 0; cb < 12; cb++) {
375         path[0][cb].cost     = 0.0f;
376         path[0][cb].prev_idx = -1;
377         path[0][cb].run      = 0;
378     }
379     for (swb = 0; swb < max_sfb; swb++) {
380         start2 = start;
381         size = sce->ics.swb_sizes[swb];
382         if (sce->zeroes[win*16 + swb]) {
383             for (cb = 0; cb < 12; cb++) {
384                 path[swb+1][cb].prev_idx = cb;
385                 path[swb+1][cb].cost     = path[swb][cb].cost;
386                 path[swb+1][cb].run      = path[swb][cb].run + 1;
387             }
388         } else {
389             float minrd = next_minrd;
390             int mincb = next_mincb;
391             next_minrd = INFINITY;
392             next_mincb = 0;
393             for (cb = 0; cb < 12; cb++) {
394                 float cost_stay_here, cost_get_here;
395                 float rd = 0.0f;
396                 for (w = 0; w < group_len; w++) {
397                     FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(win+w)*16+swb];
398                     rd += quantize_band_cost(s, sce->coeffs + start + w*128,
399                                              s->scoefs + start + w*128, size,
400                                              sce->sf_idx[(win+w)*16+swb], cb,
401                                              lambda / band->threshold, INFINITY, NULL);
402                 }
403                 cost_stay_here = path[swb][cb].cost + rd;
404                 cost_get_here  = minrd              + rd + run_bits + 4;
405                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
406                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
407                     cost_stay_here += run_bits;
408                 if (cost_get_here < cost_stay_here) {
409                     path[swb+1][cb].prev_idx = mincb;
410                     path[swb+1][cb].cost     = cost_get_here;
411                     path[swb+1][cb].run      = 1;
412                 } else {
413                     path[swb+1][cb].prev_idx = cb;
414                     path[swb+1][cb].cost     = cost_stay_here;
415                     path[swb+1][cb].run      = path[swb][cb].run + 1;
416                 }
417                 if (path[swb+1][cb].cost < next_minrd) {
418                     next_minrd = path[swb+1][cb].cost;
419                     next_mincb = cb;
420                 }
421             }
422         }
423         start += sce->ics.swb_sizes[swb];
424     }
425
426     //convert resulting path from backward-linked list
427     stack_len = 0;
428     idx       = 0;
429     for (cb = 1; cb < 12; cb++)
430         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
431             idx = cb;
432     ppos = max_sfb;
433     while (ppos > 0) {
434         cb = idx;
435         stackrun[stack_len] = path[ppos][cb].run;
436         stackcb [stack_len] = cb;
437         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
438         ppos -= path[ppos][cb].run;
439         stack_len++;
440     }
441     //perform actual band info encoding
442     start = 0;
443     for (i = stack_len - 1; i >= 0; i--) {
444         put_bits(&s->pb, 4, stackcb[i]);
445         count = stackrun[i];
446         memset(sce->zeroes + win*16 + start, !stackcb[i], count);
447         //XXX: memset when band_type is also uint8_t
448         for (j = 0; j < count; j++) {
449             sce->band_type[win*16 + start] =  stackcb[i];
450             start++;
451         }
452         while (count >= run_esc) {
453             put_bits(&s->pb, run_bits, run_esc);
454             count -= run_esc;
455         }
456         put_bits(&s->pb, run_bits, count);
457     }
458 }
459
460 static void encode_window_bands_info_fixed(AACEncContext *s,
461                                            SingleChannelElement *sce,
462                                            int win, int group_len,
463                                            const float lambda)
464 {
465     encode_window_bands_info(s, sce, win, group_len, 1.0f);
466 }
467
468
469 typedef struct TrellisPath {
470     float cost;
471     int prev;
472     int min_val;
473     int max_val;
474 } TrellisPath;
475
476 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
477                                        SingleChannelElement *sce,
478                                        const float lambda)
479 {
480     int q, w, w2, g, start = 0;
481     int i;
482     int idx;
483     TrellisPath paths[256*121];
484     int bandaddr[121];
485     int minq;
486     float mincost;
487
488     for (i = 0; i < 256; i++) {
489         paths[i].cost    = 0.0f;
490         paths[i].prev    = -1;
491         paths[i].min_val = i;
492         paths[i].max_val = i;
493     }
494     for (i = 256; i < 256*121; i++) {
495         paths[i].cost    = INFINITY;
496         paths[i].prev    = -2;
497         paths[i].min_val = INT_MAX;
498         paths[i].max_val = 0;
499     }
500     idx = 256;
501     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
502     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
503         start = w*128;
504         for (g = 0; g < sce->ics.num_swb; g++) {
505             const float *coefs = sce->coeffs + start;
506             float qmin, qmax;
507             int nz = 0;
508
509             bandaddr[idx >> 8] = w * 16 + g;
510             qmin = INT_MAX;
511             qmax = 0.0f;
512             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
513                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
514                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
515                     sce->zeroes[(w+w2)*16+g] = 1;
516                     continue;
517                 }
518                 sce->zeroes[(w+w2)*16+g] = 0;
519                 nz = 1;
520                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
521                     float t = fabsf(coefs[w2*128+i]);
522                     if (t > 0.0f)
523                         qmin = fminf(qmin, t);
524                     qmax = fmaxf(qmax, t);
525                 }
526             }
527             if (nz) {
528                 int minscale, maxscale;
529                 float minrd = INFINITY;
530                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
531                 minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
532                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
533                 maxscale = av_clip_uint8(log2(qmax)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
534                 for (q = minscale; q < maxscale; q++) {
535                     float dists[12], dist;
536                     memset(dists, 0, sizeof(dists));
537                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
538                         FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
539                         int cb;
540                         for (cb = 0; cb <= ESC_BT; cb++)
541                             dists[cb] += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
542                                                             q, cb, lambda / band->threshold, INFINITY, NULL);
543                     }
544                     dist = dists[0];
545                     for (i = 1; i <= ESC_BT; i++)
546                         dist = fminf(dist, dists[i]);
547                     minrd = fminf(minrd, dist);
548
549                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++) {
550                         float cost;
551                         int minv, maxv;
552                         if (isinf(paths[idx - 256 + i].cost))
553                             continue;
554                         cost = paths[idx - 256 + i].cost + dist
555                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
556                         minv = FFMIN(paths[idx - 256 + i].min_val, q);
557                         maxv = FFMAX(paths[idx - 256 + i].max_val, q);
558                         if (cost < paths[idx + q].cost && maxv-minv < SCALE_MAX_DIFF) {
559                             paths[idx + q].cost    = cost;
560                             paths[idx + q].prev    = idx - 256 + i;
561                             paths[idx + q].min_val = minv;
562                             paths[idx + q].max_val = maxv;
563                         }
564                     }
565                 }
566             } else {
567                 for (q = 0; q < 256; q++) {
568                     if (!isinf(paths[idx - 256 + q].cost)) {
569                         paths[idx + q].cost = paths[idx - 256 + q].cost + 1;
570                         paths[idx + q].prev = idx - 256 + q;
571                         paths[idx + q].min_val = FFMIN(paths[idx - 256 + q].min_val, q);
572                         paths[idx + q].max_val = FFMAX(paths[idx - 256 + q].max_val, q);
573                         continue;
574                     }
575                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++) {
576                         float cost;
577                         int minv, maxv;
578                         if (isinf(paths[idx - 256 + i].cost))
579                             continue;
580                         cost = paths[idx - 256 + i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
581                         minv = FFMIN(paths[idx - 256 + i].min_val, q);
582                         maxv = FFMAX(paths[idx - 256 + i].max_val, q);
583                         if (cost < paths[idx + q].cost && maxv-minv < SCALE_MAX_DIFF) {
584                             paths[idx + q].cost    = cost;
585                             paths[idx + q].prev    = idx - 256 + i;
586                             paths[idx + q].min_val = minv;
587                             paths[idx + q].max_val = maxv;
588                         }
589                     }
590                 }
591             }
592             sce->zeroes[w*16+g] = !nz;
593             start += sce->ics.swb_sizes[g];
594             idx   += 256;
595         }
596     }
597     idx -= 256;
598     mincost = paths[idx].cost;
599     minq    = idx;
600     for (i = 1; i < 256; i++) {
601         if (paths[idx + i].cost < mincost) {
602             mincost = paths[idx + i].cost;
603             minq = idx + i;
604         }
605     }
606     while (minq >= 256) {
607         sce->sf_idx[bandaddr[minq>>8]] = minq & 0xFF;
608         minq = paths[minq].prev;
609     }
610     //set the same quantizers inside window groups
611     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
612         for (g = 0;  g < sce->ics.num_swb; g++)
613             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
614                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
615 }
616
617 /**
618  * two-loop quantizers search taken from ISO 13818-7 Appendix C
619  */
620 static void search_for_quantizers_twoloop(AVCodecContext *avctx,
621                                           AACEncContext *s,
622                                           SingleChannelElement *sce,
623                                           const float lambda)
624 {
625     int start = 0, i, w, w2, g;
626     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels;
627     float dists[128], uplims[128];
628     int fflag, minscaler;
629     int its  = 0;
630     int allz = 0;
631     float minthr = INFINITY;
632
633     //XXX: some heuristic to determine initial quantizers will reduce search time
634     memset(dists, 0, sizeof(dists));
635     //determine zero bands and upper limits
636     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
637         for (g = 0;  g < sce->ics.num_swb; g++) {
638             int nz = 0;
639             float uplim = 0.0f;
640             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
641                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
642                 uplim += band->threshold;
643                 if (band->energy <= band->threshold || band->threshold == 0.0f) {
644                     sce->zeroes[(w+w2)*16+g] = 1;
645                     continue;
646                 }
647                 nz = 1;
648             }
649             uplims[w*16+g] = uplim *512;
650             sce->zeroes[w*16+g] = !nz;
651             if (nz)
652                 minthr = fminf(minthr, uplim);
653             allz = FFMAX(allz, nz);
654         }
655     }
656     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
657         for (g = 0;  g < sce->ics.num_swb; g++) {
658             if (sce->zeroes[w*16+g]) {
659                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;
660                 continue;
661             }
662             sce->sf_idx[w*16+g] = SCALE_ONE_POS + fminf(log2(uplims[w*16+g]/minthr)*4,59);
663         }
664     }
665
666     if (!allz)
667         return;
668     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
669     //perform two-loop search
670     //outer loop - improve quality
671     do {
672         int tbits, qstep;
673         minscaler = sce->sf_idx[0];
674         //inner loop - quantize spectrum to fit into given number of bits
675         qstep = its ? 1 : 32;
676         do {
677             int prev = -1;
678             tbits = 0;
679             fflag = 0;
680             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
681                 start = w*128;
682                 for (g = 0;  g < sce->ics.num_swb; g++) {
683                     const float *coefs = sce->coeffs + start;
684                     const float *scaled = s->scoefs + start;
685                     int bits = 0;
686                     int cb;
687                     float mindist = INFINITY;
688                     int minbits = 0;
689
690                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218)
691                         continue;
692                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
693                     for (cb = 0; cb <= ESC_BT; cb++) {
694                         float dist = 0.0f;
695                         int bb = 0;
696                         for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
697                             int b;
698                             dist += quantize_band_cost(s, coefs + w2*128,
699                                                        scaled + w2*128,
700                                                        sce->ics.swb_sizes[g],
701                                                        sce->sf_idx[w*16+g],
702                                                        ESC_BT,
703                                                        1.0,
704                                                        INFINITY,
705                                                        &b);
706                             bb += b;
707                         }
708                         if (dist < mindist) {
709                             mindist = dist;
710                             minbits = bb;
711                         }
712                     }
713                     dists[w*16+g] = mindist - minbits;
714                     bits = minbits;
715                     if (prev != -1) {
716                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
717                     }
718                     tbits += bits;
719                     start += sce->ics.swb_sizes[g];
720                     prev = sce->sf_idx[w*16+g];
721                 }
722             }
723             if (tbits > destbits) {
724                 for (i = 0; i < 128; i++)
725                     if (sce->sf_idx[i] < 218 - qstep)
726                         sce->sf_idx[i] += qstep;
727             } else {
728                 for (i = 0; i < 128; i++)
729                     if (sce->sf_idx[i] > 60 - qstep)
730                         sce->sf_idx[i] -= qstep;
731             }
732             qstep >>= 1;
733             if (!qstep && tbits > destbits*1.02)
734                 qstep = 1;
735             if (sce->sf_idx[0] >= 217)
736                 break;
737         } while (qstep);
738
739         fflag = 0;
740         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
741         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
742             start = w*128;
743             for (g = 0; g < sce->ics.num_swb; g++) {
744                 int prevsc = sce->sf_idx[w*16+g];
745                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60)
746                     sce->sf_idx[w*16+g]--;
747                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
748                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
749                 if (sce->sf_idx[w*16+g] != prevsc)
750                     fflag = 1;
751             }
752         }
753         its++;
754     } while (fflag && its < 10);
755 }
756
757 static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
758                                        SingleChannelElement *sce,
759                                        const float lambda)
760 {
761     int start = 0, i, w, w2, g;
762     float uplim[128], maxq[128];
763     int minq, maxsf;
764     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
765     int last = 0, lastband = 0, curband = 0;
766     float avg_energy = 0.0;
767     if (sce->ics.num_windows == 1) {
768         start = 0;
769         for (i = 0; i < 1024; i++) {
770             if (i - start >= sce->ics.swb_sizes[curband]) {
771                 start += sce->ics.swb_sizes[curband];
772                 curband++;
773             }
774             if (sce->coeffs[i]) {
775                 avg_energy += sce->coeffs[i] * sce->coeffs[i];
776                 last = i;
777                 lastband = curband;
778             }
779         }
780     } else {
781         for (w = 0; w < 8; w++) {
782             const float *coeffs = sce->coeffs + w*128;
783             start = 0;
784             for (i = 0; i < 128; i++) {
785                 if (i - start >= sce->ics.swb_sizes[curband]) {
786                     start += sce->ics.swb_sizes[curband];
787                     curband++;
788                 }
789                 if (coeffs[i]) {
790                     avg_energy += coeffs[i] * coeffs[i];
791                     last = FFMAX(last, i);
792                     lastband = FFMAX(lastband, curband);
793                 }
794             }
795         }
796     }
797     last++;
798     avg_energy /= last;
799     if (avg_energy == 0.0f) {
800         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
801             sce->sf_idx[i] = SCALE_ONE_POS;
802         return;
803     }
804     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
805         start = w*128;
806         for (g = 0; g < sce->ics.num_swb; g++) {
807             float *coefs   = sce->coeffs + start;
808             const int size = sce->ics.swb_sizes[g];
809             int start2 = start, end2 = start + size, peakpos = start;
810             float maxval = -1, thr = 0.0f, t;
811             maxq[w*16+g] = 0.0f;
812             if (g > lastband) {
813                 maxq[w*16+g] = 0.0f;
814                 start += size;
815                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
816                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
817                 continue;
818             }
819             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
820                 for (i = 0; i < size; i++) {
821                     float t = coefs[w2*128+i]*coefs[w2*128+i];
822                     maxq[w*16+g] = fmaxf(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
823                     thr += t;
824                     if (sce->ics.num_windows == 1 && maxval < t) {
825                         maxval  = t;
826                         peakpos = start+i;
827                     }
828                 }
829             }
830             if (sce->ics.num_windows == 1) {
831                 start2 = FFMAX(peakpos - 2, start2);
832                 end2   = FFMIN(peakpos + 3, end2);
833             } else {
834                 start2 -= start;
835                 end2   -= start;
836             }
837             start += size;
838             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
839             t   = 1.0 - (1.0 * start2 / last);
840             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
841         }
842     }
843     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
844     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
845     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
846         start = w*128;
847         for (g = 0;  g < sce->ics.num_swb; g++) {
848             const float *coefs  = sce->coeffs + start;
849             const float *scaled = s->scoefs   + start;
850             const int size      = sce->ics.swb_sizes[g];
851             int scf, prev_scf, step;
852             int min_scf = 0, max_scf = 255;
853             float curdiff;
854             if (maxq[w*16+g] < 21.544) {
855                 sce->zeroes[w*16+g] = 1;
856                 start += size;
857                 continue;
858             }
859             sce->zeroes[w*16+g] = 0;
860             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2(1/maxq[w*16+g])*16/3, 60, 218);
861             step = 16;
862             for (;;) {
863                 float dist = 0.0f;
864                 int quant_max;
865
866                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
867                     int b;
868                     dist += quantize_band_cost(s, coefs + w2*128,
869                                                scaled + w2*128,
870                                                sce->ics.swb_sizes[g],
871                                                scf,
872                                                ESC_BT,
873                                                1.0,
874                                                INFINITY,
875                                                &b);
876                     dist -= b;
877                 }
878                 dist *= 1.0f/512.0f;
879                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[200 - scf + SCALE_ONE_POS - SCALE_DIV_512]);
880                 if (quant_max >= 8191) { // too much, return to the previous quantizer
881                     sce->sf_idx[w*16+g] = prev_scf;
882                     break;
883                 }
884                 prev_scf = scf;
885                 curdiff = fabsf(dist - uplim[w*16+g]);
886                 if (curdiff == 0.0f)
887                     step = 0;
888                 else
889                     step = fabsf(log2(curdiff));
890                 if (dist > uplim[w*16+g])
891                     step = -step;
892                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
893                     sce->sf_idx[w*16+g] = scf;
894                     break;
895                 }
896                 scf += step;
897                 if (step > 0)
898                     min_scf = scf;
899                 else
900                     max_scf = scf;
901             }
902             start += size;
903         }
904     }
905     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
906     for (i = 1; i < 128; i++) {
907         if (!sce->sf_idx[i])
908             sce->sf_idx[i] = sce->sf_idx[i-1];
909         else
910             minq = FFMIN(minq, sce->sf_idx[i]);
911     }
912     if (minq == INT_MAX)
913         minq = 0;
914     minq = FFMIN(minq, SCALE_MAX_POS);
915     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
916     for (i = 126; i >= 0; i--) {
917         if (!sce->sf_idx[i])
918             sce->sf_idx[i] = sce->sf_idx[i+1];
919         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
920     }
921 }
922
923 static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
924                                        SingleChannelElement *sce,
925                                        const float lambda)
926 {
927     int start = 0, i, w, w2, g;
928     int minq = 255;
929
930     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
931     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
932         start = w*128;
933         for (g = 0; g < sce->ics.num_swb; g++) {
934             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
935                 FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
936                 if (band->energy <= band->threshold) {
937                     sce->sf_idx[(w+w2)*16+g] = 218;
938                     sce->zeroes[(w+w2)*16+g] = 1;
939                 } else {
940                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2(band->threshold), 80, 218);
941                     sce->zeroes[(w+w2)*16+g] = 0;
942                 }
943                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
944             }
945         }
946     }
947     for (i = 0; i < 128; i++) {
948         sce->sf_idx[i] = 140;
949         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
950     }
951     //set the same quantizers inside window groups
952     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
953         for (g = 0;  g < sce->ics.num_swb; g++)
954             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
955                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
956 }
957
958 static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
959                           const float lambda)
960 {
961     int start = 0, i, w, w2, g;
962     float M[128], S[128];
963     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
964     SingleChannelElement *sce0 = &cpe->ch[0];
965     SingleChannelElement *sce1 = &cpe->ch[1];
966     if (!cpe->common_window)
967         return;
968     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
969         for (g = 0;  g < sce0->ics.num_swb; g++) {
970             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {
971                 float dist1 = 0.0f, dist2 = 0.0f;
972                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
973                     FFPsyBand *band0 = &s->psy.psy_bands[(s->cur_channel+0)*PSY_MAX_BANDS+(w+w2)*16+g];
974                     FFPsyBand *band1 = &s->psy.psy_bands[(s->cur_channel+1)*PSY_MAX_BANDS+(w+w2)*16+g];
975                     float minthr = fminf(band0->threshold, band1->threshold);
976                     float maxthr = fmaxf(band0->threshold, band1->threshold);
977                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
978                         M[i] = (sce0->coeffs[start+w2*128+i]
979                               + sce1->coeffs[start+w2*128+i]) * 0.5;
980                         S[i] =  sce0->coeffs[start+w2*128+i]
981                               - sce1->coeffs[start+w2*128+i];
982                     }
983                     abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
984                     abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
985                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
986                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
987                     dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
988                                                 L34,
989                                                 sce0->ics.swb_sizes[g],
990                                                 sce0->sf_idx[(w+w2)*16+g],
991                                                 sce0->band_type[(w+w2)*16+g],
992                                                 lambda / band0->threshold, INFINITY, NULL);
993                     dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
994                                                 R34,
995                                                 sce1->ics.swb_sizes[g],
996                                                 sce1->sf_idx[(w+w2)*16+g],
997                                                 sce1->band_type[(w+w2)*16+g],
998                                                 lambda / band1->threshold, INFINITY, NULL);
999                     dist2 += quantize_band_cost(s, M,
1000                                                 M34,
1001                                                 sce0->ics.swb_sizes[g],
1002                                                 sce0->sf_idx[(w+w2)*16+g],
1003                                                 sce0->band_type[(w+w2)*16+g],
1004                                                 lambda / maxthr, INFINITY, NULL);
1005                     dist2 += quantize_band_cost(s, S,
1006                                                 S34,
1007                                                 sce1->ics.swb_sizes[g],
1008                                                 sce1->sf_idx[(w+w2)*16+g],
1009                                                 sce1->band_type[(w+w2)*16+g],
1010                                                 lambda / minthr, INFINITY, NULL);
1011                 }
1012                 cpe->ms_mask[w*16+g] = dist2 < dist1;
1013             }
1014             start += sce0->ics.swb_sizes[g];
1015         }
1016     }
1017 }
1018
1019 AACCoefficientsEncoder ff_aac_coders[] = {
1020     {
1021         search_for_quantizers_faac,
1022         encode_window_bands_info_fixed,
1023         quantize_and_encode_band,
1024 //        search_for_ms,
1025     },
1026     {
1027         search_for_quantizers_anmr,
1028         encode_window_bands_info,
1029         quantize_and_encode_band,
1030 //        search_for_ms,
1031     },
1032     {
1033         search_for_quantizers_twoloop,
1034         encode_window_bands_info,
1035         quantize_and_encode_band,
1036 //        search_for_ms,
1037     },
1038     {
1039         search_for_quantizers_fast,
1040         encode_window_bands_info,
1041         quantize_and_encode_band,
1042 //        search_for_ms,
1043     },
1044 };