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