FFmpeg coverage

Line	Branch	Exec	Source
1			/*
2			* AAC encoder twoloop coder
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 encoder twoloop coder
25			* @author Konstantin Shishkov, Claudio Freire
26			*/
27
28			/**
29			* This file contains a template for the twoloop coder function.
30			* It needs to be provided, externally, as an already included declaration,
31			* the following functions from aacenc_quantization/util.h. They're not included
32			* explicitly here to make it possible to provide alternative implementations:
33			* - quantize_band_cost
34			* - abs_pow34_v
35			* - find_max_val
36			* - find_min_book
37			* - find_form_factor
38			*/
39
40			#ifndef AVCODEC_AACCODER_TWOLOOP_H
41			#define AVCODEC_AACCODER_TWOLOOP_H
42
43			#include <float.h>
44			#include "libavutil/mathematics.h"
45			#include "mathops.h"
46			#include "avcodec.h"
47			#include "put_bits.h"
48			#include "aac.h"
49			#include "aacenc.h"
50			#include "aactab.h"
51			#include "aacenctab.h"
52
53			/** Frequency in Hz for lower limit of noise substitution **/
54			#define NOISE_LOW_LIMIT 4000
55
56			/* Reflects the cost to change codebooks */
57		✗	static inline int ff_pns_bits(SingleChannelElement *sce, int w, int g)
58			{
59		✗	return (!g || !sce->zeroes[w*16+g-1] || !sce->can_pns[w*16+g-1]) ? 9 : 5;
60			}
61
62			/**
63			* two-loop quantizers search taken from ISO 13818-7 Appendix C
64			*/
65		✗	static void search_for_quantizers_twoloop(AVCodecContext *avctx,
66			AACEncContext *s,
67			SingleChannelElement *sce,
68			const float lambda)
69			{
70		✗	int start = 0, i, w, w2, g, recomprd;
71		✗	int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate
72		✗	/ ((avctx->flags & AV_CODEC_FLAG_QSCALE) ? 2.0f : avctx->ch_layout.nb_channels)
73		✗	* (lambda / 120.f);
74			int toomanybits, toofewbits;
75			char nzs[128];
76			uint8_t nextband[128];
77			int maxsf[128], minsf[128];
78		✗	float dists[128] = { 0 }, qenergies[128] = { 0 }, uplims[128], euplims[128], energies[128];
79			float maxvals[128], spread_thr_r[128];
80			float min_spread_thr_r, max_spread_thr_r;
81
82			/**
83			* rdlambda controls the maximum tolerated distortion. Twoloop
84			* will keep iterating until it fails to lower it or it reaches
85			* ulimit * rdlambda. Keeping it low increases quality on difficult
86			* signals, but lower it too much, and bits will be taken from weak
87			* signals, creating "holes". A balance is necessary.
88			* rdmax and rdmin specify the relative deviation from rdlambda
89			* allowed for tonality compensation
90			*/
91		✗	float rdlambda = av_clipf(2.0f * 120.f / lambda, 0.0625f, 16.0f);
92		✗	const float nzslope = 1.5f;
93		✗	float rdmin = 0.03125f;
94		✗	float rdmax = 1.0f;
95
96			/**
97			* sfoffs controls an offset of optmium allocation that will be
98			* applied based on lambda. Keep it real and modest, the loop
99			* will take care of the rest, this just accelerates convergence
100			*/
101		✗	float sfoffs = av_clipf(log2f(120.0f / lambda) * 4.0f, -5, 10);
102
103			int fflag, minscaler, nminscaler;
104		✗	int its = 0;
105		✗	int maxits = 30;
106		✗	int allz = 0;
107			int tbits;
108		✗	int cutoff = 1024;
109			int pns_start_pos;
110			int prev;
111
112			/**
113			* zeroscale controls a multiplier of the threshold, if band energy
114			* is below this, a zero is forced. Keep it lower than 1, unless
115			* low lambda is used, because energy < threshold doesn't mean there's
116			* no audible signal outright, it's just energy. Also make it rise
117			* slower than rdlambda, as rdscale has due compensation with
118			* noisy band depriorization below, whereas zeroing logic is rather dumb
119			*/
120			float zeroscale;
121		✗	if (lambda > 120.f) {
122		✗	zeroscale = av_clipf(powf(120.f / lambda, 0.25f), 0.0625f, 1.0f);
123			} else {
124		✗	zeroscale = 1.f;
125			}
126
127		✗	if (s->psy.bitres.alloc >= 0) {
128			/**
129			* Psy granted us extra bits to use, from the reservoire
130			* adjust for lambda except what psy already did
131			*/
132		✗	destbits = s->psy.bitres.alloc
133		✗	* (lambda / (avctx->global_quality ? avctx->global_quality : 120));
134			}
135
136		✗	if (avctx->flags & AV_CODEC_FLAG_QSCALE) {
137			/**
138			* Constant Q-scale doesn't compensate MS coding on its own
139			* No need to be overly precise, this only controls RD
140			* adjustment CB limits when going overboard
141			*/
142		✗	if (s->options.mid_side && s->cur_type == TYPE_CPE)
143		✗	destbits *= 2;
144
145			/**
146			* When using a constant Q-scale, don't adjust bits, just use RD
147			* Don't let it go overboard, though... 8x psy target is enough
148			*/
149		✗	toomanybits = 5800;
150		✗	toofewbits = destbits / 16;
151
152			/** Don't offset scalers, just RD */
153		✗	sfoffs = sce->ics.num_windows - 1;
154		✗	rdlambda = sqrtf(rdlambda);
155
156			/** search further */
157		✗	maxits *= 2;
158			} else {
159			/* When using ABR, be strict, but a reasonable leeway is
160			* critical to allow RC to smoothly track desired bitrate
161			* without sudden quality drops that cause audible artifacts.
162			* Symmetry is also desirable, to avoid systematic bias.
163			*/
164		✗	toomanybits = destbits + destbits/8;
165		✗	toofewbits = destbits - destbits/8;
166
167		✗	sfoffs = 0;
168		✗	rdlambda = sqrtf(rdlambda);
169			}
170
171			/** and zero out above cutoff frequency */
172			{
173		✗	int wlen = 1024 / sce->ics.num_windows;
174			/* the bandwidth is fixed at init and shared with the psy model */
175		✗	cutoff = s->bandwidth * 2 * wlen / avctx->sample_rate;
176		✗	pns_start_pos = NOISE_LOW_LIMIT * 2 * wlen / avctx->sample_rate;
177			}
178
179			/**
180			* for values above this the decoder might end up in an endless loop
181			* due to always having more bits than what can be encoded.
182			*/
183		✗	destbits = FFMIN(destbits, 5800);
184		✗	toomanybits = FFMIN(toomanybits, 5800);
185		✗	toofewbits = FFMIN(toofewbits, 5800);
186			/**
187			* XXX: some heuristic to determine initial quantizers will reduce search time
188			* determine zero bands and upper distortion limits
189			*/
190		✗	min_spread_thr_r = -1;
191		✗	max_spread_thr_r = -1;
192		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
193		✗	for (g = start = 0; g < sce->ics.num_swb; start += sce->ics.swb_sizes[g++]) {
194		✗	int nz = 0;
195		✗	float uplim = 0.0f, energy = 0.0f, spread = 0.0f;
196		✗	for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
197		✗	FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
198		✗	if (start >= cutoff || band->energy <= (band->threshold * zeroscale) || band->threshold == 0.0f) {
199		✗	sce->zeroes[(w+w2)*16+g] = 1;
200		✗	continue;
201			}
202		✗	nz = 1;
203			}
204		✗	if (!nz) {
205		✗	uplim = 0.0f;
206			} else {
207		✗	nz = 0;
208		✗	for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
209		✗	FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
210		✗	if (band->energy <= (band->threshold * zeroscale) || band->threshold == 0.0f)
211		✗	continue;
212		✗	uplim += band->threshold;
213		✗	energy += band->energy;
214		✗	spread += band->spread;
215		✗	nz++;
216			}
217			}
218		✗	uplims[w*16+g] = uplim;
219		✗	energies[w*16+g] = energy;
220		✗	nzs[w*16+g] = nz;
221		✗	sce->zeroes[w*16+g] = !nz;
222		✗	allz |= nz;
223		✗	if (nz && sce->can_pns[w*16+g]) {
224		✗	spread_thr_r[w*16+g] = energy * nz / (uplim * spread);
225		✗	if (min_spread_thr_r < 0) {
226		✗	min_spread_thr_r = max_spread_thr_r = spread_thr_r[w*16+g];
227			} else {
228		✗	min_spread_thr_r = FFMIN(min_spread_thr_r, spread_thr_r[w*16+g]);
229		✗	max_spread_thr_r = FFMAX(max_spread_thr_r, spread_thr_r[w*16+g]);
230			}
231			}
232			}
233			}
234
235			/** Compute initial scalers */
236		✗	minscaler = 65535;
237		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
238		✗	for (g = 0; g < sce->ics.num_swb; g++) {
239		✗	if (sce->zeroes[w*16+g]) {
240		✗	sce->sf_idx[w*16+g] = SCALE_ONE_POS;
241		✗	continue;
242			}
243			/**
244			* log2f-to-distortion ratio is, technically, 2 (1.5db = 4, but it's power vs level so it's 2).
245			* But, as offsets are applied, low-frequency signals are too sensitive to the induced distortion,
246			* so we make scaling more conservative by choosing a lower log2f-to-distortion ratio, and thus
247			* more robust.
248			*/
249		✗	sce->sf_idx[w*16+g] = av_clip(
250			SCALE_ONE_POS
251		✗	+ 1.75*log2f(FFMAX(0.00125f,uplims[w*16+g]) / sce->ics.swb_sizes[g])
252		✗	+ sfoffs,
253			60, SCALE_MAX_POS);
254		✗	minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
255			}
256			}
257
258			/** Clip */
259		✗	minscaler = av_clip(minscaler, SCALE_ONE_POS - SCALE_DIV_512, SCALE_MAX_POS - SCALE_DIV_512);
260		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
261		✗	for (g = 0; g < sce->ics.num_swb; g++)
262		✗	if (!sce->zeroes[w*16+g])
263		✗	sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF - 1);
264
265		✗	if (!allz)
266		✗	return;
267		✗	s->aacdsp.abs_pow34(s->scoefs, sce->coeffs, 1024);
268		✗	ff_quantize_band_cost_cache_init(s);
269
270		✗	for (i = 0; i < sizeof(minsf) / sizeof(minsf[0]); ++i)
271		✗	minsf[i] = 0;
272		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
273		✗	start = w*128;
274		✗	for (g = 0; g < sce->ics.num_swb; g++) {
275		✗	const float *scaled = s->scoefs + start;
276			int minsfidx;
277		✗	maxvals[w*16+g] = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled);
278		✗	if (maxvals[w*16+g] > 0) {
279		✗	minsfidx = coef2minsf(maxvals[w*16+g]);
280		✗	for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
281		✗	minsf[(w+w2)*16+g] = minsfidx;
282			}
283		✗	start += sce->ics.swb_sizes[g];
284			}
285			}
286
287			/**
288			* Scale uplims to match rate distortion to quality
289			* bu applying noisy band depriorization and tonal band prioritization.
290			* Maxval-energy ratio gives us an idea of how noisy/tonal the band is.
291			* If maxval^2 ~ energy, then that band is mostly noise, and we can relax
292			* rate distortion requirements.
293			*/
294		✗	memcpy(euplims, uplims, sizeof(euplims));
295		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
296			/** psy already prioritizes transients to some extent */
297		✗	float de_psy_factor = (sce->ics.num_windows > 1) ? 8.0f / sce->ics.group_len[w] : 1.0f;
298		✗	start = w*128;
299		✗	for (g = 0; g < sce->ics.num_swb; g++) {
300		✗	if (nzs[g] > 0) {
301		✗	float cleanup_factor = ff_sqrf(av_clipf(start / (cutoff * 0.75f), 1.0f, 2.0f));
302		✗	float energy2uplim = find_form_factor(
303		✗	sce->ics.group_len[w], sce->ics.swb_sizes[g],
304		✗	uplims[w*16+g] / (nzs[g] * sce->ics.swb_sizes[w]),
305		✗	sce->coeffs + start,
306			nzslope * cleanup_factor);
307		✗	energy2uplim *= de_psy_factor;
308		✗	if (!(avctx->flags & AV_CODEC_FLAG_QSCALE)) {
309			/** In ABR, we need to prioritize less and let rate control do its thing */
310		✗	energy2uplim = sqrtf(energy2uplim);
311			}
312		✗	energy2uplim = FFMAX(0.015625f, FFMIN(1.0f, energy2uplim));
313		✗	uplims[w*16+g] *= av_clipf(rdlambda * energy2uplim, rdmin, rdmax)
314		✗	* sce->ics.group_len[w];
315
316		✗	energy2uplim = find_form_factor(
317		✗	sce->ics.group_len[w], sce->ics.swb_sizes[g],
318		✗	uplims[w*16+g] / (nzs[g] * sce->ics.swb_sizes[w]),
319		✗	sce->coeffs + start,
320			2.0f);
321		✗	energy2uplim *= de_psy_factor;
322		✗	if (!(avctx->flags & AV_CODEC_FLAG_QSCALE)) {
323			/** In ABR, we need to prioritize less and let rate control do its thing */
324		✗	energy2uplim = sqrtf(energy2uplim);
325			}
326		✗	energy2uplim = FFMAX(0.015625f, FFMIN(1.0f, energy2uplim));
327		✗	euplims[w*16+g] *= av_clipf(rdlambda * energy2uplim * sce->ics.group_len[w],
328			0.5f, 1.0f);
329			}
330		✗	start += sce->ics.swb_sizes[g];
331			}
332			}
333
334		✗	for (i = 0; i < sizeof(maxsf) / sizeof(maxsf[0]); ++i)
335		✗	maxsf[i] = SCALE_MAX_POS;
336
337			//perform two-loop search
338			//outer loop - improve quality
339			do {
340			//inner loop - quantize spectrum to fit into given number of bits
341			int overdist;
342		✗	int qstep = its ? 1 : 32;
343			do {
344		✗	int changed = 0;
345		✗	prev = -1;
346		✗	recomprd = 0;
347		✗	tbits = 0;
348		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
349		✗	start = w*128;
350		✗	for (g = 0; g < sce->ics.num_swb; g++) {
351		✗	const float *coefs = &sce->coeffs[start];
352		✗	const float *scaled = &s->scoefs[start];
353		✗	int bits = 0;
354			int cb;
355		✗	float dist = 0.0f;
356		✗	float qenergy = 0.0f;
357
358		✗	if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
359		✗	start += sce->ics.swb_sizes[g];
360		✗	if (sce->can_pns[w*16+g]) {
361			/** PNS isn't free */
362		✗	tbits += ff_pns_bits(sce, w, g);
363			}
364		✗	continue;
365			}
366		✗	cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
367		✗	for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
368			int b;
369			float sqenergy;
370		✗	dist += quantize_band_cost_cached(s, w + w2, g, coefs + w2*128,
371		✗	scaled + w2*128,
372		✗	sce->ics.swb_sizes[g],
373		✗	sce->sf_idx[w*16+g],
374			cb,
375			1.0f,
376			INFINITY,
377			&b, &sqenergy,
378			0);
379		✗	bits += b;
380		✗	qenergy += sqenergy;
381			}
382		✗	dists[w*16+g] = dist - bits;
383		✗	qenergies[w*16+g] = qenergy;
384		✗	if (prev != -1) {
385		✗	int sfdiff = av_clip(sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO, 0, 2*SCALE_MAX_DIFF);
386		✗	bits += ff_aac_scalefactor_bits[sfdiff];
387			}
388		✗	tbits += bits;
389		✗	start += sce->ics.swb_sizes[g];
390		✗	prev = sce->sf_idx[w*16+g];
391			}
392			}
393		✗	if (tbits > toomanybits) {
394		✗	recomprd = 1;
395		✗	for (i = 0; i < 128; i++) {
396		✗	if (sce->sf_idx[i] < (SCALE_MAX_POS - SCALE_DIV_512)) {
397		✗	int maxsf_i = (tbits > 5800) ? SCALE_MAX_POS : maxsf[i];
398		✗	int new_sf = FFMIN(maxsf_i, sce->sf_idx[i] + qstep);
399		✗	if (new_sf != sce->sf_idx[i]) {
400		✗	sce->sf_idx[i] = new_sf;
401		✗	changed = 1;
402			}
403			}
404			}
405		✗	} else if (tbits < toofewbits) {
406		✗	recomprd = 1;
407		✗	for (i = 0; i < 128; i++) {
408		✗	if (sce->sf_idx[i] > SCALE_ONE_POS) {
409		✗	int new_sf = FFMAX3(minsf[i], SCALE_ONE_POS, sce->sf_idx[i] - qstep);
410		✗	if (new_sf != sce->sf_idx[i]) {
411		✗	sce->sf_idx[i] = new_sf;
412		✗	changed = 1;
413			}
414			}
415			}
416			}
417		✗	qstep >>= 1;
418		✗	if (!qstep && tbits > toomanybits && sce->sf_idx[0] < 217 && changed)
419		✗	qstep = 1;
420		✗	} while (qstep);
421
422		✗	overdist = 1;
423		✗	fflag = tbits < toofewbits;
424		✗	for (i = 0; i < 2 && (overdist || recomprd); ++i) {
425		✗	if (recomprd) {
426			/** Must recompute distortion */
427		✗	prev = -1;
428		✗	tbits = 0;
429		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
430		✗	start = w*128;
431		✗	for (g = 0; g < sce->ics.num_swb; g++) {
432		✗	const float *coefs = sce->coeffs + start;
433		✗	const float *scaled = s->scoefs + start;
434		✗	int bits = 0;
435			int cb;
436		✗	float dist = 0.0f;
437		✗	float qenergy = 0.0f;
438
439		✗	if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
440		✗	start += sce->ics.swb_sizes[g];
441		✗	if (sce->can_pns[w*16+g]) {
442			/** PNS isn't free */
443		✗	tbits += ff_pns_bits(sce, w, g);
444			}
445		✗	continue;
446			}
447		✗	cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
448		✗	for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
449			int b;
450			float sqenergy;
451		✗	dist += quantize_band_cost_cached(s, w + w2, g, coefs + w2*128,
452		✗	scaled + w2*128,
453		✗	sce->ics.swb_sizes[g],
454		✗	sce->sf_idx[w*16+g],
455			cb,
456			1.0f,
457			INFINITY,
458			&b, &sqenergy,
459			0);
460		✗	bits += b;
461		✗	qenergy += sqenergy;
462			}
463		✗	dists[w*16+g] = dist - bits;
464		✗	qenergies[w*16+g] = qenergy;
465		✗	if (prev != -1) {
466		✗	int sfdiff = av_clip(sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO, 0, 2*SCALE_MAX_DIFF);
467		✗	bits += ff_aac_scalefactor_bits[sfdiff];
468			}
469		✗	tbits += bits;
470		✗	start += sce->ics.swb_sizes[g];
471		✗	prev = sce->sf_idx[w*16+g];
472			}
473			}
474			}
475		✗	if (!i && s->options.pns && its > maxits/2 && tbits > toofewbits) {
476		✗	float maxoverdist = 0.0f;
477		✗	float ovrfactor = 1.f+(maxits-its)*16.f/maxits;
478		✗	overdist = recomprd = 0;
479		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
480		✗	for (g = start = 0; g < sce->ics.num_swb; start += sce->ics.swb_sizes[g++]) {
481		✗	if (!sce->zeroes[w*16+g] && sce->sf_idx[w*16+g] > SCALE_ONE_POS && dists[w*16+g] > uplims[w*16+g]*ovrfactor) {
482		✗	float ovrdist = dists[w*16+g] / FFMAX(uplims[w*16+g],euplims[w*16+g]);
483		✗	maxoverdist = FFMAX(maxoverdist, ovrdist);
484		✗	overdist++;
485			}
486			}
487			}
488		✗	if (overdist) {
489			/* We have overdistorted bands, trade for zeroes (that can be noise)
490			* Zero the bands in the lowest 1.25% spread-energy-threshold ranking
491			*/
492		✗	float minspread = max_spread_thr_r;
493		✗	float maxspread = min_spread_thr_r;
494			float zspread;
495		✗	int zeroable = 0;
496		✗	int zeroed = 0;
497			int maxzeroed, zloop;
498		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
499		✗	for (g = start = 0; g < sce->ics.num_swb; start += sce->ics.swb_sizes[g++]) {
500		✗	if (start >= pns_start_pos && !sce->zeroes[w*16+g] && sce->can_pns[w*16+g]) {
501		✗	minspread = FFMIN(minspread, spread_thr_r[w*16+g]);
502		✗	maxspread = FFMAX(maxspread, spread_thr_r[w*16+g]);
503		✗	zeroable++;
504			}
505			}
506			}
507		✗	zspread = (maxspread-minspread) * 0.0125f + minspread;
508			/* Don't PNS everything even if allowed. It suppresses bit starvation signals from RC,
509			* and forced the hand of the later search_for_pns step.
510			* Instead, PNS a fraction of the spread_thr_r range depending on how starved for bits we are,
511			* and leave further PNSing to search_for_pns if worthwhile.
512			*/
513		✗	zspread = FFMIN3(min_spread_thr_r * 8.f, zspread,
514			((toomanybits - tbits) * min_spread_thr_r + (tbits - toofewbits) * max_spread_thr_r) / (toomanybits - toofewbits + 1));
515		✗	maxzeroed = FFMIN(zeroable, FFMAX(1, (zeroable * its + maxits - 1) / (2 * maxits)));
516		✗	for (zloop = 0; zloop < 2; zloop++) {
517			/* Two passes: first distorted stuff - two birds in one shot and all that,
518			* then anything viable. Viable means not zero, but either CB=zero-able
519			* (too high SF), not SF <= 1 (that means we'd be operating at very high
520			* quality, we don't want PNS when doing VHQ), PNS allowed, and within
521			* the lowest ranking percentile.
522			*/
523		✗	float loopovrfactor = (zloop) ? 1.0f : ovrfactor;
524		✗	int loopminsf = (zloop) ? (SCALE_ONE_POS - SCALE_DIV_512) : SCALE_ONE_POS;
525			int mcb;
526		✗	for (g = sce->ics.num_swb-1; g > 0 && zeroed < maxzeroed; g--) {
527		✗	if (sce->ics.swb_offset[g] < pns_start_pos)
528		✗	continue;
529		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
530		✗	if (!sce->zeroes[w*16+g] && sce->can_pns[w*16+g] && spread_thr_r[w*16+g] <= zspread
531		✗	&& sce->sf_idx[w*16+g] > loopminsf
532		✗	&& (dists[w*16+g] > loopovrfactor*uplims[w*16+g] || !(mcb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]))
533		✗	|| (mcb <= 1 && dists[w*16+g] > FFMIN(uplims[w*16+g], euplims[w*16+g]))) ) {
534		✗	sce->zeroes[w*16+g] = 1;
535		✗	sce->band_type[w*16+g] = 0;
536		✗	zeroed++;
537			}
538			}
539			}
540			}
541		✗	if (zeroed)
542		✗	recomprd = fflag = 1;
543			} else {
544		✗	overdist = 0;
545			}
546			}
547			}
548
549		✗	minscaler = SCALE_MAX_POS;
550		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
551		✗	for (g = 0; g < sce->ics.num_swb; g++) {
552		✗	if (!sce->zeroes[w*16+g]) {
553		✗	minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
554			}
555			}
556			}
557
558		✗	minscaler = nminscaler = av_clip(minscaler, SCALE_ONE_POS - SCALE_DIV_512, SCALE_MAX_POS - SCALE_DIV_512);
559		✗	prev = -1;
560		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
561			/** Start with big steps, end up fine-tunning */
562		✗	int depth = (its > maxits/2) ? ((its > maxits*2/3) ? 1 : 3) : 10;
563		✗	int edepth = depth+2;
564		✗	float uplmax = its / (maxits*0.25f) + 1.0f;
565		✗	uplmax *= (tbits > destbits) ? FFMIN(2.0f, tbits / (float)FFMAX(1,destbits)) : 1.0f;
566		✗	start = w * 128;
567		✗	for (g = 0; g < sce->ics.num_swb; g++) {
568		✗	int prevsc = sce->sf_idx[w*16+g];
569		✗	if (prev < 0 && !sce->zeroes[w*16+g])
570		✗	prev = sce->sf_idx[0];
571		✗	if (!sce->zeroes[w*16+g]) {
572		✗	const float *coefs = sce->coeffs + start;
573		✗	const float *scaled = s->scoefs + start;
574		✗	int cmb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
575		✗	int mindeltasf = FFMAX(0, prev - SCALE_MAX_DIFF);
576		✗	int maxdeltasf = FFMIN(SCALE_MAX_POS - SCALE_DIV_512, prev + SCALE_MAX_DIFF);
577		✗	if ((!cmb || dists[w*16+g] > uplims[w*16+g]) && sce->sf_idx[w*16+g] > FFMAX(mindeltasf, minsf[w*16+g])) {
578			/* Try to make sure there is some energy in every nonzero band
579			* NOTE: This algorithm must be forcibly imbalanced, pushing harder
580			* on holes or more distorted bands at first, otherwise there's
581			* no net gain (since the next iteration will offset all bands
582			* on the opposite direction to compensate for extra bits)
583			*/
584		✗	for (i = 0; i < edepth && sce->sf_idx[w*16+g] > mindeltasf; ++i) {
585			int cb, bits;
586			float dist, qenergy;
587		✗	int mb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]-1);
588		✗	cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
589		✗	dist = qenergy = 0.f;
590		✗	bits = 0;
591		✗	if (!cb) {
592		✗	maxsf[w*16+g] = FFMIN(sce->sf_idx[w*16+g]-1, maxsf[w*16+g]);
593		✗	} else if (i >= depth && dists[w*16+g] < euplims[w*16+g]) {
594		✗	break;
595			}
596			/* !g is the DC band, it's important, since quantization error here
597			* applies to less than a cycle, it creates horrible intermodulation
598			* distortion if it doesn't stick to what psy requests
599			*/
600		✗	if (!g && sce->ics.num_windows > 1 && dists[w*16+g] >= euplims[w*16+g])
601		✗	maxsf[w*16+g] = FFMIN(sce->sf_idx[w*16+g], maxsf[w*16+g]);
602		✗	for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
603			int b;
604			float sqenergy;
605		✗	dist += quantize_band_cost_cached(s, w + w2, g, coefs + w2*128,
606		✗	scaled + w2*128,
607		✗	sce->ics.swb_sizes[g],
608		✗	sce->sf_idx[w*16+g]-1,
609			cb,
610			1.0f,
611			INFINITY,
612			&b, &sqenergy,
613			0);
614		✗	bits += b;
615		✗	qenergy += sqenergy;
616			}
617		✗	sce->sf_idx[w*16+g]--;
618		✗	dists[w*16+g] = dist - bits;
619		✗	qenergies[w*16+g] = qenergy;
620		✗	if (mb && (sce->sf_idx[w*16+g] < mindeltasf || (
621		✗	(dists[w*16+g] < FFMIN(uplmax*uplims[w*16+g], euplims[w*16+g]))
622		✗	&& (fabsf(qenergies[w*16+g]-energies[w*16+g]) < euplims[w*16+g])
623			) )) {
624			break;
625			}
626			}
627		✗	} else if (tbits > toofewbits && sce->sf_idx[w*16+g] < FFMIN(maxdeltasf, maxsf[w*16+g])
628		✗	&& (dists[w*16+g] < FFMIN(euplims[w*16+g], uplims[w*16+g]))
629		✗	&& (fabsf(qenergies[w*16+g]-energies[w*16+g]) < euplims[w*16+g])
630			) {
631			/** Um... over target. Save bits for more important stuff. */
632		✗	for (i = 0; i < depth && sce->sf_idx[w*16+g] < maxdeltasf; ++i) {
633			int cb, bits;
634			float dist, qenergy;
635		✗	cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]+1);
636		✗	if (cb > 0) {
637		✗	dist = qenergy = 0.f;
638		✗	bits = 0;
639		✗	for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
640			int b;
641			float sqenergy;
642		✗	dist += quantize_band_cost_cached(s, w + w2, g, coefs + w2*128,
643		✗	scaled + w2*128,
644		✗	sce->ics.swb_sizes[g],
645		✗	sce->sf_idx[w*16+g]+1,
646			cb,
647			1.0f,
648			INFINITY,
649			&b, &sqenergy,
650			0);
651		✗	bits += b;
652		✗	qenergy += sqenergy;
653			}
654		✗	dist -= bits;
655		✗	if (dist < FFMIN(euplims[w*16+g], uplims[w*16+g])) {
656		✗	sce->sf_idx[w*16+g]++;
657		✗	dists[w*16+g] = dist;
658		✗	qenergies[w*16+g] = qenergy;
659			} else {
660		✗	break;
661			}
662			} else {
663		✗	maxsf[w*16+g] = FFMIN(sce->sf_idx[w*16+g], maxsf[w*16+g]);
664		✗	break;
665			}
666			}
667			}
668		✗	prev = sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], mindeltasf, maxdeltasf);
669		✗	if (sce->sf_idx[w*16+g] != prevsc)
670		✗	fflag = 1;
671		✗	nminscaler = FFMIN(nminscaler, sce->sf_idx[w*16+g]);
672		✗	sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
673			}
674		✗	start += sce->ics.swb_sizes[g];
675			}
676			}
677
678			/** SF difference limit violation risk. Must re-clamp. */
679		✗	prev = -1;
680		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
681		✗	for (g = 0; g < sce->ics.num_swb; g++) {
682		✗	if (!sce->zeroes[w*16+g]) {
683		✗	int prevsf = sce->sf_idx[w*16+g];
684		✗	if (prev < 0)
685		✗	prev = prevsf;
686		✗	sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], prev - SCALE_MAX_DIFF, prev + SCALE_MAX_DIFF);
687		✗	sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
688		✗	prev = sce->sf_idx[w*16+g];
689		✗	if (!fflag && prevsf != sce->sf_idx[w*16+g])
690		✗	fflag = 1;
691			}
692			}
693			}
694
695		✗	its++;
696		✗	} while (fflag && its < maxits);
697
698			/** Scout out next nonzero bands */
699		✗	ff_init_nextband_map(sce, nextband);
700
701		✗	prev = -1;
702		✗	for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
703			/** Make sure proper codebooks are set */
704		✗	for (g = 0; g < sce->ics.num_swb; g++) {
705		✗	if (!sce->zeroes[w*16+g]) {
706		✗	sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
707		✗	if (sce->band_type[w*16+g] <= 0) {
708		✗	if (!ff_sfdelta_can_remove_band(sce, nextband, prev, w*16+g)) {
709			/** Cannot zero out, make sure it's not attempted */
710		✗	sce->band_type[w*16+g] = 1;
711			} else {
712		✗	sce->zeroes[w*16+g] = 1;
713		✗	sce->band_type[w*16+g] = 0;
714			}
715			}
716			} else {
717		✗	sce->band_type[w*16+g] = 0;
718			}
719			/** Check that there's no SF delta range violations */
720		✗	if (!sce->zeroes[w*16+g]) {
721		✗	if (prev != -1) {
722		✗	av_unused int sfdiff = sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO;
723			av_assert1(sfdiff >= 0 && sfdiff <= 2*SCALE_MAX_DIFF);
724		✗	} else if (sce->zeroes[0]) {
725			/** Set global gain to something useful */
726		✗	sce->sf_idx[0] = sce->sf_idx[w*16+g];
727			}
728		✗	prev = sce->sf_idx[w*16+g];
729			}
730			}
731			}
732			}
733
734			#endif /* AVCODEC_AACCODER_TWOLOOP_H */
735