1 /*
2 * AAC encoder psychoacoustic model
3 * Copyright (C) 2008 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 psychoacoustic model
25 */
26
27 #include "libavutil/attributes.h"
28 #include "libavutil/ffmath.h"
29
30 #include "avcodec.h"
31 #include "aactab.h"
32 #include "psymodel.h"
33
34 /***********************************
35 * TODOs:
36 * try other bitrate controlling mechanism (maybe use ratecontrol.c?)
37 * control quality for quality-based output
38 **********************************/
39
40 /**
41 * constants for 3GPP AAC psychoacoustic model
42 * @{
43 */
44 #define PSY_3GPP_THR_SPREAD_HI 1.5f // spreading factor for low-to-hi threshold spreading (15 dB/Bark)
45 #define PSY_3GPP_THR_SPREAD_LOW 3.0f // spreading factor for hi-to-low threshold spreading (30 dB/Bark)
46 /* spreading factor for low-to-hi energy spreading, long block, > 22kbps/channel (20dB/Bark) */
47 #define PSY_3GPP_EN_SPREAD_HI_L1 2.0f
48 /* spreading factor for low-to-hi energy spreading, long block, <= 22kbps/channel (15dB/Bark) */
49 #define PSY_3GPP_EN_SPREAD_HI_L2 1.5f
50 /* spreading factor for low-to-hi energy spreading, short block (15 dB/Bark) */
51 #define PSY_3GPP_EN_SPREAD_HI_S 1.5f
52 /* spreading factor for hi-to-low energy spreading, long block (30dB/Bark) */
53 #define PSY_3GPP_EN_SPREAD_LOW_L 3.0f
54 /* spreading factor for hi-to-low energy spreading, short block (20dB/Bark) */
55 #define PSY_3GPP_EN_SPREAD_LOW_S 2.0f
56
57 #define PSY_3GPP_RPEMIN 0.01f
58 #define PSY_3GPP_RPELEV 2.0f
59
60 #define PSY_3GPP_C1 3.0f /* log2(8) */
61 #define PSY_3GPP_C2 1.3219281f /* log2(2.5) */
62 #define PSY_3GPP_C3 0.55935729f /* 1 - C2 / C1 */
63
64 #define PSY_SNR_1DB 7.9432821e-1f /* -1dB */
65 #define PSY_SNR_25DB 3.1622776e-3f /* -25dB */
66
67 #define PSY_3GPP_SAVE_SLOPE_L -0.46666667f
68 #define PSY_3GPP_SAVE_SLOPE_S -0.36363637f
69 #define PSY_3GPP_SAVE_ADD_L -0.84285712f
70 #define PSY_3GPP_SAVE_ADD_S -0.75f
71 #define PSY_3GPP_SPEND_SLOPE_L 0.66666669f
72 #define PSY_3GPP_SPEND_SLOPE_S 0.81818181f
73 #define PSY_3GPP_SPEND_ADD_L -0.35f
74 #define PSY_3GPP_SPEND_ADD_S -0.26111111f
75 #define PSY_3GPP_CLIP_LO_L 0.2f
76 #define PSY_3GPP_CLIP_LO_S 0.2f
77 #define PSY_3GPP_CLIP_HI_L 0.95f
78 #define PSY_3GPP_CLIP_HI_S 0.75f
79
80 #define PSY_3GPP_AH_THR_LONG 0.5f
81 #define PSY_3GPP_AH_THR_SHORT 0.63f
82
83 #define PSY_PE_FORGET_SLOPE 511
84
85 enum {
86 PSY_3GPP_AH_NONE,
87 PSY_3GPP_AH_INACTIVE,
88 PSY_3GPP_AH_ACTIVE
89 };
90
91 #define PSY_3GPP_BITS_TO_PE(bits) ((bits) * 1.18f)
92 #define PSY_3GPP_PE_TO_BITS(bits) ((bits) / 1.18f)
93
94 /* LAME psy model constants */
95 #define PSY_LAME_FIR_LEN 21 ///< LAME psy model FIR order
96 #define AAC_BLOCK_SIZE_LONG 1024 ///< long block size
97 #define AAC_BLOCK_SIZE_SHORT 128 ///< short block size
98 #define AAC_NUM_BLOCKS_SHORT 8 ///< number of blocks in a short sequence
99 #define PSY_LAME_NUM_SUBBLOCKS 3 ///< Number of sub-blocks in each short block
100
101 /**
102 * @}
103 */
104
105 /**
106 * information for single band used by 3GPP TS26.403-inspired psychoacoustic model
107 */
108 typedef struct AacPsyBand{
109 float energy; ///< band energy
110 float thr; ///< energy threshold
111 float thr_quiet; ///< threshold in quiet
112 float nz_lines; ///< number of non-zero spectral lines
113 float active_lines; ///< number of active spectral lines
114 float pe; ///< perceptual entropy
115 float pe_const; ///< constant part of the PE calculation
116 float norm_fac; ///< normalization factor for linearization
117 int avoid_holes; ///< hole avoidance flag
118 }AacPsyBand;
119
120 /**
121 * single/pair channel context for psychoacoustic model
122 */
123 typedef struct AacPsyChannel{
124 AacPsyBand band[128]; ///< bands information
125 AacPsyBand prev_band[128]; ///< bands information from the previous frame
126
127 float win_energy; ///< sliding average of channel energy
128 float iir_state[2]; ///< hi-pass IIR filter state
129 uint8_t next_grouping; ///< stored grouping scheme for the next frame (in case of 8 short window sequence)
130 enum WindowSequence next_window_seq; ///< window sequence to be used in the next frame
131 /* LAME psy model specific members */
132 float attack_threshold; ///< attack threshold for this channel
133 float prev_energy_subshort[AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS];
134 int prev_attack; ///< attack value for the last short block in the previous sequence
135 }AacPsyChannel;
136
137 /**
138 * psychoacoustic model frame type-dependent coefficients
139 */
140 typedef struct AacPsyCoeffs{
141 float ath; ///< absolute threshold of hearing per bands
142 float barks; ///< Bark value for each spectral band in long frame
143 float spread_low[2]; ///< spreading factor for low-to-high threshold spreading in long frame
144 float spread_hi [2]; ///< spreading factor for high-to-low threshold spreading in long frame
145 float min_snr; ///< minimal SNR
146 }AacPsyCoeffs;
147
148 /**
149 * 3GPP TS26.403-inspired psychoacoustic model specific data
150 */
151 typedef struct AacPsyContext{
152 int chan_bitrate; ///< bitrate per channel
153 int frame_bits; ///< average bits per frame
154 int fill_level; ///< bit reservoir fill level
155 struct {
156 float min; ///< minimum allowed PE for bit factor calculation
157 float max; ///< maximum allowed PE for bit factor calculation
158 float previous; ///< allowed PE of the previous frame
159 float correction; ///< PE correction factor
160 } pe;
161 AacPsyCoeffs psy_coef[2][64];
162 AacPsyChannel *ch;
163 float global_quality; ///< normalized global quality taken from avctx
164 }AacPsyContext;
165
166 /**
167 * LAME psy model preset struct
168 */
169 typedef struct PsyLamePreset {
170 int quality; ///< Quality to map the rest of the vaules to.
171 /* This is overloaded to be both kbps per channel in ABR mode, and
172 * requested quality in constant quality mode.
173 */
174 float st_lrm; ///< short threshold for L, R, and M channels
175 } PsyLamePreset;
176
177 /**
178 * LAME psy model preset table for ABR
179 */
180 static const PsyLamePreset psy_abr_map[] = {
181 /* TODO: Tuning. These were taken from LAME. */
182 /* kbps/ch st_lrm */
183 { 8, 6.60},
184 { 16, 6.60},
185 { 24, 6.60},
186 { 32, 6.60},
187 { 40, 6.60},
188 { 48, 6.60},
189 { 56, 6.60},
190 { 64, 6.40},
191 { 80, 6.00},
192 { 96, 5.60},
193 {112, 5.20},
194 {128, 5.20},
195 {160, 5.20}
196 };
197
198 /**
199 * LAME psy model preset table for constant quality
200 */
201 static const PsyLamePreset psy_vbr_map[] = {
202 /* vbr_q st_lrm */
203 { 0, 4.20},
204 { 1, 4.20},
205 { 2, 4.20},
206 { 3, 4.20},
207 { 4, 4.20},
208 { 5, 4.20},
209 { 6, 4.20},
210 { 7, 4.20},
211 { 8, 4.20},
212 { 9, 4.20},
213 {10, 4.20}
214 };
215
216 /**
217 * LAME psy model FIR coefficient table
218 */
219 static const float psy_fir_coeffs[] = {
220 -8.65163e-18 * 2, -0.00851586 * 2, -6.74764e-18 * 2, 0.0209036 * 2,
221 -3.36639e-17 * 2, -0.0438162 * 2, -1.54175e-17 * 2, 0.0931738 * 2,
222 -5.52212e-17 * 2, -0.313819 * 2
223 };
224
225 #if ARCH_MIPS
226 # include "mips/aacpsy_mips.h"
227 #endif /* ARCH_MIPS */
228
229 /**
230 * Calculate the ABR attack threshold from the above LAME psymodel table.
231 */
lame_calc_attack_threshold(int bitrate)232 static float lame_calc_attack_threshold(int bitrate)
233 {
234 /* Assume max bitrate to start with */
235 int lower_range = 12, upper_range = 12;
236 int lower_range_kbps = psy_abr_map[12].quality;
237 int upper_range_kbps = psy_abr_map[12].quality;
238 int i;
239
240 /* Determine which bitrates the value specified falls between.
241 * If the loop ends without breaking our above assumption of 320kbps was correct.
242 */
243 for (i = 1; i < 13; i++) {
244 if (FFMAX(bitrate, psy_abr_map[i].quality) != bitrate) {
245 upper_range = i;
246 upper_range_kbps = psy_abr_map[i ].quality;
247 lower_range = i - 1;
248 lower_range_kbps = psy_abr_map[i - 1].quality;
249 break; /* Upper range found */
250 }
251 }
252
253 /* Determine which range the value specified is closer to */
254 if ((upper_range_kbps - bitrate) > (bitrate - lower_range_kbps))
255 return psy_abr_map[lower_range].st_lrm;
256 return psy_abr_map[upper_range].st_lrm;
257 }
258
259 /**
260 * LAME psy model specific initialization
261 */
lame_window_init(AacPsyContext * ctx,AVCodecContext * avctx)262 static av_cold void lame_window_init(AacPsyContext *ctx, AVCodecContext *avctx)
263 {
264 int i, j;
265
266 for (i = 0; i < avctx->channels; i++) {
267 AacPsyChannel *pch = &ctx->ch[i];
268
269 if (avctx->flags & AV_CODEC_FLAG_QSCALE)
270 pch->attack_threshold = psy_vbr_map[avctx->global_quality / FF_QP2LAMBDA].st_lrm;
271 else
272 pch->attack_threshold = lame_calc_attack_threshold(avctx->bit_rate / avctx->channels / 1000);
273
274 for (j = 0; j < AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS; j++)
275 pch->prev_energy_subshort[j] = 10.0f;
276 }
277 }
278
279 /**
280 * Calculate Bark value for given line.
281 */
calc_bark(float f)282 static av_cold float calc_bark(float f)
283 {
284 return 13.3f * atanf(0.00076f * f) + 3.5f * atanf((f / 7500.0f) * (f / 7500.0f));
285 }
286
287 #define ATH_ADD 4
288 /**
289 * Calculate ATH value for given frequency.
290 * Borrowed from Lame.
291 */
ath(float f,float add)292 static av_cold float ath(float f, float add)
293 {
294 f /= 1000.0f;
295 return 3.64 * pow(f, -0.8)
296 - 6.8 * exp(-0.6 * (f - 3.4) * (f - 3.4))
297 + 6.0 * exp(-0.15 * (f - 8.7) * (f - 8.7))
298 + (0.6 + 0.04 * add) * 0.001 * f * f * f * f;
299 }
300
psy_3gpp_init(FFPsyContext * ctx)301 static av_cold int psy_3gpp_init(FFPsyContext *ctx) {
302 AacPsyContext *pctx;
303 float bark;
304 int i, j, g, start;
305 float prev, minscale, minath, minsnr, pe_min;
306 int chan_bitrate = ctx->avctx->bit_rate / ((ctx->avctx->flags & AV_CODEC_FLAG_QSCALE) ? 2.0f : ctx->avctx->channels);
307
308 const int bandwidth = ctx->cutoff ? ctx->cutoff : AAC_CUTOFF(ctx->avctx);
309 const float num_bark = calc_bark((float)bandwidth);
310
311 if (bandwidth <= 0)
312 return AVERROR(EINVAL);
313
314 ctx->model_priv_data = av_mallocz(sizeof(AacPsyContext));
315 if (!ctx->model_priv_data)
316 return AVERROR(ENOMEM);
317 pctx = ctx->model_priv_data;
318 pctx->global_quality = (ctx->avctx->global_quality ? ctx->avctx->global_quality : 120) * 0.01f;
319
320 if (ctx->avctx->flags & AV_CODEC_FLAG_QSCALE) {
321 /* Use the target average bitrate to compute spread parameters */
322 chan_bitrate = (int)(chan_bitrate / 120.0 * (ctx->avctx->global_quality ? ctx->avctx->global_quality : 120));
323 }
324
325 pctx->chan_bitrate = chan_bitrate;
326 pctx->frame_bits = FFMIN(2560, chan_bitrate * AAC_BLOCK_SIZE_LONG / ctx->avctx->sample_rate);
327 pctx->pe.min = 8.0f * AAC_BLOCK_SIZE_LONG * bandwidth / (ctx->avctx->sample_rate * 2.0f);
328 pctx->pe.max = 12.0f * AAC_BLOCK_SIZE_LONG * bandwidth / (ctx->avctx->sample_rate * 2.0f);
329 ctx->bitres.size = 6144 - pctx->frame_bits;
330 ctx->bitres.size -= ctx->bitres.size % 8;
331 pctx->fill_level = ctx->bitres.size;
332 minath = ath(3410 - 0.733 * ATH_ADD, ATH_ADD);
333 for (j = 0; j < 2; j++) {
334 AacPsyCoeffs *coeffs = pctx->psy_coef[j];
335 const uint8_t *band_sizes = ctx->bands[j];
336 float line_to_frequency = ctx->avctx->sample_rate / (j ? 256.f : 2048.0f);
337 float avg_chan_bits = chan_bitrate * (j ? 128.0f : 1024.0f) / ctx->avctx->sample_rate;
338 /* reference encoder uses 2.4% here instead of 60% like the spec says */
339 float bark_pe = 0.024f * PSY_3GPP_BITS_TO_PE(avg_chan_bits) / num_bark;
340 float en_spread_low = j ? PSY_3GPP_EN_SPREAD_LOW_S : PSY_3GPP_EN_SPREAD_LOW_L;
341 /* High energy spreading for long blocks <= 22kbps/channel and short blocks are the same. */
342 float en_spread_hi = (j || (chan_bitrate <= 22.0f)) ? PSY_3GPP_EN_SPREAD_HI_S : PSY_3GPP_EN_SPREAD_HI_L1;
343
344 i = 0;
345 prev = 0.0;
346 for (g = 0; g < ctx->num_bands[j]; g++) {
347 i += band_sizes[g];
348 bark = calc_bark((i-1) * line_to_frequency);
349 coeffs[g].barks = (bark + prev) / 2.0;
350 prev = bark;
351 }
352 for (g = 0; g < ctx->num_bands[j] - 1; g++) {
353 AacPsyCoeffs *coeff = &coeffs[g];
354 float bark_width = coeffs[g+1].barks - coeffs->barks;
355 coeff->spread_low[0] = ff_exp10(-bark_width * PSY_3GPP_THR_SPREAD_LOW);
356 coeff->spread_hi [0] = ff_exp10(-bark_width * PSY_3GPP_THR_SPREAD_HI);
357 coeff->spread_low[1] = ff_exp10(-bark_width * en_spread_low);
358 coeff->spread_hi [1] = ff_exp10(-bark_width * en_spread_hi);
359 pe_min = bark_pe * bark_width;
360 minsnr = exp2(pe_min / band_sizes[g]) - 1.5f;
361 coeff->min_snr = av_clipf(1.0f / minsnr, PSY_SNR_25DB, PSY_SNR_1DB);
362 }
363 start = 0;
364 for (g = 0; g < ctx->num_bands[j]; g++) {
365 minscale = ath(start * line_to_frequency, ATH_ADD);
366 for (i = 1; i < band_sizes[g]; i++)
367 minscale = FFMIN(minscale, ath((start + i) * line_to_frequency, ATH_ADD));
368 coeffs[g].ath = minscale - minath;
369 start += band_sizes[g];
370 }
371 }
372
373 pctx->ch = av_mallocz_array(ctx->avctx->channels, sizeof(AacPsyChannel));
374 if (!pctx->ch) {
375 av_freep(&ctx->model_priv_data);
376 return AVERROR(ENOMEM);
377 }
378
379 lame_window_init(pctx, ctx->avctx);
380
381 return 0;
382 }
383
384 /**
385 * IIR filter used in block switching decision
386 */
iir_filter(int in,float state[2])387 static float iir_filter(int in, float state[2])
388 {
389 float ret;
390
391 ret = 0.7548f * (in - state[0]) + 0.5095f * state[1];
392 state[0] = in;
393 state[1] = ret;
394 return ret;
395 }
396
397 /**
398 * window grouping information stored as bits (0 - new group, 1 - group continues)
399 */
400 static const uint8_t window_grouping[9] = {
401 0xB6, 0x6C, 0xD8, 0xB2, 0x66, 0xC6, 0x96, 0x36, 0x36
402 };
403
404 /**
405 * Tell encoder which window types to use.
406 * @see 3GPP TS26.403 5.4.1 "Blockswitching"
407 */
psy_3gpp_window(FFPsyContext * ctx,const int16_t * audio,const int16_t * la,int channel,int prev_type)408 static av_unused FFPsyWindowInfo psy_3gpp_window(FFPsyContext *ctx,
409 const int16_t *audio,
410 const int16_t *la,
411 int channel, int prev_type)
412 {
413 int i, j;
414 int br = ((AacPsyContext*)ctx->model_priv_data)->chan_bitrate;
415 int attack_ratio = br <= 16000 ? 18 : 10;
416 AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data;
417 AacPsyChannel *pch = &pctx->ch[channel];
418 uint8_t grouping = 0;
419 int next_type = pch->next_window_seq;
420 FFPsyWindowInfo wi = { { 0 } };
421
422 if (la) {
423 float s[8], v;
424 int switch_to_eight = 0;
425 float sum = 0.0, sum2 = 0.0;
426 int attack_n = 0;
427 int stay_short = 0;
428 for (i = 0; i < 8; i++) {
429 for (j = 0; j < 128; j++) {
430 v = iir_filter(la[i*128+j], pch->iir_state);
431 sum += v*v;
432 }
433 s[i] = sum;
434 sum2 += sum;
435 }
436 for (i = 0; i < 8; i++) {
437 if (s[i] > pch->win_energy * attack_ratio) {
438 attack_n = i + 1;
439 switch_to_eight = 1;
440 break;
441 }
442 }
443 pch->win_energy = pch->win_energy*7/8 + sum2/64;
444
445 wi.window_type[1] = prev_type;
446 switch (prev_type) {
447 case ONLY_LONG_SEQUENCE:
448 wi.window_type[0] = switch_to_eight ? LONG_START_SEQUENCE : ONLY_LONG_SEQUENCE;
449 next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : ONLY_LONG_SEQUENCE;
450 break;
451 case LONG_START_SEQUENCE:
452 wi.window_type[0] = EIGHT_SHORT_SEQUENCE;
453 grouping = pch->next_grouping;
454 next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE;
455 break;
456 case LONG_STOP_SEQUENCE:
457 wi.window_type[0] = switch_to_eight ? LONG_START_SEQUENCE : ONLY_LONG_SEQUENCE;
458 next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : ONLY_LONG_SEQUENCE;
459 break;
460 case EIGHT_SHORT_SEQUENCE:
461 stay_short = next_type == EIGHT_SHORT_SEQUENCE || switch_to_eight;
462 wi.window_type[0] = stay_short ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE;
463 grouping = next_type == EIGHT_SHORT_SEQUENCE ? pch->next_grouping : 0;
464 next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE;
465 break;
466 }
467
468 pch->next_grouping = window_grouping[attack_n];
469 pch->next_window_seq = next_type;
470 } else {
471 for (i = 0; i < 3; i++)
472 wi.window_type[i] = prev_type;
473 grouping = (prev_type == EIGHT_SHORT_SEQUENCE) ? window_grouping[0] : 0;
474 }
475
476 wi.window_shape = 1;
477 if (wi.window_type[0] != EIGHT_SHORT_SEQUENCE) {
478 wi.num_windows = 1;
479 wi.grouping[0] = 1;
480 } else {
481 int lastgrp = 0;
482 wi.num_windows = 8;
483 for (i = 0; i < 8; i++) {
484 if (!((grouping >> i) & 1))
485 lastgrp = i;
486 wi.grouping[lastgrp]++;
487 }
488 }
489
490 return wi;
491 }
492
493 /* 5.6.1.2 "Calculation of Bit Demand" */
calc_bit_demand(AacPsyContext * ctx,float pe,int bits,int size,int short_window)494 static int calc_bit_demand(AacPsyContext *ctx, float pe, int bits, int size,
495 int short_window)
496 {
497 const float bitsave_slope = short_window ? PSY_3GPP_SAVE_SLOPE_S : PSY_3GPP_SAVE_SLOPE_L;
498 const float bitsave_add = short_window ? PSY_3GPP_SAVE_ADD_S : PSY_3GPP_SAVE_ADD_L;
499 const float bitspend_slope = short_window ? PSY_3GPP_SPEND_SLOPE_S : PSY_3GPP_SPEND_SLOPE_L;
500 const float bitspend_add = short_window ? PSY_3GPP_SPEND_ADD_S : PSY_3GPP_SPEND_ADD_L;
501 const float clip_low = short_window ? PSY_3GPP_CLIP_LO_S : PSY_3GPP_CLIP_LO_L;
502 const float clip_high = short_window ? PSY_3GPP_CLIP_HI_S : PSY_3GPP_CLIP_HI_L;
503 float clipped_pe, bit_save, bit_spend, bit_factor, fill_level, forgetful_min_pe;
504
505 ctx->fill_level += ctx->frame_bits - bits;
506 ctx->fill_level = av_clip(ctx->fill_level, 0, size);
507 fill_level = av_clipf((float)ctx->fill_level / size, clip_low, clip_high);
508 clipped_pe = av_clipf(pe, ctx->pe.min, ctx->pe.max);
509 bit_save = (fill_level + bitsave_add) * bitsave_slope;
510 assert(bit_save <= 0.3f && bit_save >= -0.05000001f);
511 bit_spend = (fill_level + bitspend_add) * bitspend_slope;
512 assert(bit_spend <= 0.5f && bit_spend >= -0.1f);
513 /* The bit factor graph in the spec is obviously incorrect.
514 * bit_spend + ((bit_spend - bit_spend))...
515 * The reference encoder subtracts everything from 1, but also seems incorrect.
516 * 1 - bit_save + ((bit_spend + bit_save))...
517 * Hopefully below is correct.
518 */
519 bit_factor = 1.0f - bit_save + ((bit_spend - bit_save) / (ctx->pe.max - ctx->pe.min)) * (clipped_pe - ctx->pe.min);
520 /* NOTE: The reference encoder attempts to center pe max/min around the current pe.
521 * Here we do that by slowly forgetting pe.min when pe stays in a range that makes
522 * it unlikely (ie: above the mean)
523 */
524 ctx->pe.max = FFMAX(pe, ctx->pe.max);
525 forgetful_min_pe = ((ctx->pe.min * PSY_PE_FORGET_SLOPE)
526 + FFMAX(ctx->pe.min, pe * (pe / ctx->pe.max))) / (PSY_PE_FORGET_SLOPE + 1);
527 ctx->pe.min = FFMIN(pe, forgetful_min_pe);
528
529 /* NOTE: allocate a minimum of 1/8th average frame bits, to avoid
530 * reservoir starvation from producing zero-bit frames
531 */
532 return FFMIN(
533 ctx->frame_bits * bit_factor,
534 FFMAX(ctx->frame_bits + size - bits, ctx->frame_bits / 8));
535 }
536
calc_pe_3gpp(AacPsyBand * band)537 static float calc_pe_3gpp(AacPsyBand *band)
538 {
539 float pe, a;
540
541 band->pe = 0.0f;
542 band->pe_const = 0.0f;
543 band->active_lines = 0.0f;
544 if (band->energy > band->thr) {
545 a = log2f(band->energy);
546 pe = a - log2f(band->thr);
547 band->active_lines = band->nz_lines;
548 if (pe < PSY_3GPP_C1) {
549 pe = pe * PSY_3GPP_C3 + PSY_3GPP_C2;
550 a = a * PSY_3GPP_C3 + PSY_3GPP_C2;
551 band->active_lines *= PSY_3GPP_C3;
552 }
553 band->pe = pe * band->nz_lines;
554 band->pe_const = a * band->nz_lines;
555 }
556
557 return band->pe;
558 }
559
calc_reduction_3gpp(float a,float desired_pe,float pe,float active_lines)560 static float calc_reduction_3gpp(float a, float desired_pe, float pe,
561 float active_lines)
562 {
563 float thr_avg, reduction;
564
565 if(active_lines == 0.0)
566 return 0;
567
568 thr_avg = exp2f((a - pe) / (4.0f * active_lines));
569 reduction = exp2f((a - desired_pe) / (4.0f * active_lines)) - thr_avg;
570
571 return FFMAX(reduction, 0.0f);
572 }
573
calc_reduced_thr_3gpp(AacPsyBand * band,float min_snr,float reduction)574 static float calc_reduced_thr_3gpp(AacPsyBand *band, float min_snr,
575 float reduction)
576 {
577 float thr = band->thr;
578
579 if (band->energy > thr) {
580 thr = sqrtf(thr);
581 thr = sqrtf(thr) + reduction;
582 thr *= thr;
583 thr *= thr;
584
585 /* This deviates from the 3GPP spec to match the reference encoder.
586 * It performs min(thr_reduced, max(thr, energy/min_snr)) only for bands
587 * that have hole avoidance on (active or inactive). It always reduces the
588 * threshold of bands with hole avoidance off.
589 */
590 if (thr > band->energy * min_snr && band->avoid_holes != PSY_3GPP_AH_NONE) {
591 thr = FFMAX(band->thr, band->energy * min_snr);
592 band->avoid_holes = PSY_3GPP_AH_ACTIVE;
593 }
594 }
595
596 return thr;
597 }
598
599 #ifndef calc_thr_3gpp
calc_thr_3gpp(const FFPsyWindowInfo * wi,const int num_bands,AacPsyChannel * pch,const uint8_t * band_sizes,const float * coefs,const int cutoff)600 static void calc_thr_3gpp(const FFPsyWindowInfo *wi, const int num_bands, AacPsyChannel *pch,
601 const uint8_t *band_sizes, const float *coefs, const int cutoff)
602 {
603 int i, w, g;
604 int start = 0, wstart = 0;
605 for (w = 0; w < wi->num_windows*16; w += 16) {
606 wstart = 0;
607 for (g = 0; g < num_bands; g++) {
608 AacPsyBand *band = &pch->band[w+g];
609
610 float form_factor = 0.0f;
611 float Temp;
612 band->energy = 0.0f;
613 if (wstart < cutoff) {
614 for (i = 0; i < band_sizes[g]; i++) {
615 band->energy += coefs[start+i] * coefs[start+i];
616 form_factor += sqrtf(fabs(coefs[start+i]));
617 }
618 }
619 Temp = band->energy > 0 ? sqrtf((float)band_sizes[g] / band->energy) : 0;
620 band->thr = band->energy * 0.001258925f;
621 band->nz_lines = form_factor * sqrtf(Temp);
622
623 start += band_sizes[g];
624 wstart += band_sizes[g];
625 }
626 }
627 }
628 #endif /* calc_thr_3gpp */
629
630 #ifndef psy_hp_filter
psy_hp_filter(const float * firbuf,float * hpfsmpl,const float * psy_fir_coeffs)631 static void psy_hp_filter(const float *firbuf, float *hpfsmpl, const float *psy_fir_coeffs)
632 {
633 int i, j;
634 for (i = 0; i < AAC_BLOCK_SIZE_LONG; i++) {
635 float sum1, sum2;
636 sum1 = firbuf[i + (PSY_LAME_FIR_LEN - 1) / 2];
637 sum2 = 0.0;
638 for (j = 0; j < ((PSY_LAME_FIR_LEN - 1) / 2) - 1; j += 2) {
639 sum1 += psy_fir_coeffs[j] * (firbuf[i + j] + firbuf[i + PSY_LAME_FIR_LEN - j]);
640 sum2 += psy_fir_coeffs[j + 1] * (firbuf[i + j + 1] + firbuf[i + PSY_LAME_FIR_LEN - j - 1]);
641 }
642 /* NOTE: The LAME psymodel expects it's input in the range -32768 to 32768.
643 * Tuning this for normalized floats would be difficult. */
644 hpfsmpl[i] = (sum1 + sum2) * 32768.0f;
645 }
646 }
647 #endif /* psy_hp_filter */
648
649 /**
650 * Calculate band thresholds as suggested in 3GPP TS26.403
651 */
psy_3gpp_analyze_channel(FFPsyContext * ctx,int channel,const float * coefs,const FFPsyWindowInfo * wi)652 static void psy_3gpp_analyze_channel(FFPsyContext *ctx, int channel,
653 const float *coefs, const FFPsyWindowInfo *wi)
654 {
655 AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data;
656 AacPsyChannel *pch = &pctx->ch[channel];
657 int i, w, g;
658 float desired_bits, desired_pe, delta_pe, reduction= NAN, spread_en[128] = {0};
659 float a = 0.0f, active_lines = 0.0f, norm_fac = 0.0f;
660 float pe = pctx->chan_bitrate > 32000 ? 0.0f : FFMAX(50.0f, 100.0f - pctx->chan_bitrate * 100.0f / 32000.0f);
661 const int num_bands = ctx->num_bands[wi->num_windows == 8];
662 const uint8_t *band_sizes = ctx->bands[wi->num_windows == 8];
663 AacPsyCoeffs *coeffs = pctx->psy_coef[wi->num_windows == 8];
664 const float avoid_hole_thr = wi->num_windows == 8 ? PSY_3GPP_AH_THR_SHORT : PSY_3GPP_AH_THR_LONG;
665 const int bandwidth = ctx->cutoff ? ctx->cutoff : AAC_CUTOFF(ctx->avctx);
666 const int cutoff = bandwidth * 2048 / wi->num_windows / ctx->avctx->sample_rate;
667
668 //calculate energies, initial thresholds and related values - 5.4.2 "Threshold Calculation"
669 calc_thr_3gpp(wi, num_bands, pch, band_sizes, coefs, cutoff);
670
671 //modify thresholds and energies - spread, threshold in quiet, pre-echo control
672 for (w = 0; w < wi->num_windows*16; w += 16) {
673 AacPsyBand *bands = &pch->band[w];
674
675 /* 5.4.2.3 "Spreading" & 5.4.3 "Spread Energy Calculation" */
676 spread_en[0] = bands[0].energy;
677 for (g = 1; g < num_bands; g++) {
678 bands[g].thr = FFMAX(bands[g].thr, bands[g-1].thr * coeffs[g].spread_hi[0]);
679 spread_en[w+g] = FFMAX(bands[g].energy, spread_en[w+g-1] * coeffs[g].spread_hi[1]);
680 }
681 for (g = num_bands - 2; g >= 0; g--) {
682 bands[g].thr = FFMAX(bands[g].thr, bands[g+1].thr * coeffs[g].spread_low[0]);
683 spread_en[w+g] = FFMAX(spread_en[w+g], spread_en[w+g+1] * coeffs[g].spread_low[1]);
684 }
685 //5.4.2.4 "Threshold in quiet"
686 for (g = 0; g < num_bands; g++) {
687 AacPsyBand *band = &bands[g];
688
689 band->thr_quiet = band->thr = FFMAX(band->thr, coeffs[g].ath);
690 //5.4.2.5 "Pre-echo control"
691 if (!(wi->window_type[0] == LONG_STOP_SEQUENCE || (!w && wi->window_type[1] == LONG_START_SEQUENCE)))
692 band->thr = FFMAX(PSY_3GPP_RPEMIN*band->thr, FFMIN(band->thr,
693 PSY_3GPP_RPELEV*pch->prev_band[w+g].thr_quiet));
694
695 /* 5.6.1.3.1 "Preparatory steps of the perceptual entropy calculation" */
696 pe += calc_pe_3gpp(band);
697 a += band->pe_const;
698 active_lines += band->active_lines;
699
700 /* 5.6.1.3.3 "Selection of the bands for avoidance of holes" */
701 if (spread_en[w+g] * avoid_hole_thr > band->energy || coeffs[g].min_snr > 1.0f)
702 band->avoid_holes = PSY_3GPP_AH_NONE;
703 else
704 band->avoid_holes = PSY_3GPP_AH_INACTIVE;
705 }
706 }
707
708 /* 5.6.1.3.2 "Calculation of the desired perceptual entropy" */
709 ctx->ch[channel].entropy = pe;
710 if (ctx->avctx->flags & AV_CODEC_FLAG_QSCALE) {
711 /* (2.5 * 120) achieves almost transparent rate, and we want to give
712 * ample room downwards, so we make that equivalent to QSCALE=2.4
713 */
714 desired_pe = pe * (ctx->avctx->global_quality ? ctx->avctx->global_quality : 120) / (2 * 2.5f * 120.0f);
715 desired_bits = FFMIN(2560, PSY_3GPP_PE_TO_BITS(desired_pe));
716 desired_pe = PSY_3GPP_BITS_TO_PE(desired_bits); // reflect clipping
717
718 /* PE slope smoothing */
719 if (ctx->bitres.bits > 0) {
720 desired_bits = FFMIN(2560, PSY_3GPP_PE_TO_BITS(desired_pe));
721 desired_pe = PSY_3GPP_BITS_TO_PE(desired_bits); // reflect clipping
722 }
723
724 pctx->pe.max = FFMAX(pe, pctx->pe.max);
725 pctx->pe.min = FFMIN(pe, pctx->pe.min);
726 } else {
727 desired_bits = calc_bit_demand(pctx, pe, ctx->bitres.bits, ctx->bitres.size, wi->num_windows == 8);
728 desired_pe = PSY_3GPP_BITS_TO_PE(desired_bits);
729
730 /* NOTE: PE correction is kept simple. During initial testing it had very
731 * little effect on the final bitrate. Probably a good idea to come
732 * back and do more testing later.
733 */
734 if (ctx->bitres.bits > 0)
735 desired_pe *= av_clipf(pctx->pe.previous / PSY_3GPP_BITS_TO_PE(ctx->bitres.bits),
736 0.85f, 1.15f);
737 }
738 pctx->pe.previous = PSY_3GPP_BITS_TO_PE(desired_bits);
739 ctx->bitres.alloc = desired_bits;
740
741 if (desired_pe < pe) {
742 /* 5.6.1.3.4 "First Estimation of the reduction value" */
743 for (w = 0; w < wi->num_windows*16; w += 16) {
744 reduction = calc_reduction_3gpp(a, desired_pe, pe, active_lines);
745 pe = 0.0f;
746 a = 0.0f;
747 active_lines = 0.0f;
748 for (g = 0; g < num_bands; g++) {
749 AacPsyBand *band = &pch->band[w+g];
750
751 band->thr = calc_reduced_thr_3gpp(band, coeffs[g].min_snr, reduction);
752 /* recalculate PE */
753 pe += calc_pe_3gpp(band);
754 a += band->pe_const;
755 active_lines += band->active_lines;
756 }
757 }
758
759 /* 5.6.1.3.5 "Second Estimation of the reduction value" */
760 for (i = 0; i < 2; i++) {
761 float pe_no_ah = 0.0f, desired_pe_no_ah;
762 active_lines = a = 0.0f;
763 for (w = 0; w < wi->num_windows*16; w += 16) {
764 for (g = 0; g < num_bands; g++) {
765 AacPsyBand *band = &pch->band[w+g];
766
767 if (band->avoid_holes != PSY_3GPP_AH_ACTIVE) {
768 pe_no_ah += band->pe;
769 a += band->pe_const;
770 active_lines += band->active_lines;
771 }
772 }
773 }
774 desired_pe_no_ah = FFMAX(desired_pe - (pe - pe_no_ah), 0.0f);
775 if (active_lines > 0.0f)
776 reduction = calc_reduction_3gpp(a, desired_pe_no_ah, pe_no_ah, active_lines);
777
778 pe = 0.0f;
779 for (w = 0; w < wi->num_windows*16; w += 16) {
780 for (g = 0; g < num_bands; g++) {
781 AacPsyBand *band = &pch->band[w+g];
782
783 if (active_lines > 0.0f)
784 band->thr = calc_reduced_thr_3gpp(band, coeffs[g].min_snr, reduction);
785 pe += calc_pe_3gpp(band);
786 if (band->thr > 0.0f)
787 band->norm_fac = band->active_lines / band->thr;
788 else
789 band->norm_fac = 0.0f;
790 norm_fac += band->norm_fac;
791 }
792 }
793 delta_pe = desired_pe - pe;
794 if (fabs(delta_pe) > 0.05f * desired_pe)
795 break;
796 }
797
798 if (pe < 1.15f * desired_pe) {
799 /* 6.6.1.3.6 "Final threshold modification by linearization" */
800 norm_fac = norm_fac ? 1.0f / norm_fac : 0;
801 for (w = 0; w < wi->num_windows*16; w += 16) {
802 for (g = 0; g < num_bands; g++) {
803 AacPsyBand *band = &pch->band[w+g];
804
805 if (band->active_lines > 0.5f) {
806 float delta_sfb_pe = band->norm_fac * norm_fac * delta_pe;
807 float thr = band->thr;
808
809 thr *= exp2f(delta_sfb_pe / band->active_lines);
810 if (thr > coeffs[g].min_snr * band->energy && band->avoid_holes == PSY_3GPP_AH_INACTIVE)
811 thr = FFMAX(band->thr, coeffs[g].min_snr * band->energy);
812 band->thr = thr;
813 }
814 }
815 }
816 } else {
817 /* 5.6.1.3.7 "Further perceptual entropy reduction" */
818 g = num_bands;
819 while (pe > desired_pe && g--) {
820 for (w = 0; w < wi->num_windows*16; w+= 16) {
821 AacPsyBand *band = &pch->band[w+g];
822 if (band->avoid_holes != PSY_3GPP_AH_NONE && coeffs[g].min_snr < PSY_SNR_1DB) {
823 coeffs[g].min_snr = PSY_SNR_1DB;
824 band->thr = band->energy * PSY_SNR_1DB;
825 pe += band->active_lines * 1.5f - band->pe;
826 }
827 }
828 }
829 /* TODO: allow more holes (unused without mid/side) */
830 }
831 }
832
833 for (w = 0; w < wi->num_windows*16; w += 16) {
834 for (g = 0; g < num_bands; g++) {
835 AacPsyBand *band = &pch->band[w+g];
836 FFPsyBand *psy_band = &ctx->ch[channel].psy_bands[w+g];
837
838 psy_band->threshold = band->thr;
839 psy_band->energy = band->energy;
840 psy_band->spread = band->active_lines * 2.0f / band_sizes[g];
841 psy_band->bits = PSY_3GPP_PE_TO_BITS(band->pe);
842 }
843 }
844
845 memcpy(pch->prev_band, pch->band, sizeof(pch->band));
846 }
847
psy_3gpp_analyze(FFPsyContext * ctx,int channel,const float ** coeffs,const FFPsyWindowInfo * wi)848 static void psy_3gpp_analyze(FFPsyContext *ctx, int channel,
849 const float **coeffs, const FFPsyWindowInfo *wi)
850 {
851 int ch;
852 FFPsyChannelGroup *group = ff_psy_find_group(ctx, channel);
853
854 for (ch = 0; ch < group->num_ch; ch++)
855 psy_3gpp_analyze_channel(ctx, channel + ch, coeffs[ch], &wi[ch]);
856 }
857
psy_3gpp_end(FFPsyContext * apc)858 static av_cold void psy_3gpp_end(FFPsyContext *apc)
859 {
860 AacPsyContext *pctx = (AacPsyContext*) apc->model_priv_data;
861 av_freep(&pctx->ch);
862 av_freep(&apc->model_priv_data);
863 }
864
lame_apply_block_type(AacPsyChannel * ctx,FFPsyWindowInfo * wi,int uselongblock)865 static void lame_apply_block_type(AacPsyChannel *ctx, FFPsyWindowInfo *wi, int uselongblock)
866 {
867 int blocktype = ONLY_LONG_SEQUENCE;
868 if (uselongblock) {
869 if (ctx->next_window_seq == EIGHT_SHORT_SEQUENCE)
870 blocktype = LONG_STOP_SEQUENCE;
871 } else {
872 blocktype = EIGHT_SHORT_SEQUENCE;
873 if (ctx->next_window_seq == ONLY_LONG_SEQUENCE)
874 ctx->next_window_seq = LONG_START_SEQUENCE;
875 if (ctx->next_window_seq == LONG_STOP_SEQUENCE)
876 ctx->next_window_seq = EIGHT_SHORT_SEQUENCE;
877 }
878
879 wi->window_type[0] = ctx->next_window_seq;
880 ctx->next_window_seq = blocktype;
881 }
882
psy_lame_window(FFPsyContext * ctx,const float * audio,const float * la,int channel,int prev_type)883 static FFPsyWindowInfo psy_lame_window(FFPsyContext *ctx, const float *audio,
884 const float *la, int channel, int prev_type)
885 {
886 AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data;
887 AacPsyChannel *pch = &pctx->ch[channel];
888 int grouping = 0;
889 int uselongblock = 1;
890 int attacks[AAC_NUM_BLOCKS_SHORT + 1] = { 0 };
891 int i;
892 FFPsyWindowInfo wi = { { 0 } };
893
894 if (la) {
895 float hpfsmpl[AAC_BLOCK_SIZE_LONG];
896 const float *pf = hpfsmpl;
897 float attack_intensity[(AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS];
898 float energy_subshort[(AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS];
899 float energy_short[AAC_NUM_BLOCKS_SHORT + 1] = { 0 };
900 const float *firbuf = la + (AAC_BLOCK_SIZE_SHORT/4 - PSY_LAME_FIR_LEN);
901 int att_sum = 0;
902
903 /* LAME comment: apply high pass filter of fs/4 */
904 psy_hp_filter(firbuf, hpfsmpl, psy_fir_coeffs);
905
906 /* Calculate the energies of each sub-shortblock */
907 for (i = 0; i < PSY_LAME_NUM_SUBBLOCKS; i++) {
908 energy_subshort[i] = pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 1) * PSY_LAME_NUM_SUBBLOCKS)];
909 assert(pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 2) * PSY_LAME_NUM_SUBBLOCKS + 1)] > 0);
910 attack_intensity[i] = energy_subshort[i] / pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 2) * PSY_LAME_NUM_SUBBLOCKS + 1)];
911 energy_short[0] += energy_subshort[i];
912 }
913
914 for (i = 0; i < AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS; i++) {
915 const float *const pfe = pf + AAC_BLOCK_SIZE_LONG / (AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS);
916 float p = 1.0f;
917 for (; pf < pfe; pf++)
918 p = FFMAX(p, fabsf(*pf));
919 pch->prev_energy_subshort[i] = energy_subshort[i + PSY_LAME_NUM_SUBBLOCKS] = p;
920 energy_short[1 + i / PSY_LAME_NUM_SUBBLOCKS] += p;
921 /* NOTE: The indexes below are [i + 3 - 2] in the LAME source.
922 * Obviously the 3 and 2 have some significance, or this would be just [i + 1]
923 * (which is what we use here). What the 3 stands for is ambiguous, as it is both
924 * number of short blocks, and the number of sub-short blocks.
925 * It seems that LAME is comparing each sub-block to sub-block + 1 in the
926 * previous block.
927 */
928 if (p > energy_subshort[i + 1])
929 p = p / energy_subshort[i + 1];
930 else if (energy_subshort[i + 1] > p * 10.0f)
931 p = energy_subshort[i + 1] / (p * 10.0f);
932 else
933 p = 0.0;
934 attack_intensity[i + PSY_LAME_NUM_SUBBLOCKS] = p;
935 }
936
937 /* compare energy between sub-short blocks */
938 for (i = 0; i < (AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS; i++)
939 if (!attacks[i / PSY_LAME_NUM_SUBBLOCKS])
940 if (attack_intensity[i] > pch->attack_threshold)
941 attacks[i / PSY_LAME_NUM_SUBBLOCKS] = (i % PSY_LAME_NUM_SUBBLOCKS) + 1;
942
943 /* should have energy change between short blocks, in order to avoid periodic signals */
944 /* Good samples to show the effect are Trumpet test songs */
945 /* GB: tuned (1) to avoid too many short blocks for test sample TRUMPET */
946 /* RH: tuned (2) to let enough short blocks through for test sample FSOL and SNAPS */
947 for (i = 1; i < AAC_NUM_BLOCKS_SHORT + 1; i++) {
948 const float u = energy_short[i - 1];
949 const float v = energy_short[i];
950 const float m = FFMAX(u, v);
951 if (m < 40000) { /* (2) */
952 if (u < 1.7f * v && v < 1.7f * u) { /* (1) */
953 if (i == 1 && attacks[0] < attacks[i])
954 attacks[0] = 0;
955 attacks[i] = 0;
956 }
957 }
958 att_sum += attacks[i];
959 }
960
961 if (attacks[0] <= pch->prev_attack)
962 attacks[0] = 0;
963
964 att_sum += attacks[0];
965 /* 3 below indicates the previous attack happened in the last sub-block of the previous sequence */
966 if (pch->prev_attack == 3 || att_sum) {
967 uselongblock = 0;
968
969 for (i = 1; i < AAC_NUM_BLOCKS_SHORT + 1; i++)
970 if (attacks[i] && attacks[i-1])
971 attacks[i] = 0;
972 }
973 } else {
974 /* We have no lookahead info, so just use same type as the previous sequence. */
975 uselongblock = !(prev_type == EIGHT_SHORT_SEQUENCE);
976 }
977
978 lame_apply_block_type(pch, &wi, uselongblock);
979
980 wi.window_type[1] = prev_type;
981 if (wi.window_type[0] != EIGHT_SHORT_SEQUENCE) {
982
983 wi.num_windows = 1;
984 wi.grouping[0] = 1;
985 if (wi.window_type[0] == LONG_START_SEQUENCE)
986 wi.window_shape = 0;
987 else
988 wi.window_shape = 1;
989
990 } else {
991 int lastgrp = 0;
992
993 wi.num_windows = 8;
994 wi.window_shape = 0;
995 for (i = 0; i < 8; i++) {
996 if (!((pch->next_grouping >> i) & 1))
997 lastgrp = i;
998 wi.grouping[lastgrp]++;
999 }
1000 }
1001
1002 /* Determine grouping, based on the location of the first attack, and save for
1003 * the next frame.
1004 * FIXME: Move this to analysis.
1005 * TODO: Tune groupings depending on attack location
1006 * TODO: Handle more than one attack in a group
1007 */
1008 for (i = 0; i < 9; i++) {
1009 if (attacks[i]) {
1010 grouping = i;
1011 break;
1012 }
1013 }
1014 pch->next_grouping = window_grouping[grouping];
1015
1016 pch->prev_attack = attacks[8];
1017
1018 return wi;
1019 }
1020
1021 const FFPsyModel ff_aac_psy_model =
1022 {
1023 .name = "3GPP TS 26.403-inspired model",
1024 .init = psy_3gpp_init,
1025 .window = psy_lame_window,
1026 .analyze = psy_3gpp_analyze,
1027 .end = psy_3gpp_end,
1028 };
1029