FFmpeg coverage

Line	Branch	Exec	Source
1			/*
2			* G.729, G729 Annex D postfilter
3			* Copyright (c) 2008 Vladimir Voroshilov
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			#include <stdint.h>
23			#include <string.h>
24
25			#include "libavutil/common.h"
26			#include "libavutil/intmath.h"
27
28			#include "audiodsp.h"
29			#include "g729.h"
30			#include "g729postfilter.h"
31			#include "celp_math.h"
32			#include "acelp_filters.h"
33			#include "acelp_vectors.h"
34			#include "celp_filters.h"
35
36			#define FRAC_BITS 15
37			#include "mathops.h"
38
39			/**
40			* short interpolation filter (of length 33, according to spec)
41			* for computing signal with non-integer delay
42			*/
43			static const int16_t ff_g729_interp_filt_short[(ANALYZED_FRAC_DELAYS+1)*SHORT_INT_FILT_LEN] = {
44			0, 31650, 28469, 23705, 18050, 12266, 7041, 2873,
45			0, -1597, -2147, -1992, -1492, -933, -484, -188,
46			};
47
48			/**
49			* long interpolation filter (of length 129, according to spec)
50			* for computing signal with non-integer delay
51			*/
52			static const int16_t ff_g729_interp_filt_long[(ANALYZED_FRAC_DELAYS+1)*LONG_INT_FILT_LEN] = {
53			0, 31915, 29436, 25569, 20676, 15206, 9639, 4439,
54			0, -3390, -5579, -6549, -6414, -5392, -3773, -1874,
55			0, 1595, 2727, 3303, 3319, 2850, 2030, 1023,
56			0, -887, -1527, -1860, -1876, -1614, -1150, -579,
57			0, 501, 859, 1041, 1044, 892, 631, 315,
58			0, -266, -453, -543, -538, -455, -317, -156,
59			0, 130, 218, 258, 253, 212, 147, 72,
60			0, -59, -101, -122, -123, -106, -77, -40,
61			};
62
63			/**
64			* formant_pp_factor_num_pow[i] = FORMANT_PP_FACTOR_NUM^(i+1)
65			*/
66			static const int16_t formant_pp_factor_num_pow[10]= {
67			/* (0.15) */
68			18022, 9912, 5451, 2998, 1649, 907, 499, 274, 151, 83
69			};
70
71			/**
72			* formant_pp_factor_den_pow[i] = FORMANT_PP_FACTOR_DEN^(i+1)
73			*/
74			static const int16_t formant_pp_factor_den_pow[10] = {
75			/* (0.15) */
76			22938, 16057, 11240, 7868, 5508, 3856, 2699, 1889, 1322, 925
77			};
78
79			/**
80			* \brief Residual signal calculation (4.2.1 if G.729)
81			* \param[out] out output data filtered through A(z/FORMANT_PP_FACTOR_NUM)
82			* \param filter_coeffs (3.12) A(z/FORMANT_PP_FACTOR_NUM) filter coefficients
83			* \param in input speech data to process
84			* \param subframe_size size of one subframe
85			*
86			* \note in buffer must contain 10 items of previous speech data before top of the buffer
87			* \remark It is safe to pass the same buffer for input and output.
88			*/
89		✗	static void residual_filter(int16_t* out, const int16_t* filter_coeffs, const int16_t* in,
90			int subframe_size)
91			{
92			int i, n;
93
94		✗	for (n = subframe_size - 1; n >= 0; n--) {
95		✗	int sum = 0x800;
96		✗	for (i = 0; i < 10; i++)
97		✗	sum += filter_coeffs[i] * in[n - i - 1];
98
99		✗	out[n] = in[n] + (sum >> 12);
100			}
101		✗	}
102
103			/**
104			* \brief long-term postfilter (4.2.1)
105			* \param dsp initialized DSP context
106			* \param pitch_delay_int integer part of the pitch delay in the first subframe
107			* \param residual filtering input data
108			* \param[out] residual_filt speech signal with applied A(z/FORMANT_PP_FACTOR_NUM) filter
109			* \param subframe_size size of subframe
110			*
111			* \return 0 if long-term prediction gain is less than 3dB, 1 - otherwise
112			*/
113		✗	static int16_t long_term_filter(AudioDSPContext *adsp, int pitch_delay_int,
114			const int16_t* residual, int16_t *residual_filt,
115			int subframe_size)
116			{
117			int i, k, tmp, tmp2;
118			int sum;
119			int L_temp0;
120			int L_temp1;
121			int64_t L64_temp0;
122			int64_t L64_temp1;
123			int16_t shift;
124			int corr_int_num, corr_int_den;
125
126			int ener;
127			int16_t sh_ener;
128
129			int16_t gain_num,gain_den; //selected signal's gain numerator and denominator
130			int16_t sh_gain_num, sh_gain_den;
131			int gain_num_square;
132
133			int16_t gain_long_num,gain_long_den; //filtered through long interpolation filter signal's gain numerator and denominator
134			int16_t sh_gain_long_num, sh_gain_long_den;
135
136			int16_t best_delay_int, best_delay_frac;
137
138			int16_t delayed_signal_offset;
139			int lt_filt_factor_a, lt_filt_factor_b;
140
141			int16_t * selected_signal;
142			const int16_t * selected_signal_const; //Necessary to avoid compiler warning
143
144			int16_t sig_scaled[SUBFRAME_SIZE + RES_PREV_DATA_SIZE];
145			int16_t delayed_signal[ANALYZED_FRAC_DELAYS][SUBFRAME_SIZE+1];
146			int corr_den[ANALYZED_FRAC_DELAYS][2];
147
148		✗	tmp = 0;
149		✗	for(i=0; i<subframe_size + RES_PREV_DATA_SIZE; i++)
150		✗	tmp |= FFABS(residual[i]);
151
152		✗	if(!tmp)
153		✗	shift = 3;
154			else
155		✗	shift = av_log2(tmp) - 11;
156
157		✗	if (shift > 0)
158		✗	for (i = 0; i < subframe_size + RES_PREV_DATA_SIZE; i++)
159		✗	sig_scaled[i] = residual[i] >> shift;
160			else
161		✗	for (i = 0; i < subframe_size + RES_PREV_DATA_SIZE; i++)
162		✗	sig_scaled[i] = (unsigned)residual[i] << -shift;
163
164			/* Start of best delay searching code */
165		✗	gain_num = 0;
166
167		✗	ener = adsp->scalarproduct_int16(sig_scaled + RES_PREV_DATA_SIZE,
168			sig_scaled + RES_PREV_DATA_SIZE,
169			subframe_size);
170		✗	if (ener) {
171		✗	sh_ener = av_log2(ener) - 14;
172		✗	sh_ener = FFMAX(sh_ener, 0);
173		✗	ener >>= sh_ener;
174			/* Search for best pitch delay.
175
176			sum{ r(n) * r(k,n) ] }^2
177			R'(k)^2 := -------------------------
178			sum{ r(k,n) * r(k,n) }
179
180
181			R(T) := sum{ r(n) * r(n-T) ] }
182
183
184			where
185			r(n-T) is integer delayed signal with delay T
186			r(k,n) is non-integer delayed signal with integer delay best_delay
187			and fractional delay k */
188
189			/* Find integer delay best_delay which maximizes correlation R(T).
190
191			This is also equals to numerator of R'(0),
192			since the fine search (second step) is done with 1/8
193			precision around best_delay. */
194		✗	corr_int_num = 0;
195		✗	best_delay_int = pitch_delay_int - 1;
196		✗	for (i = pitch_delay_int - 1; i <= pitch_delay_int + 1; i++) {
197		✗	sum = adsp->scalarproduct_int16(sig_scaled + RES_PREV_DATA_SIZE,
198		✗	sig_scaled + RES_PREV_DATA_SIZE - i,
199			subframe_size);
200		✗	if (sum > corr_int_num) {
201		✗	corr_int_num = sum;
202		✗	best_delay_int = i;
203			}
204			}
205		✗	if (corr_int_num) {
206			/* Compute denominator of pseudo-normalized correlation R'(0). */
207		✗	corr_int_den = adsp->scalarproduct_int16(sig_scaled + RES_PREV_DATA_SIZE - best_delay_int,
208		✗	sig_scaled + RES_PREV_DATA_SIZE - best_delay_int,
209			subframe_size);
210
211			/* Compute signals with non-integer delay k (with 1/8 precision),
212			where k is in [0;6] range.
213			Entire delay is qual to best_delay+(k+1)/8
214			This is archieved by applying an interpolation filter of
215			legth 33 to source signal. */
216		✗	for (k = 0; k < ANALYZED_FRAC_DELAYS; k++) {
217		✗	ff_acelp_interpolate(&delayed_signal[k][0],
218		✗	&sig_scaled[RES_PREV_DATA_SIZE - best_delay_int],
219			ff_g729_interp_filt_short,
220			ANALYZED_FRAC_DELAYS+1,
221			8 - k - 1,
222			SHORT_INT_FILT_LEN,
223			subframe_size + 1);
224			}
225
226			/* Compute denominator of pseudo-normalized correlation R'(k).
227
228			corr_den[k][0] is square root of R'(k) denominator, for int(T) == int(T0)
229			corr_den[k][1] is square root of R'(k) denominator, for int(T) == int(T0)+1
230
231			Also compute maximum value of above denominators over all k. */
232		✗	tmp = corr_int_den;
233		✗	for (k = 0; k < ANALYZED_FRAC_DELAYS; k++) {
234		✗	sum = adsp->scalarproduct_int16(&delayed_signal[k][1],
235		✗	&delayed_signal[k][1],
236			subframe_size - 1);
237		✗	corr_den[k][0] = sum + delayed_signal[k][0 ] * delayed_signal[k][0 ];
238		✗	corr_den[k][1] = sum + delayed_signal[k][subframe_size] * delayed_signal[k][subframe_size];
239
240		✗	tmp = FFMAX3(tmp, corr_den[k][0], corr_den[k][1]);
241			}
242
243		✗	sh_gain_den = av_log2(tmp) - 14;
244		✗	if (sh_gain_den >= 0) {
245
246		✗	sh_gain_num = FFMAX(sh_gain_den, sh_ener);
247			/* Loop through all k and find delay that maximizes
248			R'(k) correlation.
249			Search is done in [int(T0)-1; intT(0)+1] range
250			with 1/8 precision. */
251		✗	delayed_signal_offset = 1;
252		✗	best_delay_frac = 0;
253		✗	gain_den = corr_int_den >> sh_gain_den;
254		✗	gain_num = corr_int_num >> sh_gain_num;
255		✗	gain_num_square = gain_num * gain_num;
256		✗	for (k = 0; k < ANALYZED_FRAC_DELAYS; k++) {
257		✗	for (i = 0; i < 2; i++) {
258			int16_t gain_num_short, gain_den_short;
259			int gain_num_short_square;
260			/* Compute numerator of pseudo-normalized
261			correlation R'(k). */
262		✗	sum = adsp->scalarproduct_int16(&delayed_signal[k][i],
263			sig_scaled + RES_PREV_DATA_SIZE,
264			subframe_size);
265		✗	gain_num_short = FFMAX(sum >> sh_gain_num, 0);
266
267			/*
268			gain_num_short_square gain_num_square
269			R'(T)^2 = -----------------------, max R'(T)^2= --------------
270			den gain_den
271			*/
272		✗	gain_num_short_square = gain_num_short * gain_num_short;
273		✗	gain_den_short = corr_den[k][i] >> sh_gain_den;
274
275		✗	tmp = MULL(gain_num_short_square, gain_den, FRAC_BITS);
276		✗	tmp2 = MULL(gain_num_square, gain_den_short, FRAC_BITS);
277
278			// R'(T)^2 > max R'(T)^2
279		✗	if (tmp > tmp2) {
280		✗	gain_num = gain_num_short;
281		✗	gain_den = gain_den_short;
282		✗	gain_num_square = gain_num_short_square;
283		✗	delayed_signal_offset = i;
284		✗	best_delay_frac = k + 1;
285			}
286			}
287			}
288
289			/*
290			R'(T)^2
291			2 * --------- < 1
292			R(0)
293			*/
294		✗	L64_temp0 = (int64_t)gain_num_square << ((sh_gain_num << 1) + 1);
295		✗	L64_temp1 = ((int64_t)gain_den * ener) << (sh_gain_den + sh_ener);
296		✗	if (L64_temp0 < L64_temp1)
297		✗	gain_num = 0;
298			} // if(sh_gain_den >= 0)
299			} // if(corr_int_num)
300			} // if(ener)
301			/* End of best delay searching code */
302
303		✗	if (!gain_num) {
304		✗	memcpy(residual_filt, residual + RES_PREV_DATA_SIZE, subframe_size * sizeof(int16_t));
305
306			/* Long-term prediction gain is less than 3dB. Long-term postfilter is disabled. */
307		✗	return 0;
308			}
309		✗	if (best_delay_frac) {
310			/* Recompute delayed signal with an interpolation filter of length 129. */
311		✗	ff_acelp_interpolate(residual_filt,
312		✗	&sig_scaled[RES_PREV_DATA_SIZE - best_delay_int + delayed_signal_offset],
313			ff_g729_interp_filt_long,
314			ANALYZED_FRAC_DELAYS + 1,
315			8 - best_delay_frac,
316			LONG_INT_FILT_LEN,
317			subframe_size + 1);
318			/* Compute R'(k) correlation's numerator. */
319		✗	sum = adsp->scalarproduct_int16(residual_filt,
320			sig_scaled + RES_PREV_DATA_SIZE,
321			subframe_size);
322
323		✗	if (sum < 0) {
324		✗	gain_long_num = 0;
325		✗	sh_gain_long_num = 0;
326			} else {
327		✗	tmp = av_log2(sum) - 14;
328		✗	tmp = FFMAX(tmp, 0);
329		✗	sum >>= tmp;
330		✗	gain_long_num = sum;
331		✗	sh_gain_long_num = tmp;
332			}
333
334			/* Compute R'(k) correlation's denominator. */
335		✗	sum = adsp->scalarproduct_int16(residual_filt, residual_filt, subframe_size);
336
337		✗	tmp = av_log2(sum) - 14;
338		✗	tmp = FFMAX(tmp, 0);
339		✗	sum >>= tmp;
340		✗	gain_long_den = sum;
341		✗	sh_gain_long_den = tmp;
342
343			/* Select between original and delayed signal.
344			Delayed signal will be selected if it increases R'(k)
345			correlation. */
346		✗	L_temp0 = gain_num * gain_num;
347		✗	L_temp0 = MULL(L_temp0, gain_long_den, FRAC_BITS);
348
349		✗	L_temp1 = gain_long_num * gain_long_num;
350		✗	L_temp1 = MULL(L_temp1, gain_den, FRAC_BITS);
351
352		✗	tmp = ((sh_gain_long_num - sh_gain_num) * 2) - (sh_gain_long_den - sh_gain_den);
353		✗	if (tmp > 0)
354		✗	L_temp0 >>= tmp;
355			else
356		✗	L_temp1 >>= FFMIN(-tmp, 31);
357
358			/* Check if longer filter increases the values of R'(k). */
359		✗	if (L_temp1 > L_temp0) {
360			/* Select long filter. */
361		✗	selected_signal = residual_filt;
362		✗	gain_num = gain_long_num;
363		✗	gain_den = gain_long_den;
364		✗	sh_gain_num = sh_gain_long_num;
365		✗	sh_gain_den = sh_gain_long_den;
366			} else
367			/* Select short filter. */
368		✗	selected_signal = &delayed_signal[best_delay_frac-1][delayed_signal_offset];
369
370			/* Rescale selected signal to original value. */
371		✗	if (shift > 0)
372		✗	for (i = 0; i < subframe_size; i++)
373		✗	selected_signal[i] *= 1 << shift;
374			else
375		✗	for (i = 0; i < subframe_size; i++)
376		✗	selected_signal[i] >>= -shift;
377
378			/* necessary to avoid compiler warning */
379		✗	selected_signal_const = selected_signal;
380			} // if(best_delay_frac)
381			else
382		✗	selected_signal_const = residual + RES_PREV_DATA_SIZE - (best_delay_int + 1 - delayed_signal_offset);
383			#ifdef G729_BITEXACT
384			tmp = sh_gain_num - sh_gain_den;
385			if (tmp > 0)
386			gain_den >>= tmp;
387			else
388			gain_num >>= -tmp;
389
390			if (gain_num > gain_den)
391			lt_filt_factor_a = MIN_LT_FILT_FACTOR_A;
392			else {
393			gain_num >>= 2;
394			gain_den >>= 1;
395			lt_filt_factor_a = (gain_den << 15) / (gain_den + gain_num);
396			}
397			#else
398		✗	L64_temp0 = (((int64_t)gain_num) << sh_gain_num) >> 1;
399		✗	L64_temp1 = ((int64_t)gain_den) << sh_gain_den;
400		✗	lt_filt_factor_a = FFMAX((L64_temp1 << 15) / (L64_temp1 + L64_temp0), MIN_LT_FILT_FACTOR_A);
401			#endif
402
403			/* Filter through selected filter. */
404		✗	lt_filt_factor_b = 32767 - lt_filt_factor_a + 1;
405
406		✗	ff_acelp_weighted_vector_sum(residual_filt, residual + RES_PREV_DATA_SIZE,
407			selected_signal_const,
408			lt_filt_factor_a, lt_filt_factor_b,
409			1<<14, 15, subframe_size);
410
411			// Long-term prediction gain is larger than 3dB.
412		✗	return 1;
413			}
414
415			/**
416			* \brief Calculate reflection coefficient for tilt compensation filter (4.2.3).
417			* \param dsp initialized DSP context
418			* \param lp_gn (3.12) coefficients of A(z/FORMANT_PP_FACTOR_NUM) filter
419			* \param lp_gd (3.12) coefficients of A(z/FORMANT_PP_FACTOR_DEN) filter
420			* \param speech speech to update
421			* \param subframe_size size of subframe
422			*
423			* \return (3.12) reflection coefficient
424			*
425			* \remark The routine also calculates the gain term for the short-term
426			* filter (gf) and multiplies the speech data by 1/gf.
427			*
428			* \note All members of lp_gn, except 10-19 must be equal to zero.
429			*/
430		✗	static int16_t get_tilt_comp(AudioDSPContext *adsp, int16_t *lp_gn,
431			const int16_t *lp_gd, int16_t* speech,
432			int subframe_size)
433			{
434			int rh1,rh0; // (3.12)
435			int temp;
436			int i;
437			int gain_term;
438
439		✗	lp_gn[10] = 4096; //1.0 in (3.12)
440
441			/* Apply 1/A(z/FORMANT_PP_FACTOR_DEN) filter to hf. */
442		✗	ff_celp_lp_synthesis_filter(lp_gn + 11, lp_gd + 1, lp_gn + 11, 22, 10, 0, 0, 0x800);
443			/* Now lp_gn (starting with 10) contains impulse response
444			of A(z/FORMANT_PP_FACTOR_NUM)/A(z/FORMANT_PP_FACTOR_DEN) filter. */
445
446		✗	rh0 = adsp->scalarproduct_int16(lp_gn + 10, lp_gn + 10, 20);
447		✗	rh1 = adsp->scalarproduct_int16(lp_gn + 10, lp_gn + 11, 20);
448
449			/* downscale to avoid overflow */
450		✗	temp = av_log2(rh0) - 14;
451		✗	if (temp > 0) {
452		✗	rh0 >>= temp;
453		✗	rh1 >>= temp;
454			}
455
456		✗	if (FFABS(rh1) > rh0 || !rh0)
457		✗	return 0;
458
459		✗	gain_term = 0;
460		✗	for (i = 0; i < 20; i++)
461		✗	gain_term += FFABS(lp_gn[i + 10]);
462		✗	gain_term >>= 2; // (3.12) -> (5.10)
463
464		✗	if (gain_term > 0x400) { // 1.0 in (5.10)
465		✗	temp = 0x2000000 / gain_term; // 1.0/gain_term in (0.15)
466		✗	for (i = 0; i < subframe_size; i++)
467		✗	speech[i] = (speech[i] * temp + 0x4000) >> 15;
468			}
469
470		✗	return -(rh1 * (1 << 15)) / rh0;
471			}
472
473			/**
474			* \brief Apply tilt compensation filter (4.2.3).
475			* \param[in,out] res_pst residual signal (partially filtered)
476			* \param k1 (3.12) reflection coefficient
477			* \param subframe_size size of subframe
478			* \param ht_prev_data previous data for 4.2.3, equation 86
479			*
480			* \return new value for ht_prev_data
481			*/
482		✗	static int16_t apply_tilt_comp(int16_t* out, int16_t* res_pst, int refl_coeff,
483			int subframe_size, int16_t ht_prev_data)
484			{
485			int tmp, tmp2;
486			int i;
487			int gt, ga;
488			int fact, sh_fact;
489
490		✗	if (refl_coeff > 0) {
491		✗	gt = (refl_coeff * G729_TILT_FACTOR_PLUS + 0x4000) >> 15;
492		✗	fact = 0x2000; // 0.5 in (0.15)
493		✗	sh_fact = 14;
494			} else {
495		✗	gt = (refl_coeff * G729_TILT_FACTOR_MINUS + 0x4000) >> 15;
496		✗	fact = 0x400; // 0.5 in (3.12)
497		✗	sh_fact = 11;
498			}
499		✗	ga = (fact << 16) / av_clip_int16(32768 - FFABS(gt));
500		✗	gt >>= 1;
501
502			/* Apply tilt compensation filter to signal. */
503		✗	tmp = res_pst[subframe_size - 1];
504
505		✗	for (i = subframe_size - 1; i >= 1; i--) {
506		✗	tmp2 = (gt * res_pst[i-1]) * 2 + 0x4000;
507		✗	tmp2 = res_pst[i] + (tmp2 >> 15);
508
509		✗	tmp2 = (tmp2 * ga + fact) >> sh_fact;
510		✗	out[i] = tmp2;
511			}
512		✗	tmp2 = (gt * ht_prev_data) * 2 + 0x4000;
513		✗	tmp2 = res_pst[0] + (tmp2 >> 15);
514		✗	tmp2 = (tmp2 * ga + fact) >> sh_fact;
515		✗	out[0] = tmp2;
516
517		✗	return tmp;
518			}
519
520		✗	void ff_g729_postfilter(AudioDSPContext *adsp, int16_t* ht_prev_data, int* voicing,
521			const int16_t *lp_filter_coeffs, int pitch_delay_int,
522			int16_t* residual, int16_t* res_filter_data,
523			int16_t* pos_filter_data, int16_t *speech, int subframe_size)
524			{
525			int16_t residual_filt_buf[SUBFRAME_SIZE+11];
526			int16_t lp_gn[33]; // (3.12)
527			int16_t lp_gd[11]; // (3.12)
528			int tilt_comp_coeff;
529			int i;
530
531			/* Zero-filling is necessary for tilt-compensation filter. */
532		✗	memset(lp_gn, 0, 33 * sizeof(int16_t));
533
534			/* Calculate A(z/FORMANT_PP_FACTOR_NUM) filter coefficients. */
535		✗	for (i = 0; i < 10; i++)
536		✗	lp_gn[i + 11] = (lp_filter_coeffs[i + 1] * formant_pp_factor_num_pow[i] + 0x4000) >> 15;
537
538			/* Calculate A(z/FORMANT_PP_FACTOR_DEN) filter coefficients. */
539		✗	for (i = 0; i < 10; i++)
540		✗	lp_gd[i + 1] = (lp_filter_coeffs[i + 1] * formant_pp_factor_den_pow[i] + 0x4000) >> 15;
541
542			/* residual signal calculation (one-half of short-term postfilter) */
543		✗	memcpy(speech - 10, res_filter_data, 10 * sizeof(int16_t));
544		✗	residual_filter(residual + RES_PREV_DATA_SIZE, lp_gn + 11, speech, subframe_size);
545			/* Save data to use it in the next subframe. */
546		✗	memcpy(res_filter_data, speech + subframe_size - 10, 10 * sizeof(int16_t));
547
548			/* long-term filter. If long-term prediction gain is larger than 3dB (returned value is
549			nonzero) then declare current subframe as periodic. */
550		✗	i = long_term_filter(adsp, pitch_delay_int,
551			residual, residual_filt_buf + 10,
552			subframe_size);
553		✗	*voicing = FFMAX(*voicing, i);
554
555			/* shift residual for using in next subframe */
556		✗	memmove(residual, residual + subframe_size, RES_PREV_DATA_SIZE * sizeof(int16_t));
557
558			/* short-term filter tilt compensation */
559		✗	tilt_comp_coeff = get_tilt_comp(adsp, lp_gn, lp_gd, residual_filt_buf + 10, subframe_size);
560
561			/* Apply second half of short-term postfilter: 1/A(z/FORMANT_PP_FACTOR_DEN) */
562		✗	ff_celp_lp_synthesis_filter(pos_filter_data + 10, lp_gd + 1,
563			residual_filt_buf + 10,
564			subframe_size, 10, 0, 0, 0x800);
565		✗	memcpy(pos_filter_data, pos_filter_data + subframe_size, 10 * sizeof(int16_t));
566
567		✗	*ht_prev_data = apply_tilt_comp(speech, pos_filter_data + 10, tilt_comp_coeff,
568		✗	subframe_size, *ht_prev_data);
569		✗	}
570
571			/**
572			* \brief Adaptive gain control (4.2.4)
573			* \param gain_before gain of speech before applying postfilters
574			* \param gain_after gain of speech after applying postfilters
575			* \param[in,out] speech signal buffer
576			* \param subframe_size length of subframe
577			* \param gain_prev (3.12) previous value of gain coefficient
578			*
579			* \return (3.12) last value of gain coefficient
580			*/
581		✗	int16_t ff_g729_adaptive_gain_control(int gain_before, int gain_after, int16_t *speech,
582			int subframe_size, int16_t gain_prev)
583			{
584			unsigned gain; // (3.12)
585			int n;
586			int exp_before, exp_after;
587
588		✗	if(!gain_after && gain_before)
589		✗	return 0;
590
591		✗	if (gain_before) {
592
593		✗	exp_before = 14 - av_log2(gain_before);
594		✗	gain_before = bidir_sal(gain_before, exp_before);
595
596		✗	exp_after = 14 - av_log2(gain_after);
597		✗	gain_after = bidir_sal(gain_after, exp_after);
598
599		✗	if (gain_before < gain_after) {
600		✗	gain = (gain_before << 15) / gain_after;
601		✗	gain = bidir_sal(gain, exp_after - exp_before - 1);
602			} else {
603		✗	gain = ((gain_before - gain_after) << 14) / gain_after + 0x4000;
604		✗	gain = bidir_sal(gain, exp_after - exp_before);
605			}
606		✗	gain = FFMIN(gain, 32767);
607		✗	gain = (gain * G729_AGC_FAC1 + 0x4000) >> 15; // gain * (1-0.9875)
608			} else
609		✗	gain = 0;
610
611		✗	for (n = 0; n < subframe_size; n++) {
612			// gain_prev = gain + 0.9875 * gain_prev
613		✗	gain_prev = (G729_AGC_FACTOR * gain_prev + 0x4000) >> 15;
614		✗	gain_prev = av_clip_int16(gain + gain_prev);
615		✗	speech[n] = av_clip_int16((speech[n] * gain_prev + 0x2000) >> 14);
616			}
617		✗	return gain_prev;
618			}
619