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1 /******************************************************************************
2  *                                                                            *
3  * Copyright (C) 2018 The Android Open Source Project
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at:
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  *
17  *****************************************************************************
18  * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
19 */
20 #include <float.h>
21 #include <stdlib.h>
22 #include <stdio.h>
23 #include <math.h>
24 #include <string.h>
25 
26 #include <ixheaacd_type_def.h>
27 
28 #include "ixheaacd_bitbuffer.h"
29 
30 #include "ixheaacd_interface.h"
31 
32 #include "ixheaacd_tns_usac.h"
33 #include "ixheaacd_cnst.h"
34 
35 #include "ixheaacd_acelp_info.h"
36 
37 #include "ixheaacd_td_mdct.h"
38 
39 #include "ixheaacd_sbrdecsettings.h"
40 #include "ixheaacd_info.h"
41 #include "ixheaacd_sbr_common.h"
42 #include "ixheaacd_drc_data_struct.h"
43 #include "ixheaacd_drc_dec.h"
44 #include "ixheaacd_sbrdecoder.h"
45 #include "ixheaacd_mps_polyphase.h"
46 #include "ixheaacd_sbr_const.h"
47 #include "ixheaacd_main.h"
48 #include "ixheaacd_arith_dec.h"
49 #include "ixheaacd_func_def.h"
50 
51 #include "ixheaacd_acelp_com.h"
52 
53 #define F_PIT_SHARP 0.85F
54 #define MEAN_ENER 30
55 
56 extern const FLOAT32 ixheaacd_interpol_filt[INTER_LP_FIL_LEN];
57 
ixheaacd_acelp_pitch_sharpening(FLOAT32 * x,WORD32 pit_lag)58 VOID ixheaacd_acelp_pitch_sharpening(FLOAT32 *x, WORD32 pit_lag) {
59   WORD32 i;
60   for (i = pit_lag; i < LEN_SUBFR; i++) {
61     x[i] += x[i - pit_lag] * F_PIT_SHARP;
62   }
63   return;
64 }
65 
ixheaacd_acelp_decode_1sp_per_track(WORD32 idx_1p,WORD32 M,WORD32 ixheaacd_drc_offset,WORD32 track,FLOAT32 code_vec[])66 static VOID ixheaacd_acelp_decode_1sp_per_track(WORD32 idx_1p, WORD32 M,
67                                                 WORD32 ixheaacd_drc_offset,
68                                                 WORD32 track,
69                                                 FLOAT32 code_vec[]) {
70   WORD32 sign_index, mask, m;
71   WORD32 sp_pos;
72   mask = ((1 << M) - 1);
73 
74   sp_pos = (idx_1p & mask) + ixheaacd_drc_offset;
75   sign_index = ((idx_1p >> M) & 1);
76 
77   m = (sp_pos << 2) + track;
78   if (sign_index == 1)
79     code_vec[m] = (code_vec[m] - 1.0f);
80   else
81     code_vec[m] = (code_vec[m] + 1.0f);
82 
83   return;
84 }
85 
ixheaacd_acelp_decode_2sp_per_track(WORD32 idx_2p,WORD32 M,WORD32 ixheaacd_drc_offset,WORD32 track,FLOAT32 code_vec[])86 static VOID ixheaacd_acelp_decode_2sp_per_track(WORD32 idx_2p, WORD32 M,
87                                                 WORD32 ixheaacd_drc_offset,
88                                                 WORD32 track,
89                                                 FLOAT32 code_vec[]) {
90   WORD32 sign_index;
91   WORD32 mask, m0, m1;
92   WORD32 sp_pos[2];
93   mask = ((1 << M) - 1);
94 
95   sp_pos[0] = (((idx_2p >> M) & mask) + ixheaacd_drc_offset);
96   sp_pos[1] = ((idx_2p & mask) + ixheaacd_drc_offset);
97 
98   sign_index = (idx_2p >> 2 * M) & 1;
99 
100   m0 = (sp_pos[0] << 2) + track;
101   m1 = (sp_pos[1] << 2) + track;
102 
103   if ((sp_pos[1] - sp_pos[0]) < 0) {
104     if (sign_index == 1) {
105       code_vec[m0] = (code_vec[m0] - 1.0f);
106       code_vec[m1] = (code_vec[m1] + 1.0f);
107     } else {
108       code_vec[m0] = (code_vec[m0] + 1.0f);
109       code_vec[m1] = (code_vec[m1] - 1.0f);
110     }
111   } else {
112     if (sign_index == 1) {
113       code_vec[m0] = (code_vec[m0] - 1.0f);
114       code_vec[m1] = (code_vec[m1] - 1.0f);
115     } else {
116       code_vec[m0] = (code_vec[m0] + 1.0f);
117       code_vec[m1] = (code_vec[m1] + 1.0f);
118     }
119   }
120   return;
121 }
122 
ixheaacd_acelp_decode_3sp_per_track(WORD32 idx_3p,WORD32 M,WORD32 ixheaacd_drc_offset,WORD32 track,FLOAT32 code_vec[])123 static VOID ixheaacd_acelp_decode_3sp_per_track(WORD32 idx_3p, WORD32 M,
124                                                 WORD32 ixheaacd_drc_offset,
125                                                 WORD32 track,
126                                                 FLOAT32 code_vec[]) {
127   WORD32 j, mask, idx_2p, idx_1p;
128 
129   mask = ((1 << (2 * M - 1)) - 1);
130   idx_2p = idx_3p & mask;
131   j = ixheaacd_drc_offset;
132   if (((idx_3p >> ((2 * M) - 1)) & 1) == 1) {
133     j += (1 << (M - 1));
134   }
135   ixheaacd_acelp_decode_2sp_per_track(idx_2p, M - 1, j, track, code_vec);
136   mask = ((1 << (M + 1)) - 1);
137   idx_1p = (idx_3p >> 2 * M) & mask;
138   ixheaacd_acelp_decode_1sp_per_track(idx_1p, M, ixheaacd_drc_offset, track,
139                                       code_vec);
140   return;
141 }
142 
ixheaacd_d_acelp_decode_4sp_per_track_section(WORD32 index,WORD32 ixheaacd_drc_offset,WORD32 track,FLOAT32 code_vec[])143 static VOID ixheaacd_d_acelp_decode_4sp_per_track_section(
144     WORD32 index, WORD32 ixheaacd_drc_offset, WORD32 track,
145     FLOAT32 code_vec[]) {
146   WORD32 j, idx_2p;
147 
148   idx_2p = index & 31;
149   j = ixheaacd_drc_offset;
150   if (((index >> 5) & 1) == 1) {
151     j += 4;
152   }
153   ixheaacd_acelp_decode_2sp_per_track(idx_2p, 2, j, track, code_vec);
154   idx_2p = (index >> 6) & 127;
155   ixheaacd_acelp_decode_2sp_per_track(idx_2p, 3, ixheaacd_drc_offset, track,
156                                       code_vec);
157   return;
158 }
159 
ixheaacd_acelp_decode_4sp_per_track(WORD32 idx_4p,WORD32 track,FLOAT32 code_vec[])160 static VOID ixheaacd_acelp_decode_4sp_per_track(WORD32 idx_4p, WORD32 track,
161                                                 FLOAT32 code_vec[]) {
162   WORD32 idx_1p, idx_2p, idx_3p;
163 
164   switch ((idx_4p >> 14) & 3) {
165     case 0:
166       if (((idx_4p >> 13) & 1) == 0)
167         ixheaacd_d_acelp_decode_4sp_per_track_section(idx_4p, 0, track,
168                                                       code_vec);
169       else
170         ixheaacd_d_acelp_decode_4sp_per_track_section(idx_4p, 8, track,
171                                                       code_vec);
172       break;
173     case 1:
174       idx_1p = idx_4p >> 10;
175       ixheaacd_acelp_decode_1sp_per_track(idx_1p, 3, 0, track, code_vec);
176       ixheaacd_acelp_decode_3sp_per_track(idx_4p, 3, 8, track, code_vec);
177       break;
178     case 2:
179       idx_2p = idx_4p >> 7;
180       ixheaacd_acelp_decode_2sp_per_track(idx_2p, 3, 0, track, code_vec);
181       ixheaacd_acelp_decode_2sp_per_track(idx_4p, 3, 8, track, code_vec);
182       break;
183     case 3:
184       idx_3p = idx_4p >> 4;
185       ixheaacd_acelp_decode_3sp_per_track(idx_3p, 3, 0, track, code_vec);
186       ixheaacd_acelp_decode_1sp_per_track(idx_4p, 3, 8, track, code_vec);
187       break;
188   }
189   return;
190 }
191 
ixheaacd_d_acelp_add_pulse(WORD32 pos[],WORD32 nb_pulse,WORD32 track,FLOAT32 code[])192 static VOID ixheaacd_d_acelp_add_pulse(WORD32 pos[], WORD32 nb_pulse,
193                                        WORD32 track, FLOAT32 code[]) {
194   WORD32 i, k;
195   for (k = 0; k < nb_pulse; k++) {
196     i = ((pos[k] & (16 - 1)) << 2) + track;
197     if ((pos[k] & 16) == 0) {
198       code[i] = (WORD16)(code[i] + 1.0f);
199     } else {
200       code[i] = (WORD16)(code[i] - 1.0f);
201     }
202   }
203   return;
204 }
205 
ixheaacd_d_acelp_decode_1p_n1(WORD32 index,WORD32 N,WORD32 ixheaacd_drc_offset,WORD32 pos[])206 static VOID ixheaacd_d_acelp_decode_1p_n1(WORD32 index, WORD32 N,
207                                           WORD32 ixheaacd_drc_offset,
208                                           WORD32 pos[]) {
209   WORD32 i, pos1, mask;
210   mask = ((1 << N) - 1);
211 
212   pos1 = ((index & mask) + ixheaacd_drc_offset);
213   i = ((index >> N) & 1);
214   if (i == 1) {
215     pos1 += 16;
216   }
217   pos[0] = pos1;
218   return;
219 }
220 
ixheaacd_acelp_decode_pulses_per_track(WORD32 cb_index[],WORD16 code_bits,FLOAT32 code_vec[])221 VOID ixheaacd_acelp_decode_pulses_per_track(WORD32 cb_index[], WORD16 code_bits,
222                                             FLOAT32 code_vec[]) {
223   WORD32 track_idx, index, ixheaacd_drc_offset, pos[6], i;
224   memset(code_vec, 0, 64 * sizeof(FLOAT32));
225 
226   if (code_bits == 12) {
227     for (track_idx = 0; track_idx < 4; track_idx += 2) {
228       ixheaacd_drc_offset = cb_index[2 * (track_idx / 2)];
229       index = cb_index[2 * (track_idx / 2) + 1];
230       ixheaacd_d_acelp_decode_1p_n1(index, 4, 0, pos);
231       ixheaacd_d_acelp_add_pulse(
232           pos, 1, 2 * ixheaacd_drc_offset + track_idx / 2, code_vec);
233     }
234   } else if (code_bits == 16) {
235     i = 0;
236     ixheaacd_drc_offset = cb_index[i++];
237     ixheaacd_drc_offset = (ixheaacd_drc_offset == 0) ? 1 : 3;
238     for (track_idx = 0; track_idx < 4; track_idx++) {
239       if (track_idx != ixheaacd_drc_offset) {
240         index = cb_index[i++];
241         ixheaacd_d_acelp_decode_1p_n1(index, 4, 0, pos);
242         ixheaacd_d_acelp_add_pulse(pos, 1, track_idx, code_vec);
243       }
244     }
245   } else if (code_bits == 20) {
246     for (track_idx = 0; track_idx < 4; track_idx++) {
247       index = cb_index[track_idx];
248       ixheaacd_acelp_decode_1sp_per_track(index, 4, 0, track_idx, code_vec);
249     }
250   } else if (code_bits == 28) {
251     for (track_idx = 0; track_idx < 2; track_idx++) {
252       index = cb_index[track_idx];
253       ixheaacd_acelp_decode_2sp_per_track(index, 4, 0, track_idx, code_vec);
254     }
255     for (track_idx = 2; track_idx < 4; track_idx++) {
256       index = cb_index[track_idx];
257       ixheaacd_acelp_decode_1sp_per_track(index, 4, 0, track_idx, code_vec);
258     }
259   } else if (code_bits == 36) {
260     for (track_idx = 0; track_idx < 4; track_idx++) {
261       index = cb_index[track_idx];
262       ixheaacd_acelp_decode_2sp_per_track(index, 4, 0, track_idx, code_vec);
263     }
264   } else if (code_bits == 44) {
265     for (track_idx = 0; track_idx < 2; track_idx++) {
266       index = cb_index[track_idx];
267       ixheaacd_acelp_decode_3sp_per_track(index, 4, 0, track_idx, code_vec);
268     }
269     for (track_idx = 2; track_idx < 4; track_idx++) {
270       index = cb_index[track_idx];
271       ixheaacd_acelp_decode_2sp_per_track(index, 4, 0, track_idx, code_vec);
272     }
273   } else if (code_bits == 52) {
274     for (track_idx = 0; track_idx < 4; track_idx++) {
275       index = cb_index[track_idx];
276       ixheaacd_acelp_decode_3sp_per_track(index, 4, 0, track_idx, code_vec);
277     }
278   } else if (code_bits == 64) {
279     for (track_idx = 0; track_idx < 4; track_idx++) {
280       index = ((cb_index[track_idx] << 14) + cb_index[track_idx + 4]);
281       ixheaacd_acelp_decode_4sp_per_track(index, track_idx, code_vec);
282     }
283   }
284   return;
285 }
286 
ixheaacd_acelp_decode_gains(WORD32 index,FLOAT32 code_vec[],FLOAT32 * pitch_gain,FLOAT32 * codebook_gain,FLOAT32 mean_exc_energy,FLOAT32 * energy)287 static void ixheaacd_acelp_decode_gains(WORD32 index, FLOAT32 code_vec[],
288                                         FLOAT32 *pitch_gain,
289                                         FLOAT32 *codebook_gain,
290                                         FLOAT32 mean_exc_energy,
291                                         FLOAT32 *energy) {
292   WORD32 i;
293   FLOAT32 avg_innov_energy, est_gain;
294   const FLOAT32 *gain_table = ixheaacd_int_leave_gain_table;
295 
296   avg_innov_energy = 0.01f;
297   for (i = 0; i < LEN_SUBFR; i++) {
298     avg_innov_energy += code_vec[i] * code_vec[i];
299   }
300   *energy = avg_innov_energy;
301 
302   avg_innov_energy =
303       (FLOAT32)(10.0 * log10(avg_innov_energy / (FLOAT32)LEN_SUBFR));
304 
305   est_gain = mean_exc_energy - avg_innov_energy;
306 
307   est_gain = (FLOAT32)pow(10.0, 0.05 * est_gain);
308   *pitch_gain = gain_table[index * 2];
309 
310   *codebook_gain = gain_table[index * 2 + 1] * est_gain;
311 
312   return;
313 }
314 
ixheaacd_cb_exc_calc(FLOAT32 xcitation_curr[],WORD32 pitch_lag,WORD32 frac)315 static VOID ixheaacd_cb_exc_calc(FLOAT32 xcitation_curr[], WORD32 pitch_lag,
316                                  WORD32 frac) {
317   WORD32 i, j;
318   FLOAT32 s, *x0, *x1, *x2;
319   const FLOAT32 *c1, *c2;
320 
321   x0 = &xcitation_curr[-pitch_lag];
322   frac = -frac;
323   if (frac < 0) {
324     frac += UP_SAMP;
325     x0--;
326   }
327   for (j = 0; j < LEN_SUBFR + 1; j++) {
328     x1 = x0++;
329     x2 = x1 + 1;
330     c1 = &ixheaacd_interpol_filt[frac];
331     c2 = &ixheaacd_interpol_filt[UP_SAMP - frac];
332     s = 0.0;
333     for (i = 0; i < INTER_LP_FIL_ORDER; i++, c1 += UP_SAMP, c2 += UP_SAMP) {
334       s += (*x1--) * (*c1) + (*x2++) * (*c2);
335     }
336     xcitation_curr[j] = s;
337   }
338   return;
339 }
340 
ixheaacd_acelp_alias_cnx(ia_usac_data_struct * usac_data,ia_td_frame_data_struct * pstr_td_frame_data,WORD32 k,FLOAT32 lp_filt_coeff[],FLOAT32 stability_factor,ia_usac_lpd_decoder_handle st)341 WORD32 ixheaacd_acelp_alias_cnx(ia_usac_data_struct *usac_data,
342                                 ia_td_frame_data_struct *pstr_td_frame_data,
343                                 WORD32 k, FLOAT32 lp_filt_coeff[],
344                                 FLOAT32 stability_factor,
345                                 ia_usac_lpd_decoder_handle st) {
346   WORD32 i, subfr_idx;
347   WORD32 pitch_lag, pitch_lag_frac, index, pitch_flag, pitch_lag_max;
348   WORD32 pitch_lag_min = 0;
349   FLOAT32 tmp, pitch_gain, gain_code, voicing_factor, r_v, innov_energy,
350       pitch_energy, mean_ener_code;
351   FLOAT32 gain_smooth, gain_code0, cpe;
352   FLOAT32 code[LEN_SUBFR], synth_temp[128 + 16];
353   FLOAT32 post_process_exc[LEN_SUBFR];
354   FLOAT32 gain_smooth_factor;
355   FLOAT32 *ptr_lp_filt_coeff;
356   WORD32 pitch_min;
357   WORD32 pitch_fr2;
358   WORD32 pitch_fr1;
359   WORD32 pitch_max;
360   WORD32 subfr_nb = 0;
361   WORD16 num_codebits_table[8] = {20, 28, 36, 44, 52, 64, 12, 16};
362   FLOAT32 x[FAC_LENGTH], xn2[2 * FAC_LENGTH + 16];
363   WORD32 int_x[FAC_LENGTH];
364   WORD32 TTT;
365   WORD32 len_subfr = usac_data->len_subfrm;
366   WORD32 fac_length;
367   WORD8 shiftp;
368   WORD32 preshift;
369   WORD32 *ptr_scratch = &usac_data->scratch_buffer[0];
370   WORD32 *int_xn2 = &usac_data->x_ac_dec[0];
371   WORD32 loop_count = 0;
372   WORD32 core_mode = pstr_td_frame_data->acelp_core_mode;
373   FLOAT32 *synth_signal =
374       &usac_data->synth_buf[len_subfr * k + MAX_PITCH +
375                             (((NUM_FRAMES * usac_data->num_subfrm) / 2) - 1) *
376                                 LEN_SUBFR];
377   FLOAT32 *xcitation_curr =
378       &usac_data->exc_buf[len_subfr * k + MAX_PITCH + (INTER_LP_FIL_ORDER + 1)];
379   FLOAT32 *ptr_pitch_gain =
380       &usac_data->pitch_gain[k * usac_data->num_subfrm +
381                              (((NUM_FRAMES * usac_data->num_subfrm) / 2) - 1)];
382   WORD32 *ptr_pitch =
383       &usac_data->pitch[k * usac_data->num_subfrm +
384                         (((NUM_FRAMES * usac_data->num_subfrm) / 2) - 1)];
385   WORD32 err = 0;
386   fac_length = len_subfr / 2;
387 
388   if (st->mode_prev > 0) {
389     for (i = 0; i < fac_length / 2; i++) {
390       x[i] = st->fac_gain * pstr_td_frame_data->fac[k * FAC_LENGTH + 2 * i];
391       x[fac_length / 2 + i] =
392           st->fac_gain *
393           pstr_td_frame_data->fac[k * FAC_LENGTH + fac_length - 2 * i - 1];
394     }
395     for (i = 0; i < fac_length / 8; i++) {
396       x[i] *= st->fac_fd_data[2 * i];
397       x[fac_length - i - 1] *= st->fac_fd_data[2 * i + 1];
398     }
399 
400     preshift = 0;
401     shiftp = ixheaacd_float2fix(x, int_x, fac_length);
402 
403     err =
404         ixheaacd_acelp_mdct(int_x, int_xn2, &preshift, fac_length, ptr_scratch);
405     if (err == -1) return err;
406     ixheaacd_fix2float(int_xn2, xn2 + fac_length, fac_length, &shiftp,
407                        &preshift);
408 
409     ixheaacd_vec_cnst_mul((2.0f / (FLOAT32)fac_length), xn2 + fac_length,
410                           xn2 + fac_length, fac_length);
411 
412     memset(xn2, 0, fac_length * sizeof(FLOAT32));
413 
414     ixheaacd_lpc_wt_synthesis_tool(st->lp_flt_coeff_a_prev, xn2 + fac_length,
415                                    fac_length);
416 
417     for (i = 0; i < 2 * fac_length; i++)
418       xn2[i] += synth_signal[i - (2 * fac_length)];
419 
420     memcpy(synth_signal - fac_length, xn2 + fac_length,
421            fac_length * sizeof(FLOAT32));
422 
423     tmp = 0.0;
424     ixheaacd_preemphsis_tool_float(xn2, PREEMPH_FILT_FAC, 2 * fac_length, tmp);
425 
426     ptr_lp_filt_coeff = st->lp_flt_coeff_a_prev;
427     TTT = fac_length % LEN_SUBFR;
428     if (TTT != 0) {
429       ixheaacd_residual_tool_float(
430           ptr_lp_filt_coeff, &xn2[fac_length],
431           &xcitation_curr[fac_length - (2 * fac_length)], TTT, 1);
432       ptr_lp_filt_coeff += (ORDER + 1);
433     }
434 
435     loop_count = (fac_length + TTT) / LEN_SUBFR;
436     ixheaacd_residual_tool_float(ptr_lp_filt_coeff, &xn2[fac_length + TTT],
437                                  &xcitation_curr[TTT - fac_length], LEN_SUBFR,
438                                  loop_count);
439   }
440 
441   for (i = 0; i < ORDER; i++)
442     synth_temp[i] = synth_signal[i - ORDER] -
443                     (PREEMPH_FILT_FAC * synth_signal[i - ORDER - 1]);
444 
445   i = (((st->fscale * TMIN) + (FSCALE_DENOM / 2)) / FSCALE_DENOM) - TMIN;
446   pitch_min = TMIN + i;
447   pitch_fr2 = TFR2 - i;
448   pitch_fr1 = TFR1;
449   pitch_max = TMAX + (6 * i);
450 
451   ptr_lp_filt_coeff = lp_filt_coeff;
452   for (subfr_idx = 0; subfr_idx < len_subfr; subfr_idx += LEN_SUBFR) {
453     pitch_flag = subfr_idx;
454     if ((len_subfr == 256) && (subfr_idx == (2 * LEN_SUBFR))) {
455       pitch_flag = 0;
456     }
457     index = pstr_td_frame_data->acb_index[k * 4 + subfr_nb];
458 
459     if (pitch_flag == 0) {
460       if (index < (pitch_fr2 - pitch_min) * 4) {
461         pitch_lag = pitch_min + (index / 4);
462         pitch_lag_frac = index - (pitch_lag - pitch_min) * 4;
463       } else if (index <
464                  ((pitch_fr2 - pitch_min) * 4 + (pitch_fr1 - pitch_fr2) * 2)) {
465         index -= (pitch_fr2 - pitch_min) * 4;
466         pitch_lag = pitch_fr2 + (index / 2);
467         pitch_lag_frac = index - (pitch_lag - pitch_fr2) * 2;
468         pitch_lag_frac *= 2;
469       } else {
470         pitch_lag = index + pitch_fr1 - ((pitch_fr2 - pitch_min) * 4) -
471                     ((pitch_fr1 - pitch_fr2) * 2);
472         pitch_lag_frac = 0;
473       }
474       pitch_lag_min = pitch_lag - 8;
475       if (pitch_lag_min < pitch_min) pitch_lag_min = pitch_min;
476 
477       pitch_lag_max = pitch_lag_min + 15;
478       if (pitch_lag_max > pitch_max) {
479         pitch_lag_max = pitch_max;
480         pitch_lag_min = pitch_lag_max - 15;
481       }
482     } else {
483       pitch_lag = pitch_lag_min + index / 4;
484       pitch_lag_frac = index - (pitch_lag - pitch_lag_min) * 4;
485     }
486 
487     ixheaacd_cb_exc_calc(&xcitation_curr[subfr_idx], pitch_lag, pitch_lag_frac);
488 
489     mean_ener_code =
490         (((FLOAT32)pstr_td_frame_data->mean_energy[k]) * 12.0f) + 18.0f;
491 
492     if (pstr_td_frame_data->ltp_filtering_flag[k * 4 + subfr_nb] == 0) {
493       for (i = 0; i < LEN_SUBFR; i++)
494         code[i] = (FLOAT32)(0.18 * xcitation_curr[i - 1 + subfr_idx] +
495                             0.64 * xcitation_curr[i + subfr_idx] +
496                             0.18 * xcitation_curr[i + 1 + subfr_idx]);
497 
498       ixheaacd_mem_cpy(code, &xcitation_curr[subfr_idx], LEN_SUBFR);
499     }
500 
501     ixheaacd_acelp_decode_pulses_per_track(
502         &(pstr_td_frame_data->icb_index[k * 4 + subfr_nb][0]),
503         num_codebits_table[core_mode], code);
504 
505     tmp = 0.0;
506     ixheaacd_preemphsis_tool_float(code, TILT_CODE, LEN_SUBFR, tmp);
507     i = pitch_lag;
508     if (pitch_lag_frac > 2) i++;
509     if (i >= 0) ixheaacd_acelp_pitch_sharpening(code, i);
510 
511     index = pstr_td_frame_data->gains[k * 4 + subfr_nb];
512 
513     ixheaacd_acelp_decode_gains(index, code, &pitch_gain, &gain_code,
514                                 mean_ener_code, &innov_energy);
515 
516     pitch_energy = 0.0;
517     for (i = 0; i < LEN_SUBFR; i++)
518       pitch_energy +=
519           xcitation_curr[i + subfr_idx] * xcitation_curr[i + subfr_idx];
520 
521     pitch_energy *= (pitch_gain * pitch_gain);
522 
523     innov_energy *= gain_code * gain_code;
524 
525     r_v = (FLOAT32)((pitch_energy - innov_energy) /
526                     (pitch_energy + innov_energy));
527 
528     for (i = 0; i < LEN_SUBFR; i++)
529       post_process_exc[i] = pitch_gain * xcitation_curr[i + subfr_idx];
530 
531     for (i = 0; i < LEN_SUBFR; i++)
532       xcitation_curr[i + subfr_idx] =
533           pitch_gain * xcitation_curr[i + subfr_idx] + gain_code * code[i];
534 
535     i = pitch_lag;
536     if (pitch_lag_frac > 2) i++;
537 
538     if (i > pitch_max) i = pitch_max;
539 
540     *ptr_pitch++ = i;
541     *ptr_pitch_gain++ = pitch_gain;
542 
543     voicing_factor = (FLOAT32)(0.5 * (1.0 - r_v));
544     gain_smooth_factor = stability_factor * voicing_factor;
545     gain_code0 = gain_code;
546     if (gain_code0 < st->gain_threshold) {
547       gain_code0 = (FLOAT32)(gain_code0 * 1.19);
548       if (gain_code0 > st->gain_threshold) gain_code0 = st->gain_threshold;
549     } else {
550       gain_code0 = (FLOAT32)(gain_code0 / 1.19);
551       if (gain_code0 < st->gain_threshold) gain_code0 = st->gain_threshold;
552     }
553     st->gain_threshold = gain_code0;
554     gain_smooth = (FLOAT32)((gain_smooth_factor * gain_code0) +
555                             ((1.0 - gain_smooth_factor) * gain_code));
556     for (i = 0; i < LEN_SUBFR; i++) code[i] *= gain_smooth;
557 
558     cpe = (FLOAT32)(0.125 * (1.0 + r_v));
559 
560     post_process_exc[0] += code[0] - (cpe * code[1]);
561 
562     for (i = 1; i < LEN_SUBFR - 1; i++)
563       post_process_exc[i] += code[i] - (cpe * (code[i - 1] + code[i + 1]));
564 
565     post_process_exc[LEN_SUBFR - 1] +=
566         code[LEN_SUBFR - 1] - (cpe * code[LEN_SUBFR - 2]);
567 
568     ixheaacd_synthesis_tool_float(ptr_lp_filt_coeff, post_process_exc,
569                                   &synth_signal[subfr_idx], LEN_SUBFR,
570                                   synth_temp);
571     memcpy(synth_temp, &synth_signal[subfr_idx + LEN_SUBFR - ORDER],
572            ORDER * sizeof(FLOAT32));
573 
574     ptr_lp_filt_coeff += (ORDER + 1);
575     subfr_nb++;
576   }
577 
578   ixheaacd_deemphsis_tool(synth_signal, len_subfr, synth_signal[-1]);
579 
580   memset(synth_temp + 16, 0, 128 * sizeof(FLOAT32));
581   ixheaacd_synthesis_tool_float1(ptr_lp_filt_coeff, synth_temp + 16, 128);
582 
583   ptr_lp_filt_coeff -= (2 * (ORDER + 1));
584   memcpy(st->lp_flt_coeff_a_prev, ptr_lp_filt_coeff,
585          (2 * (ORDER + 1)) * sizeof(FLOAT32));
586 
587   memcpy(st->exc_prev, synth_signal + len_subfr - (1 + fac_length),
588          (1 + fac_length) * sizeof(FLOAT32));
589 
590   memcpy(st->exc_prev + 1 + fac_length, synth_temp + 16,
591          fac_length * sizeof(FLOAT32));
592   ixheaacd_deemphsis_tool(st->exc_prev + 1 + fac_length, fac_length,
593                           synth_signal[len_subfr - 1]);
594 
595   return err;
596 }
597