1 /*
2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 /******************************************************************
12
13 iLBC Speech Coder ANSI-C Source Code
14
15 WebRtcIlbcfix_DoThePlc.c
16
17 ******************************************************************/
18
19 #include "defines.h"
20 #include "constants.h"
21 #include "comp_corr.h"
22 #include "bw_expand.h"
23
24 /*----------------------------------------------------------------*
25 * Packet loss concealment routine. Conceals a residual signal
26 * and LP parameters. If no packet loss, update state.
27 *---------------------------------------------------------------*/
28
WebRtcIlbcfix_DoThePlc(int16_t * PLCresidual,int16_t * PLClpc,int16_t PLI,int16_t * decresidual,int16_t * lpc,int16_t inlag,iLBC_Dec_Inst_t * iLBCdec_inst)29 void WebRtcIlbcfix_DoThePlc(
30 int16_t *PLCresidual, /* (o) concealed residual */
31 int16_t *PLClpc, /* (o) concealed LP parameters */
32 int16_t PLI, /* (i) packet loss indicator
33 0 - no PL, 1 = PL */
34 int16_t *decresidual, /* (i) decoded residual */
35 int16_t *lpc, /* (i) decoded LPC (only used for no PL) */
36 int16_t inlag, /* (i) pitch lag */
37 iLBC_Dec_Inst_t *iLBCdec_inst
38 /* (i/o) decoder instance */
39 ){
40 int16_t i, pick;
41 int32_t cross, ener, cross_comp, ener_comp = 0;
42 int32_t measure, maxMeasure, energy;
43 int16_t max, crossSquareMax, crossSquare;
44 int16_t j, lag, tmp1, tmp2, randlag;
45 int16_t shift1, shift2, shift3, shiftMax;
46 int16_t scale3;
47 int16_t corrLen;
48 int32_t tmpW32, tmp2W32;
49 int16_t use_gain;
50 int16_t tot_gain;
51 int16_t max_perSquare;
52 int16_t scale1, scale2;
53 int16_t totscale;
54 int32_t nom;
55 int16_t denom;
56 int16_t pitchfact;
57 int16_t use_lag;
58 int ind;
59 int16_t randvec[BLOCKL_MAX];
60
61 /* Packet Loss */
62 if (PLI == 1) {
63
64 (*iLBCdec_inst).consPLICount += 1;
65
66 /* if previous frame not lost,
67 determine pitch pred. gain */
68
69 if (iLBCdec_inst->prevPLI != 1) {
70
71 /* Maximum 60 samples are correlated, preserve as high accuracy
72 as possible without getting overflow */
73 max = WebRtcSpl_MaxAbsValueW16((*iLBCdec_inst).prevResidual, (int16_t)iLBCdec_inst->blockl);
74 scale3 = (WebRtcSpl_GetSizeInBits(max)<<1) - 25;
75 if (scale3 < 0) {
76 scale3 = 0;
77 }
78
79 /* Store scale for use when interpolating between the
80 * concealment and the received packet */
81 iLBCdec_inst->prevScale = scale3;
82
83 /* Search around the previous lag +/-3 to find the
84 best pitch period */
85 lag = inlag - 3;
86
87 /* Guard against getting outside the frame */
88 corrLen = WEBRTC_SPL_MIN(60, iLBCdec_inst->blockl-(inlag+3));
89
90 WebRtcIlbcfix_CompCorr( &cross, &ener,
91 iLBCdec_inst->prevResidual, lag, iLBCdec_inst->blockl, corrLen, scale3);
92
93 /* Normalize and store cross^2 and the number of shifts */
94 shiftMax = WebRtcSpl_GetSizeInBits(WEBRTC_SPL_ABS_W32(cross))-15;
95 crossSquareMax = (int16_t)WEBRTC_SPL_MUL_16_16_RSFT(WEBRTC_SPL_SHIFT_W32(cross, -shiftMax),
96 WEBRTC_SPL_SHIFT_W32(cross, -shiftMax), 15);
97
98 for (j=inlag-2;j<=inlag+3;j++) {
99 WebRtcIlbcfix_CompCorr( &cross_comp, &ener_comp,
100 iLBCdec_inst->prevResidual, j, iLBCdec_inst->blockl, corrLen, scale3);
101
102 /* Use the criteria (corr*corr)/energy to compare if
103 this lag is better or not. To avoid the division,
104 do a cross multiplication */
105 shift1 = WebRtcSpl_GetSizeInBits(WEBRTC_SPL_ABS_W32(cross_comp))-15;
106 crossSquare = (int16_t)WEBRTC_SPL_MUL_16_16_RSFT(WEBRTC_SPL_SHIFT_W32(cross_comp, -shift1),
107 WEBRTC_SPL_SHIFT_W32(cross_comp, -shift1), 15);
108
109 shift2 = WebRtcSpl_GetSizeInBits(ener)-15;
110 measure = WEBRTC_SPL_MUL_16_16(WEBRTC_SPL_SHIFT_W32(ener, -shift2),
111 crossSquare);
112
113 shift3 = WebRtcSpl_GetSizeInBits(ener_comp)-15;
114 maxMeasure = WEBRTC_SPL_MUL_16_16(WEBRTC_SPL_SHIFT_W32(ener_comp, -shift3),
115 crossSquareMax);
116
117 /* Calculate shift value, so that the two measures can
118 be put in the same Q domain */
119 if(((shiftMax<<1)+shift3) > ((shift1<<1)+shift2)) {
120 tmp1 = WEBRTC_SPL_MIN(31, (shiftMax<<1)+shift3-(shift1<<1)-shift2);
121 tmp2 = 0;
122 } else {
123 tmp1 = 0;
124 tmp2 = WEBRTC_SPL_MIN(31, (shift1<<1)+shift2-(shiftMax<<1)-shift3);
125 }
126
127 if ((measure>>tmp1) > (maxMeasure>>tmp2)) {
128 /* New lag is better => record lag, measure and domain */
129 lag = j;
130 crossSquareMax = crossSquare;
131 cross = cross_comp;
132 shiftMax = shift1;
133 ener = ener_comp;
134 }
135 }
136
137 /* Calculate the periodicity for the lag with the maximum correlation.
138
139 Definition of the periodicity:
140 abs(corr(vec1, vec2))/(sqrt(energy(vec1))*sqrt(energy(vec2)))
141
142 Work in the Square domain to simplify the calculations
143 max_perSquare is less than 1 (in Q15)
144 */
145 tmp2W32=WebRtcSpl_DotProductWithScale(&iLBCdec_inst->prevResidual[iLBCdec_inst->blockl-corrLen],
146 &iLBCdec_inst->prevResidual[iLBCdec_inst->blockl-corrLen],
147 corrLen, scale3);
148
149 if ((tmp2W32>0)&&(ener_comp>0)) {
150 /* norm energies to int16_t, compute the product of the energies and
151 use the upper int16_t as the denominator */
152
153 scale1=(int16_t)WebRtcSpl_NormW32(tmp2W32)-16;
154 tmp1=(int16_t)WEBRTC_SPL_SHIFT_W32(tmp2W32, scale1);
155
156 scale2=(int16_t)WebRtcSpl_NormW32(ener)-16;
157 tmp2=(int16_t)WEBRTC_SPL_SHIFT_W32(ener, scale2);
158 denom=(int16_t)WEBRTC_SPL_MUL_16_16_RSFT(tmp1, tmp2, 16); /* denom in Q(scale1+scale2-16) */
159
160 /* Square the cross correlation and norm it such that max_perSquare
161 will be in Q15 after the division */
162
163 totscale = scale1+scale2-1;
164 tmp1 = (int16_t)WEBRTC_SPL_SHIFT_W32(cross, (totscale>>1));
165 tmp2 = (int16_t)WEBRTC_SPL_SHIFT_W32(cross, totscale-(totscale>>1));
166
167 nom = WEBRTC_SPL_MUL_16_16(tmp1, tmp2);
168 max_perSquare = (int16_t)WebRtcSpl_DivW32W16(nom, denom);
169
170 } else {
171 max_perSquare = 0;
172 }
173 }
174
175 /* previous frame lost, use recorded lag and gain */
176
177 else {
178 lag = iLBCdec_inst->prevLag;
179 max_perSquare = iLBCdec_inst->perSquare;
180 }
181
182 /* Attenuate signal and scale down pitch pred gain if
183 several frames lost consecutively */
184
185 use_gain = 32767; /* 1.0 in Q15 */
186
187 if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>320) {
188 use_gain = 29491; /* 0.9 in Q15 */
189 } else if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>640) {
190 use_gain = 22938; /* 0.7 in Q15 */
191 } else if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>960) {
192 use_gain = 16384; /* 0.5 in Q15 */
193 } else if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>1280) {
194 use_gain = 0; /* 0.0 in Q15 */
195 }
196
197 /* Compute mixing factor of picth repeatition and noise:
198 for max_per>0.7 set periodicity to 1.0
199 0.4<max_per<0.7 set periodicity to (maxper-0.4)/0.7-0.4)
200 max_per<0.4 set periodicity to 0.0
201 */
202
203 if (max_perSquare>7868) { /* periodicity > 0.7 (0.7^4=0.2401 in Q15) */
204 pitchfact = 32767;
205 } else if (max_perSquare>839) { /* 0.4 < periodicity < 0.7 (0.4^4=0.0256 in Q15) */
206 /* find best index and interpolate from that */
207 ind = 5;
208 while ((max_perSquare<WebRtcIlbcfix_kPlcPerSqr[ind])&&(ind>0)) {
209 ind--;
210 }
211 /* pitch fact is approximated by first order */
212 tmpW32 = (int32_t)WebRtcIlbcfix_kPlcPitchFact[ind] +
213 WEBRTC_SPL_MUL_16_16_RSFT(WebRtcIlbcfix_kPlcPfSlope[ind], (max_perSquare-WebRtcIlbcfix_kPlcPerSqr[ind]), 11);
214
215 pitchfact = (int16_t)WEBRTC_SPL_MIN(tmpW32, 32767); /* guard against overflow */
216
217 } else { /* periodicity < 0.4 */
218 pitchfact = 0;
219 }
220
221 /* avoid repetition of same pitch cycle (buzzyness) */
222 use_lag = lag;
223 if (lag<80) {
224 use_lag = 2*lag;
225 }
226
227 /* compute concealed residual */
228 energy = 0;
229
230 for (i=0; i<iLBCdec_inst->blockl; i++) {
231
232 /* noise component - 52 < randlagFIX < 117 */
233 iLBCdec_inst->seed = (int16_t)(WEBRTC_SPL_MUL_16_16(iLBCdec_inst->seed, 31821)+(int32_t)13849);
234 randlag = 53 + (int16_t)(iLBCdec_inst->seed & 63);
235
236 pick = i - randlag;
237
238 if (pick < 0) {
239 randvec[i] = iLBCdec_inst->prevResidual[iLBCdec_inst->blockl+pick];
240 } else {
241 randvec[i] = iLBCdec_inst->prevResidual[pick];
242 }
243
244 /* pitch repeatition component */
245 pick = i - use_lag;
246
247 if (pick < 0) {
248 PLCresidual[i] = iLBCdec_inst->prevResidual[iLBCdec_inst->blockl+pick];
249 } else {
250 PLCresidual[i] = PLCresidual[pick];
251 }
252
253 /* Attinuate total gain for each 10 ms */
254 if (i<80) {
255 tot_gain=use_gain;
256 } else if (i<160) {
257 tot_gain=(int16_t)WEBRTC_SPL_MUL_16_16_RSFT(31130, use_gain, 15); /* 0.95*use_gain */
258 } else {
259 tot_gain=(int16_t)WEBRTC_SPL_MUL_16_16_RSFT(29491, use_gain, 15); /* 0.9*use_gain */
260 }
261
262
263 /* mix noise and pitch repeatition */
264
265 PLCresidual[i] = (int16_t)WEBRTC_SPL_MUL_16_16_RSFT(tot_gain,
266 (int16_t)WEBRTC_SPL_RSHIFT_W32( (WEBRTC_SPL_MUL_16_16(pitchfact, PLCresidual[i]) +
267 WEBRTC_SPL_MUL_16_16((32767-pitchfact), randvec[i]) + 16384),
268 15),
269 15);
270
271 /* Shifting down the result one step extra to ensure that no overflow
272 will occur */
273 energy += WEBRTC_SPL_MUL_16_16_RSFT(PLCresidual[i],
274 PLCresidual[i], (iLBCdec_inst->prevScale+1));
275
276 }
277
278 /* less than 30 dB, use only noise */
279 if (energy < (WEBRTC_SPL_SHIFT_W32(((int32_t)iLBCdec_inst->blockl*900),-(iLBCdec_inst->prevScale+1)))) {
280 energy = 0;
281 for (i=0; i<iLBCdec_inst->blockl; i++) {
282 PLCresidual[i] = randvec[i];
283 }
284 }
285
286 /* use the old LPC */
287 WEBRTC_SPL_MEMCPY_W16(PLClpc, (*iLBCdec_inst).prevLpc, LPC_FILTERORDER+1);
288
289 /* Update state in case there are multiple frame losses */
290 iLBCdec_inst->prevLag = lag;
291 iLBCdec_inst->perSquare = max_perSquare;
292 }
293
294 /* no packet loss, copy input */
295
296 else {
297 WEBRTC_SPL_MEMCPY_W16(PLCresidual, decresidual, iLBCdec_inst->blockl);
298 WEBRTC_SPL_MEMCPY_W16(PLClpc, lpc, (LPC_FILTERORDER+1));
299 iLBCdec_inst->consPLICount = 0;
300 }
301
302 /* update state */
303 iLBCdec_inst->prevPLI = PLI;
304 WEBRTC_SPL_MEMCPY_W16(iLBCdec_inst->prevLpc, PLClpc, (LPC_FILTERORDER+1));
305 WEBRTC_SPL_MEMCPY_W16(iLBCdec_inst->prevResidual, PLCresidual, iLBCdec_inst->blockl);
306
307 return;
308 }
309