Alexandre Lision | 8af73cb | 2013-12-10 14:11:20 -0500 | [diff] [blame^] | 1 | |
| 2 | /****************************************************************** |
| 3 | |
| 4 | iLBC Speech Coder ANSI-C Source Code |
| 5 | |
| 6 | doCPLC.c |
| 7 | |
| 8 | Copyright (C) The Internet Society (2004). |
| 9 | All Rights Reserved. |
| 10 | |
| 11 | ******************************************************************/ |
| 12 | |
| 13 | #include <math.h> |
| 14 | #include <string.h> |
| 15 | #include <stdio.h> |
| 16 | |
| 17 | |
| 18 | |
| 19 | |
| 20 | |
| 21 | #include "iLBC_define.h" |
| 22 | |
| 23 | /*----------------------------------------------------------------* |
| 24 | * Compute cross correlation and pitch gain for pitch prediction |
| 25 | * of last subframe at given lag. |
| 26 | *---------------------------------------------------------------*/ |
| 27 | |
| 28 | void compCorr( |
| 29 | float *cc, /* (o) cross correlation coefficient */ |
| 30 | float *gc, /* (o) gain */ |
| 31 | float *pm, |
| 32 | float *buffer, /* (i) signal buffer */ |
| 33 | int lag, /* (i) pitch lag */ |
| 34 | int bLen, /* (i) length of buffer */ |
| 35 | int sRange /* (i) correlation search length */ |
| 36 | ){ |
| 37 | int i; |
| 38 | float ftmp1, ftmp2, ftmp3; |
| 39 | |
| 40 | /* Guard against getting outside buffer */ |
| 41 | if ((bLen-sRange-lag)<0) { |
| 42 | sRange=bLen-lag; |
| 43 | } |
| 44 | |
| 45 | ftmp1 = 0.0; |
| 46 | ftmp2 = 0.0; |
| 47 | ftmp3 = 0.0; |
| 48 | for (i=0; i<sRange; i++) { |
| 49 | ftmp1 += buffer[bLen-sRange+i] * |
| 50 | buffer[bLen-sRange+i-lag]; |
| 51 | ftmp2 += buffer[bLen-sRange+i-lag] * |
| 52 | buffer[bLen-sRange+i-lag]; |
| 53 | ftmp3 += buffer[bLen-sRange+i] * |
| 54 | buffer[bLen-sRange+i]; |
| 55 | } |
| 56 | |
| 57 | if (ftmp2 > 0.0) { |
| 58 | *cc = ftmp1*ftmp1/ftmp2; |
| 59 | *gc = (float)fabs(ftmp1/ftmp2); |
| 60 | *pm=(float)fabs(ftmp1)/ |
| 61 | ((float)sqrt(ftmp2)*(float)sqrt(ftmp3)); |
| 62 | } |
| 63 | else { |
| 64 | *cc = 0.0; |
| 65 | *gc = 0.0; |
| 66 | *pm=0.0; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | |
| 71 | |
| 72 | |
| 73 | |
| 74 | /*----------------------------------------------------------------* |
| 75 | * Packet loss concealment routine. Conceals a residual signal |
| 76 | * and LP parameters. If no packet loss, update state. |
| 77 | *---------------------------------------------------------------*/ |
| 78 | |
| 79 | void doThePLC( |
| 80 | float *PLCresidual, /* (o) concealed residual */ |
| 81 | float *PLClpc, /* (o) concealed LP parameters */ |
| 82 | int PLI, /* (i) packet loss indicator |
| 83 | 0 - no PL, 1 = PL */ |
| 84 | float *decresidual, /* (i) decoded residual */ |
| 85 | float *lpc, /* (i) decoded LPC (only used for no PL) */ |
| 86 | int inlag, /* (i) pitch lag */ |
| 87 | iLBC_Dec_Inst_t *iLBCdec_inst |
| 88 | /* (i/o) decoder instance */ |
| 89 | ){ |
| 90 | int lag=20, randlag; |
| 91 | float gain, maxcc; |
| 92 | float use_gain; |
| 93 | float gain_comp, maxcc_comp, per, max_per=0; |
| 94 | int i, pick, use_lag; |
| 95 | float ftmp, randvec[BLOCKL_MAX], pitchfact, energy; |
| 96 | |
| 97 | /* Packet Loss */ |
| 98 | |
| 99 | if (PLI == 1) { |
| 100 | |
| 101 | iLBCdec_inst->consPLICount += 1; |
| 102 | |
| 103 | /* if previous frame not lost, |
| 104 | determine pitch pred. gain */ |
| 105 | |
| 106 | if (iLBCdec_inst->prevPLI != 1) { |
| 107 | |
| 108 | /* Search around the previous lag to find the |
| 109 | best pitch period */ |
| 110 | |
| 111 | lag=inlag-3; |
| 112 | compCorr(&maxcc, &gain, &max_per, |
| 113 | iLBCdec_inst->prevResidual, |
| 114 | lag, iLBCdec_inst->blockl, 60); |
| 115 | for (i=inlag-2;i<=inlag+3;i++) { |
| 116 | compCorr(&maxcc_comp, &gain_comp, &per, |
| 117 | iLBCdec_inst->prevResidual, |
| 118 | i, iLBCdec_inst->blockl, 60); |
| 119 | |
| 120 | if (maxcc_comp>maxcc) { |
| 121 | maxcc=maxcc_comp; |
| 122 | |
| 123 | |
| 124 | |
| 125 | |
| 126 | |
| 127 | gain=gain_comp; |
| 128 | lag=i; |
| 129 | max_per=per; |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | } |
| 134 | |
| 135 | /* previous frame lost, use recorded lag and periodicity */ |
| 136 | |
| 137 | else { |
| 138 | lag=iLBCdec_inst->prevLag; |
| 139 | max_per=iLBCdec_inst->per; |
| 140 | } |
| 141 | |
| 142 | /* downscaling */ |
| 143 | |
| 144 | use_gain=1.0; |
| 145 | if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>320) |
| 146 | use_gain=(float)0.9; |
| 147 | else if (iLBCdec_inst->consPLICount* |
| 148 | iLBCdec_inst->blockl>2*320) |
| 149 | use_gain=(float)0.7; |
| 150 | else if (iLBCdec_inst->consPLICount* |
| 151 | iLBCdec_inst->blockl>3*320) |
| 152 | use_gain=(float)0.5; |
| 153 | else if (iLBCdec_inst->consPLICount* |
| 154 | iLBCdec_inst->blockl>4*320) |
| 155 | use_gain=(float)0.0; |
| 156 | |
| 157 | /* mix noise and pitch repeatition */ |
| 158 | ftmp=(float)sqrt(max_per); |
| 159 | if (ftmp>(float)0.7) |
| 160 | pitchfact=(float)1.0; |
| 161 | else if (ftmp>(float)0.4) |
| 162 | pitchfact=(ftmp-(float)0.4)/((float)0.7-(float)0.4); |
| 163 | else |
| 164 | pitchfact=0.0; |
| 165 | |
| 166 | |
| 167 | /* avoid repetition of same pitch cycle */ |
| 168 | use_lag=lag; |
| 169 | if (lag<80) { |
| 170 | use_lag=2*lag; |
| 171 | } |
| 172 | |
| 173 | /* compute concealed residual */ |
| 174 | |
| 175 | |
| 176 | |
| 177 | |
| 178 | |
| 179 | |
| 180 | energy = 0.0; |
| 181 | for (i=0; i<iLBCdec_inst->blockl; i++) { |
| 182 | |
| 183 | /* noise component */ |
| 184 | |
| 185 | iLBCdec_inst->seed=(iLBCdec_inst->seed*69069L+1) & |
| 186 | (0x80000000L-1); |
| 187 | randlag = 50 + ((signed long) iLBCdec_inst->seed)%70; |
| 188 | pick = i - randlag; |
| 189 | |
| 190 | if (pick < 0) { |
| 191 | randvec[i] = |
| 192 | iLBCdec_inst->prevResidual[ |
| 193 | iLBCdec_inst->blockl+pick]; |
| 194 | } else { |
| 195 | randvec[i] = randvec[pick]; |
| 196 | } |
| 197 | |
| 198 | /* pitch repeatition component */ |
| 199 | pick = i - use_lag; |
| 200 | |
| 201 | if (pick < 0) { |
| 202 | PLCresidual[i] = |
| 203 | iLBCdec_inst->prevResidual[ |
| 204 | iLBCdec_inst->blockl+pick]; |
| 205 | } else { |
| 206 | PLCresidual[i] = PLCresidual[pick]; |
| 207 | } |
| 208 | |
| 209 | /* mix random and periodicity component */ |
| 210 | |
| 211 | if (i<80) |
| 212 | PLCresidual[i] = use_gain*(pitchfact * |
| 213 | PLCresidual[i] + |
| 214 | ((float)1.0 - pitchfact) * randvec[i]); |
| 215 | else if (i<160) |
| 216 | PLCresidual[i] = (float)0.95*use_gain*(pitchfact * |
| 217 | PLCresidual[i] + |
| 218 | ((float)1.0 - pitchfact) * randvec[i]); |
| 219 | else |
| 220 | PLCresidual[i] = (float)0.9*use_gain*(pitchfact * |
| 221 | PLCresidual[i] + |
| 222 | ((float)1.0 - pitchfact) * randvec[i]); |
| 223 | |
| 224 | energy += PLCresidual[i] * PLCresidual[i]; |
| 225 | } |
| 226 | |
| 227 | /* less than 30 dB, use only noise */ |
| 228 | |
| 229 | |
| 230 | |
| 231 | |
| 232 | |
| 233 | |
| 234 | if (sqrt(energy/(float)iLBCdec_inst->blockl) < 30.0) { |
| 235 | gain=0.0; |
| 236 | for (i=0; i<iLBCdec_inst->blockl; i++) { |
| 237 | PLCresidual[i] = randvec[i]; |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | /* use old LPC */ |
| 242 | |
| 243 | memcpy(PLClpc,iLBCdec_inst->prevLpc, |
| 244 | (LPC_FILTERORDER+1)*sizeof(float)); |
| 245 | |
| 246 | } |
| 247 | |
| 248 | /* no packet loss, copy input */ |
| 249 | |
| 250 | else { |
| 251 | memcpy(PLCresidual, decresidual, |
| 252 | iLBCdec_inst->blockl*sizeof(float)); |
| 253 | memcpy(PLClpc, lpc, (LPC_FILTERORDER+1)*sizeof(float)); |
| 254 | iLBCdec_inst->consPLICount = 0; |
| 255 | } |
| 256 | |
| 257 | /* update state */ |
| 258 | |
| 259 | if (PLI) { |
| 260 | iLBCdec_inst->prevLag = lag; |
| 261 | iLBCdec_inst->per=max_per; |
| 262 | } |
| 263 | |
| 264 | iLBCdec_inst->prevPLI = PLI; |
| 265 | memcpy(iLBCdec_inst->prevLpc, PLClpc, |
| 266 | (LPC_FILTERORDER+1)*sizeof(float)); |
| 267 | memcpy(iLBCdec_inst->prevResidual, PLCresidual, |
| 268 | iLBCdec_inst->blockl*sizeof(float)); |
| 269 | } |
| 270 | |