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-rwxr-xr-xcodecs/ilbc/doCPLC.c303
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diff --git a/codecs/ilbc/doCPLC.c b/codecs/ilbc/doCPLC.c
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+
+/******************************************************************
+
+ iLBC Speech Coder ANSI-C Source Code
+
+ doCPLC.c
+
+ Copyright (c) 2001,
+ Global IP Sound AB.
+ All rights reserved.
+
+******************************************************************/
+
+#include <math.h>
+#include <string.h>
+
+#include "iLBC_define.h"
+
+/*----------------------------------------------------------------*
+ * Compute cross correlation and pitch gain for pitch prediction
+ * of last subframe at given lag.
+ *---------------------------------------------------------------*/
+
+void compCorr(
+ float *cc, /* (o) cross correlation coefficient */
+ float *gc, /* (o) gain */
+ float *buffer, /* (i) signal buffer */
+ int lag, /* (i) pitch lag */
+ int bLen, /* (i) length of buffer */
+ int sRange /* (i) correlation search length */
+){
+ int i;
+ float ftmp1, ftmp2;
+
+ ftmp1 = 0.0;
+ ftmp2 = 0.0;
+ for (i=0; i<sRange; i++) {
+ ftmp1 += buffer[bLen-sRange+i] *
+ buffer[bLen-sRange+i-lag];
+ ftmp2 += buffer[bLen-sRange+i-lag] *
+ buffer[bLen-sRange+i-lag];
+ }
+
+ if (ftmp2 > 0.0) {
+ *cc = ftmp1*ftmp1/ftmp2;
+ *gc = (float)fabs(ftmp1/ftmp2);
+ }
+ else {
+ *cc = 0.0;
+ *gc = 0.0;
+ }
+}
+
+/*----------------------------------------------------------------*
+ * Packet loss concealment routine. Conceals a residual signal
+ * and LP parameters. If no packet loss, update state.
+ *---------------------------------------------------------------*/
+
+void doThePLC(
+ float *PLCresidual, /* (o) concealed residual */
+ float *PLClpc, /* (o) concealed LP parameters */
+ int PLI, /* (i) packet loss indicator
+ 0 - no PL, 1 = PL */
+ float *decresidual, /* (i) decoded residual */
+ float *lpc, /* (i) decoded LPC (only used for no PL) */
+ int inlag, /* (i) pitch lag */
+ iLBC_Dec_Inst_t *iLBCdec_inst
+ /* (i/o) decoder instance */
+){
+ int lag=20, randlag;
+ float gain, maxcc;
+ float gain_comp, maxcc_comp;
+ int i, pick, offset;
+ float ftmp, ftmp1, randvec[BLOCKL], pitchfact;
+
+ /* Packet Loss */
+
+ if (PLI == 1) {
+
+ (*iLBCdec_inst).consPLICount += 1;
+
+ /* if previous frame not lost,
+ determine pitch pred. gain */
+
+ if ((*iLBCdec_inst).prevPLI != 1) {
+
+ /* Search around the previous lag to find the
+ best pitch period */
+
+ lag=inlag-3;
+ compCorr(&maxcc, &gain, (*iLBCdec_inst).prevResidual,
+ lag, BLOCKL, 60);
+ for (i=inlag-2;i<=inlag+3;i++) {
+ compCorr(&maxcc_comp, &gain_comp,
+ (*iLBCdec_inst).prevResidual,
+ i, BLOCKL, 60);
+
+ if (maxcc_comp>maxcc) {
+ maxcc=maxcc_comp;
+ gain=gain_comp;
+ lag=i;
+ }
+ }
+
+ if (gain > 1.0) {
+ gain = 1.0;
+ }
+ }
+
+ /* previous frame lost, use recorded lag and gain */
+
+ else {
+ lag=(*iLBCdec_inst).prevLag;
+ gain=(*iLBCdec_inst).prevGain;
+ }
+
+ /* Attenuate signal and scale down pitch pred gain if
+ several frames lost consecutively */
+
+
+ if ((*iLBCdec_inst).consPLICount > 1) {
+ gain *= (float)0.9;
+ }
+
+ /* Compute mixing factor of picth repeatition and noise */
+
+
+ if (gain > PLC_XT_MIX) {
+ pitchfact = PLC_YT_MIX;
+ } else if (gain < PLC_XB_MIX) {
+ pitchfact = PLC_YB_MIX;
+ } else {
+ pitchfact = PLC_YB_MIX + (gain - PLC_XB_MIX) *
+ (PLC_YT_MIX-PLC_YB_MIX)/(PLC_XT_MIX-PLC_XB_MIX);
+ }
+
+ /* compute concealed residual */
+
+ (*iLBCdec_inst).energy = 0.0;
+ for (i=0; i<BLOCKL; i++) {
+
+ /* noise component */
+
+ (*iLBCdec_inst).seed=((*iLBCdec_inst).seed*69069L+1) &
+ (0x80000000L-1);
+ randlag = 50 + ((signed long) (*iLBCdec_inst).seed)%70;
+ pick = i - randlag;
+
+ if (pick < 0) {
+ randvec[i] = gain *
+ (*iLBCdec_inst).prevResidual[BLOCKL+pick];
+ } else {
+ randvec[i] = gain * randvec[pick];
+ }
+
+ /* pitch repeatition component */
+
+ pick = i - lag;
+
+ if (pick < 0) {
+ PLCresidual[i] = gain *
+ (*iLBCdec_inst).prevResidual[BLOCKL+pick];
+ } else {
+ PLCresidual[i] = gain * PLCresidual[pick];
+ }
+
+ /* mix noise and pitch repeatition */
+
+ PLCresidual[i] = (pitchfact * PLCresidual[i] +
+ ((float)1.0 - pitchfact) * randvec[i]);
+
+ (*iLBCdec_inst).energy += PLCresidual[i] *
+ PLCresidual[i];
+ }
+
+ /* less than 30 dB, use only noise */
+
+ if (sqrt((*iLBCdec_inst).energy/(float)BLOCKL) < 30.0) {
+ (*iLBCdec_inst).energy = 0.0;
+ gain=0.0;
+ for (i=0; i<BLOCKL; i++) {
+ PLCresidual[i] = randvec[i];
+ (*iLBCdec_inst).energy += PLCresidual[i] *
+ PLCresidual[i];
+ }
+ }
+
+ /* conceal LPC by bandwidth expansion of old LPC */
+
+ ftmp=PLC_BWEXPAND;
+ PLClpc[0]=(float)1.0;
+ for (i=1; i<LPC_FILTERORDER+1; i++) {
+ PLClpc[i] = ftmp * (*iLBCdec_inst).prevLpc[i];
+ ftmp *= PLC_BWEXPAND;
+ }
+
+ }
+
+ /* previous frame lost and this frame OK, mixing in
+ with new frame */
+
+ else if ((*iLBCdec_inst).prevPLI == 1) {
+
+ lag = (*iLBCdec_inst).prevLag;
+ gain = (*iLBCdec_inst).prevGain;
+
+ /* if pitch pred gain high, do overlap-add */
+
+ if (gain >= PLC_GAINTHRESHOLD) {
+
+ /* Compute mixing factor of pitch repeatition
+ and noise */
+
+ if (gain > PLC_XT_MIX) {
+ pitchfact = PLC_YT_MIX;
+ } else if (gain < PLC_XB_MIX) {
+ pitchfact = PLC_YB_MIX;
+ } else {
+ pitchfact = PLC_YB_MIX + (gain - PLC_XB_MIX) *
+ (PLC_YT_MIX-PLC_YB_MIX)/(PLC_XT_MIX-PLC_XB_MIX);
+ }
+
+ /* compute concealed residual for 3 subframes */
+
+ for (i=0; i<3*SUBL; i++) {
+
+ (*iLBCdec_inst).seed=((*iLBCdec_inst).seed*
+ 69069L+1) & (0x80000000L-1);
+ randlag = 50 + ((signed long)
+ (*iLBCdec_inst).seed)%70;
+
+ /* noise component */
+
+ pick = i - randlag;
+
+ if (pick < 0) {
+ randvec[i] = gain *
+ (*iLBCdec_inst).prevResidual[BLOCKL+pick];
+ } else {
+ randvec[i] = gain * randvec[pick];
+ }
+
+ /* pitch repeatition component */
+
+ pick = i - lag;
+
+ if (pick < 0) {
+ PLCresidual[i] = gain *
+ (*iLBCdec_inst).prevResidual[BLOCKL+pick];
+ } else {
+ PLCresidual[i] = gain * PLCresidual[pick];
+ }
+
+ /* mix noise and pitch repeatition */
+
+ PLCresidual[i] = (pitchfact * PLCresidual[i] +
+ ((float)1.0 - pitchfact) * randvec[i]);
+ }
+
+ /* interpolate concealed residual with actual
+ residual */
+
+ offset = 3*SUBL;
+ for (i=0; i<offset; i++) {
+ ftmp1 = (float) (i+1) / (float) (offset+1);
+ ftmp = (float)1.0 - ftmp1;
+ PLCresidual[i]=PLCresidual[i]*ftmp+
+ decresidual[i]*ftmp1;
+ }
+
+ memcpy(PLCresidual+offset, decresidual+offset,
+ (BLOCKL-offset)*sizeof(float));
+
+ } else {
+ memcpy(PLCresidual, decresidual, BLOCKL*sizeof(float));
+ }
+
+ /* copy LPC */
+
+ memcpy(PLClpc, lpc, (LPC_FILTERORDER+1)*sizeof(float));
+
+ (*iLBCdec_inst).consPLICount = 0;
+ }
+
+ /* no packet loss, copy input */
+
+ else {
+ memcpy(PLCresidual, decresidual, BLOCKL*sizeof(float));
+ memcpy(PLClpc, lpc, (LPC_FILTERORDER+1)*sizeof(float));
+ }
+
+ /* update state */
+
+ (*iLBCdec_inst).prevLag = lag;
+ (*iLBCdec_inst).prevGain = gain;
+ (*iLBCdec_inst).prevPLI = PLI;
+ memcpy((*iLBCdec_inst).prevLpc, PLClpc,
+ (LPC_FILTERORDER+1)*sizeof(float));
+ memcpy((*iLBCdec_inst).prevResidual, PLCresidual,
+ BLOCKL*sizeof(float));
+}
+
+
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