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Diffstat (limited to 'trunk/codecs/ilbc/doCPLC.c')
| -rw-r--r-- | trunk/codecs/ilbc/doCPLC.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/trunk/codecs/ilbc/doCPLC.c b/trunk/codecs/ilbc/doCPLC.c new file mode 100644 index 000000000..bb4b56c10 --- /dev/null +++ b/trunk/codecs/ilbc/doCPLC.c @@ -0,0 +1,259 @@ + +/****************************************************************** + + iLBC Speech Coder ANSI-C Source Code + + doCPLC.c + + Copyright (C) The Internet Society (2004). + All Rights Reserved. + +******************************************************************/ + +#include <math.h> +#include <string.h> +#include <stdio.h> + +#include "iLBC_define.h" +#include "doCPLC.h" + +/*----------------------------------------------------------------* + * Compute cross correlation and pitch gain for pitch prediction + * of last subframe at given lag. + *---------------------------------------------------------------*/ + +static void compCorr( + float *cc, /* (o) cross correlation coefficient */ + float *gc, /* (o) gain */ + float *pm, + 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, ftmp3; + + /* Guard against getting outside buffer */ + if ((bLen-sRange-lag)<0) { + sRange=bLen-lag; + } + + ftmp1 = 0.0; + ftmp2 = 0.0; + ftmp3 = 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]; + ftmp3 += buffer[bLen-sRange+i] * + buffer[bLen-sRange+i]; + } + + if (ftmp2 > 0.0) { + *cc = ftmp1*ftmp1/ftmp2; + *gc = (float)fabs(ftmp1/ftmp2); + *pm=(float)fabs(ftmp1)/ + ((float)sqrt(ftmp2)*(float)sqrt(ftmp3)); + } + else { + *cc = 0.0; + *gc = 0.0; + *pm=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 use_gain; + float gain_comp, maxcc_comp, per, max_per; + int i, pick, use_lag; + + + float ftmp, randvec[BLOCKL_MAX], pitchfact, energy; + + /* 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, &max_per, + iLBCdec_inst->prevResidual, + lag, iLBCdec_inst->blockl, 60); + for (i=inlag-2;i<=inlag+3;i++) { + compCorr(&maxcc_comp, &gain_comp, &per, + iLBCdec_inst->prevResidual, + i, iLBCdec_inst->blockl, 60); + + if (maxcc_comp>maxcc) { + maxcc=maxcc_comp; + gain=gain_comp; + lag=i; + max_per=per; + } + } + + } + + /* previous frame lost, use recorded lag and periodicity */ + + else { + lag=iLBCdec_inst->prevLag; + max_per=iLBCdec_inst->per; + } + + /* downscaling */ + + use_gain=1.0; + if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>320) + use_gain=(float)0.9; + else if (iLBCdec_inst->consPLICount* + iLBCdec_inst->blockl>2*320) + use_gain=(float)0.7; + else if (iLBCdec_inst->consPLICount* + iLBCdec_inst->blockl>3*320) + use_gain=(float)0.5; + else if (iLBCdec_inst->consPLICount* + + + iLBCdec_inst->blockl>4*320) + use_gain=(float)0.0; + + /* mix noise and pitch repeatition */ + ftmp=(float)sqrt(max_per); + if (ftmp>(float)0.7) + pitchfact=(float)1.0; + else if (ftmp>(float)0.4) + pitchfact=(ftmp-(float)0.4)/((float)0.7-(float)0.4); + else + pitchfact=0.0; + + + /* avoid repetition of same pitch cycle */ + use_lag=lag; + if (lag<80) { + use_lag=2*lag; + } + + /* compute concealed residual */ + + energy = 0.0; + for (i=0; i<iLBCdec_inst->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] = + iLBCdec_inst->prevResidual[ + iLBCdec_inst->blockl+pick]; + } else { + randvec[i] = randvec[pick]; + } + + /* pitch repeatition component */ + pick = i - use_lag; + + if (pick < 0) { + PLCresidual[i] = + iLBCdec_inst->prevResidual[ + iLBCdec_inst->blockl+pick]; + } else { + PLCresidual[i] = PLCresidual[pick]; + } + + /* mix random and periodicity component */ + + if (i<80) + PLCresidual[i] = use_gain*(pitchfact * + + + PLCresidual[i] + + ((float)1.0 - pitchfact) * randvec[i]); + else if (i<160) + PLCresidual[i] = (float)0.95*use_gain*(pitchfact * + PLCresidual[i] + + ((float)1.0 - pitchfact) * randvec[i]); + else + PLCresidual[i] = (float)0.9*use_gain*(pitchfact * + PLCresidual[i] + + ((float)1.0 - pitchfact) * randvec[i]); + + energy += PLCresidual[i] * PLCresidual[i]; + } + + /* less than 30 dB, use only noise */ + + if (sqrt(energy/(float)iLBCdec_inst->blockl) < 30.0) { + gain=0.0; + for (i=0; i<iLBCdec_inst->blockl; i++) { + PLCresidual[i] = randvec[i]; + } + } + + /* use old LPC */ + + memcpy(PLClpc,iLBCdec_inst->prevLpc, + (LPC_FILTERORDER+1)*sizeof(float)); + + } + + /* no packet loss, copy input */ + + else { + memcpy(PLCresidual, decresidual, + iLBCdec_inst->blockl*sizeof(float)); + memcpy(PLClpc, lpc, (LPC_FILTERORDER+1)*sizeof(float)); + iLBCdec_inst->consPLICount = 0; + } + + /* update state */ + + if (PLI) { + iLBCdec_inst->prevLag = lag; + iLBCdec_inst->per=max_per; + } + + iLBCdec_inst->prevPLI = PLI; + memcpy(iLBCdec_inst->prevLpc, PLClpc, + (LPC_FILTERORDER+1)*sizeof(float)); + memcpy(iLBCdec_inst->prevResidual, PLCresidual, + iLBCdec_inst->blockl*sizeof(float)); +} + + + + |