www.pudn.com > SMV_Code.rar > lib_evad.c
/*=========================================================================*/
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/*=========================================================================*/
/* */
/*-------------------------------------------------------------------*/
/*===================================================================*/
/* LIBRARY: lib_evad.c */
/*-------------------------------------------------------------------*/
/* PURPOSE : Library of Voice Activity Detection based on EVAD VAD. */
/*===================================================================*/
#include
#include "typedef.h"
#include "lib_evad.h"
#include "lib_evad.tab"
#ifdef VAD_B
#define rint(x) (int)((x) + 0.5) /*...define non-ANSI function...*/
/**********************************************************************/
/* Initialize rate. */
/**********************************************************************/
void initialize_rate (
ENCODER_MEM* e_mem
)
{
INT32 i,j,k;
e_mem->last_rate = EIGHTH; /* Added by D. Pian 12-Sep-94 */
/* rate decision initialization */
e_mem->frame_num=0;
e_mem->num_full_frames=0;
e_mem->hangover=10;
e_mem->hangover_in_progress=0;
e_mem->adaptcount=0;
e_mem->pitchrun=0;
e_mem->frame_energy_sm[0] = 32000;/*changed by D. Pian 08-Feb-95*/
/* changed from 3200000*16 by khaled, Dec., 20, 2000 */
e_mem->frame_energy_sm[1] = 3200;/*changed by D. Pian 08-Feb-95*/
/* changed from 320000*16 by khaled, Dec., 20, 2000 */
e_mem->signal_energy[0] = 3200000*16;/* Added by D. Pian 12-Sep-94 */
e_mem->signal_energy[1] = 320000*16; /* and Changed 5-Apr-95 */
e_mem->snr_stat_once=0;
for (j=0; jband_noise_sm[j]= HIGH_THRESH_LIM;
for (i=0; ir_filt[j][i]=0;
for (k=0; kr_filt[j][i]+=rate_filt[j][k]*rate_filt[j][k+i];
}
}
}
for (j=0; jsnr[j] = e_mem->signal_energy[j]/e_mem->band_noise_sm[j];
e_mem->snr_map[j] = 0;
}
}
/**********************************************************************/
/* Band energy. */
/**********************************************************************/
void band_energy_fcn (
FLOAT64* R,
FLOAT32* energy,
ENCODER_MEM* e_mem
)
{
INT32 i,j;
/* find the energy in each band */
for (j=0; jr_filt[j][0]*R[0];
for(i=1;ir_filt[j][i]*R[i];
}
energy[j]*=2.0/3.0;
}
}
/**********************************************************************/
/* Update background. */
/**********************************************************************/
void update_background (
INT16 rate,
ENCODER_MEM* e_mem,
FLOAT64 beta
)
{
INT32 i;
for(i=0;iframe_energy_sm[i] = SMSNR*e_mem->frame_energy_sm[i] + (1.0-SMSNR)*e_mem->band_power[i];
}
/*************************************************************************/
/* Section 2.4.4.2.2 Updating background noise */
/* Now do the threshold adaptation */
/* don't adapt thresholds unless NACF < NACF_ADAP_BGN_THR over ADP frames*/
/* we're assuming the background noise here doesn't have periodicity in */
/* the range of typical speech */
if (beta < NACF_ADAP_BGN_THR) {
e_mem->adaptcount++;
} else {
e_mem->adaptcount = 0;
}
if(e_mem->adaptcount > ADP) {
/* change the predictor filter for the noise whitening */
/* noise */
/* update our background noise estimate */
for(i=0;iband_noise_sm[i]+1 < e_mem->band_noise_sm[i]*INC_FACTOR) {
e_mem->band_noise_sm[i] *= INC_FACTOR;
} else {
e_mem->band_noise_sm[i] += 1.0;
}
}
e_mem->adaptcount = ADP + 1;
} else{
/*if SNR map est. is valid & above SNR_MAP_THRESHOLD let background noise */
/* estimate slowly inch up like it does in IS-96. This will allow */
/* the rate decision to perform as well as IS-96 in babble noise and */
/* other non-stationary noises */
if(e_mem->snr_stat_once == 1) { /* snr is valid */
for(i=0;isnr_map[i] > SNR_MAP_THRESHOLD) &&
(e_mem->band_noise_sm[i] < e_mem->frame_energy_sm[i]) ){
if(e_mem->band_noise_sm[i]+1.0 < e_mem->band_noise_sm[i]*IS96_INC) {
e_mem->band_noise_sm[i] *= IS96_INC;
} else {
e_mem->band_noise_sm[i] += 1.0;
}
}
}
}
}
/* if input energy is lower than noise estimate, */
/* reduce background noise estimate immediately */
for(i=0;iframe_energy_sm[i] < e_mem->band_noise_sm[i]) {
e_mem->band_noise_sm[i] = e_mem->frame_energy_sm[i];
}
}
for(i=0;iband_noise_sm[i] > HIGH_THRESH_LIM) {
e_mem->band_noise_sm[i] = HIGH_THRESH_LIM;
}
if (e_mem->band_noise_sm[i] < LOWEST_LEVEL[i]) {
e_mem->band_noise_sm[i] = LOWEST_LEVEL[i];
}
}
/* end of updating backgound noise energy */
/***************************************************************/
/***************************************************************/
/* Section 2.4.4.2.2 Updating Signal Energy Estimate */
/* pitchrun keeps track of the number of frames in a row with periodicity*/
if (beta > NACF_SOLID_VOICED) {
e_mem->pitchrun += 1;
} else {
e_mem->pitchrun = 0;
}
if (e_mem->pitchrun > STATVOICED) { /* decrease the signal energy */
/* if we're in a voiced segment */
e_mem->snr_stat_once = 1; /* confidence that we have seen speech */
/* indicates a stationary voiced segment */
for(i=0;isignal_energy[i] *= SCALE_DOWN_ENERGY;
}
}
/* assume that the highest energy sounds are speech signals and */
/* thus the highest energy frames contain speech and can be used */
/* to define the SNR */
for(i=0;iframe_energy_sm[i] > e_mem->signal_energy[i]) {
e_mem->signal_energy[i] = e_mem->frame_energy_sm[i];
}
}
/* end updating signal energy estimate */
/************************************************************************/
/* This is now done near the top of select_mode1() */
/* update SNR estimates */
for(i=0;iband_noise_sm[i] > 0.0) {
e_mem->snr[i] = e_mem->signal_energy[i]/e_mem->band_noise_sm[i];
} else {
e_mem->snr[i] = 100000000.0; /* a very high snr if noise =0.0 */
}
}
if(e_mem->snr_stat_once != 0) {
/* we have seen some speech and are confident in our SNR measure */
e_mem->snr_stat_once = 1;
/* UPDATE THIS FOR GENERAL SNR MAPS! */
for(i=0;isnr[i] > 0.0){
e_mem->snr_map[i] = (INT32) rint((10*log10(e_mem->snr[i])-20.0)/5.0);
} else {
e_mem->snr_map[i] = 0;
}
if(e_mem->snr_map[i] < 0) e_mem->snr_map[i]=0;
if(e_mem->snr_map[i] > 7) e_mem->snr_map[i]=7;
}
} else {
/* we haven't seen speech, aren't confident in our estimate of the */
/* signal energy and will use a nominal energy of */
/* VOICE_INITIAL dB (-18dbm0) for our signal energy */
for(i=0;iband_noise_sm[i] > 0.0){
if (i == 0) {
e_mem->snr_map[i]= (INT32) rint((VOICE_INITIAL- 10*log10(e_mem->band_noise_sm[i])-20.0)/5.0);
} else {
e_mem->snr_map[i]= (INT32) rint((VOICE_INITIAL_HI- 10*log10(e_mem->band_noise_sm[i])-20.0)/5.0);
}
} else {
e_mem->snr_map[i] = 7;
}
if(e_mem->snr_map[i] < 0) e_mem->snr_map[i]=0;
if(e_mem->snr_map[i] > 7) e_mem->snr_map[i]=7;
}
}
e_mem->last_rate = rate;
e_mem->last_rate_2nd_stage = rate;
}
/**********************************************************************/
/* Select rate. */
/**********************************************************************/
INT16 EVAD_voice_detection (
INT16 smv_mode,
FLOAT64* R_interp,
INT16 max_rate,
INT16 min_rate,
FLOAT64 beta,
ENCODER_MEM *e_mem
)
{
static INT16 first = 0;
static FLOAT32 (*THRESH_SNR)[TLEVELS][2];
static INT32 *hangover;
INT16 rate;
INT32 i;
INT32 k;
// e_mem = &rate_mem; /* done for rate integration with AT&T simulation*/
if(first == 0){
/*do initialization of rate_mem */
initialize_rate(e_mem);
first = 1;
}
if (smv_mode==0) {
hangover=hangover0;
THRESH_SNR=THRESH_SNR0;
}
else if (smv_mode==1) {
hangover=hangover1;
THRESH_SNR=THRESH_SNR1;
}
else {
hangover=hangover2;
THRESH_SNR=THRESH_SNR2;
}
/* this is the acf of the noise reducing prediction filter */
/* now filter the input speech by bandpass filters and */
/* derive the necessary band energies */
band_energy_fcn(R_interp, e_mem->band_power, e_mem);
/* now our threshold comparison and background noise estimation */
/* is done for all frequency bands */
/* rate thresholds are calculated below, but not saved */
for(k=0; kband_rate[k]=EIGHTH;
for (i=0; i<2; i++) {
/* rate_thresh[k][i] = THRESH_SNR[k][e_mem->snr_map[k]][i]* e_mem->band_noise_sm[k]; */
/* since we changed SMSNR to 0.6 from 0.8 */
if (e_mem->band_power[k]>THRESH_SNR[k][e_mem->snr_map[k]][i]* e_mem->band_noise_sm[k])
{
if(e_mem->band_rate[k] == EIGHTH) {
e_mem->band_rate[k]=HALFRATE_VOICED;
} else if (e_mem->band_rate[k] == HALFRATE_VOICED) {
e_mem->band_rate[k]=FULLRATE_VOICED;
}
}
}
} /* do threshold comparisons for full and half rates */
/* use 10log10(e_mem->band_power[k]/band_noise_sm[k]) */
/* the maximum rate for all bands is chosen as the rate */
rate = e_mem->band_rate[0];
for(k=1;k< FREQBANDS;k++) {
if(e_mem->band_rate[k] > rate) rate = e_mem->band_rate[k];
}
/* Section 2.4.4.1.3 Calculating Hangover Frames as Function of SNR */
if((e_mem->num_full_frames > FULL_THRESH) || e_mem->hangover_in_progress == 1) {
/* only use hangover after so many full rate frames in a row*/
if(rate != FULLRATE_VOICED) {
e_mem->hangover += 1;
if (e_mem->hangover <= hangover[e_mem->snr_map[0]]) {
rate = FULLRATE_VOICED;
e_mem->hangover_in_progress = 1;
} else {
e_mem->hangover_in_progress = 0;
}
} else {
e_mem->hangover_in_progress = 0;
}
}
if((rate == FULLRATE_VOICED) && (e_mem->hangover_in_progress == 0)) {
e_mem->hangover=0;
e_mem->num_full_frames+=1;
} else {
e_mem->num_full_frames = 0;
}
/* end of hangover algorithm */
/* assuming only 1/8,1/2,and full rates pluse some 1/2 and full rates modes */
/* if last rate is full force 1/2 rate before going to 1/8 */
/* Section 2.4.4.1.4 Constraints on Rate Selection */
if ((e_mem->last_rate_1st_stage == FULLRATE_VOICED) && rate == EIGHTH) {
rate = HALFRATE_VOICED;
}
/* allows fast convergence for EIGHTH rate */
if(e_mem->frame_num == 0){
rate = FULLRATE_VOICED;
}
if (rate > max_rate) {
rate = max_rate;
}
if (rate < min_rate) {
rate = min_rate;
}
e_mem->last_rate_1st_stage = rate;
e_mem->last_rate = rate;
/* update background noise and signal energy estimates */
update_background(rate,e_mem,beta);
e_mem->frame_num += 1;
return(rate);
}
#endif