114 lines
3.1 KiB
C
114 lines
3.1 KiB
C
|
|
/******************************************************************
|
|
|
|
iLBC Speech Coder ANSI-C Source Code
|
|
|
|
FrameClassify.c
|
|
|
|
Copyright (C) The Internet Society (2004).
|
|
All Rights Reserved.
|
|
|
|
******************************************************************/
|
|
|
|
#include "iLBC_define.h"
|
|
|
|
/*---------------------------------------------------------------*
|
|
* Classification of subframes to localize start state
|
|
*--------------------------------------------------------------*/
|
|
|
|
int FrameClassify( /* index to the max-energy sub-frame */
|
|
iLBC_Enc_Inst_t *iLBCenc_inst,
|
|
/* (i/o) the encoder state structure */
|
|
float *residual /* (i) lpc residual signal */
|
|
) {
|
|
float max_ssqEn, fssqEn[NSUB_MAX], bssqEn[NSUB_MAX], *pp;
|
|
int n, l, max_ssqEn_n;
|
|
const float ssqEn_win[NSUB_MAX-1]={(float)0.8,(float)0.9,
|
|
(float)1.0,(float)0.9,(float)0.8};
|
|
const float sampEn_win[5]={(float)1.0/(float)6.0,
|
|
(float)2.0/(float)6.0, (float)3.0/(float)6.0,
|
|
(float)4.0/(float)6.0, (float)5.0/(float)6.0};
|
|
|
|
/* init the front and back energies to zero */
|
|
|
|
memset(fssqEn, 0, NSUB_MAX*sizeof(float));
|
|
memset(bssqEn, 0, NSUB_MAX*sizeof(float));
|
|
|
|
/* Calculate front of first seqence */
|
|
|
|
n=0;
|
|
pp=residual;
|
|
for (l=0; l<5; l++) {
|
|
fssqEn[n] += sampEn_win[l] * (*pp) * (*pp);
|
|
pp++;
|
|
}
|
|
for (l=5; l<SUBL; l++) {
|
|
|
|
|
|
|
|
|
|
|
|
fssqEn[n] += (*pp) * (*pp);
|
|
pp++;
|
|
}
|
|
|
|
/* Calculate front and back of all middle sequences */
|
|
|
|
for (n=1; n<iLBCenc_inst->nsub-1; n++) {
|
|
pp=residual+n*SUBL;
|
|
for (l=0; l<5; l++) {
|
|
fssqEn[n] += sampEn_win[l] * (*pp) * (*pp);
|
|
bssqEn[n] += (*pp) * (*pp);
|
|
pp++;
|
|
}
|
|
for (l=5; l<SUBL-5; l++) {
|
|
fssqEn[n] += (*pp) * (*pp);
|
|
bssqEn[n] += (*pp) * (*pp);
|
|
pp++;
|
|
}
|
|
for (l=SUBL-5; l<SUBL; l++) {
|
|
fssqEn[n] += (*pp) * (*pp);
|
|
bssqEn[n] += sampEn_win[SUBL-l-1] * (*pp) * (*pp);
|
|
pp++;
|
|
}
|
|
}
|
|
|
|
/* Calculate back of last seqence */
|
|
|
|
n=iLBCenc_inst->nsub-1;
|
|
pp=residual+n*SUBL;
|
|
for (l=0; l<SUBL-5; l++) {
|
|
bssqEn[n] += (*pp) * (*pp);
|
|
pp++;
|
|
}
|
|
for (l=SUBL-5; l<SUBL; l++) {
|
|
bssqEn[n] += sampEn_win[SUBL-l-1] * (*pp) * (*pp);
|
|
pp++;
|
|
}
|
|
|
|
/* find the index to the weighted 80 sample with
|
|
most energy */
|
|
|
|
if (iLBCenc_inst->mode==20) l=1;
|
|
else l=0;
|
|
|
|
max_ssqEn=(fssqEn[0]+bssqEn[1])*ssqEn_win[l];
|
|
max_ssqEn_n=1;
|
|
for (n=2; n<iLBCenc_inst->nsub; n++) {
|
|
|
|
|
|
|
|
|
|
|
|
|
|
l++;
|
|
if ((fssqEn[n-1]+bssqEn[n])*ssqEn_win[l] > max_ssqEn) {
|
|
max_ssqEn=(fssqEn[n-1]+bssqEn[n]) *
|
|
ssqEn_win[l];
|
|
max_ssqEn_n=n;
|
|
}
|
|
}
|
|
|
|
return max_ssqEn_n;
|
|
}
|
|
|