/*
* A good frame was received and decoded.
* If right after an erasure, do an overlap add with the synthetic signal.
* Add the frame to history buffer.
*/
void PLC_addtohistory(G711_PLC_state *PLC, short *s)
{
if (erasecnt) {
short overlapbuf[FRAMESZ];
/*
* longer erasures require longer overlaps
* to smooth the transition between the synthetic
* and real signal.
*/
int olen = poverlap + (erasecnt - 1) * EOVERLAPINCR;
if (olen > FRAMESZ)
olen = FRAMESZ;
getfespeech(PLC, overlapbuf, olen);
overlapaddatend(PLC, s, overlapbuf, olen);
erasecnt = 0;
}
savespeech(PLC, s);
}
void PLC_dofe(G711_PLC_state *PLC, short *out)
{
if (erasecnt == 0) {
ippsCopy_16s(history, pitchbuf, HISTORYLEN); /* get history */
pitch = findpitch(PLC); /* find pitch */
poverlap = pitch >> 2; /* OLA 1/4 wavelength */
/* save original last poverlap samples */
ippsCopy_16s(pitchbufend - poverlap, lastq, poverlap);
poffset = 0; /* create pitch buffer with 1 period */
pitchblen = pitch;
pitchbufstart = pitchbufend - pitchblen;
overlapadd(lastq, pitchbufstart - poverlap,
pitchbufend - poverlap, poverlap);
/* update last 1/4 wavelength in history buffer */
ippsCopy_16s(pitchbufend - poverlap, &history[HISTORYLEN-poverlap],
poverlap);
getfespeech(PLC, out, FRAMESZ); /* get synthesized speech */
} else if (erasecnt == 1 || erasecnt == 2) {
/*
* Generate the synthetic signal.
* At the beginning of an erasure determine the pitch, and extract
* one pitch period from the tail of the signal. Do an OLA for 1/4
* of the pitch to smooth the signal. Then repeat the extracted signal
* for the length of the erasure. If the erasure continues for more than
* 10 ms, increase the number of periods in the pitchbuffer. At the end
* of an erasure, do an OLA with the start of the first good frame.
* The gain decays as the erasure gets longer.
*/
void LowcFE::dofe(short *out)
{
pitchbufend = &pitchbuf[HISTORYLEN];
if (erasecnt == 0) {
convertsf(history, pitchbuf, HISTORYLEN); /* get history */
pitch = findpitch(); /* find pitch */
poverlap = pitch >> 2; /* OLA 1/4 wavelength */
/* save original last poverlap samples */
copyf(pitchbufend - poverlap, lastq, poverlap);
poffset = 0; /* create pitch buffer with 1 period */
pitchblen = pitch;
pitchbufstart = pitchbufend - pitchblen;
overlapadd(lastq, pitchbufstart - poverlap,
pitchbufend - poverlap, poverlap);
/* update last 1/4 wavelength in history buffer */
convertfs(pitchbufend - poverlap, &history[HISTORYLEN-poverlap],
poverlap);
getfespeech(out, FRAMESZ); /* get synthesized speech */
} else if (erasecnt == 1 || erasecnt == 2) {
