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aacenc_tns: add moving average filter for LTP 

The decoder does this so I guess we better do that as well.
There's barely any difference between the autoregressive and
the moving average filters looking at spectrals though.
This commit is contained in:
Rostislav Pehlivanov 2015-10-17 10:50:41 +01:00
parent 801eca1372
commit 8d18d28918
1 changed files with 16 additions and 5 deletions
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21
libavcodec/aacenc_tns.c
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@ -91,7 +91,7 @@ void ff_aac_apply_tns(AACEncContext *s, SingleChannelElement *sce)
IndividualChannelStream *ics = &sce->ics;
int w, filt, m, i, top, order, bottom, start, end, size, inc;
const int mmm = FFMIN(ics->tns_max_bands, ics->max_sfb);
float lpc[TNS_MAX_ORDER];
float lpc[TNS_MAX_ORDER], tmp[TNS_MAX_ORDER+1];
for (w = 0; w < ics->num_windows; w++) {
bottom = ics->num_swb;
@ -117,10 +117,21 @@ void ff_aac_apply_tns(AACEncContext *s, SingleChannelElement *sce)
}
start += w * 128;
// ar filter
for (m = 0; m < size; m++, start += inc)
for (i = 1; i <= FFMIN(m, order); i++)
sce->coeffs[start] += lpc[i-1]*sce->pcoeffs[start - i*inc];
if (!s->options.ltp) { // ar filter
for (m = 0; m < size; m++, start += inc) {
for (i = 1; i <= FFMIN(m, order); i++) {
sce->coeffs[start] += lpc[i-1]*sce->pcoeffs[start - i*inc];
}
}
} else { // ma filter
for (m = 0; m < size; m++, start += inc) {
tmp[0] = sce->pcoeffs[start];
for (i = 1; i <= FFMIN(m, order); i++)
sce->coeffs[start] += lpc[i-1]*tmp[i];
for (i = order; i > 0; i--)
tmp[i] = tmp[i - 1];
}
}
}
}
}