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aacenc_ltp: use an AR filter for LTP encoding as well

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Seems to work better. Information on why the decoder does this is
lacking.

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
This commit is contained in:
Rostislav Pehlivanov 2015-12-05 19:06:39 +00:00
parent 3112501daf
commit dcbe8d8abc
1 changed files with 5 additions and 14 deletions
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19
libavcodec/aacenc_tns.c
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@ -107,7 +107,7 @@ 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], tmp[TNS_MAX_ORDER+1];
float lpc[TNS_MAX_ORDER];
for (w = 0; w < ics->num_windows; w++) {
bottom = ics->num_swb;
@ -133,19 +133,10 @@ void ff_aac_apply_tns(AACEncContext *s, SingleChannelElement *sce)
}
start += w * 128;
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];
/* 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];
}
}
}