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AAC encoder: enforce SF delta in PNS and IS SFs 

Make sure to properly enforce maximum scalefactor delta in PNS
and I/S, not as an absolute range but relative to the previous
and first scalefactor, the latter important since PNS uses an
implicit inicial scalefactor derived from the global gain, and
encoded in a different way, which makes a big difference in the
allowed range.
This commit is contained in:
Claudio Freire 2016-01-16 20:44:36 -03:00
parent 4c430738d9
commit 60a76f8be8
1 changed files with 10 additions and 8 deletions
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18
libavcodec/aaccoder.c
View File

@ -195,23 +195,23 @@ typedef struct TrellisPath {
static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement *sce)
{
int w, g, start = 0;
int minscaler_n = sce->sf_idx[0], minscaler_i = sce->sf_idx[0];
int w, g;
int prevscaler_n = -255, prevscaler_i = 0;
int bands = 0;
for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
start = 0;
for (g = 0; g < sce->ics.num_swb; g++) {
if (sce->zeroes[w*16+g])
continue;
if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
sce->sf_idx[w*16+g] = av_clip(roundf(log2f(sce->is_ener[w*16+g])*2), -155, 100);
minscaler_i = FFMIN(minscaler_i, sce->sf_idx[w*16+g]);
bands++;
} else if (sce->band_type[w*16+g] == NOISE_BT) {
sce->sf_idx[w*16+g] = av_clip(3+ceilf(log2f(sce->pns_ener[w*16+g])*2), -100, 155);
minscaler_n = FFMIN(minscaler_n, sce->sf_idx[w*16+g]);
if (prevscaler_n == -255)
prevscaler_n = sce->sf_idx[w*16+g];
bands++;
}
start += sce->ics.swb_sizes[g];
}
}
@ -221,10 +221,12 @@ static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement
/* Clip the scalefactor indices */
for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
for (g = 0; g < sce->ics.num_swb; g++) {
if (sce->zeroes[w*16+g])
continue;
if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_i, minscaler_i + SCALE_MAX_DIFF);
sce->sf_idx[w*16+g] = prevscaler_i = av_clip(sce->sf_idx[w*16+g], prevscaler_i - SCALE_MAX_DIFF, prevscaler_i + SCALE_MAX_DIFF);
} else if (sce->band_type[w*16+g] == NOISE_BT) {
sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_n, minscaler_n + SCALE_MAX_DIFF);
sce->sf_idx[w*16+g] = prevscaler_n = av_clip(sce->sf_idx[w*16+g], prevscaler_n - SCALE_MAX_DIFF, prevscaler_n + SCALE_MAX_DIFF);
}
}
}