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aacenc: TLS: Try to preserve some energy in each non-zero band.

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Reduce scalefactors in non-zero bands that underflow by twice as much as those
in bands that just fail to hit psy targets.

Originally committed as revision 24482 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Alex Converse 2010-07-24 16:36:01 +00:00
parent 6cce7cabdb
commit fe461767e6
1 changed files with 6 additions and 1 deletions
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7
libavcodec/aaccoder.c
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@ -806,13 +806,18 @@ static void search_for_quantizers_twoloop(AVCodecContext *avctx,
for (g = 0; g < sce->ics.num_swb; g++) {
int prevsc = sce->sf_idx[w*16+g];
const float *scaled = s->scoefs + start;
if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60)
if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60) {
if (find_min_book(find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled), sce->sf_idx[w*16+g]-1))
sce->sf_idx[w*16+g]--;
else //Try to make sure there is some energy in every band
sce->sf_idx[w*16+g]-=2;
}
sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
if (sce->sf_idx[w*16+g] != prevsc)
fflag = 1;
sce->band_type[w*16+g] = find_min_book(find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled), sce->sf_idx[w*16+g]);
//av_log(NULL, AV_LOG_ERROR, "w %d swb %2d sf %3d bt %2d dist %f uplim %f ratio %f\n", w, g, sce->sf_idx[w*16+g], sce->band_type[w*16+g], dists[w*16+g], uplims[w*16+g], dists[w*16+g]/uplims[w*16+g]);
start += sce->ics.swb_sizes[g];
}
}