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Make the faac inspired quantizer search make sense for a slightly narrower definition of "make sense."

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Originally committed as revision 23035 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Alex Converse 2010-05-06 20:18:36 +00:00
parent 9e94bd3e80
commit 32fa7725d2
1 changed files with 9 additions and 7 deletions
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16
libavcodec/aaccoder.c
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@ -763,7 +763,7 @@ static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
const float *scaled = s->scoefs + start; const float *scaled = s->scoefs + start;
const int size = sce->ics.swb_sizes[g]; const int size = sce->ics.swb_sizes[g];
int scf, prev_scf, step; int scf, prev_scf, step;
int min_scf = 0, max_scf = 255; int min_scf = -1, max_scf = 256;
float curdiff; float curdiff;
if (maxq[w*16+g] < 21.544) { if (maxq[w*16+g] < 21.544) {
sce->zeroes[w*16+g] = 1; sce->zeroes[w*16+g] = 1;
@ -797,21 +797,23 @@ static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
} }
prev_scf = scf; prev_scf = scf;
curdiff = fabsf(dist - uplim[w*16+g]); curdiff = fabsf(dist - uplim[w*16+g]);
if (curdiff == 0.0f) if (curdiff <= 1.0f)
step = 0; step = 0;
else else
step = fabsf(log2(curdiff)); step = log2(curdiff);
if (dist > uplim[w*16+g]) if (dist > uplim[w*16+g])
step = -step; step = -step;
scf += step;
av_clip_uint8(scf);
step = scf - prev_scf;
if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) { if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {
sce->sf_idx[w*16+g] = scf; sce->sf_idx[w*16+g] = av_clip(scf, min_scf, max_scf);
break; break;
} }
scf += step;
if (step > 0) if (step > 0)
min_scf = scf; min_scf = prev_scf;
else else
max_scf = scf; max_scf = prev_scf;
} }
start += size; start += size;
} }