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

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 int size = sce->ics.swb_sizes[g];
int scf, prev_scf, step;
int min_scf = 0, max_scf = 255;
int min_scf = -1, max_scf = 256;
float curdiff;
if (maxq[w*16+g] < 21.544) {
sce->zeroes[w*16+g] = 1;
@ -797,21 +797,23 @@ static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
}
prev_scf = scf;
curdiff = fabsf(dist - uplim[w*16+g]);
if (curdiff == 0.0f)
if (curdiff <= 1.0f)
step = 0;
else
step = fabsf(log2(curdiff));
step = log2(curdiff);
if (dist > uplim[w*16+g])
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)) {
sce->sf_idx[w*16+g] = scf;
sce->sf_idx[w*16+g] = av_clip(scf, min_scf, max_scf);
break;
}
scf += step;
if (step > 0)
min_scf = scf;
min_scf = prev_scf;
else
max_scf = scf;
max_scf = prev_scf;
}
start += size;
}