ref: e0066b4725069ce120acde8d584ade9bc2d3d0cf
parent: 1142f086784e83999d53a560448aa80e392f0811
author: Krzysztof Nikiel <knik@users.sourceforge.net>
date: Sat Oct 28 09:48:41 EDT 2017
scalefactor step more compliant with AAC specs
--- a/libfaac/quantize.c
+++ b/libfaac/quantize.c
@@ -146,8 +146,12 @@
)
{int sb, cnt;
- // 1.5dB step
- static const double sfstep = 20.0 / 1.5 / M_LN10;
+#ifndef __clang__
+ /* 2^0.25 (1.50515 dB) step from AAC specs */
+ static const double sfstep = 1.0 / log10(sqrt(sqrt(2.0)));
+#else
+ static const double sfstep = 20 / 1.50515;
+#endif
int gsize = coderInfo->groups.len[gnum];
#ifdef __SSE2__
int cpuid[4];
@@ -200,11 +204,11 @@
}
//printf("qual:%f/%f\n", bandqual[sb], bandqual[sb]/rmsx);- sfac = lrint(log(bandqual[sb] / rmsx) * sfstep);
+ sfac = lrint(log10(bandqual[sb] / rmsx) * sfstep);
if ((SF_OFFSET - sfac) < 10)
sfacfix = 0.0;
else
- sfacfix = exp(sfac / sfstep);
+ sfacfix = pow(10, sfac / sfstep);
xr = xr0 + start;
end -= start;