Displaying 1 result from an estimated 1 matches for "sqrt_fromdb".
2000 Nov 26
1
Trivial 12% performance gain in encoding
(well, YMMV, but it got me 12% on Mac OS X Public Beta on my test case).
In vorbis/lib/scales.h, add the following after fromdB()
#define sqrt_fromdB(x) (exp((x)*.11512925*0.5))
In vorbis/lib/psy.c at the bottom of bark_noise(), do:
< noise[i]=sqrt(fromdB(v));
> noise[i]=sqrt_fromdB(v);
This avoids the sqrt() call entirely by just doing it as part of the exp().
(I'd send a patch, but my local source tree is severely...