> From: Mark Taylor [mailto:[EMAIL PROTECTED]]
>
> I dont think we should make this change. Preserving the amplitude
> (and thus the actual shape of the wave form) seems more important than
> the energy. Also, using fabs(i^8/3 -x^2) is an unusual definition of
> noise that I have never seen in any of the technical papers.
>
> > I think this is right, Segher.
> >
> > with my poor listening test, I think we should take noise
> calculation
> > >> fabs(i^8/3 - x^2)
> > instead of
> > >> ( i^4/3 -x ) ^2
AFAIK, x and i are energy terms, in which case the first formula gives error
in (energy^2); the second gives (error in energy)^2, which is I think a more
useful value.
The noise calculation formula in calc_noise1 (calc_noise2 is similar)
noise = 10*log10(Max(.001,xfsf[i+1][sfb] / l3_xmin->s[gr][ch][sfb][i] ));
apparently includes a division by two (mutliplying by 10 instead of 20 to
give dB), to compensate for the squaring of the error in energy.
BTW, calc_noise2 generates its own pow43 table, when we already have a
global version.
-- Mat.
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