>
> > From: Segher Boessenkool <[EMAIL PROTECTED]>
> > Date: Mon, 29 Nov 1999 12:44:30 +0100 (CET)
> >
> > > Segher, shouldn't the formula be:
> > >
> > > > if (x > (0.5 * (pow(i, 4.0/3.0) + pow(i+1, 4.0/3.0))
> > > > i++;
> > >
> > >
> > > Mark
> >
> > No, if you use 4/3, you optimize for sample amplitude; but we'd like
> > the sample _energy_ to be optimal, so 8/3.
> >
> > Ciao,
> >
> > Segher
> >
>
> hmm, I'm not so sure about this. The noise measure used in LAME
> is based *not* on the error in the energy
>
> fabs(i^8/3 - x^2)
>
> but instead on the energy of the error:
>
> ( i^4/3 -x ) ^2
>
> Since LAME picks scalefactors to try to minimize the second quantity,
> I think we should use a quantization consistant with this error measure?
Ahah. I think the scalefactor picking should be consistent with the first
formula instead :-)
But seriously, what the ear hears is energy, not amplitude; so the second
formula is not an accurate description of the audible error.
Ciao,
Segher
--
MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
