>
> > Hello Gabriel,
> >
> > Saturday, May 27, 2000, 2:44:36 PM, you wrote:
> >
> > GB> Good point here. If I'm not too wrong, a kind of normalization can be
> done
> > GB> by just changing the scalefactor value. In this case, such an option
> would not change the
> > GB> encoding process. Lame could encode each frame as usual, but could
> change
> > GB> this value during the frame packaging. I think this should not
> interfere
> > GB> much with the main goal of Lame, wich is mp3 encoding.
> >
> > This "scalefactor", would this touch the "non uniform quantization" as
> > described in the Davis Yen Pan doc?
> > free quote: LIII raises input to 3/4th power to get more consistent SN
> ratio
> > over the range of quant values.
> >
> > I don't understand why you would raise a input level by 3/4th, encode
> > and raise to 4/3th whilst decoding, but I take there was a reason for
> > this, and maybe this is not something to tinker with?
> >
>
> I don't really understand the real utility of this 3/4 power. If someone
> knows about it, please drop us a line.
>
I dont really know either, but I think it is to normalize the MDCT
coefficients. For music, the amplitudes of these coefficients
drop off sharply as the frequency is increased. Rasing them
all to the 3/4 power before quantization has the effect of
allocating more bits to the smaller coefficients.
Mark
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