>
> > Has anyone ever considered tossing the stupid bands as far as
> > psycoacoustics are concerned, it seems much more sensible to do all
> > calculations over the non-segmented frequence space and breakup into bands
> > just for packing into the file. This would probably also make more
> > sophicated masking (like temporal masking) easier to impliment.
>
> Bands are ok, but the layerIII bands are too wide for good psycho acoustics.
> Take the bands smaller (about 1/4 bark), do your calculations, and take
> for calculation of the scalefactors the minimum of the calculated allowable
> distortions for the psycho bands that match that scalefactor band.
>
> Ciao,
>
> Segher
>
The ISO model (and LAME) does the calculations in 'partition bands',
which are about 1/2 or 1/3 of a bark since there are 64 of
them, and I think 0-22.05kHz is about 25 barks?
But then it averages the partition bands into the scalefactor bands,
rather than taking the min. There is some paper which recommends
using an average if there are less than 4 partition bands in a scalefactor
band, and using the min if there are more than 4. But I dont recall
if they had a good reason for this.
Anyway, we are slowly replacing all the table data with formulas, and
this it will be easy to adjust all these parameters.
Mark
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