[vorbis] Beta3 impressions

[brian]

On Mon, 20 Nov 2000, Segher Boessenkool wrote:

> > > In his interview to Slashdot, Monty said that wavelets will be used in
> > > Vorbis (after version 1.0). I guess that wavelets will be able to eradicate
> > > pre-echo more thoroughly ?
> > 
> > Yes, wavelets are my attempt at solving the problem correctly.
> 
> Do you already have an algorithm to decide which part to encode with
> mdct, and which part with wavelets? I'm currently working on something
> like this.

Perhaps it's a little early to search for algorithms until we really know
what methods will be employed in the encoding process.

I am curious as to what wavelet methods are going to be used for the 
pre-echo control.  I've recently obtained an advisor to do a thesis in
wavelet audio coding.  I was thinking of two approaches, primarily because
of mixed results in other people's work in the subject:

   (1) Perform the traditional wavelet analysis methods, look for good
       bases in different situations, etc.

   (2) Instead of transforming time-signal data, look at the frequency
       information spit out of the fft or preferable method.  Perform some
       sort of wavelet packet analysis and reconstruct an approximation of
       the frequency signal using the psychoacoustic model to direct
       precision.  Granted, this would simply be quantization via
       wavelet packets.  However, it would be interesting to see what
       happens when performed.  (It would obviously not solve the
       problem of pre-echo control, but may be an interesting thing
       to investigate altogether).

I was curious to the methods that Monty had in mind (as far as choosing
bases, etc).  Comments?

Brian

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