[vorbis-dev] Why LSP?

[Jean-Marc Valin]

> It's also the case that Vorbis floor0 is encoding a very low resolution
> version of the envelope; typically 30 poles and 50 or so bits for the whole
> envelope in a 1024 sample frame.  It seems what you're describing would be a
> better solution for an envelope with a great deal more fine detail.  My
> envelope is more of a whitening filter.

Well, that's probably the kind of resolution I was dealing with. In my case, I
could represent my envelope with about 8-12 DCT coefficients and could vector
quantize it with enough (for me) precision with about 10 bits (It was a
[3500-8000] Hz envelope and I was getting ~3.5 dB distortion with an 8-bit
vector quantizer). I don't know whether the 50 bits is an important contribution
to the total bitstream, but I'm sure there'd be a way to reduce that (if it's
worth it, of course).

        Jean-Marc


-- 
Jean-Marc Valin
Universite de Sherbrooke - Genie Electrique
valj01 at gel.usherb.ca

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/