[vorbis-dev] Large codebook?
xiphmont at xiph.org
Sat Jun 23 14:39:26 PDT 2001
On Fri, Jun 22, 2001 at 02:32:33PM +0300, Juhana Sadeharju wrote:
> >Is this going to give results significantly better than IMA-ADPCM,
> >which gives a similar compression ratio for a fairly low decode
> >overhead and simpler decode loop?
> Also the quality matters, but I have no idea. I suppose a VQ method
> outperforms the adpcm method because VQ keeps an external codebook but
> adpcm just reduced the total number of bytes.
> How IMA-ADPCM works? Documentation? What would be the error signal?
> Are there any source code? Sox could not decode IMA-ADPCM files I have
> found from one game.
> Could someone of you tell me how to use the VQ code of Vorbis to
> make the codebook for the simple system I proposed?
The vq tools are not production code and as such are much less
polished than the main libraries. They work, but they're limited,
buggy and slow.
The basic model of the tools is to take a data file consisting of
vectors of comma seperated scalars, vectors seperated by newlines, and
training/generating codebooks from these vectors using one of a few
different algorithms, mostly varaition of the classic LBG algorithm,
or by just entropy training against a predefined square lattice.
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