Vorbis - Oct 2000 - Vector quantization - is it a bad thing?

Hi.

I have been talking with Psytel MPEG-4 AAC developer (www.psytel.com)
about various compression formats, and to make it short he said that one
of the main drawbacks of Vorbis is its vector quantization - it introduces
more error then other quantization methods (like non-uniform scalar
quantization, if I got it right), probably used in AAC and other similar
codecs. I know vector quantization is good for low-bitrates, but since I'm
no expert in these areas, I would like if someone (Monty, or someone
knowledgeable) could shed some light on this subject?

Greetings,
Aleksandar

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> I have been talking with Psytel MPEG-4 AAC developer (www.psytel.com)
> about various compression formats, and to make it short he said that one
> of the main drawbacks of Vorbis is its vector quantization - it introduces
> more error then other quantization methods (like non-uniform scalar
> quantization, if I got it right), probably used in AAC and other similar
> codecs.
He's either confused you, or he's confused himself by only considering
a narrow class of vector quantization.  Scalar quantization is simply
a special case of vector quantization where the vector size is
hardwired to 1.

The error charachteristics are built into the codebook set, and one
can choose any characteristics one wants.  The current Vorbis books
(for example) are non-uniform.

Monty

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