[Vorbis-dev] data reduction on Vorbis

Monty xiphmont at xiph.org
Tue Jul 19 18:34:17 PDT 2005

On Tue, Jul 19, 2005 at 01:42:03PM +0200, evil wrote:

> How is the data reduction reached, with Vorbis? 

In terms of modelling or back-end entropy encoding?

Given that vorbis is all about data reduction, this is a bit like
asking 'How does a car work?'  First we need to establish which part
of the car you're talking about :-)

> Does the data reduction depend on the quantization noise, like MP3? 

No.  ...and quantization noise is a really lousy objective function
for performing psychoacoustics.  Brandenburg goofed somewhat by
choosing it, but that wasn't clear for a long time (he was the guru,
and no one really questioned the decision; there aren't many people in
the world knowledgeable enough to second-guess him).

> Which data are then actually stored?

"Everything that's not removed"

I understand you're being vague because English is a foreign language,
but you'll need to be more verbose about what you're really asking.
Mistakes are fine, it will still be easier to figure out what you
really mean.  We can struggle through it with Babelfish :-)


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