[theora] Fixed Quantizer - Fixed Quality

Stan Seibert volsung at mailsnare.net
Tue Mar 25 17:34:26 PST 2003

On Tue, 2003-03-25 at 19:25, Dan Miller wrote:
> So, for my money, the codecs should be doing a better job of
> incorporating some intelligence to correlate their 'Q' values to
> actual perceived quality, rather than some arbitrary pixel difference
> value.  That way, fixed-Q could actually mean something useful.  I
> suspect that audio codecs, particularly Vorbis, do this intrinsically,
> because their internal psycho-accoustic models tend to be rather
> complex.  In the video world, for reasons that elude me, this is not
> the case.  I know of no codec that incorporates any useful
> psycho-visual model into its encoder (though there are encoding apps
> that sit on top of codecs that claim to do this).

I'll ask the obvious follow-up.  :)

Is there a reasonable "psycho-visual" model to work with?

Stan Seibert

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