[FFmpeg-devel] a64 encoder

Michael Niedermayer michaelni
Sat Jan 17 17:21:57 CET 2009

On Sat, Jan 17, 2009 at 04:52:00PM +0100, Bitbreaker/METALVOTZE wrote:
> > reducing the colors before seems quite suboptimal, id rather convert each
> > fullcolor "char" with dithering to what is available afterwards or even
> > during the elbg code.
> >   
> I have tried converting to a charset beforehand already some time ago, 
> it can lead to other problems therefore, depending on what area i 
> calculate the error. If i do a pixelwise compare, i gotta stick to the 
> ditherpatterns or error goes up.

you shouldnt be comparing pixel wise, because if a minimal per pixel
difference where the goal dither would always be inferrior to taking the
closest color ...
A likely better comparission is in 2d dct domain, with the low frequency
coefficients more strongly weightet. But maybe some psychovissual
comparission (x264 has some code for this ...) would work as well or
even better.

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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