Re: [Algorithms] RGB to XYZ conversion

[Jon O. <jon...@gm...>]

Hi Simon,

YCoCg is not lossless. You need an extra bit in order to be lossless which
is called YCoCg-R. Also, when using DXT texture compression, putting the Y
in the alpha channel and then the Co and Cg in the color channels gives
better quality compression. Decompression in a fragment program is only a
few instructions and can be well worth it for the quality improvement.

Best,
Jon Olick

On Wed, Apr 23, 2008 at 5:14 AM, Simon Fenney <sim...@po...>
wrote:

> Sam Martin wrote:
> > Out of interest, did you try exposing the YCoCg colour space to your
> > artists at all? It's nice and simple, but I'm wondering if anyone has
> > had any issues with it in practice?
> >
>
> Out of curiosity, what did you mean by "had any issues with it"? YCoCg
> is primarily a replacement for YUV/YCbCr that allows cheaper (and
> lossless) transforms between the two colour spaces and typically does a
> good job of extracting the correlation in the RGB. If you want to use it
> for image compression, then it's a good first step.
>
> Simon
>
>
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