scott wrote:

>> OK, I rephrase: It looks pretty exotic to me. ;-)
> 
> It's much better than RGB for two reasons.
> 
> 1) The Y matches the high resolution bit of your eye, and the CbCr bits 
> match the lower resolution color detector bits of your eye.  Thus they 
> can be compressed different amounts.
> 
> 2) Equal distances in the CbCr space give a roughly equal difference in 
> colour perception.
> 
> If you tried to compress RGB channels separately the same amount as a 
> YCbCr signal it would look much worse.

Yes, I'm sure this is exactly why they use it. Still, it's not very easy 
to comprehend...

(Similarly, almost all known audio codecs don't compress the left and 
right stereo channels seperately; they compress "center and side" 
instead, since usually the side channel will contain very much less 
signal energy - and getting it wrong is far less serious sonically.)

PS. Is this why all MPEG-based algorithms utterly mutilate blue images?

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