On Wed, 30 Aug 2006, pär F wrote:
YUV is a method for defining colors. 4-2-2 and 4-1-1 are ways of reducing the file size of an image that are possible only in an YUV space (not quite true, but at least not possible in RGB). YUV is in reality mainly used for video.
It's "possible" in RGB, it just doesn't give pretty results on average, which is one reason why those kinds of downsampling are done in YUV, and why JPEG compression is done in YUV, etc.
(The real original reason for YUV is that it was backwards-compatible with greyscale TV, but we can safely ignore that fact because YUV is nice for its own reasons)
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju | Freelance Digital Arts Engineer, Montréal QC Canada