2014-03-24, 22:51
(2014-03-24, 20:12)lmyllari Wrote: I think that would be ok if you were just scaling luminance back and forth, but you are also doing YCbCr -> RGB in the first step.That's a very good point. YCrCb/RGB round-tripping in 8-bit truncated space isn't a good idea is it...
I knocked up an Excel sheet to go from Limited to Full to Limited level space - with rounding to nearest integer - but hadn't considered the RGB matrix.
Presumably XBMC copes with ITU 601 and 709 levelspace on input content (either by reading header information or by taking a punt that <=720 horizontally is 601 and >720 horizontally is 709. I assume you'd use horizontal resolution rather than vertical to cope with the letterbox cropping that happens on >16:9 aspect ration 720p and 1080p sourced content?)
I assume there is some driver interaction on the output level space and RGB to YCrCb conversion - so no real control over whether output is 601 or 709 colour space if YCrCb?