4K Blu-ray content on the horizon?

[Anthony P]

Originally Posted by kristoffer

How much room does a 4K movie at same compression as the best BDs today need?
200 GB?

tough question. If movies where not compressed in any form the answer would be 4x the BD but in order to answer your question one would need to define what does "same compression" means.

But no matter how it is defined it would be much less then 4x what the BD uses for 2k. In order to understand why one needs to understand how video compression work. p and b frames only save the changes from the previous /next frame so if two frames are identical, there should not be any difference in information in the p/b frame no matter what the resolution it is it would only have the header info and no pixel/block info. Even if the frame is not 100% the same a large chunk of it will most likely be (or else the encoder would have used an i frame). Also even if one looks at a single frame, because each pixel is smaller, there can be better blocking opportunities that don't destroy any more information (actually could destroy less) so it could save there as well (i.e. let's assume at 2k we have a checker board where each square is 4 pixels, since MPEG2/AVC only have 8pixel blocks that would need to be encoded as pixels or it would really destroy the image, but if you move to 4k each of the checker board squares is 8 pixels and so the perfect size to block without ruining the picture.