Assuming that Canon 5D Mark II and Canon 60D both have the same processor, DIGIC 4 (single), why does the former shoots a better quality video? Better quality I mean the technical aspect, the video/compression itself.
Let's ignore the visual aspect like more shallow depth of field, for example.
I know 5D is a full-frame, but the video is 1920px wide. The 60D shoots 18MPx, which scaled down to 1920px wide should still look almost the same as if shot on full-frame initially, right?
Therefore, and this is my point:
UNCOMPRESSED INPUT -> DIGIC 4 -> OUTPUTTED VIDEO
If we exclude the depth of field and a better ISO handling from our equation, it's possible that the uncompressed input is the same on both cameras, right? Then, it goes to the digic 4 processor to be compressed, which is the same on both cameras. Yet, we end up with a better quality video on one of those cammeras. Why?