[astrange]

At those two resolutions you'd pick the higher resolution one. I agree that generation of codec doesn't scale all the way up to 4K and at that point you might need to make some smart decisions.

I think it should be possible to decide in one shot in the codec though. My memory is that codecs (image and video) have tried implementing scalable resolutions before, but it didn't catch on simply because dropping resolution is almost never better than dropping bitrate.