Hi Marcin – thanks for the reply! Those articles make for interesting reading.
One method I stumbled across was to import the footage into Photoshop CC, then resize in photoshop and make image adjustments using Camera Raw. Strikes me as a good, if cumbersome, method of doing it.
I’m just running a test now to upscale 1080p footage to 4k – just to see if it works.
I’m at 24 minutes per frame, and there are 429 frames. Yeowch.