Some of those iTunes versions have been ripped. iTunes usually replaces their version when a new ‘restoration’ is done.
Unfortunately, the quality from digital compression makes these poor sources and not much better than DVD.
I have the “Sword in the Stone” iTunes rip, and it looks considerably better than the DVD (and doesn’t show that awful DNR of the Blu-ray). I’m especially looking for the 1080p version of “Pooh’s Grand Adventure: The Search for Christopher Robin”. I’ve managed to get it recorded from Cinemagic HD, and it looks actually really good. It’s been cropped to 1.6:1 and scrubbed of most noise, sure, but it’s nowhere near a DNR-mess like “Sword in the Stone” or “Mickey’s Christmas Carol” and it’s true HD instead of just an upscale. The weird thing is, around the 41 minute mark there’s a fade to black, and when it comes back on, the quality has dropped massively. No clean up, vertical resolution seems to be halved, mute colors… it’s as if they weren’t finished with the restoration (if you want to call it that).
Here are a few screengrabs from it: http://imgur.com/a/ZuDj6
The first six images are from before the quality drop, the last six from after the fade to black.
And that’s why I hope the iTunes HD version is “finished”, so I can at least replace the latter half of the movie with it (plus paint out the Cinemagic logo). Anybody?