Rerendeirng old cinema cg is anything but trivial. Production pipelines are incredibly complex and are a fast moving target. Getting something going again is a very complex and tedious task of software archeology against projects that often only had a single company using them. Many dependencies will be unavailable or incompatible with current systems.
When old content that doesn't have a high resolution film or digital master copy is remastered to HD, it's done using super resolution tools that do their best to infer extra detail based on the existing data.
As with software development, some people have done this before and learned their lesson, others never do.
Once upon a time it was completely normal to have manual processes in your final build process. Something like a word processor in the 1990s would have one of the team sat at a machine building the "gold" binaries by hand, maybe following a checklist, likely hand written. OK, so we need to drag all the files except these two into this folder, then run this program...
Today, hopefully most of you today would see that's awful and you'd forbid it on a project you led and insist on CI instead.
Toy Story in particular had to be re-rendered to produce the 3D re-release over a decade later, and Pixar did that. They chose not to later re-render to 4K because in their opinion it isn't worth the effort compared to just upscaling it.
Also, often special effects are done as manual one-offs on top of what comes out of the renderer (with whatever software package and techniques that happened to fit the bill for that particular effect); it's not like you can just type “make” and out comes the movie. It's certainly _easier_ to do a higher-res version of an animated movie than a live-action one, but it's still a lot of work.
As another comment pointed out: Toy Story was re-rendered at great effort for 3D. That's the exception not the norm. They didn't feel it was worth it to do it yet again for the 4K version which is simply upscaled.
It is in no way a "download the archive and type make again" sort of situation. It's a huge effort.
Are your comments actually informed or are they just synthesis (guessing)?
> “We had to have some very, very smart people at Pixar go back in and write some software and figure out a way to make it so that those files would render on our current computers,” he said.
>It took four months to resurrect the old data and get it in working order. Then, adding 3-D to each of the films took six months per film.
I am a filmmaker and VFX artist and boy are you wrong.
Doing a 4k scan of a film that only ever was scanned for a DVD release is trivial, provided you still have the masters.
Doing the same thing with a film which was made 1995 as a digital animation is anything but trivial. This is not your "I just have to select a higher resolution and render everything"-thing.
- certain visual results might be bound to software versions that are so old grabbing a copy of them and making them run would be a challenge in itself
- there might be manual processes which need to be redone in order to get the final result — IF they have been documented
- there might be file formats in use which are no longer readable, or might be read differently
Scaning a film and retouching it is trivial, redoing a digital animation that was top notch in 1995 is not.
A good example of this was the recreation of Star Trek: The Next Generation in Blu-Ray resolution. The main scenes were still available on film and could be rescanned. But all the special effects (phaser beams, transporter sparkles, etc) had been rendered using late 80's technology. And had to be recreated from scratch.
Some of the model shots also had to be entirely redone via 3D effects, such as the Crystalline Entity in S05E04. Paramount spent millions on this project, which were never recouped as the discs were released just as streaming took off.
When old content that doesn't have a high resolution film or digital master copy is remastered to HD, it's done using super resolution tools that do their best to infer extra detail based on the existing data.