> we have somebody who has somehow obtained a "weird" video file
Why are you arriving at the conclusion that this requires complex software, rather than just a simple UI that says "Drop video file here" and "Fix It" below? E.g., instead of your conclusion "stick to your walled-garden-padded-room reality where somebody else gives you a video file that works", another possibility is the simple UI I described? That seemed to me the point of the post.
This is really just my read for why this sort of software isn't more common. Go ahead and make it, and if it ends up being popular I'll look the fool.
I don't think that's true at all. The tool linked here is exactly the kind of utility that does one single task and that people are happy to download. Most people use software to solve a problem, not to play around with it and figure out if they have a use for it.