I looked into upscaling for the original episodes of Police Squad. Paid a good chunk of money for an AI upscaler because I was too curious how good of a job it could do.
The results were not great. When there's too many different things impacting the quality of the source, the AI just can't do a great job. In the case of Police Squad DVD rips, they were low res and noisy.
When I eventually found a higher resolution Bluray version, I ran that through just to denoise it and got much better results. My understanding is that it also would have been able to do a good job upscaling given a source that wasn't noisy.
Maybe you can use a chain of models to handle both problems. I didn't try anything like that. Though I would expect the tool to have that as an option if it is something that worked well.
