Comment by mh-

Seconding the Topaz recommendation. Although be aware that is the Image upscaler model, and the parent commenter asked about video.

Here's the Fal-hosted video endpoint: https://fal.ai/models/fal-ai/topaz/upscale/video

They also offer (multiple; confusing product lineup!) interactive apps for upscaling video on their own website - Topaz Video and Astra. And maybe more, who knows.

I have access to the interactive apps, and there are a lot of knobs that aren't exposed in the Fal API.

edit: lol I found a third offering on the Topaz site for this, "Video upscale" within the Express app. I have no idea which is the best, despite apparently having a subscription to all of them.