50 is BATSHIT INSANE, did you even read the suggestion of the guide on the filter's usage? Going over 2 will be already too much with most sources and most likely a detail killer in any case!
Anyway, give blockbuster
a chance (try to call it as blockbuster("noise") and if that doesn't work, check the readme
). And don't forget to scale back to 480p since it's just an upscale, I think that might actually help out ─ I'd say call blockbuster("noise") before the resize and gradfun2dbmod(1.05) after.