VLC of course.
There is option for software upscaling under filters tab, with quite a selection, but it seems since version 3 of the program, is left behind not working.
I'm one of those guys who liked to use Lanczos, but for the past 10 years swscale it's not working, and workarounds are to much hassle.
So I wonder, will this useless for now option will be removed or fixed?