I've installed Recalbox on my Raspberry Pi 5 and i've seen videos on the Recalbox World YouTube channel which shows upscaling for the Saturn and Dreamcast. How is that achieved?
Sega Saturn upscaling video: https://www.youtube.com/watch?v=r7OCG_J9ndA
Dreamcast upscaling video: https://www.youtube.com/watch?v=r7OCG_J9ndA

Ideally i'd like to do it for the PS1, Saturn, N64 and Dreamcast.

If someone could give me some simple instructions (as I am new to this) i'd be forever grateful.

Thanks.