Even though the software is on Steam, the "top" GitHub contributors in the gaming community often provide the underlying code for the shaders used in scaling. Browsing GitHub for "spatial scaling" or "frame generation" can lead you to free, open-source alternatives if you are on a strict budget, though they often lack the user-friendly interface of Lossless Scaling.
The story goes that the team, led by developer Jérôme Licini, was working on improving FFmpeg's scaling capabilities. They experimented with various algorithms, eventually developing the zimg scaler, which provides exceptional quality and performance. lossless scaling download github top