VapourSynth is a versatile application, plugin, or library for video manipulation that combines the power of a core C++ library with a Python module. Created as an alternative to Avisynth, this software takes advantage of modern computer advancements. Some notable features include multithreading, support for customizable colorspaces, per frame properties, and a Python-based scripting module. VapourSynth can also handle video with format changes, making it compatible with a wide range of videos. Developed by Fredrik Mellbin, who has a background in electrical engineering and a passion for video editing, VapourSynth is the result of his efforts during a period of unemployment. For any assistance or sponsorship opportunities, please feel free to contact Fredrik Mellbin.
https://www.vapoursynth.com/doc/introduction.html