VapourSynth is an application for video manipulation. Or a plugin. Or a library. It’s hard to tell because it has a core library written in C++ and a Python module to allow video scripts to be created. It came to be when I started thinking about alternative designs for Avisynth and most of it was written over a 3 month period. The software has been heavily inspired by Avisynth and aims to be a 21st century rewrite, taking advantage of the advancements computers have made since the late 90s. The main features compared to Avisynth are:

• Multithreaded – Frame level multithreading
• Generalized Colorspaces – New Colorspaces can be specified at runtime
• Per Frame Properties – Additional metadata can be attached to frames
• Python Based – The scripting part is implemented as a Python module so you don’t have have to learn a special language
• Support for video with format changes – Some video just can’t stick to one format or frame size VapourSynth can handle any kind of change