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 that scales well
* 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 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
* Compatible with a large number of already existing Avisynth plugins