AviSynth is a powerful tool for video post-production. It provides
almost unlimited ways of editing and processing videos. AviSynth works
as a frameserver, providing instant editing without the need for
temporary files.
AviSynth itself does not provide a graphical user interface (GUI)
but instead relies on a script system that allows advanced non-linear
editing. While this may at first seem tedious and unintuitive, it is
remarkably powerful and is a very good way to manage projects in a
precise, consistent, and reproducible manner. Because text-based
scripts are human readable, projects are inherently self-documenting.
The scripting language is simple yet powerful, and complex filters can
be created from basic operations to develop a sophisticated palette of
useful and unique effects.