PiTiVi allows users to easily edit audio/video projects based on the GStreamer framework: Capture audio and video; mix, resize, cut, apply effects to audio/video sources
Diva is a project to build an easy to use, scalable, open-source video editing software for the Gnome desktop.
QTCoffee is a set of command-line Mac OS X utilities for manipulating QuickTime movies and other QuickTime readable media.