I did a search, this wasnt listed, so without knowing if you know about it already,
I thought it worth the post, could be a cool app as time goes bye.
Can't say no to some Free Tools.
Natron is an open source node-based compositing software that relies on OpenColorIO for color management, OpenImageIO for file formats support, and Qt for user interface. It’s available for OS X, Windows and Linux, and offers 32-bit channel precision as well as support for OFX plugins.
http://natron.inria.fr/features/