Cinelerra is the most advanced non-linear video editor and compositor for Linux. It is developed by Adam Williams (formerly known as Jack Crossfire) at Heroine Virtual Ltd..
To know more see the official Cinelerra home page and the SourceForge project page.
Cinelerra's source code is available under the GNU General Public License (GPL).
However, unlike most large Free Open Source projects, the development of Cinelerra is not open to distributed collaboration and there is no support for the software.
Cinelerra is tested on Fedora. Cinelerra4 is available also as Ubuntu packages.