WinFF is available for many Linux distributions, languages, and Windows 95 to Windows - it is a very simple and easy to use video format converter. It will also extract audio streams from video media files.
Shotcut is a free, open source, cross-platform video editor for Windows, Mac and Linux. Major features include support for a wide range of formats; no import required meaning native timeline editing; Blackmagic Design support for input and preview monitoring; and resolution support to 4k.
OpenShot Video Editor is a free, open-source video editor for Linux, Mac, and Windows. We designed OpenShot to be an easy to use, quick to learn, and surprisingly powerful video editor. Easily cut, slice, and edit any video or film. Check out the full feature list, view screenshots, or watch videos of OpenShot in action!
Note their new site: http://www.openshotvideo.com/ which hosts version 2.3.3 onwards
Free, open source, cross-platform audio software
Audacity is an easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems.Developed by a group of volunteers as open source.