Here is a guide to install Avidemux on Ubuntu 13.04. You can install Avidemux using the Ubuntu Software Center.
Avidemux is a free video editor designed for simple cutting, filtering and encoding tasks. It supports many file types, including AVI, DVD compatible MPEG files, MP4 and ASF, using a variety of codecs. Tasks can be automated using projects, job queue and powerful scripting capabilities. Visit the Avidemux Homepage.
To install Avidemux click on the link below
When the software center is opened click on the Install button and enter your password to authenticate the installation. When Avidemux is installed you can close the software center, to start Avidemux press the SuperKey and type: avidemux
Version: avidemux 1:2.5.4-0ubuntu13
Total size: 7,4 MB to download, 18,2 MB when installed
License: Open source
How to open the apt link? Read this article.