Avidemux is a free multi platform video editor currently available for Windows, Linux and Mac OS X.

Avidemux can encode files from one format to another using various codecs, such as mp4 tp xvid, mp3 to aac, etc. Avidemux can also convert a DVD into various formats such as xvid for storage on a personal media player, such as a playstation 3 or even various DLNA compatibale hardware device. Other features include editing, cutting and adding filter effects to video sources. It is possible for example to add a fade effect by using a filter and specifying where you want the fade to start and end. There are many useful filters included such as adding borders, resizing, sharpen image and adding colour effects such as boosting saturation.

With all these features available with Avidemux, it does also make it harder to learn but with so many features it is worth it.