Convert .webm file to AVI (and others)

A nice feature of GNOME3 is that you can easily create a simple screen recording by pressing Shift-Ctrl-Alt-R (and again to finish the video).

The video file is then located below ~/Videos/ as a .webm file ( The result is a very compact, high resolution video.

If you want to convert the file to another format, simply use ffpmeg, like

ffmpeg -i VIDEO.webm VIDEO.avi