Well, if you have easy debian installed, you can go in iceweasel the debian firefox, go to moduled and plugins, add one called download helper, and after that you'll be able to download any video from any site! if you setup correctly the options of the plugin you'll be able to automatically re encode the video in other format (i.e mp4) and even choose the qulity. I have tested it and it works very well but.... it's a very very very long process! et voila.