Thank you guys, exactly what I was looking for!. Josiah, the crop command worked perfectly but I couldnt manage to get the expand command to work, when I tried it, it only made the video really small and thats it, I couldnt change the size of the video. Well nevermind.
It would be great to do this automatically, maybe a program with some kind of gui. Like I said the onlyone I tried (the olny one I know) was smplayer, but it only hungs the device.
Let me know if you find a way of doing this automatically.

Thanks