Ok, pressing c on the movie will change the fullscreen
resolution, but there really is no way to know what
resolution you justed changed it to. This makes it difficult
you one was trying to watch a movie at a specific resolution.
I think the best way would be to have pressing "C" cycle
through the list of resolutions as text on the screen. Finally,
after a pause of about 2 or 3 seconds, once the user has
settled on a resolution, then it changes.