Since updating my Nokia 625 to 8.1 my ripped videos all play in letterbox.In windows 8 they all played in full screen.There is no option to change to full screen.
I noticed the option to change that in Xbox Video vanished.
I don't know what to say other than hope it comes back or use another player like MoliPlayer.
Also, very minor detail, but its Windows Phone 8, not Windows 8, despite being similarly named, they are very different.
Easy to confuse, just trying to clear that up.