I've had my 4k tv for about a week now, it playes everything perfectly fine apart from 4K movies (ironic), I have 4k movies on my usb, i connect them to the tv and play them, but in the bottom 20% of the screen, there is a load of graining in purple and white blocks, and the movie only takes up about 2/3 of the screen with weird white boarders around it. I have no idea why this is happening, i have tried MKV and MP4 4K movies, but for some reason they all act the same.