The cable that plugs into back of your playstation for the picture, unplug it and put it back in firmly, also check the scart cable/red, white, and yellow cables are plugged into the TV properly, I used to get this problem, but jiggling the picture cable at the back of the PS2 when the film was playing seemed to do the trick.
Also, it could be your TV, my scart sockets on my old TV were wasted, when I ad something plugged into them I would have to stack either books or something underneath to get it to work, if you're using scart sockets, see if your TV has the red white and yellow circle sockets on the front or back and plug your playstation into them, they might be underneath a cover though...
Hope this helps matey :)