I got the music fix and UB expansion in TR1 but the FMVs play at a crap "window" size, their picture on the black screen is too small. and the game has a bit of a lag problem. Any help please?

I installed the FMV patch but I realised the FMVs excluding the game intro are not playing at all. it's just stuttering on a black screen. I need help NOW. and I refuse to view them outside the game on a video viewer (I forget its name) because that's not how you're meant to view them in the first place.

EDIT: disabling DPI scaling appears to have fixed it but I can't be certain it will stay that way given music fix trickery TR2 GOG played on me until I installed the multiplatch.