How to flip screens?

I just upgraded my pub table to a 32 inch screen which resparked my interest. It is running retropie and the Dreamcast emulator is the only one that has the screens oriented upside down for each player. The others are fine. Is there and easy fix for this?

I just upgraded my pub table to a 32 inch screen which resparked my interest. It is running retropie and the Dreamcast emulator is the only one that has the screens oriented upside down for each player. The others are fine. Is there and easy fix for this?