If you want to play AVI-videos in your game with script command "PlayVideo", you must have installed correct video codecs on your computer, of course.
But does Flic-animations need some kind of codec too (if you want to use "PlayFlic" script command)? On the other words, if you use only Flic-animations in your game, can you be sure that the game works correctly in every system?
No, you don't need additional codecs to play FLICs, and it works in both the DOS and WIN engine too. (crap AVIs wont play in DOS engine)