First of all, the GP Cinema cpu clock are 100, 120, 133, 150, 166 Mhz.
The best is to watch movie at 150 Mhz (a lot of GP32 can do it) with 18 fps, video bitrate at 128 kbps max with VirtualDub 1.5.10 (depending on the movie length), 40 kbps 20 050 Hz for sound (good quality on GP and not too...