I'm playing around with a simple ray tracer and I would like to end up with a short animated clip. Right now I'm rendering the scene to a bitmap. I would like the simplest motion picture format possible since I'll probably have to implement it from scratch (in erlang). Animated gifs come to mind. Is there anything else that would provide the same bang for the buck? I'm not interested in fidelity or high compression.
PS: I would like to avoid rendering the frames into individual files and combining them into a GIF or an AVI with external tool like ImageMagick.