Stream:
It is my understanding that the AH film files are recordings of game code events. When you hit Alt-R, the AH software starts copying all the game events... aircraft positions, terrain, and 3d object states(blown buildings), VOX coms, text coms, etc. to a file that HiTech calls a film file. When you run the film viewer, the the AH game code replays all the events and renders video frames that your video card displays. So, it looks like a video replay, but really isn't. Avi, quicktime, and mpeg are actual film codec types. So, you have to capture the AH game generated frames to one of the film file formats.
There is software out there that will record what is displayed by your video card and transform it into avi, quicktime, or mpeg formats, but the name escapes me at the moment.