RAD Movie Files (.rmv)

[handsomematt]

looks like they're just Bink videos, could be something extra tho

[polybiusproxy]

RAD Movie Files are actually Bink videos.
They can be played using RAD Video Tools, by just renaming the rmv file extension to bik or bk2.

FFMPEG can play Bink files, so it should be easy to implement.