The sample video (653k) shows the 30-frame test sequence used for the various compression tests. It also shows the optical flow between each frame and the previous frame. This short clip is intended to show the parallels between the normal frames and the optical flow frames.
Normally, the raw data is rendered in real-time on a Silicon Graphics R4000 Crimson Reality Engine. The software MPEG encoder runs off-line, since it can take up to several seconds per frame.