1. A computer-implemented process for compressing video data comprising sequential sets of contemporaneous video frames wherein the video frames in a set depict substantially the same scene from different viewpoints, said process comprising using a computer to perform the following process actions: designating a plurality of keyframes for each set of contemporaneous frames; and for each set of contemporaneous video frames in time sequence order, compressing each video frame that is not a keyframe using a multi-directional spatial prediction technique.