A video data communication system for transmitting ultra-high definition (UHD) video or three dimensional (3D, stereoscopic) video stream over a packet switched network (PSN, Gigabit Ethernet) comprises: input means for receiving or obtaining plural high definition video streams, each representing a ultra high definition stream or 3D video stream part (segment); a packet switched network (PSN) transmitting at least part of the plural high definition video streams in parallel (concurrently, simultaneously) from a transmitter to a receiver (Figs 2, 3: lower parts), e.g. using stream splitter; means for receiving the plural high definition (HD) video streams; a videogenlocker (genlocker) generating a clock for the HDTV video streams, providing synchronization; and a video stream combining means. UHD stream latency may be less than one inter-frame period. Also claimed is a set of HD video streams, all being representative of a segment of an ultra-high definition video stream, wherein the video streams comprise a header comprising information regarding the spatial configuration of the high definition video streams with respect to an ultra-high definition video stream.