Further developments in the use of DATV for bandwidth compression of HDTV

Perhaps the most problematic question posed by the advent of high definition television is how to distribute the high bandwidth source signals to the viewer with a minimal loss of quality. The most successful solution investigated so far is to bandwidth reduce the HDTV source signal, using the most advanced motion compensation techniques, combined with an effective digital assistance channel (DATV). This approach, when correctly engineered, can allow near transparent transmission of HDTV through restricted bandwidth channels such as DBS, videodisc, video cassette and cable. The authors describe work carried out by the DATV working party of the Eureka 95 project, which was led by the BBC, to develop DATV strategies for signal processing chains. They also describe further investigations which have been undertaken by the BBC into the possibility of bit rate reduction of the DATV information. This would allow an increased information content to be signalled via the existing capacity of the HDMAC signal, which is limited to a little over 1 Mbit/s. Promising degrees of bit rate reduction have been achieved, opening up the possibility of attaining the desired flexibility for future performance enhancements