Data reduction for VTRs

The author describes some simple aspects of information theory as applied to television signals and the reduction of data therein. He then explains the advantages of using data reduction in video tap recorders, particularly in HDTV, and why it has now become feasible to do so. A method of data reduction (using DCT and variable length coding) which has gained favour is briefly described, together with a look at how it can be implemented in the VTR environment. Next, development work within the framework of EUREKA 95 is outlined, with criteria for the performance and testing of a practical system. Results so far achieved are discussed. Finally, the future impact of data reduction on recording techniques is forecast