Picture Quality in Cascaded Video-Compression Systems for Digital Broadcasting

In anticipation of future digital broadcasting, we have evaluated digital video compression schemes to determine which would be most suitable for the storage and transmission of contribution television program material. Various digital compression devices for transmitting and storing video images have been researched and developed, and some are now being applied to broadcasting applications. In evaluating their picture quality, no problems were encountered when using a single device; however, when connecting several compression devices in a cascaded sequence, picture quality deteriorated. The application of digital video-compression techniques to digital-broadcasting distribution and transmission was investigated. This paper describes important factors that determine video quality in cascaded compression systems. It interprets the requirements placed on compression techniques in transmission and post-production and concludes by examining results from several cascaded compression experiments using MPEG-2, Motion JPEG, etc.