Digital HDTV Compression at 44 Mbit/s Using Parallel Motion-Compensated Transform Coders

High Definition Television (HDTV) promises to offer wide-screen, much better quality pictures as compared to the to-day's television. However, without compression a digital HDTV channel may cost up to 1 Gbit/s transmission bandwidth. We suggest a parallel processing structure using the proposed international standard for visual telephony (CCITT Px64 kbs standard) as processing elements, to compress the digital HDTV pictures. The basic idea is to partition an HDTV picture into smaller sub-pictures and then compress each sub-picture using a CCITT Px64kbs coder, which is cost-effective, by to-day's technology, only on small size pictures. Since each sub-picture is processed by an independent coder, without coordination these coded sub-pictures may have unequal picture quality. To maintain a uniform quality HDTV picture, the following two issues are studied: (1) sub-channel control strategy (bits allocated to each sub-picture), and (2) quantization and buffer control strategy for individual sub-picture coder. Algorithms to resolve the above problems and their computer simulations are presented.