Design of an HDTV codec for terrestrial transmission at 25 Mbit/s

The authors outline the development of an experimental codec for HDTV signals aimed at terrestrial transmission on around 25 Mbit/s fitting into 8 MHz channel space using advanced digital modulation. The codec uses an extension of the basic motion compensated hybrid-DCT coding algorithm adopted in CCITT (H261), ISO/MPEG and CCIR/ETSI. These extensions include advanced motion estimation/compensation and compression of the motion vector field by the use of intra/inter-DCT coding. The system is based on 1250 lines, 50 Hz 2:1 interlaced pictures using 54 MHz sampling for luminance and 13.5 MHz for chrominance. The system consists of a coder and a decoder with an interface to a COFDM modem for 27 Mbit/s transmission including forward error correction (FEC) suitable for 8 MHz terrestrial channels