HDTV: a 140 Mbit/s coded for `contribution´ quality coding

Digitising the luminance and chrominance components of an HDTV signal results in a bit rate of about 1.2 Gbit/s. For long-distance transmission an obvious goal is to reduce this bit rate by a factor of about 10 in order to fit into the current standard bit rate of 140 Mbit/s. In order to maintain contribution quality for such bit-rate reduction factors, it is necessary to use a combination of techniques such as transform coding, motion-compensated interframe prediction and variable-length coding. The BBC, as part of the RACE HIVITS Project (No. 1018) has participated in the construction of a such a 140 Mbit/s codec for HDTV. This codec is based around a codec, that has also been developed within the HIVITS project and manufactured by Thomson, for the coding of conventional-definition television within 34 Mbit/s