A hardware motion compensator for a videoconferencing codec

In December 1984 a CCITT specialists group was formed to standardise video coding at rates between 384 and 2048 kbit/s for video telephony. After much computer simulation work in many countries a combination of interframe prediction and hybrid transform coding was chosen for further investigation with real-time hardware. Several organisations in Europe, Japan and the USA began construction of flexible test-beds to permit verification, optimisation and enhancement of the algorithm. The algorithm performed well and it was decided to extend the range of bit rates down to 64 kbit/s. An outline diagram of the encoder is shown. International tests of this revised algorithm took place towards the end of 1989. The countries involved were Germany, Japan, UK and USA. The recommendation is known as H.261