This paper describes a parallel architecture for a variety of algorithms for video compression. It has been designed to meet the requirements of encoding and decoding according to the ITU-T standard H.263. The architecture is an implementation of the instruction systolic array (ISA) model which combines the simplicity of systolic arrays with the flexibility of a programmable parallel computer. Although the parallel accelerator unit is implemented on no more than 9 mm2 of silicon it suffices to meet the compression rate necessary to send a compressed video stream through a standard ISDN terminal interface.