Motion-compensated visual pattern image sequence coding for full-motion multisession videoconferencing on multimedia workstations

Motion-compensated visual pattern image sequence coding (MCVPISC) is an improved motion-compensated version of the visual pattern image sequence coding (VPISC) encoder. It is a high-performance video codec that is easily implemented in software. The MCVPISC codec is intended for real-time desktop computer applications such as multimedia delivery and local area network and point-to-point (modem) video conferencing. We describe a version of MCVPISC that has achieved bit rates of 0.15 bits/pixel or better for MPEG-2 test sequences (source encoding reduces this bit rate by about half). The computational complexity of the monochrome and color versions of the encoder is less than three integer operations per pixel. The decoder is bounded between 0.016 and 0.125 logical and integer operations per pixel. A prototype video conferencing system based on the MCVPISC codec has been implemented. The system hardware is comprised of two multimedia personal computers, two camcorders, two frame grabbers, and an ethernet connection. The prototype system software has a simple structure and runs under DOS and Windows(TM) 3.1. It includes a user interface, a video IIO interface, an event driven network interface, and a free running or frame synchronous video codec that also acts as the controller for the video and network interfaces. We have demonstrated that this prototype can support up to five full duplex full-motion video conferencing sessions. Future work will concentrate on expanding the prototype to support synchronous audio, multiple hardware and software platforms, and network protocols. (C) 1996 SPIE and IS&T.