Architectures for multi-source multi-user video compositing

Video compositing is the editing and integrating of many video images into a single presentation. Several single-user compositing systems have already been suggested, but the multiple users problem remains unstudied. We propose two new architectures for digital video compositing in a multiuser environment that are both memory efficient and can operate in real-time. We show that under hard throughput and bandwidth constraints, a memoryless solution for transferring data from many video sources to many users does not exist. We overcome this using (i) a dynamic memory buffering architecture ; and (ii) a constant memory bandwidth solution that transforms the sources-to-users transfer schedule into 2 schedules, then pipelines the computation. The architectures support opaque overlapping of images, arbitrarily shaped images, and images whose shapes dynamically change from frame to frame.