A multicast scheme for parallel software-only video effects processing

We have developed a parallel software-only processing system for creating real-time video effects such as titling and compositing (e.g., picture-in-picture) using compressed Internet video sources. The system organizes processors into a hierarchy of levels. Processes at each level of the hierarchy can exploit different types of parallelism and coordinate the actions of lower levels. To control the effect, control messages must be distributed to processors in the hierarchy while preserving the independence of each level. This requires a control mechanism that supports efficient delivery of messages to groups of processors, tunable reliability semantics, and recoverable state information. We describe a mechanism that meets these requirements that uses IP-Multicast, the Scalable Reliable Multicast protocol, and the Scalable Naming and Announcement Protocol. We also describe an optimization that provides a flexible framework for linking the control of different aspects of one or more related video effects.