Managing the Effect of Delay Jitter on the Display of Live Continuous Media

This dissertation addresses the problem of displaying live continuous media (e.g., digital audio and video) with low latency in the presence of delay jitter, where delay jitter is defined as variation in processing and transmission delay. Display in the presence of delay jitter requires a tradeoff between two goals: displaying frames with low latency and displaying every frame. Applications must choose a display latency that balances these goals. The driving problem for my work is workstation-based videoconferencing using conventional data networks. I propose a two-part approach. First, delay jitter at the source and destination should be controlled, leaving network transmission as the only uncontrolled source. Second, the remaining delay jitter should be accommodated by dynamically adjusting display latency in response to observed delay jitter. My thesis is that this approach is sufficient to support the low-latency display of continuous media transmitted over building-sized networks. Delay jitter at the source and destination is controlled by implementing the application as a real-time system. The key problem addressed is that of showing that frames are processed with bounded delay. The analysis framework required to demonstrate this property includes a new formal model of real-time systems and a set of techniques for representing continuous media applications in the model. The remaining delay jitter is accommodated using a new policy called queue monitoring that manages the queue of frames waiting to be displayed. This policy adapts to delay jitter by increasing display latency in response to long delays and by decreasing display