Optimal streaming of layered video: joint scheduling and error concealment

We consider streaming layered video (live and stored) over a lossy packet network in order to maximize the video quality that is rendered at the receiver. We propose a framework, called joint scheduling and error concealment (Joint S+EC), in which packet scheduling decisions at the sender explicitly account for the error concealment mechanism at the receiver. We show how the theory of infinite--horizon, average--reward Markov decision processes (MDPs) with average--cost constraints can be applied to the joint scheduling and error concealment problem for low--delay transmission channels. The formulation allows for a wide variety of performance metrics, including metrics that take quality variation into account. We demonstrate the framework and MDP solution procedure using MPEG--4 FGS video traces. The main conclusions are (1) Joint S+EC optimal policies perform better than Disjoint S+EC optimal policies, and (2) the performance of the optimal Disjoint S+EC policy is not significantly better than very simple static policies.