On the complexity of rate-distortion optimal streaming of packetized media

We consider the problem of rate-distortion optimal streaming of packetized media with sender-driven transmission over a single-QoS network using feedback and retransmissions. For a single data unit, we prove that the problem is NP-hard and provide efficient branch and bound algorithms that are in practice much faster than the best known solution. For a group of interdependent data units, we show how to compute optimal solutions with branch and bound algorithms. The branch and bound algorithms for a group of data units are slower than the current state of the art, the heuristic sensitivity adaptation algorithm, but provide a significantly better rate-distortion performance in many real-world situations.