Media coding for streaming in networks with source and path diversity
Novel network architectures such as overlay networks offer significant diversity that can compensate for the lack of strict quality of service in today's communication infrastructures. In order to take advantage of this diversity for delay-sensitive media streaming applications, the network systems can employ efficient mechanisms based on source, channel and even network coding. In particular, fountain codes offer interesting benefits for streaming with server diversity. When they are used independently at each server, they permit to avoid explicit coordination between the senders that only have to provide the receivers with enough innovative packets. In addition, network coding allows for improved throughput and error robustness in multipath transmission where the network nodes participate to increase the symbol diversity in the system. We review in this chapter the most popular rateless codes that enable the deployment of low-cost decentralized communication protocols in self-organized dynamic networks. We then describe their application in distributed multimedia streaming solutions. We further discuss the most popular network coding algorithms in practical media streaming schemes. Finally, we show that hybrid systems based on both rateless coding and network coding can deliver high quality media streams with low computational complexity, as they permit to benefit from both server and path diversity in overlay architectures.