Issues in multiple description coding : algorithm design, analysis and applications

Abstract

In the modern packet-switched networks, an information source can be transmitted from multiple servers to multiple clients via different paths. However, current networks do not provide a guaranteed performance in terms of bandwidth or delay and therefore the desired quality of service may not be achieved. Especially for some real-time services, such as voice over Internet (VoiP) and video conferencing which require high bandwidth, low delay and low packet-loss rates, the problem of reliable delivering is a significant issue.

Multiple description coding (MDC) is a promising technique to support error resilient multimedia communications with low delay over lossy networks such as the Internet and wireless networks. In an MDC implementation, an encoder generates M descriptions (or streams) for one source. The streams are transmitted from one or multiple servers to a receiver over separate channels (paths) respectively, where each channel may have its own constraints. At the receiver, depending on the number of descriptions received correctly, different reconstruction qualities will be obtained. Due to source diversity and path diversity, MDC can adapt to the network conditions much better than single description coding, especially in real-time communications where retransmission may not be viable.