Optimal multiple description subband coding
Multiple description coding refers to encoding an information source into multiple bitstreams, in a way that various levels of tradeoff between decoding quality and channel protection can be supported. This paper addresses the design of two-channel orthonormal filter banks to optimize the redundancy rate-distortion performance of multiple description subband coding. The problem is formulated in a Lagrangian optimization framework, and is solved directly in the frequency domain to produce the optimal filter responses. By varying the Lagrangian parameter, our design obtains all points on the information redundancy rate-distortion curve for Gaussian wide sense stationary input processes. Application of the proposed algorithm to the popular AR(1) model yields very interesting and insightful results. Comparisons with popularly deployed filter banks reveal large gaps from the theoretical performance bound.