Error resilient multiple description coding based on wavelet tree coding and EREC for wireless networks

In this paper, we propose an integrated error resilient MDC scheme for wireless networks with both packet loss and random bit errors. Two descriptions are first generated independently by using index assignment MDSQ. For each description, multiple bitstreams are then generated based on wavelet trees along the spatial orientations. The spatial-orientation trees in the wavelet domain are individually encoded using SPIHT. Error propagation is thus limited within each bitstreams. However, synchronization words are usually needed to avoid error propagation across multiple independent bitstreams. In order to maintain high compression efficiency robust synchronization, we adopt EREC to re-organize these variable-length bitstreams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bitstream can be automatically obtained at the receiver. Finally, to alleviate the devastating image degradation resulted from errors in the beginning of the bitstreams, we propose an error concealment technique to both constrain the EREC/MDC decoding and post-process the decoded wavelet coefficients.