MULTIPLE DESCRIPTION VIDEO DECODING USING MAP

The problem of efficient video transmission over noisy channels involves good compression rates and robustness in presence of channel failures. The proposed framework of joint source-channel (JSC) coding is a balanced multiple description coding (MDC) scheme for scan-based wavelet transform video coding. This MDC scheme includes an efficient bit allocation procedure that dispatches the source video redundancy between the different descriptions, depending of the characteristics of the channel. The paper focuses on the joint decoding of two descriptions received at decoder and corrupted by noise. The challenge is to reconstruct a 'central' signal with central distortion as small as possible using the knowledge of the two descriptions. We propose in this paper a maximum a posteriori (MAP) algorithm for the decoding, using the knowledge of the probability density function (pdf) of the different subband descriptions. Promising experimental results are presented.