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Historically, multiple description coding (MDC) and postprocessing error concealment (ECN) algorithms have evolved separately. In this paper, we propose a coordinated application of multiple description scalar quantizers (MDSQ) and ECN, where the smoothness of the video signal helps to compensate for the loss of descriptions. In particular, we perform a reconstruction that is consistent with the data received at the decoder. When only a single description is available, the video is reconstructed in such a way that: 1) if we were to regenerate two descriptions (from the reconstructed video), one of them would be equivalent to the received description and 2) the reconstructed video is spatiotemporally smooth. Experimental results with several video sequences demonstrated a peak signal-to-noise ratio (PSNR) improvement of 0.9-2.8 dB for intracoded frames. The PSNR improvements for intercoded frames were negligible. However, for both cases, the visual improvements were much more striking than what the PSNR improvement suggested. Index Terms--Error concealment (ECN), error resilient video, MPEG, multiple description coding (MDC), multiple description scalar quantizers (MDSQ), postprocessing, video streaming.

Multiple description coding (MDC) is a source coding technique that exploits path diversity to increase the robustness of transmitting a compressed signal over error-prone channels. However, the application of MDC to video coding is still problematic because a prediction mismatch problem, called drift, may occur at the decoder when one description is lost. In the literature, it has been shown that drift can be effectively prevented by encoding this prediction mismatch and sending it as side information in a three-prediction-loop structure. However, this side information is totally redundant when both descriptions are received. In this paper, we propose a very simple, but efficient two-stage MDC in the central prediction loop based on Reibman's three-prediction-loop structure. In our design, an additional multiple description scalar quantizer is introduced into the central prediction loop. The encoding of the side information is modified in such a way that it can be used to improve the video quality when no drift occurs, but still maintain drift prevention capability. The simulation results with different video sequences at various packet loss rates demonstrate that the proposed two-stage MDC structure indeed enhances the quality when the channel is error-free, yet effectively avoids drift when one description is completely lost. Index Terms--Drift problem, error-resilient video coding, motion-compensated multiple description prediction, multiple description coding (MDC), multiple description scalar quantization (MDSQ), video streaming.

An innovative multiframe recovery principle is proposed that analyzes the error propagation of the lost macroblock (MB) and minimizes the propagation of the error across multiple frames.