Compressed bitstreams are, in general, very sensitive to channel errors. For instance, a single bit error in a coded video bitstream may cause severe degradation on picture quality. When bit errors occur during transmission and cannot be corrected by an error correction scheme, error concealment is needed to conceal the corrupted image at the receiver. Error concealment algorithms attempt to repair damaged portions of the picture by exploiting both the spatial and the temporal redundancies in the received and reconstructed video signal. In this paper, we discuss several temporal, spatial, and transform-domain error concealment techniques for MPEG coded pictures, and propose a new scheme based on directional interpolation. We also compare the performances of these techniques by computer simulation.
