Reconstruction of motion vector missing macroblocks in H.263 encoded video transmission over lossy networks

Errors caused by loss of coded data can seriously affect an H.263 decoded image sequence. Several scenarios may occur that include: (1) loss of macroblocks in I or P frames, and (2) loss of motion vectors of macroblocks in P frames. The missing macroblocks in I and P frames can be reasonably reconstructed by exploiting the correlation between adjacent macroblocks. Existing methods which reconstruct the motion vector of a macroblock rely on existing motion vectors of surrounding macroblocks, and the results are not always satisfactory. A novel reconstruction technique for restoration of macroblocks with missing motion vectors is proposed. This method exploits the image continuity inside and across the borders of the macroblocks. Simulation results indicate that the performance of the proposed algorithm is good, both subjectively and objectively.