Temporal error concealment based on optical flow in the H.264/AVC standard

The H.264/AVC standard uses new coding tools to improve coding efficiency. Among the tools, motion estimation using smaller block sizes leads to higher correlation between the motion vectors of neighboring blocks. This characteristic of H.264/AVC is useful for motion vector recovery to conceal a lost macroblock. In this paper, we propose a motion vector recovery method based on optical flow in H.264/AVC video coding. We first determine the optical flow region to alleviate the complexity, and choose an initial value of flow velocity using neighboring motion vectors of a lost macroblock. The proposed method recovers the motion vectors of 4x4 blocks included in a lost macroblock using the weighted average of obtained flow velocities. Simulation results show that our proposed method gives higher objective and subjective visual qualities than conventional approaches.