Backward tracking of B-pictures bidirectional motion for interframe concealment of anchor pictures

A novel interframe error concealment technique is proposed for video packet losses in IP environments. The proposed technique benefits from the bidirectional motion parameters of bidirectionally predicted pictures `B-pictures´ to conceal large portions (up to 100%) of corrupted anchor pictures. The lost anchor picture is interframe concealed by backward tracking its motion to its anchor picture through the intermediate bidirectional motion of B-pictures. Furthermore, we show that by constraining the motion compensation of the B-pictures to strengthen the tie between their bidirectional motion and that of the future anchor pictures, better concealment of the latter is achieved. The paper then elaborates on the impact of the proposed constrained-encoding in terms of encoding efficiency and concealment quality