The invention is related to methods and apparatus that encode redundant
motion vectors for predictive-coded visual object planes (P-VOPs) to
increase the robustness of transmitted video signals. One embodiment
provides the redundant motion vectors in a user data video packet of an
MPEG-4 compliant bitstream, which thereby allows the enhanced bitstream
to remain compliant with MPEG-4 syntax and backwards compatible with
MPEG-4 decoders. The enhanced bitstreams allow a video decoder to display
a video with a better picture and relatively less error and error
propagation when portions of the bitstream are disturbed or corrupted by
interference, delays, and the like.