Adaptive intra update for video coding over noisy channels

An algorithm for increasing error robustness in an H.263 video coding system in the absence of a feedback channel is proposed. For each 16/spl times/16 macroblock, the encoder accumulates a metric representing the vulnerability to channel errors. As each new frame is encoded, the accumulated metric for each block is examined, and those blocks deemed to have an unacceptably high metric are sent using intra as opposed to inter coding. This approach is fully compatible with H.263 and involves a negligible increase in encoder complexity and no change in the decoder complexity. Simulations performed using an H.263 bitstream corrupted by channel errors demonstrate a significant improvement over non-adaptive intra update strategies.