Temporal error concealment with block boundary smoothing

When a block is lost due to a transmission error in compressed bitstream, conventional temporal error concealment schemes try to conceal the lost block by recovering its motion vector based on some matching criteria. Since essential information for deblocking process and residual data are lost, discontinuity occurs at block boundary, and this discontinuity greatly degrades subjective quality of reconstructed video. To enhance the subjective video quality caused by the discontinuity, we propose a new temporal error concealment (TEC) technique capable of block boundary smoothing. In the proposed scheme, the extended boundary pixels in reference frame are overlapped with the lost block boundary with some weighting factor. For effective error concealment, the flexible macroblock ordering (FMO) technique in H.264 standard is used. The experimental results show that the proposed method provides enhanced subjective quality especially in homogeneous region.