视频压缩码流在信道传输时，由于受到信道带宽或者稳定性的影响，容易发生数据的损坏或者丢失，这样不仅会对当前的视频帧产生影响，而且差错会延续到随后的视频帧，因此，需要采用某种技术来降低差错的影响。针对这一问题，在对最新视频压缩标准 H.2 6 4研究的基础上，基于 H.2 6 4标准的框架，对已有的差错掩盖算法进行了改进，提出了适合 H.2 6 4编码标准的时域子块匹配差错掩盖算法。该算法首先采用 8× 8的子块代替 16× 16的宏块，作为差错掩盖的运算单元，然后对不同的子块采用不同的边界像素，利用边界匹配算法，并通过改进的 1/ 4像素精度菱形搜索法在参考帧内找到最佳匹配块。实验结果证明，由于该算法有效地利用了 H.2 6 4压缩码流里的信息，因此，同传统的时域差错掩盖算法相比，对差错信号有更好的恢复效果。

When compressed video stream is transmitted over internet or wireless network, it is sensitive to packet loss and error occurrence due to the limited bandwidth and the instability of the channel, especially for motion compensation-based video coding standard. An error in one frame not only debases the reconstructed quality of the current frame, but propagates to the succeeding frames which use current frame as their reference frame. As a result, error concealment algorithms are developed for hiding erroneous blocks by exploiting high correlation in video sequence. In this paper, a new temporal error concealment algorithm which suits for H.264, the latest international video coding standard, is proposed. In this algorithm, an erroneous macroblock is firstly divided into four 8×8 blocks, which work as the concealment unit instead of the macroblock. Then, a modified boundary matching algorithm is exploited to recover the lost motion vectors with different boundary pixels for different blocks. Finally, the best-matched blocks are obtained using one-quarter pixel diamond search method. Experimental results show that the proposed algorithm makes use of the information in H.264-compressed bit stream efficiently, and has a better reconstruction quality for erroneous blocks than conventional temporal error concealment algorithms.