Abstract: Video communication is one of the main applications in multimedia communication, and plays an essential part in people??s daily communication. However, the information which video carries is very huge. It is inevitable to compress the video before transmission. The compressed bitstream will be sensitive to channel impairment. Therefore, video data face inevitable errors during transmission. Error concealment technology serves an important role as the last line of defense in resisting the transmission errors. A spatio-temporal adaptive error concealment algorithm based on the block division is put forward in view of existing algorithm insufficiency. The match criterion of the proposed algorithm combines structural similarity index with boundary matching algorithm. The experiment shows that the proposed algorithm can further improve the objective quality of the decoded video sequence, and the video subjective quality can match to subjective feeling of human vision well. After weighing the performance of   error concealment and the time complexity, the proposed algorithm greatly outperforms other conventional algorithms.

Key words: video communication, error concealment, adaptive error concealment, boundary matching, structural similarity index (SSIM)

摘要： 视频通信是多媒体通信的主要应用方向之一，它在人们信息交流中起着重要的作用,但是视频信息携带的信息量非常大，在传输之前必须要对视频信号进行压缩编码以降低码率，压缩后的码流对传输差错十分敏感，使得视频信息传输过程中面临不可避免的差错和损失。差错掩盖技术作为视频通信系统中抵抗差错的最后一道防线，起着不可或缺的重要作用。针对现有差错掩盖算法的不足，提出了将结构相似性（structural similarity index，SSIM）失真评价准则和边界匹配准则相结合寻找最佳替代块的匹配准则，并在此基础上，提出了一种基于宏块划分的空时域自适应差错掩盖算法。实验表明，利用该算法进行差错掩盖后的视频序列不仅具有更高的客观质量，而且掩盖后的视频视觉质量也更符合人眼的主观感受。对各算法的平均解码帧率的调查结果显示，在权衡掩盖效果和时间复杂度后，该算法优于其他对比算法。

关键词: 视频通信, 差错掩盖, 自适应差错掩盖, 边界匹配, 结构相似性