用软件实现在低码率信道上的实时视频编解码是图象压缩领域的研究热点，本文就此提出了一种基于离散余弦变换（DCT）系数的频域块匹配法，通过引入阈值矩阵，降低了运动估值的运算量，提高了搜索效率。计算机仿真表明，该算法可在PC机上用软件实时实现，具有较好的实用价值。

To realize the real time video coding in low bit rate communication by PC software is the hotspot in image compression field, thus a frequency domain block matching algorithm based on discrete cosine transform(DCT) coefficients is proposed in this paper. By utilizing threshold matrix, the motion estimation computation is greatly reduced and the time used in searching motion vectors is saved. The DCT based frequency domain block matching algorithm can encode and decode motion pictures quickly and efficiently. Its reconstructed picture quality is higher than the 3SS algorithm and is closer to the FS algorithm. Simulation results show that the proposed DCT based block matching algorithm and the video coding scheme has high performance and is easy for implementation. Because of its low computing complexity, it can be real time realized by PC software and has a good value in practice.