Abstract: This article studies the compressed domain motion compensation technology in video transcoding, complements and perfects existing algorithm, solves the problem in existing algorithm: can’t handle negative motion vectors, and gives out detailed algorithms and some necessary analysis from the realization point of view. The result of the experiment shows that MPEG-2 TM5 decoder reconstructed based on the algorithms and analysis this article gives out can realize compressed domain motion compensation and spatial definition downscaling correctly.

Key words: Transcoding, Compressed domain, Motion compensation, Spatial definition

摘要： 研究视频转换编码中的压缩域运动补偿技术，对已有算法加以补充和完善，解决了现有算法不能处理运动矢量为负的问题。从具体实现角度，给出了详细的算法和必要的分析。实验结果表明基于该文所述的算法和分析改造的MPEG-2 TM5解码程序可以正确地实现压缩域运动补偿和空间分辨率下变换。

关键词: 转换编码, 压缩域, 运动补偿, 空间分辨率