方块效应是基于块的混合视频编码算法产生的重要特征失真，严重影响了压缩后视频的主观质量。分析产生方块效应的根本原因，在此基础上提出一种有效降低方块效应的DCT系数量化方法。该方法通过调整量化过程，减小量化误差在块边界处的变化，增强相邻块间量化误差的相关性，从而降低了压缩后视频的方块效应。实验结果表明该方法能够有效降低方块效应，改善视频帧的主观质量。另外，该算法计算复杂度较低，并且与视频压缩标准兼容，具有实用性。

Blocking artifacts are serious artifacts caused by block-based hybrid video coding, and significantly impair the subjective quality of the compressed video. In this paper, the fundamental reasons of blocking artifacts are explored, based on which an effective quantization method for DCT coefficients for reducing blocking artifacts is proposed. The proposed method adjusts the quantization process to reduce the variation of the quantization error at block edges, which increases the correlation of the quantization error of adjacent blocks and therefore reduces the blocking artifacts of the compressed video. Experimental results have demonstrated the effectiveness of the proposed method in reducing blocking artifacts and improving the subjective quality of video frames. Furthermore, the proposed method is practical in implementation since it has a low computational complexity and is compatible with video coding standards.