Abstract: This paper firstly analyzes the theory of computing BS in the deblocking filter system.And because the most computational resource consumed is the determination of BS，proposes an optimized pre-judging BS algorithm to reduce the computational complexity.The computer simulation results indicate that the proposed algorithm can decrease approximately 75% computing time compares to the JM filter algorithm，and the PSNR is the same to JM.The reduction of the computational complexity and the great efficiency of decoder are good for the real time application of H.264 decoder.

Key words: H.264/AVC, deblocking filter, block strength, pre-judging

摘要： 首先介绍了H.264去块滤波的滤波强度计算原理，并基于滤波强度的计算量为去块滤波过程中最大的部分，提出了一种滤波强度提前预判的优化算法。通过仿真实验证明该算法在对解码图像质量没有任何影响的情况下较标准算法降低了75％左右的滤波运算时间，有效地缓解了H.264解码运算复杂度，提高整体解码时间，以有助于实时应用的实现。

关键词: H.264/AVC, 去块滤波, 滤波强度, 预判