In the previous work [3] we presented a SATD-based intra mode decision algorithm for H.264/AVC to reduce the computational complexity, based upon SATD coefficients. In this paper, we extend the previous work and propose an improved SATD-based intra mode decision, which uses low-frequency components to provide local characteristics for intra mode selection. The experimental results reveal that our proposed algorithm can achieve significant reduction of computation time compared to the reference program, while still maintaining good coding performance. The proposed algorithm is also compared with two distinct algorithms and the results indicate that the proposed algorithm brings out higher reduction in computation that these two algorithms.