关键词: 分级B帧, 量化步长, 编码

Abstract: This paper proposes a hierarchical quantization technique based on hierarchical B pictures coding.By efficiently exploiting the motion information within the B pictures in the same Gop and allocating different quantization steps between B pictures of different ranks according to hierarchical order，this paper achieves the goal of coding optimization.Simulated results show that the proposed technique saves the coding bitrates better than the traditional technique in the same quality of reconstructed pictures.

Key words: hierarchical B pictures, quantization step, coding