A scalable extension design is proposed for High Efficiency Video Coding (HEVC), which can provide temporal, spatial,
and quality scalability. This technique achieves high coding efficiency and error resilience, but increases the
computational complexity. To reduce the complexity of the quality scalable video coding, this paper proposes a fast
mode selection method based on mode distribution of coding units(CUs). Some experiments are tested which show that
the proposed algorithm can achieve up to 63.70% decrease in encoding time with a negligible loss of video quality.