Fast encoding method using CU depth for quality scalable HEVC

In this paper, a new fast encoding scheme using CU depth information for quality scalable HEVC was proposed. The proposed scheme based on the correlation between the base layer and enhancement layer, as well as the correlation between current frame and reference frame, which obtained by experiment. The main idea of the algorithm is that when each LCU is encoded in enhancement layer, it´s corresponding encoded LCU´s best coding depth in base layer is used as the new maximum encoding depth in enhancement layer, thereby, it can reduce the unnecessary CU division process then reduce the computational complexity. On the other hand, for base layer, when each LCU encoding in current frame, the corresponding LCU´s depth in already coded reference frame is utilized to skip parts process of mode selection before reach this reference depth, so that the computational complexity can be reduced again. Experimental results show that compared with the original SHM5.1, our proposed method saves about 59.45% and 67.71% encoding time in whole encoding layers and enhancement layer respectively, with a negligible decrease in PSNR of 0.014 dB and bitrate increase of 0.46% in EL, as well as PSNR of 0.05 dB and bitrate increase of 1.15% in BL averagely.