The fast intra CU size decision algorithm using gray value range in HEVC

High Efficiency Video Coding (HEVC) has its very advantages than the former video coding standard. Different from the previous standard, HEVC adopts hierarchical and flexible Coding Unit size decision, which is suitable for high resolution video coding, but it leads to high computational complexity. In order to reduce the complexity, this paper proposes a fast intra CU size decision algorithm using gray value range checking. Since gray value range checking simplifies rate-distortion optimization of the original HEVC encoder, our proposed algorithm can reduce coding time effectively without obvious loss of rate-distortion performance. Experimental results illustrate that the proposed intra CU size algorithm can reduce 35.8% computational complexity as well as make 0.10 dB decrease in PSNR and 2.33% increase in bitrate.