Characterization of the HEVC Coding Efficiency Advance Using 20 Scenes, ITU-T Rec. P.913 Compliant Subjective Methods, VQM, and PSNR

The new video coding standard, MPEG-H Part 2 High Efficiency Video Coding (HEVC) or H.265, was developed to be roughly twice as efficient as H.264/AVC -- meaning H.265/HEVC could deliver the same quality as H.264/AVC using roughly half the bitrate. In this paper we describe a subjective experiment designed to test this claim. We present an experiment using 20 different 1080p 29.97 fps scenes and 12 impairment levels spanning MPEG-2, H.264/AVC and H.265/HEVC. Additionally we compare the results obtained from the subjective assessment to quality estimates from two objective metrics: VQM and PSNR. Our subjective results show that H.265/HEVC can deliver the same quality at half the bitrate compared to H.264/AVC and can perform better at one quarter the bitrate compared to MPEG-2 in many, but not all, situations. For all 20 scenes coded with H.265/HEVC at 4 Mbps mean opinion scores span 38% of the subjective scale, which indicates the importance of scene selection. Objective quality estimations of HEVC have a low correlation with subjective results (0.60 for VQM, 0.64 for PSNR).