Andrew A. Catellier and Margaret H. Pinson

Abstract: 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).

Keywords: subjective testing; H.264; MPEG-2; PSNR; VQM; compression; video coding; AVC; HEVC; H.265

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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