Subjective quality assessment comparing UHD and HD resolution in HEVC transmission chains
Résumé
Ultra High Definition Television (UHDTV) is an emerging broadcasting system, aiming to replace the current High Def- inition Television (HDTV) in the near future. One aspect of UHDTV is to allow for higher resolutions, notably UHD1, which requires a four times increased datarate for uncom- pressed transmission compared to Full-HD resolution. As bandwidth for transmission channels in television broadcast is often a fixed value, this study provides information about the perceived quality for transmitting UHD1 content compared to Full-HD content at the same bitrate encoded with HEVC. Content influence is tested with 15 video contents and 4 bi- trates are individually chosen per content to span the range of the perceptual scale. The methodology of Absolute Category Rating with Hidden Reference (ACR-HR) is used to collect votes from 24 viewers. The statistical analysis of the collected data shows that, in most cases, there is no significant quality difference between videos transmitted in Full-HD and UHD1 resolution but that the results strongly depend on the content type and on the capture quality. It is also shown that the re- quired bitrate for achieving a chosen broadcast quality level varies with content by a factor of about 14 in HEVC coding.