HDR for Full HD
(Paper available in the Proceedings of the 2020 BEIT Conference)
Although 4K/UHD, High Dynamic Range (HDR) and Wide Color Gamut (WCG) are usually mentioned together, HDR/WCG is not limited to 4K/UHD. Full HD (1080p60) can also benefit from a dramatic improvement in picture quality with HDR and WCG. The average worldwide viewing distance of 9 feet is too far away to see the optimum 4K/UHD resolution on a typical 65” TV. A properly set-up HD image with HDR will look better than a 4K/UHD image with Standard Dynamic Range (SDR). Upconversion by consumer UHD TVs will provide nearly the same visual experience, but consumes about ¼ of delivery and storage requirements of 4K/UHD.
One enduring misconception about HDR is it produces brighter pictures. In fact, the Average Picture Level (APL) will not change. Only peak highlights will be brighter. In addition to recovering detail from dark shadows or bright areas, HDR offers a more realistic picture, like the way the Human Visual System sees things in real life. Another misconception is that HDR is incompatible with existing Standard Dynamic Range (SDR) TVs. Modern flat-panel SDR displays are capable of higher luminance, contrast ratio and wider color gamut than is standardized in today’s program production. Hybrid Log Gamma (HLG) can produce better pictures on these SDR TV displays even without HDR processing. However, for SMPTE ST-2084/PQ and Dolby Vision, the latest UHD HDR TVs are required.
Producing and delivering both SDR and HDR signals is the next big challenge. Acquisition and production systems will need to handle SDR and HDR signals for compatible mixing of content. This presentation deals with both the technology and workflow related to HDR. Newly developed techniques will allow video engineers to shade HDR cameras while using standard SDR monitoring. This is accomplished using an inverse HDR gamma and remapping gamma for SDR. With this process, cameras can output both HDR and SDR feeds in UHD and HD. Conversion of other SDR signals to HDR may be required in the short term. Program production may require UHD, HD, SDR, and HDR versions for wide distribution.
Many US mobile companies and sports networks are moving toward adopting Full HD with HDR for both archive and OTT delivery. For broadcast, ATSC 3.0 can use the HDR SL-1 standard to deliver all HDR profiles in a compatible transmission system for delivery of HD and UHD in SDR and HDR.
Due to the different requirements for live sports and post-produced programs, it is highly likely that multiple HDR profiles will be used in the future.
This session will be rebroadcast on the BEIT Express channel on May 14, 2020 at 2:30 and 10:30 a.m. EDT (UTC -4).