ATSC 3.0 HDR Progress Report
By MADELEINE NOLAND, LG Electronics
Chair, S34, ATSC Specialist Group on Applications & Presentation
Since the A/341 Video–HEVC standard (including high dynamic range or HDR) was approved in May, the ATSC has been considering additional technologies related to HDR and wide color gamut (WCG).
A number of technologies have been developed for HDR/WCG imagery that use metadata designed to optimize the viewing experience across the wide range of devices available today. A/341 currently includes so-called “static metadata” – one set of metadata that applies to an entire program. This static metadata technology is often referred to as “HDR10” metadata.
The ATSC is currently considering additional technologies with so-called “dynamic metadata,” which specify metadata that can change continuously – frame by frame, rather than one set of metadata for the whole program, for instance. Dynamic metadata is designed to enable more “intelligent” HDR optimization based on the characteristics of each scene or frame.
In addition to metadata technologies, the ATSC is considering enabling “full range coding” for HDR/WCG content. This is designed to enable a slightly smoother transition from the darkest to the brightest pixels.
Also being considered is an alternate color representation, giving broadcasters a choice between non-constant luminance (Y’C’BC’R) and constant intensity (ICTCP). The constant intensity color representation is designed to enable computations to be performed with minimal error, such as color volume transforms.
Some of these technologies already have reached Candidate Standard status and, if and when approved, they will be incorporated as amendments to A/341. The goal of the Candidate Standard phase is to acquire experience with the technology; both ATSC members and non-members alike are invited to work with the technology implementations and provide feedback to the ATSC.
The continuing work on HDR is a good example of how ATSC standards can evolve with amendments that continue to improve flexibility and performance and further enhance the user experience.
In addition to her role in shepherding HDR work as S34 Chair, Noland chairs the S33-3 Ad Hoc Group on System Requirements. She also serves as vice chair of the S31 Specialist Group on System requirements and the Advanced Emergency Alerting Implementation Team.