While the UHD story from IBC 2017 was how High Dynamic Range (HDR) had re-emerged as the 4K format’s battleground, this year in Amsterdam it appeared that peace had broken out – at least as regards the distribution standard. Ian Nock, Chairman of the Interoperability Working Group of the 4K industry body, the UHD Forum, said: “We have fine-tuned the message because we realised people weren’t getting it. There are only two distribution HDR formats: there is HLG and there’s PQ – that is it.”
HDR is the technology that brings extra ‘sparkle’ to UHD TV pictures, both through higher contrast and its associated wider colour gamut. It has been viewed for some time as having the same importance as 4K resolution, if not more, to future consumer adoption of UHD TV. The principal difference between the two HDR standards is that HLG, created by the BBC in collaboration with Japanese broadcaster NHK, is backwards-compatible with Standard Dynamic Range (SDR) sets, while PQ, developed by Dolby, is not.
But what about Dolby Vision – isn’t that a separate HDR standard? “In the way that it is deployed for distribution, it actually isn’t,” argues Nock. “It’s PQ with a dynamic metadata format that happens to be known as Dolby Vision on top. It’s the same when you talk about HDR 10+. It is a dynamic metadata system, not an HDR system.”
More on ‘dynamic metadata’ later. The point is, says, Nock, that “if you’ve got a television that is an HDR TV produced since the beginning of 2016, it supports both PQ and HLG. So it is not an issue to have those two formats, especially when all the TVs and set-top boxes support them.”
Nock concedes that there is some variation country-by-country, since connection rates for Smart TVs determine whether the necessary upgrades to TV sets have occurred. But in the UK, the figure is around 93%, because of the popularity of the BBC’s iPlayer platform. “There are very few people who have not upgraded their television [there],” he claims.
With the HDR distribution battle seemingly over, the contest has now migrated to which ‘dynamic’ variant of HDR the market should settle on. HLG and PQ are both ‘static’ HDR systems: the dynamic range ‘setting’ remains constant throughout the film or video being shown. On the other hand, ‘dynamic’ systems, such as Dolby Vision and HDR 10+ systems, support metadata that changes scene-by-scene.
Speaking at a Technicolor round-table at IBC, Frédéric Guillanneuf, Head of HDR Business Development at Royal Philips Electronics, argued that “more and more, you see the need for an excellent experience in the homes and this high-quality HDR is going to be [supplied] by Dynamic HDR. This is important because it captures the real artistic intent or the artistic beauty of a certain type of content and allows it to be broadcast on all of the sets that are out there.”
One of the concepts behind Dynamic HDR is that in addition to adjusting dynamic range to changing content, it also configures the experience to the type of TV set that content is being shown on (for instance, a low-end TV set unable to cope with an extended range of bright or dark tones), in an attempt to create the optimal ‘match’ between the quality of the original and the actual viewer experience.
Guillanneuf noted that Philips is currently partnering with Technicolor in the development of its Dynamic HDR technology – dubbed ‘Advanced HDR by Technicolor’. He predicted that although “the current level of HDR that we see coming on the market is Static HDR, I think that after that you will start seeing Dynamic HDR succeeding.”
Speaking at the same round-table, Gaetan Delcroix, Vice President, Video Product Unit at Technicolor, noted that LG was already selling TV sets that used its Dynamic HDR system, and that Franco-German public broadcaster Arte was broadcasting UHD content over SES’s satellite platform that featured it. The Philips/Technicolor standard has also been included in the US ATSC 3.0 standard, he pointed out.
Delcroix predicted that by the end of this year, Technicolor would be able to announce “at least three” new manufacturers, in addition to LG, that had opted to use its Dynamic HDR standard.