‘The best bang for the bits’
With Freeview HD lacking the bandwidth to support 4K broadcasts, many believe that HDR+ could provide a very acceptable stopgap. Barry Fox reports
What would dealers most like for Christmas? Live 4K UHD broadcasts on Freeview to sell 4K UHD sets would do nicely.
Unfortunately, Santa isn’t bringing that. There is not enough Freeview airspace to accommodate 4K broadcasts as well as current 1080p HD and bog-standard SD.
But there is a stopgap that is technically doable and will be just as eye-catching in-store.
It’s called HDR+, and it became the hot topic at the recent SES Ultra HD conference in London. According to Matthew Goldman (pictured), senior vice-president for technology at Ericsson (which makes high-quality broadcasting equipment), HDR+ is an easy way to kick-start UHD broadcasting, sell more 4K sets and give the millions of people some live 4K TV to watch.
HDR+ could be up and running by the end of 2016/17, argues Mr Goldman, and it’s the best way to make images ‘pop’ and get ‘‘the best bang for the bit”.
Neema Shah Khan, senior brand and partnerships manager at Freeview, adds: “Any feature that can enhance the viewing experience is welcome. Further testing, collaboration and agreement from broadcasters and manufacturers are still needed. In the context of Freeview Play, we are currently working to introduce optional support for IP-delivered 4K and 1080 HDR content within the technical specification for 2017 devices.”
What is HDR+? It’s a catchy phrase Mr Goldman coined to describe a three-part approach.
Programmes will be broadcast in 1080p – as currently done on the Freeview HD – but with added Wide Colour Gamut (“to display the green of grass and red of brake lights”) and 10-bit High Dynamic Range (brighter whites and more shadow detail). The upscaling already built into virtually all UHD sets then puts 4K pictures on the 4K screen.
“We need to get on air with UHD now,” says Mr Goldman. “If you can do it all, with no bandwidth constraints, then do it, and broadcast 4K. But if you can’t, focus on your best bang for the bits available. Whereas 4K broadcasts need 250 per cent more bandwidth, HDR+ adds between zero and 20 per cent. Broadcast HDR+ and anyone with an HDR 4K set will see a big difference. Upscaling in the set to 4K 2160p will give something much better than you can offer now. Ericsson’s consumer tests reveal that if you show people 2160p with SDR and 1080p with HDR, they prefer 1080p. Which is better? Go on waiting for bandwidth or live with some slight compromises?”
But he warns: “1080p should be viewed from a distance of three picture heights, but 4K should be viewed from 1.5 picture heights. If you are not close enough, you might as well watch HD.”
One obvious question is which of the several competing HDR systems should be used for HDR+. It could be proprietary Technicolor/Philips, proprietary Dolby Vision or the open HDR10 system already used in UHD Blu-ray players and HDR TV sets, or the HLG (Hybrid Log Gamma) system developed by the BBC and NHK.
Ironically, the biggest bar to using HDR+ to kick-start UHD broadcasting is not technical. It’s the industry’s all-too-familiar failure to agree a common language for coordinated promotion. Different manufacturers are using different words for various similar, but not identical, 4K/UHD features.
A feature called HDR+ can already be found in the picture menu for some new Samsung TVs.
“HDR+ will be on all 2016 SUHD and UHD TV models and is currently going through a rollout process,” says a Samsung spokesman.
But Mr Goldman warns: “Samsung appears to use the term HDR+ for its proprietary method of stretching SDR to simulate an ‘HDR-like’ experience.”
Panasonic sets upscale, but the company says it is not yet offering an HDR+ setting.
At Philips/TP Vision, director for product strategy and planning, Danny Tack, says: “HDR+ looks to me like 4K upscaling or what we call Ultra Resolution.”
A spokesman for LG adds: “Our understanding is that HDR+ is a term being used to represent High Dynamic Range) plus Wide Colour Gamut, plus 10-bit sampling – which LG delivers. LG is committed to offering superior HDR images to customers and already supports many forms of HDR, including HDR10 and Dolby Vision.”
The good news, Mr Goldman sums up, is that there should be a standards lock-down soon. The bad news? Standards will not select one HDR solution.
The missing link is agreement on a name and agreed usage on UHD TVs, STBs and broadcasts. Without agreement, there will be customer confusion and a golden opportunity will be lost.