The European TV standards-setting body the DVB Project has brought TV broadcasters a step closer to receiving a UHDTV technical specification, to potentially become available during 2017.
Requirements for a ‘UHD-1 Phase 2’ delivery format were approved this week, at a meeting of the DVB Steering Board in Geneva. This is all about phasing in UHD in three or four or five steps. The first being 4K including 60 frames per second, the next likely to be High Dynamic Range (HDR) and then a wider color gamut (WCG). DVB has said that HDR is likely to be one of the first features included in the newly approved UHD-1 Phase 2.
Following the board’s approval, DVB expects it will take a further 12 months to translate these into agreed technical specifications for UHD-1 Phase 2.
The path to UHDTV was set in the International Telecommunication Union (ITU) in 2012 with a potential list of new features for future television. DVB UHD-1 Phase 1 was the first system developed in 2014, delivering a 2160p resolution at 60fps – four times that of HDTV.
The next challenge for DVB is to convert the requirements into a specification for submission to the European Telecommunications Standards Institute (ETSI) for standardization. It is expected that the specification will be finalized in 2016. We should expect the first DVB UHD-1 Phase 2 services including HDR, to become available from 2017 onwards.
As well as HDR, the standards body also mentions phasing in a higher frame rate (HFR) into the specification, which is the capability to provide images with sharper moving objects. The development of consumer equipment capable of supporting HFR is expected to take several years longer than other features. There are TVs out there that support 60 frames a second and some that refresh at 240 times a second (240 Hz), but this does not translate to being able to handle 60 frames of 4K HDR.
At DVB’s press conference at IBC this year, Chairman Philip Laven said that High Efficiency Video Coding (HEVC) was coming to the aid of broadcasters, we noted that perhaps he has not seen the HEVC Advance Royalties. We were also told to expect DVB’s ‘Defining the Long Term Vision for Terrestrial Broadcast’ report by the end of 2015.
As we await the release of The ‘Long Term Vision’, it’s uncertain if DVB’s Phase 1 4K stream, that uses 2160 x 3840 pixels at up to 60fps, is able to cope with data transfer speeds of 108/128 Mbps posed by the full UHD of Blu-ray.
The now-confirmed technical capabilities of Blu-ray are hard to argue with. Its speed is almost ten times greater than the 15.6 Mbps the HEVC/h.265 compression tech which allows Netflix to deliver a 4K episode of House of Cards.
Before this week’s announcement, the IBC press conference revealed that DVB members developing the next phase of its UHD specification were split over the deadline for introducing features such as HDR, HFR and WCG. David Wood, chair of the DVB’s commercial module for UHD TV, said at IBC that some members wanted the specification fixed now so services can start from 2017, while others want to wait until 2019 to see what the decoder chip development cycle delivers.
We said after IBC that there have to be at least 3 or 4 major technological breakthroughs before the phased approach to UHD could happen, and Laven eventually conceded that the internet and IPTV would be important for delivering UHDTV, and that leads to access speed issues.
“This is a major achievement for DVB and the television industry,” said Laven. “We now have a plan for the evolution of television into the age of Ultra High Definition Television. It’s an exciting future that will bring a new quality of experience to television.”
The Society of Motion Picture and Television Engineers (SMPTE) recently issued the recommendations of its HDR Imaging Ecosystem technical committee (10E SG). The SMPTE noted that the WCG that will be used alongside HDR mean that implementers of both technologies should be aware of the impact that will arise from video with HFR. It notes that with 4K and 8K resolutions, new workflow infrastructure will be required. HDR and WCG can be accommodated on the existing 1.5Gbps and 3Gbps multilink interfaces, or 10Gbps optical links, but not at 4K or 8K resolutions.
DVB has been evaluating whether HEVC needs to be modified to support HDR, as has the Motion Picture Experts Group (MPEG) Committee, and the ITU with its Rapporteur Group (RG24) looking at HDR recommendations for broadcast TV. Over in Japan, NHK has announced a time table for the delivery of HDR and WCG content in homes. The Blu-ray Disc Association has already included three versions of HDR in its UHD Blu-ray standard, supporting Dolby, Technicolor, and the SMPTE.
Separately, Matthew Goldman, SVP for TV compression at Ericsson, has referred to a combination of HDR, WCG, and 10-bit sample depth, in what he calls ‘HDR+’ – to gain 2160p/4K on an HDTV set would require quadrupling the pixels, and halving viewing distance. “The amazing thing about HDR+ is, it’s not impacted by viewing distance. It probably is going to turn out to be the most significant change in the television viewing experience since going from black-and-white to color,” said Goldman.
MPEG and the Video Coding Experts Group (VCEG) are reportedly working together on a project to more efficiently encode HDR+, hoping to finalize around October 2016. That would mean that the first UHD-1 Phase 2 services containing HDR+ could be launched “in the 2017, 2018 timeframe,” Goldman estimates.
HDR essentially effects levels of brightness, allowing for whiter whites and deeper blacks. One of the chief benefits of this is during broadcasting sports events, when on a bright day, the sunlit area of the pitch becomes washed out and unwatchable on the screen – HDR allows detail and contrast as the human eye would experience it.
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