Cable Satellite International
Back in 2012 when the ITU-R enshrined UHD in two phases, 4K UHD was already seen as a stepping stone to 8K. UHD-2 was considered so far away that little other than resolution was considered in the specification. While the industry is some way from deploying 4K heads are turning towards what’s next. For some this is an unwelcome distraction from the practicalities of 4K transition, with possible risk of consumer confusion, others view it as the natural progression of an industry which has technological advance written in its DNA.
“It’s not unusual for a new technology to emerge and move forward while an earlier one is still being rolled out,” asserts Peter Siebert, DVB Head of Technology. “In this case, it’s relevant to note that 8K TV sets are not necessarily threats to 4K production and delivery, as they could bring improvements in image quality for lower resolution content through upscaling.”
“There will always be technology Luddites,” says Ben Schwarz, speaking as an independent expert, founder CTOi Consulting and communications chair of the Ultra HD Forum. “A devil's advocate would say that 4K is a distraction from HD deployment.”
For William Cooper, founder of consultancy Informitv, 8K represents a natural evolution of video resolution. “HD is now mainstream, 4K is already a reality and 8K is now a possibility,” he says. “Although there may be diminishing returns with each increase in resolution, if the objective is a representation of the highest fidelity, then 8K or beyond may be technologically inevitable.”
He points out that there are many dimensions to improving the fidelity of video reproduction. “Spatial resolution is one, the precision of each pixel is another, and temporal sampling is a further dimension,” he says. “Traditional television technology is compromised in all these dimensions, with plenty of room for improvement.”
The entire industry is now working to deploy 4K with HDR and NGA (Next Gen Audio), as a result of efforts that have cumulated over the last five years.
The Ultra HD Forum, at pains to put 8K on the back burner, recommends that the industry focuses on these added value services such as HDR with dynamic mapping, NGA and HFR for sports.
“The industry has yet to explore the right combination of resolutions, taking into account HDR, HFR and NGA,” notes Thierry Fautier, VP of Video Strategy at Harmonic and president of the Ultra HD Forum.
Rian Bester, who runs 4K channel Insight TV, agrees, “If you show a consumer 4K verses HD the difference is not that apparent but if you show them HDR verses non HDR or HFR verses non HFR - especially in fast moving content like sport - the difference is very apparent and there is no doubt as to the benefit. Those two aspects are far more valuable than going from 4K to 8K for current screen sizes.”
While no-one is suggesting 8K holds any benefit over mobile (and even telcos like BT Sport argue for HD HDR as optimum for handsets) the claim that you need to sit closer to the home screen to perceive the benefit needs re-examining.
Screen sizes are getting bigger – by about an inch a year according to some reports. What’s more, what we think of as a TV set, could be on verge of a radical format overhaul with MicroLED and rollable screens on the horizon.
“In the not too distant future we will have screens that are significantly bigger than currently and they will be multi-application devices like our phones,” Bester suggests. “For that reason, I don’t think people should get too hung up on the science of traditional viewing distance and screen size. This is completely changing.”
Cooper supports this, “The whole point of increasing resolution is that the pixel structure of the image should be imperceptible. It is a psychovisual effect that results in an image that appears to be more realistic.”
Will the tail wag the dog? This is perhaps the most voluble charge against 8K promotion especially since TV makers don’t always get it right (see stereoscopic 3D for details).
It is no coincidence that brands including Hisense, Panasonic, Samsung and TCL are primary backers of the 8K Association nor that Samsung, LG and Philips are partnering Japanese-owned Spanish streamer Rakuten TV’s plans to stream 8K content later this year, nor that Samsung and Sony are sponsoring 8K productions by Insight TV for marketing purposes.
“Although models are already available as low as $5000 they need to be five times cheaper, and up-scalers don't yet make all 4K or HD content shine at 8K,” notes Schwarz.
HDMI 2.1 is provisioned to support 8Kp120 and we are still in the interoperability phase.
The potential for consumer confusion could be high if misleading messages about near-term 8K content availability are made, which could result in 4K market destabilisation.
“While it’s folly to think that the industry can stymie the natural technological progression of display technology, the industry does owe a responsibility to correctly inform consumers of the availability of native 8K content and when it will reach a reasonable critical mass,” says Matthew Goldman, SVP Technology, MediaKind. He believes 8K will only be available for occasional special events like the Olympics or World Cup over the next five years. “We all need to find a compromise between one part of our industry pushing 8K to sell more ‘better’ consumer TVs to increase profit versus another part of our industry pushing back to prevent undermining the wider marketplace for 4K content creation and consumption.”
There is a certain inevitability in cost reduction from TV sets to distribution bandwidth. “We know 8K TV sets will be affordable at some point in time, and that’s when consumers will adopt them at mass scale,” says Fautier. “Therefore, the industry needs to make sure it can offer attractive services for broadcast, live and on-demand streaming, as well as immersive experiences.”
Bester says Insight TV’s 8K experiments are not necessarily because to build up a library, “but because we want to understand where we need to adapt the workflow chain from production through to delivery.”
While there is equipment from cameras to finishing systems and video switchers capable of a full production chain the workflow is embryonic. Data volumes alone present a challenge and a cost.
Nonetheless, the industry is steadily moving toward capturing video at higher resolutions to enable pan, scan and zooming. Production costs for HD and 4K can be reduced by capturing in 8K using one camera and extracting the region of interest via AI.
For immersive experiences such as VR, it’s necessary to capture at 8K resolution and deliver the field of view to either an HD or 4K display. The benefit of 8K here, according to Fautier, is that it provides “an exceptional QoE in contrast to conventional VR approaches where the full frame is sent and the player up-samples the field of view, leading to a poor experience.”
In the same manner, for personalised broadcast, content can be captured in 8K for end-users to navigate the content (at lower resolution) on mobile devices.
“8K offers a more personalised experience with a high QoE compared to other approaches where the zoom leads to fuzzy picture,” says Fautier. This was demonstrated at the French Open with Harmonic encoding and Tiledmedia packaging.
The applications for ultra-high quality source material are not limited because of the production technology. The biggest bottleneck is distribution.
“Even if you look at a high resolution VR application, the problem is not displaying the picture it is getting the content to the consumer via download or streaming,” says Bester.
The only broadcast network capable of supporting 8K today is ARIB DTH (heavily subsidised by the Japanese government via state-run NHK). Neither ATSC or DVB have made any provision to support 8K.
“In 2019, DTH is probably the only viable way to deliver 8K at scale [but] satellite distribution hasn't yet managed to ride the 4K wave successfully despite active promotion by the likes of SES or Eutelsat,” says Schwarz.
“As far as compression is concerned, the numbers circulating throughout the industry for bandwidth requirements vary. NHK’s commercial service uses 100Mbps, but recent trials with HEVC have shown live sports content at 85Mbps and VOD at 65Mbps.”
VVC promises to half those requirements in a few years. The proposed standard winding its way through MPEG “is the silver bullet” identified by Bester required to drive things forward “because whether the content is 4K or 8K, it really addresses the bottlenecks like CDN costs and bandwidth.”
Proofs of concept, by BBC R&D among others, show VVC being meaningfully more effective than HEVC with the goal of decreasing bitrate by half. But we will have to wait until 2020 when the MPEG specification is finalised and then 2022 to see it implemented in the first devices.
“We also need to resolve the licensing model of VVC, and the MCIF is working hard toward that,” says Fautier.
Harmonic’s take is that 8K will start with DTH, “but very quickly we will see IP delivery to connected TVs and mobile devices,” though probably limited to 4K.
The codec is an important element, but high-speed broadband networks - fibre, DOCSIS 3.1, and 5G –“are the best fit to carry 8K content, even using the HEVC codec,” says Fautier.
For live applications at scale, multicast will likely be needed, with 5G FeMBMS (Further evolved Multimedia Broadcast Multicast Service) an attractive solution (being trialled in Bavaria).
Globecast, which reports more than 60 percent of its customers in Europe still to make the transition to HD, identifies OTT as the preferred method for content delivery in new formats.
“That was true for 4K and will likely stay true for 8K,” says Juliet Walker, CMO. “That’s because you don’t need to wait for an industry-approved new interoperable tech standard for the signal transmission chain. Innovation comes fast on the internet and device/display vendors are quick to adopt new technologies to sell ‘boxes’.”
As with 4K, Walker thinks sports will lead the way in 8K, even while 4K rollout remains sluggish. Expect to see the first wave of 8K content produced at the 2020 Tokyo Olympics, as well as VoD in 8K streamed to connected TVs in the same time frame.
That’s why, argues 8K Association and the UHD Forum, that it’s important to agree on a standard for 8K that includes support for IP delivery (VoD and live) across all type of networks, 5G included, on all devices (TVs to smartphones). Immersive applications being different from broadcast ones, will also require guidelines.
The DVB for its part has completed a report into media formats beyond UHD-1 4K. “These formats have the potential to be commercially viable in the coming years,” says Siebert. The report was submitted to DVB’s Steering Board in July as an input document for potential future specification work.
The prevailing view, voiced by Antonio Corrado, CEO at video delivery network MainStreaming, is that “broadcasters won’t be able to justify the cost for a small niche audience that will be able to experience streaming in 8K until its wider adoption by device makers and consumers.”
Thomas Wrede, VP, New Technology & Standards, SES Video says the key ingredient is an effective business model. “We need an equation that encourages subscribers to pay for the quality of the content itself, and not just the screen they unboxed.”
To lay the groundwork for 8K the industry needs an aligned end-to-end ecosystem. Even with two organisations (the UHD Alliance and Ultra HD Forum), guiding 4K deployments, “it was not an easy process,” Fautier admits. “However, member companies have learned to work together, even if they compete in the marketplace. The same collaboration needs to exist for 8K, and the 8K Association is at the forefront to drive those efforts.”
In summary, there is a ton of work required to make 8K a reality. This is a multi-year effort, at least five to ten years depending on the application. The fear is that too much focus is put on classical broadcast, while IP is a low hanging fruit, at least to connected TVs and mobile devices and that the immersive experience is still the wild west and will take time to mature, likely in the 2022-2024 period.
“The next generation of video entertainment is based on several pillars of which a higher resolution is but one aspect,” says Schwarz. “I expect a paradigm change on the whole concept of resolution. Specific content will be produced at given resolutions. 8K will remain the upper limit until some new disruptive technology makes something akin to vector-based video a practical reality.”
By the same token, certain territories lagging now but unencumbered by legacy infrastructure in future, could see 8K leapfrog 4K in the same way that cellular did over DSL.
“This is why we shouldn’t get too hung up on the science,” Bester says. “Let us imagine you have an entire wall in your living room at 16K, if you go beyond that it will not make a difference. I think 16K is the top limit where the drive for higher resolutions will end.”
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