Manufacturers are pushing 8K sets, but are we ready? Do we have the content, infrastructure and standards to take this format forward? Thierry Fautier explores the challenges and solutions for making 8K an industry standard.
Thierry Fautier is Vice President of Video Strategy at Harmonic and President of the Ultra HD Forum.
At CES 2019, 8K TVs were introduced by a handful of manufacturers, including LG, Samsung, Sony and TCL. It was one of the first times that 8K displays were shown publicly, and attendees were mesmerised by the 33m pixels that 8K TVs provide, compared with 8m for 4K TVs. At CES 2020 there was a lot of buzz, and all TV manufacturers announced 8K sets.
What we know is that volume is minuscule. Analysts do not predict 8K to be more than 1% of 2024 sales, while 4K now represents 66% of TV sales in the US. Content is not there yet, and the industry is looking at streaming possibilities. The 8K Association is pushing hard to write an end-to-end specification.
Everyone wants to know: Is the industry ready for 8K? What challenges still need to be overcome? And how will future technologies like 5G assist with bringing 8K to a mass market?
While 8K TVs have made their way onto store shelves and living rooms, the market is still in its infancy. There is not a lot of 8K content available for viewing, and 8K screens are still too expensive to appeal to consumers on a mass scale. That is partially due to the screen size required. In order to fully take advantage of 8K resolution, a screen size of at least 65 inches is required. The higher the screen size, the higher the cost. At the same screen size, there is still a two- to four-fold price difference versus 4K, making it difficult to justify without compelling 8K content.
8K makes the viewing experience much more immersive, so the obvious application for 8K is live sports. But there are even richer use cases that can be explored, including high-quality 8K capture, personalised broadcasts to mobile devices (with the opportunity to pan and scan within the 8K content), and free viewport (Intel TrueView or Canon technology).
The most cost-effective way to enable pan, scan and zooming is to capture 8K by using one camera for HD production and extracting the region of interest via AI. For VR applications, 8K resolution will need to be captured and the FoV delivered to an HD or a 4K display. 8K resolution improves the QoE for VR, compared with a classical VR approach that sends the full-frame and upsamples the FoV area at the player stage, degrading the experience. For personalised broadcast, content is captured in 8K and end users can navigate the content on mobile devices.
A standard needs to be agreed upon for 8K. Japan has chosen ARIB DTH to broadcast 8K. Today, ARIB is the only broadcast network capable of supporting 8K. There has not yet been an announcement from ATSC or DVB in support of 8K. Both organisations are at the research stage. Beyond broadcast, a standard is needed for IP delivery of VOD and live content to any screen from any network, including 5G. Whatever standard is used will need to take into account resolution parameters like HDR, HFR and NGA. Once a standard for delivering 8K with HDR, HFR and NGA over IP networks is created, it will help to push the industry forward towards adopting 8K.
On the production side, the tools available to produce 8K live content in HDR have not been widely deployed yet, as many in the industry are in the middle of implementing 4K HDR.
What’s lacking is content that exploits the properties of 8K, such as its very large field of view and high resolution. 8K production guidelines are also needed, especially for immersive applications.
NHK has announced that it will cover the Tokyo Olympics in 8K. This will be the first live 8K delivery on a big stage. A key challenge for NHK while preparing for the 2020 Olympics is bandwidth. Transmitting an 8K signal using HEVC Main 10 codec requires 100Mbps, compared to 25Mbps for 4K. At InterBee 2019 in Japan, Harmonic demonstrated 8K content from the tennis French Open, delivered over IP at 20-40Mbps using CAE (content-aware encoding). In order to reduce this bitrate, MPEG is defining a new codec called VVC (versatile video codec) that will offer a 50% improvement in HEVC bandwidth by 2020.
Given these challenges, the 8K streaming market has the biggest potential. High-speed broadband networks such as fibre, DOCSIS 3.1 and 5G are most suitable to deliver 8K content, requiring less than 40Mbps to deliver premium 8K content when using CAE.
8K trials have begun, outside of NHK’s coverage of the Tokyo Olympics. One notable trial occurred last year when French public service broadcaster France Télévisions demonstrated the first live 8K broadcast over 5G during the French Open tennis tournament. The demo was successful thanks to the tight collaboration with telco Orange and more than 16 technology providers, including Harmonic.
While this was on a much smaller scale than the Olympics, it was a massive technology breakthrough in terms of validating that 5G networks can be used to deliver exceptional video quality at bitrates as low as 20Mbps for IP delivery. During the event, the demo partners were able to create and deliver live, VOD and catch-up TV content to a variety of 5G-connected devices, including TVs and smartphones, in 8K resolution.
A key lesson learned during the trial is that the infrastructure for 8K delivery over 5G can be set up rapidly. From start to finish, the entire technical system for the trial was set up in merely two months. Once scalable cloud-based servers had been installed, it only took a few days to set up Harmonic’s VOS360 cloud-based live video delivery platform. Cloud infrastructure is what enabled such a rapid deployment time.
To summarise, 8K still needs several years before widespread adoption takes place, in terms of content availability, an established business model, device availability and potentially a new codec. At Harmonic, we see 8K as more than a mirage. We think the market will take off in 2022 and be mature by 2024.
Some critical issues need to be addressed before the industry is prepared to transmit 8K. There needs to be an economical way to distribute it. A standard for broadcast is a significant missing piece. After the Tokyo 2020 Olympics, more infrastructure improvements, such as IP workflows and cloud infrastructure, will help simplify 8K delivery during the Beijing Winter Olympics in 2022 and future events.
Streaming appears to be the path of least resistance for 8K. To enable 8K streaming, high-speed broadband networks are still needed. A better codec will also be required down the road. Technologies such as CAE can play a role in bringing down the bitrates to a more affordable level. However, for this to work, network infrastructure providers need to add eMBMS support for 5G. The good news is that eMBMS is currently being standardised within 3GPP. Device support will be crucial to its success.
For now, the industry will continue investing in 8K production. Once more 8K content is available and the prices of 8K TV sets drop, and a good high-speed IP infrastructure has been built, consumers will be able to truly enjoy the spectacular clarity that 8K provides.