An announcement that may slipped under the radar for many as the dust settles from the carnage of CES, was the unveiling of the new HDMI 2.1 cable standard – upgrading bandwidth from 18 Gbps to 48Gbps, with support for 8K resolutions and scene-by-scene HDR (high dynamic range).
HDMI 2.1 is expected to roll out in the second quarter of 2017, but while most HDMI devices won’t support the standard until 2018, version 2.1 sets a significant benchmark for how premium video and gaming will look in the near future, starting one year from now.
A data rate of 18 Gbps, which its predecessor HDMI 2.0 handles, is more than adequate for the majority of HDMI users today. Although the industry knows this will change sooner than we think, particularly as the nascent VR ecosystem makes it into mainstream – with VR industry players reportedly targeting 8K at 240Hz.
The HDMI Forum is more than prepared for the surge of data that will be sent over its cables. HDMI 2.1’s 48 Gbps bandwidth may seem, on the face of it, excessive, but it is specifically designed to accommodate the uncompressed delivery of 8K, HDR content. The signaling of HDMI is based on patented transition minimized differential signaling (TMDS) which is held by its inventor Silicon Image, a company since acquired by Lattice Semiconductor in 2015 for $606 million. Annual HDMI shipments have been above 1 billion since 2011.
Japan is at the forefront of pushing the standard, as national broadcaster NHK has stated its intention to deliver an 8K broadcast stream soon – hoping to encourage consumer device manufacturers and content developers to follow suit. The 2020 Olympic Games in Tokyo is being heralded as by Japanese Prime Minister Shinzo Abe as an event that will represent a pedestal for 8K content.
Perhaps the most significant component of the imminent HDMI 2.1 cable is its support for Dynamic HDR – a technology hailed by most as the crowning glory of TV imaging techniques. HDMI 2.1 will build on Dynamic HDR by applying the HDR metadata on a scene by scene basis.
Jeff Park, Director of Marketing at HDMI Licensing, told TechRadar at CES: “Today, HDR is done by taking average values for HDR across an entire movie, so while you still get some benefit, it doesn’t apply to each scene perfectly. Dynamic HDR enables the HDR metadata to be applied as precisely as frame by frame, or more practically, scene by scene.”
The idea of frame by frame Dynamic HDR has been floated, but apparently takes an unjustifiable amount of time and effort to produce.
Beyond TV sets, HDMI is the primary video and audio feed for game consoles, streaming devices, PCs and Blu-ray players. Sony is leading the charge of Japanese CE technology companies trying to establish dominance in 4K and 8K, especially in the broadcast industry. Not to mention all the usual suspects including LG, Panasonic, Samsung and Sharp all with their own (wildly priced) 8K TVs on the market.
There have also been suggestions that operators and broadcasters are planning to leapfrog 4K, instead going directly from Full HD to 8K. The incentive here for cable operators is that if they feel they missed the boat with 4K, then investments in network upgrades should give them enough time to arrive on time for 8K.
But once more of the last-mile connections are able to support the minimum speeds needed for 4K content, let alone 8K, operators will want to be able to upsell that content to their customers, probably by way of the set top, but perhaps also via the TV set if the latter doesn’t have an HDMI connector with enough bandwidth. To push premium 4K content, pay TV operators will need consumer equipment with enough grunt to handle the decode and transcode, which is where the semiconductor makers come in.
Unlike the earliest 4K sets that lacked an input with the capacity to actually display a 4K image at anything over 24fps (frames per second), the launch of HDMI 2.0 saw it provide enough bandwidth to push a UHD signal to a TV screen.
Whereas HDMI 2.1 can carry frame rates of 120fps – an irrelevant feature at present due to the absence of any device on the market with this rate of output. But there is growing conviction that frame rates of up to 120 a second, and even 12 bit color, will soon be desirable, implying that HDMI 2.1 is not trying to run before it can walk.
Additional features of HDMI 2.1 include more advanced eARC (enhanced audio return channel) formats such as object-based audio, as well as Game Mode VRR which enables a 3D graphics processor to tackle lag issues.
“This new release of the Specification offers a broad range of advanced features for enhancing the consumer entertainment experience, as well as providing robust solutions to the commercial AV sector,” said Robert Blanchard of Sony Electronics, president of the HDMI Forum. “This is part of the HDMI Forum’s continuing mission to develop specifications for the HDMI eco-system that meet the growing demand for compelling, high-performance and exciting features.”
It’s worth noting that the new specification will be available to all HDMI 2.0 Adopters.