FEATURE: 4K [HDMI 2.0]
HDMI (High-Definition Multimedia Interface) has been around since 2002, and currently stands at rev. 1.4. For ‘true’ 4K, however, HDMI 2.0 is required. HDMI 1.4’s throughput specification is 10.2Gbps – enough bandwidth for all ~8 million pixels, but only at frame rates of less than 30Hz – and only supporting 8-bit colour. The lower frame rate is
“4K video requires
Analog Way has added HDMI 4K and DVI 4K connectors to its Ascender-48 AV processor
– who showcased the 4K-capable Galileo Display Processor at InfoComm – points out: 4K isn’t just about delivering a single 4K image. “We are definitely seeing an uptick in the number of customers who require 4K capabilities in the products that they choose in their installations,” he says. “4K-capable solutions are not just for displaying 4K content – they can also display multiple HD signals without downscaling them.”
INCREASING AT A FAST RATE But Kamran Ahmed, CEO and co-founder of AptoVision, a provider of chipsets for AV signal distribution, is bullish. “Demand for 4K capable solutions has been increasing at a much faster rate than demand for 2K solutions ever did,” he claims. “The rapid decrease in 4K display prices has been one of the main contributors. The speed at which 4K has come to the market has further fuelled the fear of obsolescence, increasing the desire for future-proofing.” Companies like his will have a significant impact on the uptake of 4K resolution – not least because it is not yet straightforward to deploy in all its glory. In fact, according to Davies, there is, in effect, no such thing as ‘4K’. “The technical challenges should not be the major concern for the industry, as history proves these will all be overcome in time and the release of the HDMI 2.0 definition is a significant step towards this,” he says. “The true issue today is a lack of understanding with regard to what 4K is on the part of both the industry and the end-users. 4K in itself is not a single defined standard, which means nobody can
question the validity of any claims regarding the support of 4K by an individual product, unless you drill down into the technicalities as to the exact flavour of 4K being discussed. 4K is definitely a space where early adopters could be paying a high premium for solutions that will very quickly prove to be outdated and worse still, bring them no real benefits in the short term.” “AMX has focused on ensuring our underlying product design approach will allow us to quickly and effectively bring ‘true’ 4K support to our ENOVA DGX product line,” he goes on, “with the minimum cost to existing installations.” So what are the challenges to which Davies refers?
“MARKEDLY DIFFERENT” “Education is Crestron’s main focus at this stage as there are five key challenges that make 4K a tricky, non- plug-and-play technology,” avers Buck. “Mixed aspect ratios, new frame rates, signal integrity, cable length restrictions and source/ display compatibility are the stumbling blocks that integrators need to be aware of and each one is as important as the next. If there is to be one issue to flag up with 4K, it is that it is markedly different to 720p, 1080p and 3D, which integrated into commercial AV applications with ease. 4K is a more complex upgrade.” 4K resolution, of course,
delivers not twice as much resolution as 2K – but four times as much. “As a provider of chipsets
exclusively used for AV signal distribution, the single biggest challenge presented by 4K is the increase in bandwidth,” says Ahmed. “While 4K/30Hz requires roughly 10Gbps – a
www.installation-international.com
bandwidth level supported by a wide variety of readily available technologies – the full specification of 4K/60Hz requires over 18Gbps. The technology components required to support this bandwidth are beyond cost- prohibitive for mainstream signal distribution platforms. Moreover, this level of bandwidth poses a significant challenge for video transmission over copper cabling (such as CatX), limiting reach to under 50m as compared to about 150m
extremely high bandwidth – at 10.2Gbps it’s perhaps the highest frequency most of us deal with on a routine basis,” echoes Bill Schripsema, commercial product manager at Atlona. “Compared with 1080i, bandwidth changes by a factor of nearly four – which is a very significant consideration for system design. Connectors and cable all need to be of high quality and installed with care and precision for a successful project.”
‘Installation techniques and cables that were “good enough” for 1080p aren’t good enough for 4K’
Bill Schripsema, Atlona
for 2K signals. AptoVision is overcoming this challenge by using an innovative two-cable solution which maintains 2K equivalent reach while still providing real-time, zero-latency transmission and leveraging inexpensive 10Gbps components.”
NO LONGER GOOD ENOUGH “Installation techniques and cables that were ‘good enough’ for 1080p aren’t good enough for 4K, Schripsema continues. “For example, the 70m HDBaseT extenders will only work to 40m at 4K resolutions – less if Cat5e/6 are the cables of choice. Many users will need to use the 100m versions of HDBaseT products to reach the full required distance. They will find the cables they pulled and the connectors they installed for 1080p signal distribution won’t work for 4K systems.” For Deame, it’s also about bandwidth – and about the plethora of options. “The increased bandwidth is definitely the most significant factor when you consider the differences in 4K and 2K signal handling,” he claims. “4K data busses, FPGAs, crosspoints and transceivers must run four times faster than 2K ones, which adds complexity and cost to the hardware.” “Then there’s the challenge of dealing with the myriad of different signal types and interfaces,” he continues. “Choices include dual-link DVI, HDMI 1.4, DisplayPort, and HDMI 2.0 – the implementations of which currently only support 4:2:0 colour space, due to a lack of silicon availability. The best way to overcome this challenge is to have a good collection of 4K signal
acceptable for, for example, movies – but the 50/60MHz bandwidth required by other applications (such as TV) will need HDMI 2.0, which also supports 10- to 12-bit colour depth.
The HDMI 2.0 specification
was announced in September 2013, but the HDMI 2.0 Compliance Test Specification didn’t become available until April 2014.
converters on-hand, as there seems to be no standard interface rising to the top.” Despite what some commentators would have you believe, it’s possible – given Ahmed’s reference to 4K/30Hz and 4K/60Hz and Deame’s description of the connection options available, for example – to see that AMX’s Davies has a point: there appears to be still much to be done before 4K becomes a single, coherent, deployable technology. Higher pixel counts have
given rise to the need for more sophisticated codecs in order to minimise bandwidth requirements. For most of the industry, HEVC/H.265 is the answer – but it, too, comes at a price: the significantly increased sophistication of the algorithm is said to require 10 times the computational power of the H.264 codec used in current 2K deployments – and the silicon to deliver that capability is, as yet, far from a commodity item.
SIGNIFICANT TECHNICAL CHALLENGE “H.265 represents a significant technical challenge,” says Watts. “The CPU performance required in PC-based software decoders is likely to keep 4K away from the corporate desktop for a while yet.”
Much also seems to hang on HDMI 2.0 [see boxout]. “Better-informed potential customers will wait for the first ‘real’ HDMI 2.0 displays that will support higher bandwidth, colour depth and refresh rates as well as support for multiple audio/ video streams over a single HDMI cable,” believes Stephan Vinke, product manager at Gefen Europe. “It’s similar to what we saw in the early years of HDTV.” Martin Featherstone,
CYP/audio visual product manager at CIE Group, tells a similar story. “To view a true 4K image on a display requires HDMI 2.0 to deliver
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