Evolution of 4K/UltraHD and HDR continues to strain bandwidth of HDMI

The development of display technologies including 4K/UltraHD and HDR is moving too fast for the bandwidth capabilities of CPE infrastructure, specifically HDMI cabling.

With bandwidth needs often exceeding the 18 Gbps standard for HDMI cables – which often deliver even less bandwidth than that – experts are advising video system installers to deploy alternative methods for wiring video systems.

“My advice is to run conduit,” said Joel Silver, president and founder of the Imaging Science Foundation (ISF), speaking on a panel event at the CEDIA 2016 trade show in Dallas last month. The event was covered by trade pub CEPro, among other outlets.

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With bandwidth needs expanding at a rapid rate, Silver said that even this is a temporary solution. “I am pretty confident on telling people what to do up to about 2020, but then my crystal ball goes dim,” he added. “Even with fiber, I still tell people to pull conduit. I don’t know what’s coming down the pike, but I do know that it will require more bandwidth.”

Robert D’Addario, president and managing director for Cleerline Technology Group, suggested fiber may be the only future-proof display conduit. 

“What works today might not work tomorrow,” he said. “Hybrid HDMI is a very good alternative to bulk fiber and we are working on incorporating SSF [a Cleerline line of fiber-based solutions] into products like that in the near future to replace our current active HDMI cables branded Planet Waves. But I’m a big advocate of putting in an infrastructure that you know you’ll be able to utilize regardless of the format of the future. Traditionally that was coax, then Cat-5e, then Cat-6, but now we’re saying emphatically fiber.”

Silver said he conducted tests on first-generation UltraHD Blu-ray players from Samsung and Philips. Both outputted at about 13.5 Gbps. Once these signals hit the A/V receivers through HDMI cables, the bandwidth was squeezed to about 9 Gbps and the HDR signal was gone.

The problem isn’t just native to HDMI cables. A/V receivers, matrix switches and even displays may not support Ultra HD, high dynamic range (HDR), wide color gamuts (WCGs) and other technologies associated with 4K/UltraHD.

“The issue may not always be a cabling problem. It could be anything from an older device such as an A/V receiver, switcher, display or source. It could be firmware that could be the limiting factor,” added Brent McCall, product manager for Metra Home Theater Group.