It’s a Miracle: Patented Technology Makes HDMI CEC Work
HydraConnect products such as the HHS-3 8x8 matrix switcher with HDBaseT offer “highly integrated CEC control for almost all televisions and projectors, BluRay players, and A/V receivers.”
U.S. Patent 8,260,975 describes an HDMI switch that “provides for CEC-controlled AV systems with multiple displays, e.g., in different rooms.”
CEC has been built into consumer products for many years. It was designed to eliminate the usual coffee table of remotes that are required for a system with a TV, A/V receiver and maybe a Blu-ray player.
With CEC, theoretically, a consumer should be able to use a single remote to turn on the entire system. For example, when the Blu-ray player turns on, it turns on the TV and tells the A/V receiver to connect to the correct input.
“However, in the CI [custom installer] world, none of this works,” says HydraConnect’s David Schanin. “Because there are multiple TVs and sources all under control of an automation system, you cannot just let the devices ‘talk’ to each other using CEC – the automation system would lose control of everything.”
So the first thing most installers do is turn off CEC for all devices that have it.
“Our patent covers a way to make CEC work in a CI environment,” Schanin says. “Simply put, our system isolates all of the CEC devices so they can’t talk to each other, and we use a sophisticated discovery software system that allows us to identify every connected device.”
With such discovery, says Schanin, the HydraConnect product would “have the knowledge on how to control every CEC device, and we use this capability to invisibly control nearly every device in the system - no IR blasters, wiring, any gear to drive the IR blasters, etc. Just one HDMI cable to each device which provides video, audio and control.”
This should work regardless of the brand of product and the number of displays. The patent notes the solution “can be manufacturer specific so that devices with different CEC implementations can be combined in a single system.”
Among the many implementations of CEC, we have:
Aquos Link (Sharp)
NetCommand for HDMI (Mitsubishi)
The patent notes:
CEC communications between HDMI devices is precluded or at least controlled to avoid problems due to incompatible CEC implementations and unwanted interactions. The CEC processor causes the HDMI switch to appear as an HDMI source to HDMI sink devices and as an HDMI sink to HDMI source devices for the purposes of assigning physical addresses. While CEC is designed to handle AV systems having only one sink (display), the novel HDMI switch provides for CEC-controlled AV systems with multiple displays, e.g., in different rooms….
Custom home entertainment systems can include matrix switches controlled by a central control system that allow a user to select among plural sources for video contents and among plural displays on which to view content. Such arrangements can allow different family members to view different contents in different rooms and allow a viewing in progress to follow a viewer who moves from one room to another. This arrangement also allows for all of the various video sources to be hidden in a remote location, leaving only the video display visible in the living areas.
However, the transition to high-definition video has introduced some challenges to matrix switching. The predominant audio and video interconnect system for high-definition video is HDMI, which includes an optional Consumer Electronics Control (CEC) protocol that allows any HDMI connected device to issue commands to any other HDMI connected device that supports the CEC protocol. The CEC protocol assumes a single video sink, e.g., display, and cannot readily be used with a home entertainment system having the two or more video sinks. Moreover, CEC implementations tend to be manufacturer-specific, which complicates control of home entertainment systems with devices from different manufacturers. While video devices can be controlled without using CEC, e.g., using a network of IR transmitters, such approaches tend to be cumbersome, expensive, and unreliable. What is needed is a more convenient and elegant approach to selecting HDMI sources and sinks.
HydraConnect has already implemented this CEC technology in some of its switchers, including the 8x8 HSS-2 and HSS-3 (with HDBaseT).