Audio/Video

Crestron’s DigitalMedia Switchers Offer Ultimate HDMI/IP Distribution & Control

DM-MD8X8 and DM-MD16X16 switchers fix HDMI problems related to distance, switching lags, HDCP authentication and more. Gig Ethernet switch built in for IP.


Crestron’s DigitalMedia Switchers Offer Ultimate HDMI/IP Distribution & Control
System automatically checks all connections from the source to the display, revealing points of failure via the LCD screen and LEDs on the front panel.
Julie Jacobson · September 1, 2008

Crestron has a Cat 5 switching solution that apparently fixes everything that is wrong with HDMI, from switching lags to HDCP authentication to distance limitations and more.

The technology is part of Crestron’s new DigitalMedia line, which includes the DM-MD8X8 and DM-MD16X16 switchers in 8x8 and 16x16 configurations, respectively.

The switchers are modular solutions with card slots that accommodate virtually any type of input.

A full selection of switcher input cards, wall plate transmitters, and room controllers provides extensive connectivity throughout the home, supporting a complete range of analog and digital signal types.

DigitalMedia manages all of the different signals and devices, matching each source’s output to the capabilities of the selected display(s) without using scaling or compression.

Crestron claims that very signal is preserved in its native video resolution and audio format, ensuring a lossless signal path throughout.

The DigitalMedia line can be considered the next generation of Crestron’s huge-selling PVID Series of Cat 5-based component distribution systems. Compared to that and other analog-based solutions, DigitalMedia will cost about 30 percent more.

Combining HDMI, IP, Control

A couple of years in the making, Crestron went back to the drawing board to create the DM series, determining the best way to distribute a huge variety of audio/video formats – analog, IP, HDMI and otherwise—over a pair of Cat 5 cables (or a single fiber cable).

Crestron struggled with how to get streaming video and uncompressed HDMI content out of one box, without compromising video quality, and without requiring digital/audio converters and other processors that add latency and cost.

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“We did a study, asking ‘Where does content come from?’” says Crestron’s Fred Bargetzi, vice president of technology. “If you can get it all in an MPEG format, then you can easily stream it over Ethernet/Cat 5. But sometimes you can’t “touch” the content in its digital form, and it comes out in uncompressed HDMI.”

If Bargetzi had his choice, he says, “I would want to move it [content] all around over Ethernet.”

But if you crunch the numbers, it just doesn’t add up.

HDMI 1.3 supports resolutions up to 1440p. “That’s 10+ Gbps,” Bargetzi says. “To send that over a gigabit Ethernet network requires expensive endpoints just to take something that was compressed (MPEG) and then uncompressed (HDMI), just to compress it again to send it over the network, and finally uncompress it at the display. You get the picture”

Regardless of expense, the process would still introduce latency into the system. Crestron eliminates the latency by maintaining the full HDMI 1.3 stream from point to point – over 450 feet over shielded twisted pair (with optional repeaters or extra cable for power) or 3,280 feet (1K) for fiber.

But it does more than that. The system also streams IP-based content via a built-in gigabit switch. USB mouse and keyboard distribution allows computers, media servers, and video game consoles to be installed out-of-sight and accessed from anywhere in the house.

And naturally, Crestron’s control technology is built in for automating the switcher and controlling everything connected to it – no additional wires required.

QuickSwitch Fixes HDMI Lags

If you’ve ever switched between two HDMI sources, you know the delay can be painful – often up to 10 seconds or so.

That’s how long it takes to authenticate a device for proper digital rights management (HDCP).

Crestron’s proprietary QuickSwitch HD technology maintains a constant HDCP connection with each HDMI device in the signal path, eliminating the need to re-authenticate each time a different source is selected.

“We maintain the HDMI and HDCP connections from the source to the switcher, and the switcher to the display,” says Bargetzi. “Now, when you switch back, instead of it taking eight or 10 seconds, it happens almost immediately.”

He tells of a particularly annoying HDMI switching scenario that involves a Blu-ray player. In his tests, it took 11 seconds to switch between a satellite and a Blu-ray source. And that ain’t the half of it.

“Imagine you are watching a movie on your Blu-ray player, and switch over to your satellite to check the scores of the game,” he says. “A minute later you switch back to the Blu-ray player, only only to find that it went to sleep because it lost its HDMI connection to the display. Worse yet, most Blu-ray players take one or two minutes to start up again, and most don’t go back to where you left off in the movie.”

With QuickSwitch, that problem disappears.

In June Silicon Image, developer of HDMI technology, launched a similar technology called InstaPort. But “InstaPort isn’t a system-wide solution,” says Bargetzi. “Plus, it requires display manufacturers to implement the technology. Our solution is built into a single box serving all displays.”

Self Diagnostics Optimize HDMI

After you set up your system, press a button on the DM unit and it runs through a “Systems Commissioning” routine that includes a variety of diagnostic tests to ensure users get the most of their sources and displays.

“It checks all connections from the source to display so it can tell you if there’s any point of failure,” Bargetzi says.

Optimizing the Display

The switcher polls the EDID (Extended Display Identification Data) for each display to find out the optimum resolution and frequency.

Bargetzi explains, “It will come back and say, ‘If you want to route every display to every source, here is the optimal resolution. Do you want me to set it?’”

The system offers a choice so, for example, if you want to route some sources just to the home theater, “you don’t have to dumb down the resolution,” Bargetzi says.

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Confirming HDCP Keys

“The problem with sources today,” says Bargetzi, “is that many of them cannot hold enough HDCP keys to work in a whole system.”

A source can play simultaneously only on the number of displays for which it has keys.

If a source can only implement four keys (a common scenario), then it can only play on four TVs simultaneously.

The problem is that many integrators test their multiroom video systems one source at a time. “What often happens,” Bargetzi says, “is that they’ll put in an 8x8 switcher and test one source to each display. It all works great. But later the customer decides he wants to show Blu-ray on all of the displays simultaneously. After he gets past the fourth display, not only does nothing show up on the fifth display, but all four of the previous displays go black until you de-select the fifth display.”

Phew.

As part of its diagnostics, the Crestron DM switchers “identify issues like that,” Bargetzi says. “It would tell you up front that the Blu-ray only holds four keys, so you can address these issues in the installation phase rather than when you get that ‘special call’ from your customer.”

Crestron plans to create an online database of devices, posting the number HDCP keys they accommodate. He suggests that dealers may want to pick sources based on the number of displays they can support.

Bargetzi says that very few dealers know about these issues, “which suggests that dealers really aren’t implementing whole-house HDMI distribution.”


Next Page: DigitalMedia Switchers - Features and Specs


 


  About the Author

Julie Jacobson, recipient of the 2014 CEA TechHome Leadership Award, is co-founder of EH Publishing, producer of CE Pro, Electronic House, Commercial Integrator, Security Sales and other leading technology publications. She currently spends most of her time writing for CE Pro in the areas of home automation, security, networked A/V and the business of home systems integration. Julie majored in Economics at the University of Michigan, spent a year abroad at Cambridge University, earned an MBA from the University of Texas at Austin, and has never taken a journalism class in her life. She's a washed-up Ultimate Frisbee player currently residing in Carlsbad, Calif. Email Julie at [email protected]

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