Plug And Pray

Two more AV interfaces are on their way. Here's what you can expect.
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Plug And Pray

Two more AV interfaces are on their way. Here's what you can expect.

Something for everyone?

DOES AV really need another interface standard? The question is almost rhetorical because although the debate rages on, new standards continue to appear. The two latest: the Unified Display Interface (UDI) and version 1.3 of the High-Definition Multimedia Interface (HDMI).

HDMI debuted in December 2002, and the latest major revision, 1.2, was released in August 2005. The HDMI 1.3 spec should be released this month, with the first commercial products available by late summer. “I imagine that there will be some products taking advantage of 1.3 features coming out shortly after its release,” says Les Chard, president of HDMI Licensing, the Sunnyvale, CA-based association that oversees the technology. “I see a significant number of products with 1.3 features in the latter part of this year, especially in Q4.”

Like its predecessors, HDMI 1.3 supports uncompressed high-definition (HD) video and multichannel audio in a single cable, along with High-Bandwidth Digital Content Protection (HDCP). Content protection isn't a must-have for many pro applications, such as videoconferences and company presentations, but pro gets it anyway because like much of AV today, HDMI is driven largely by the consumer side of the market.

The current HDMI 1.2 version supports throughput of up to 5 Gb/s, a cap that was chosen in order to make it compatible with other technologies, particularly Digital Visual Interface (DVI). The new 1.3 version is expected to be significantly faster, although the actual amount was still being hashed out at press time. “We're looking at increasing the speed initially about 50 percent,” Chard says.

A 5-Gb/s pipe is big enough to handle 1080p HD content and 24-bit RGB color. By going beyond the high end of today's market, HDMI 1.3 hopes to be the protocol that vendors and integrators adopt for the long haul.

“This additional bandwidth will enable us to support what we're calling ‘deep color,'” Chard says. “Currently you're looking at 24-bit RGB, which works out to about 16 million colors. The human eye can distinguish between those. There are some applications where you'll see that difference onscreen, such as in tiling.”

To help erase those differences, HDMI 1.3 supports up to 48-bit color, which translates into billions of different colors. “That's beyond the range that the human eye can distinguish,” Chard says. “We feel that that's where things are going to end up, and HDMI will be a leader in enabling that evolution.”

HDMI already has a major vendor following. “We're now at over 390 adopters,” Chard says. “Since the first of the year, we've gained 90 adopters.”

Despite that backing, there are plenty of other technologies that could one day displace HDMI. HDMI hopes to win over more of the market and build a bigger beachhead with several other features in 1.3, including:

  • Tighter PC integration — HDMI 1.3 is designed in a way that's supposed to encourage graphics-card vendors to build the technology into their products. The technology's backers also see that adoption as making HDMI the de facto standard for digital multimedia in PCs and consumer electronics applications. If that ambition pans out, it could affect pro AV by, for example, producing equipment volumes that significantly reduce the cost of HDMI technology and thus make vendors more receptive to using it.
  • Smaller footprint — HDMI 1.3 will let vendors offer a mini connector, although how much smaller is still being ironed out. A smaller connector could improve the chances of HDMI getting into more laptop PCs, where space is always limited. If that happens, then the trend could affect requirements for projectors, which often need to plug directly into laptops for presentations. The smaller connector also could be a good fit — literally — for discrete cameras, such as in a fancy boardroom.
  • More audio — With 1.3, HDMI expands its audio support to include new compressed formats, such as Dolby TrueHD and DTS-HD.
  • Lip sync — Designed primarily to address audio-video syncing problems with consumer products, HDMI 1.3 adds a feature called lip sync. “This allows the system to communicate the latency of each device back to the source so it can get everything in sync across the entire system,” Chard says. HDMI was founded by Hitachi, Matsushita Electric (Panasonic), Royal Philips Electronics, Silicon Image, Sony, Thomson, and Toshiba — all major, deep-pocketed companies. Some smaller AV vendors have complained about the technology's licensing fees, which currently are $15,000 annually, plus a 4-cent royalty for each unit sold. “For small companies that ship limited numbers of products, we've created an alternative annual fee structure with a $5,000 annual payment and a $1 per unit fee,” Chard says.

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Plug And Pray

Two more AV interfaces are on their way. Here's what you can expect.


Chard expects HDMI 1.3 to have the same basic fee structures as its predecessors, but he hints that it might be tweaked to help address vendor concerns. “It's not going up,” Chard says.

The licensing issue is key because if it develops into a major rift, at least among smaller vendors, it could translate into more backing for DisplayPort, which the Video Electronics Standards Association (VESA) approved as an official standard in early May. (No commercial products are available yet.) DisplayPort would work in a wide variety of applications — such as displays, PCs, and projectors —where DVI and VGA are currently used. Like HDMI, DisplayPort is designed to support HD video, with throughput of up to 10.8 Gb/s.

The HDMI camp downplays the DisplayPort threat, partly by arguing that an HDMI cousin, UDI, can fill many of the same needs. “UDI is, in some ways, a counterpoint to DisplayPort,” Chard says. “When you need PC-specific functions only —that is, when you don't need audio — you can use UDI. It's completely compatible with HDMI, so you don't have to design a new connector or put a whole new interface in your device.”

UDI is a forthcoming technology backed by major computer-industry vendors such as Apple, Intel, LG, National Semiconductor, and Samsung, as well as Silicon Image. Although UDI is being developed in order to replace analog VGA as the display interface for PCs, “display” is a catch-all term that includes more than just monitors. For example, the UDI Special Interest Group (SIG) says that the technology could be used to connect PCs to projectors, too. That's one reason why UDI bears watching by pro AV.

Intel describes UDI as “HDMI optimized for the PC,” and that's not a stretch: Roughly 90 percent of their two specs are identical. The main difference is audio, which UDI doesn't support.

“UDI's greatest benefit will be realized with corporate PCs, which don't require multimedia functionality and are most sensitive to cost,” says Joe Lee, director of product marketing at Silicon Image.

As a result, HDMI might win out for PC-based pro applications that require audio, such as desk-top videoconferencing. Time will tell whether that turns out to be the case: UDI was announced in December 2005, and the initial 1.0 spec won't be released until early summer, followed by inter-operability testing to ensure that one vendor's product can use UDI to connect to another's. If that schedule holds, the first commercial products could debut sometime in late 2006.

HDMI also could trump UDI in applications involving the two new DVD technologies: Blu-Ray and HD-DVD.

“We're seeing tremendous demand and growth for HDMI on PCs, especially laptops and models equipped with HD-DVD or Blu-Ray drives,” Lee says.

For AV vendors and integrators alike, the connector choice has financial consequences, especially if they choose one that turns out not to be widely used by the rest of the market. In the case of vendors, changing connectors in equipment that's already in production can take from three to six months. That time span stems from the fact that a connector isn't just the physical jack. It's also the circuit board and software living behind it, both which may have to be replaced.

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Plug And Pray

Two more AV interfaces are on their way. Here's what you can expect.

“If you have to change the circuit board underneath, you're looking at whatever production time it takes to clear out your pipeline, implement the ‘spin' of the circuit board, do quality assurance on that spin, and then get it back into the pipeline,” says Jim Smith, a systems engineer with Polycom, a Pleasanton, CA-based maker of conferencing equipment.

Those changes have a ripple effect, which includes changing the manual and any cables that ship with the AV product. “Everything goes awry,” Smith says. “For a small company, it can be catastrophic.”

For vendors and integrators, the fall-out can also be measured in terms of a damaged reputation. “AV is an elephant-memory kind of community,” Smith says. “If you make the wrong decision, and it costs people money, they don't forget.”

Tim Kridel is a freelance writer and analyst who covers telecom and technology. He's based in Kansas City and can be reached at

For more information about display interfaces and related standards, check out:

  • HDMI Licensing– The consortium's website at provides updated information about HDMI standards work and companies developing the technology.
  • UDI SIG– The trade association's website at provides updated information about UDI standards work and companies developing the technology. For an overview of UDI, see Intel's presentation at
  • VESA– The Video Electronics Standards Association's website at has information about a variety of interface technologies, including DisplayPort.
  • Coping with Changing Connectivity Standards–Does pro AV really need yet another connection protocol? November 2005
  • What's Next: Two's a Crowd— Next-generation DVD promises major improvements – and yet another standards war, April 2004

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