Picture This: The New Format War?
Aug 1, 2008 12:00 PM,
By Jeff Sauer
Competition over wireless HD technology.
Competing wireless HD technologies may have found their match with Amimon’s Wireless Home Digital Interface, which is supported by Hitachi, Motorola, Samsung, Sharp, and Sony.
At CES this past January, there were several companies talking about wireless HD video. And why not? The advantages are clear: Fewer cables in the home, office, or public spaces makes for easier physical display placement, more efficient installation, and a cleaner appearance. Indeed, wireless high-definition video would likely have been at the top of the list of “next big things” coming out of CES had it not also been promised the year before.
There are, of course, competing technologies for wireless HD — WirelessHD, Ultra-wideband (UWB), etc. — and, as in any good format war, competing patent holders hoping to cash in on that next big thing. But false starts and unmet delivery timetables over the last couple of years have not allowed any to come forward as a realistic leading contender. However, a recent announcement by a new group of vendors may.
Amimon, the inventor and proponent of Wireless Home Digital Interface (WHDI), has been joined by major manufacturers Hitachi, Motorola, Samsung, Sharp, and Sony to announce the formation of a special interest group charged with creating an industry standard around WHDI technology. Interestingly, many of those companies are already promoters and adopters of the WirelessHD consortium, and their willingness to support WHDI — at least with this standards initiative — is a good sign that they are not digging in their heels for a Blu-ray-versus-HD DVD-type wireless format war. More importantly, it’s a sign that the industry sees the big picture of how big a thing wireless might be and it is acting to make it happen.
Known as the WHDI Special Interest Group (SIG), this new collection of companies hopes to have the standard specification framework in place by the end of 2008. If this deadline is met, that could make compliant products — or at least demonstrations of them — a possibility for next year’s Consumer Electronics Show, with interoperable products ready perhaps as early as next fall. Naturally, that is a best-case scenario; real-world results rarely match such planned timetables.
Nonetheless, the announcement does take a big step in the right direction. While Amimon has — like the other wireless technology initiatives — had a few delays moving from demonstration to production, one of the company’s biggest challenges in the marketplace may have been the fact that WHDI has been a proprietary, and guarded, technology. With technologies patents now in hand, Amimon is able to be more open with its intellectual property and to accept input from others in an effort to create a standard method of operation and integration for WHDI.
Picture This: The New Format War?
Aug 1, 2008 12:00 PM,
By Jeff Sauer
Competition over wireless HD technology.
WHY WHDI?
Why would companies such as Sony, Sharp, and Samsung now come to support WHDI after months working toward the WirelessHD standard? First, each likely recognizes that establishing a working, interoperable, wireless HD technology will help sell their core display products of the future. If nothing else, they are hedging their bets with multiple efforts to create one. And of the competing wireless options, WHDI seems to be the furthest along and thus the quickest to implement into forthcoming products. Amimon is now offering WHDI technology on silicon integrated circuits for integration.
Amimon has demonstrated that WHDI has enough channel bandwidth (1.5Gbps) to send uncompressed 1080i HD video — as well as XGA for data — wirelessly, and it will soon support 1080p at 3Gbps. It does so over the same potentially crowded 5GHz frequency as 802.11a, but Amimon claims that the technology is able to find other frequencies if necessary to ensure delivery of the data stream.
However, although the transmission frequency is important, Amimon’s secret sauce is in how it prioritizes video information to accommodate the inevitable wireless network congestion or less-than-ideal transmission conditions one is likely to face in the real world. Amimon insists that such prioritizing is not a form of video compression, but rather a hierarchy of data that amounts to an on-the-fly method of reacting to the uncertainly of wireless bandwidth.
Amimon remains tight-lipped about its specific prioritization methods, but other examples of prioritization are as old as recorded video, and many have been used at the highest levels of video production. For example, because our eyes are more aware of luminance variations than chromanance subtleties, chroma sub-sampling — or taking one color sample for every two (or more) luminance samples — typically goes unnoticed. The longtime professional videotape standard, Betacam SP, used 3:1:1 sub-sampling with only one sample of red and blue for each of the three luminance samples. The MPEG-1 digital video format and the DV tape format both use a 4:1:1 color sub-sampling, while high-quality MPEG-2 in the standard profile uses 4:2:2.
Although it’s not literally the same, WHDI similarly places greater importance on core aspects of an image and sends those data bits first, with others following. If those later image elements are delayed by network congestion and are not received in time, WHDI is still able to display the picture — and usually still without any visible degradation.
Thus, while Amimon has focused on the 5GHz frequency for transmission, the company’s core solution could ultimately remain viable even if the industry moves toward a different transmission method or alternative transmission frequencies. For example, WirelessHD focuses on the unlicensed 60GHz frequency band to achieve data rate of several gigabits per second. However, where the 5GHz frequency allows wireless transmission through walls to roughly 100ft. through a building or house, 60GHz has a much shorter, in-room range.
Given that difference, it’s possible that WirelessHD and WHDI might even coexist in the future — with Amimon’s secret-sauce prioritization at the center of both. Indeed, regardless of the theoretical bandwidth of any wireless frequency range, there will always be the probability of network congestion. And for wireless HD video to successfully reach the consumer market, there has to be a foolproof way to accommodate non-ideal situations. It’s even possible that Amimon’s technology could ultimately be married to other competitive solutions such as UWB or 802.11n.
For the most part, each of the competing technologies focuses on a different way to send video and each promotes its own as the better way to send video. Amimon’s solution, on the other hand, begins with making the video better to send. And with major display manufacturers joining the effort, wireless HD video may yet be the next big thing coming to a display near you.
