Everyone likes the idea of Wireless HDMI. The ability to wirelessly transmit HD content would help clean up the wiring of home theaters and would reduce the problems associated with running long lengths of HDMI wire. But Wireless HDMI has limitations which prevent it from being the next big thing.
Something like Magic
Wireless revolutionized home and business networks. The ability to beam data from a router to a laptop or PC many yards away without any physical connection changed everyone's expectations about what was possible. Just as importantly, it made home networking easier for the average user. Figuring out where to plug wires can be difficult to a home user looking at the rear of a Dell with two or three places to put an Ethernet jack, and becomes infinitely more complex when connecting two devices in different rooms.
Now, with wireless networking well established, the same concept is being applied to devices beyond desktops and laptops. Game consoles were probably the earliest examples of this wireless expansion, as they allowed people to buy all kinds of content and stream it via a wireless network connection. Now, HDTVs are looking to jump on the bandwagon. It may sound fanciful, as video is well known to consume large amounts of bandwidth. Video also reacts poorly if the stream of incoming data is temporarily broken or weakened. But the potential of this technology is great. Imagine if your HDTV required no connection physical connection besides the power cord. Such a thing may seem like magic, but we're already seeing the earliest implementations of this tech.
Although wireless HDMI is only recently starting to gain press, the fundamentals are nothing new. The standards are no different for Wireless HDMI than for HDMI, but it is only recently the manufacturers have seriously attempted to push the technology. The wireless technology itself is also common. Some wireless HDMI solutions use the 802.11g standard that is used for wireless routers. Many, such as Belkin and Gefen, use custom solutions or less common standards such as UWB, but the basic wireless technology is not advanced even in these proprietary devices.
That said, the technology has to be tweaked in many ways to make wireless HDMI a reality. As mentioned, video is extremely bandwidth intensive. Video also does not like hiccups which cause temporary loss of data. Failure of bandwidth or connection integrity can result in skips in the video stream, and producing a wireless product that can reliably stream high definition content requires specific hardware solutions. It is worth noting that those companies which do use custom solutions rather than using simple 802.11g seem to be putting out much higher quality products. This is likely because the companies using less common wireless standards or a proprietary standard have put more work into addressing the specific concerns of wireless video.
Limitations So Far
While companies like Gefen have put a lot of effort into making high-quality wireless HDMI solutions, there are still some obvious limitations. Full 1080p video at 60hz, which is the standard the HDTV industry is pushing towards, takes an obscene amount of theoretical bandwidth. Uncompressed, this 1080p video stream would require about 3Gbps of bandwidth to stream. Compression schemes are extremely common in the realm of high-definition video, and they reduce this requirement by a large amount, but even a fraction of this number is still more than most wireless solutions will be able to handle. As a result, there is no current wireless HDMI solution that can provide 1080p at 60hz. The best you will manage is 1080p at 30hz or 1080i at 60hz. This is still quite good, but it isn't up to par with the quality of a wired connection.
Price is also a serious limitation. Surfing Newegg, you can find numerous so-called HDMI solutions which retail for between $100 and $400 dollars from companies like common wireless networking companies like D-Link, Linksys, and Netgear. These cheap boxes all use 802.11g, and are technically capable of streaming a video signal from a HD source to an HDTV. Their marketing as wireless HD devices is somewhat deceptive, however, as these products are rarely capable of 720p, much less 1080p. The high quality products capable of 1080p at 30hz, like the GefenTV, cost near a grand.
The Waiting Game
At this time, it is difficult to recommend a wireless HDMI solution for most users. I don't find the cheaper solutions worth using, as they are useful only for streaming sub-720p content. You would be better off building a HTPC or buying a game console and connecting to your main router via a powerline network. The effective solutions are the most expensive ones, but a grand will buy you a good HDTV in today's market, which makes laying down another grand for the convenience of wireless HDMI a losing proposition. The companies making these solutions know this, and are marketing mainly to businesses so far. Even if you have a more expensive set, buying wireless HDMI doesn't seem like a good idea. Chances are you bought that expensive HDTV so you could see images in the greatest detail possible. Spending more money on wireless HDMI will only decrease the quality of your picture.
That said, there are reasons why you might want wireless HDMI. Some simply hate wires, and are willing to take the trade-offs in order to get rid of as many as possible. Others may want to put an HDTV into an area of their home where a mass of wires isn't an option - this is often the case with wall mounted HDTVs. If you do want wireless HDMI, then I suggest putting down the cash for the best and buying something like the GefenTV or the Belkin Flywire. These expensive solutions are the only products that have a hope of providing 1080i quality.