Wireless HDMI and HDTV Extenders: What to Know Before You Buy
written by: M.S. Smith•edited by: Simon Hill•updated: 12/5/2009
The term wireless HDMI implies a technology not much different from the wireless internet that we're all familiar with. But wireless HDMI is a much newer and much less standardized technology. There is still some confusion about what it means and so there are some basic pitfalls to avoid.
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The Wireless Wish
Wireless HDMIis starting to become a hot new item in the home theater market. It is easy to see why. Most people are already familiar with the idea of wireless thanks to the popularity of wireless Internet. Many homes have been spared the need to run countless feet of Ethernet wire thanks to a single wireless router. Being able to do the same for the televisions in a home is enough to get any home theater enthusiast all riled up.
But hold on. Wireless HDMI is still an infant technology which has few standards associated with it. Wireless HDMI is certainly possible and can be a valuable addition to a home, but there are some hazards to watch out for.
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Wireless HDMI Doesn't Mean Wireless HD
HDMI is simply a method of relaying video and audio data from a source to a display. It was created to support the high bandwidth needed to output high-definition images and high-quality audio to an HDTV and surround sound system, but it makes no promises about the quality of the image which it transmits. A low-resolution image transmitted via HDMI is still a low-resolution image.
This easily forgotten point has been capitalized on by many companies, such as D-Link. The D-Link Wireless HD Media Player is easy to mistake as a wireless HDMI device. But in fact it is simply a media server which has wireless networking capabilities. It connects to an HDTV using a standard HDMI port.
Wireless HDMI devices built for the purpose of transmitting HD video from one room to another are far more expensive. Gefen and Brite-view are two major manufacturers of these products right now and both have products which sell for well over $800 dollars. Even these products have their limitations as they are typically capable of 1080p at 24hz only.
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Range is Limited
The reason why wireless products actually capable of transmitting high-definition images with quality similar to a wired connection are expensive is that high definition content takes a huge amount of bandwidth. Uncompressed 1080p would require about 3Gbps of uninterrupted bandwidth in order to stream wirelessly from a source to an HDTV.
As a result the range of wireless HDMI tends to be quite limited. While line-of-sight ranges of up to 75 feet are possible with some products, it is rare that this kind of range will be useful in a home. That range is cut down by more than half if walls are in the way, as most wireless HDMI devices have a maximum range of 30 feet if line-of-sight is not available. And even that is often an exaggeration. The true range can be a lot less depending on the home.
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Another serious limitation of wireless HDMI is that most lack control over the source. They simply beam the information from the transmitter unit to the receiver unit. This can be an obvious problem. It might be interesting to be able to transmit HD video from a Blu-ray player in the den to an HDTV in the bedroom, but it won't be much fun to have to go downstairs to pause the movie!
Of course, there are ways to get around this problem. Many universal remotes have RF capability which allows them to control sources through walls if paired with a receiver capable of reading these signals. It is an issue to keep in mind, however, in order to prevent any nasty surprises.
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These problems might scare some thinking of purchasing a wireless HDMI product. They are certainly large obstacles, and at times they are insurmountable. That said, wireless HDMI products from Gefen and Bright-view are extremely useful in certain situations. Sometimes it just isn't practical or even possible to have an HDMI wire spanning across a home, and in these situations wireless HDMI is the obvious solution.