WHDI vs WiHD? VHS vs Betamax again?
Wireless is one of today’s hot buzzwords. My last post was about connecting rear speakers in a surround system wirelessly (sort of). This post is about sending audio/video signals, specifically of HD-quality normally associated with the HDMI (High Definition Multimedia Interface) wired connection prevalent in today’ TVs, DVDs, Cable and Satellite systems.
The powers that be have been working on this issue since 2007 and have come up with approaches to the problem that are supported by some of the biggest names in the electronics business. These solutions cost $1000 or so until recently. Now the price is down to around $200, and promises to be much less in the not-too-distant future. In fact, solutions have been implemented at the chip level and will be embedded into equipment including TVs, receivers, computers, tablets, etc. where the incremental cost will hardly be noticed.
Unfortunately, there are two competing technologies, reminiscent of the VHS – Betamax confrontation of decades ago, with a big difference. That is, the same companies are supporting both technologies, hedging their bets as it were. The two technologies are called WHDI (Wireless Home Digital Interface) and WiHD (Wireless High Definition). Neither of them have beed adopted by any recognized international standards body (such as the IEEE) and are sponsored by the euphemistic word “Consortium.” To further confuse the consumer, there is something called Intel Wireless Display, or WiDi!
In any event, the objective is to eliminate the need for connecting an HDMI source device (cable receiver, DVD player, computer, etc.) from an HDMI playing device (TV, tablet, etc.). This capability is especially useful when the TV is mounted in a location that is remote from the source equipment.
If you buy a kit to add to an existing equipment setup, you will get a transmitter that plugs into the source equipment’s HDMI-out jack and a receiver that plugs into the TV’s HDMI-in jack. One or both devices aren’t needed if the technology is built-in to the equipment, assuming both the sending and receiving devices are using the same technology. Your next question (obviously) is – Which technology should I choose?
That is a tough one to answer, just like the VHS-Betamax query of yore. WHDI was created by an Israeli semiconductor company called Amimon. The technology uses the 5- 6 GHz carrier band, the same as some wifi networks, wireless telephones and other consumer devices. WiHD uses a 60 GHz carrier frequency, which is currently unoccupied by almost anything else one is like to encounter in a home. Its adherents claim that nothing will interfere with its signals.
However, the laws of physics dictate that the higher the frequency, the shorter the range. Early adopters report that WiHD works well for line-of-sight up to 30-odd feet, while WHDI devotees claim that the signal will go through walls and accommodate distances up to 100 feet. Thus it would seem that the WHDI solution is more flexible. Indeed, it is the technology used in the heavily advertised AT&T U-Verse receivers touted to be able to wirelessly broadcast a signal to up to four TVs in a single home.
However, at this stage of the game, it may be dangerous to jump to conclusions. If you peruse the many online forums dealing with the subject, you will find that user experiences with either technology are all over the map, ranging from excellent to awful. Besides the range and line-of-site issues, others are latency and whether or not video compression is used. The watch-phrase is “Don’t buy an HDMI wireless system unless you can return it.”
Back to WiDi. This is nothing more than WHDI circuitry embedded in some Intel laptop chips. The idea is that anything you can see on your laptop can be sent wirelessly to any device supporting the WHDI standard. It is currently being promoted by Dell (as one example) under the banner “Connected Home.”
A note of caution: Many of the many wireless HDMI kits on the market come in packaging that does not state which technology is being used, nor does its advertising. Therefore, if you want one that supports WiHD, you might well buy one that supports WHDI. As usual, do your homework before laying out your money. I also recommend that you peruse the forums (e.g. http://www.avsforum.com) on this subject and read the product reviews by users and independent agencies like ZDNet and CNET.