If you are thinking of setting up a home theater and don't want to worry about where to put your media playback equipment relative to the TV, a WHDI device could be the answer.
Wireless Digital Home Interface is a technology designed to wirelessly connect video playback devices to displays. Members of the WHDI consortium, which includes Hitachi, Motorola, Samsung, Sharp, Sony, LG and founding member Amimon, are promoting it as "the only viable option available for connecting the content on all HD devices to the TV."
Strictly speaking this isn't true because HD-capable computers without HDMI sockets can be connected to an HDTV using a USB device like Warpia's StreamHD. WHDI technology is superior, however, to the extent that it delivers lag free, picture-perfect video in true plug-and-play fashion (i.e., without the need to install software drivers).
Recently I was given an opportunity to test Amimon's WHDI Stick, a two-part device that is similar in principle to the StreamHD but that connects via HDMI rather than USB. Amimon makes the WHDI Stick but doesn't sell it directly. Currently it is available under the Galaxy brand in China. Companies in Europe and the U.S. will be able to put their logos on it later this year. The review sample I was sent is sold by Crystal Video Technology Company from Shenzhen, China.
Like the StreamHD, the WHDI Stick consists of a transmitter and a receiver. The former (above) looks like a fat USB wireless Internet adapter, while the latter (below) is about the size of a moderately thick paperback book. The receiver I tested was decorated with a pleasant swirling graphic and came with a cradle that allowed it to stand upright or lay flat.
In addition to these two components, the Crystal Video package contained a small remote control, a power adapter, a USB cable, a regular HDMI cable and an HDMI extender. The last of these is provided for situations where you can't plug the transmitter straight into a device because another cable gets in the way of the Stick's power chord. The power for the transmitter and receiver can be delivered via mini USB sockets hooked up to a suitably equipped A/V component. The receiver also has a mains input that the included power adapter plugs into.
In principle all you have to do to set up the WHDI Stick is plug the transmitter into the HDMI output on a video playback device such as a Blu-ray disc player or games console, connect the receiver to one of HDMI inputs on an HDTV, attach power supplies to each component and wait for them to connect. Each device has two small lights, red on the transmitter and green on the receiver. One light indicates when a wireless connection has been made between the transmitter and receiver and the other shows when video is being sent or received.
Getting the components to connect consistently was the main problem I had with the sample I was sent. Sometimes the receiver would detect the transmitter within a few seconds. On other occasions I would get a message on the TV saying they were connecting but they didn't. There were also occasions when I would start up the device and for no apparent reason be told that the wireless was off. These issues happened even when the transmitter and receiver were only a few feet apart.
I could often rectify a failed connection by unplugging the power supply from both devices and reattaching it. A more reliable solution, however, was to leave the transmitter and receiver powered on all the time. The downside of this was that I couldn't turn them off at night with the rest of my A/V system to reduce power consumption.
Even when the above workaround worked for the wireless connection, I found that the video signal wouldn't always go through when I turned on the device it was coming from. Again, this could generally be corrected by removing and replacing the power cords. If this is a problem with all Sticks and not just the one I received, however, some users may find it more annoying than the sight of cables, which are effectively guaranteed to connect until they fail altogether.
To test whether these are issues with WHDI devices in general, I compared the performance of the WHDI Stick with that of ASUS' WiCast. The WiCast, which is similar in form and function and uses WHDI technology, was able to establish a reliable wireless and video signal between transmitter and receiver almost every time. The inference, therefore, is that the connection problems I encountered were with the Stick I was testing.
When I did get the WHDI Stick to make a connection between video source and TV it produced excellent picture and sound quality at standard definition and full HD (1080p). Video quality was only negligibly lower than that achieved via a wired connection and showed no perceptible lag, stuttering or pixilation. The WHDI Stick could even handle HDCP-encoded content. I tested it using Disney-Pixar's Cars on Blu-ray and the disc played without a problem. Amimon claims that the Stick will also work with Blu-ray 3D.
One of the advantages of the WHDI Stick over the WiCast is that it is designed so that a single receiver can be connected to more than one transmitter. Using the remote control it should be possible to switch between devices via an on-screen menu in the same way that you switch between video sources if you use an HDMI hub. Assuming that having multiple transmitters connecting to one receiver isn't undermined by the connection issues I encountered, this could provide an efficient way to link the various components of a home theater system while only using one of the TV's HDMI inputs.
Amimon has incorporated the capacity for firmware upgrades in the WHDI Stick. This is another advantage it has over the WiCast and gives Amimon and resellers the opportunity to fix some inherent flaws and add functionality. The Stick is also less bulky than its Asus equivalent. Moreover, Amimon has said that it intends to make these devices self-powered in the future, which would eliminate the need for power cables.
Given its relatively small size and ability to transmit high quality full HD and HDCP-encoded content, the WHDI Stick has the edge over the WiCast and the StreamHD for laptop and tablet applications. These features make it a convenient, if relatively expensive, add-on that allows a portable computer to be used with an HDTV for making business and educational presentations and as a media server, games machine or Blu-ray disc player.
The biggest downside of the WHDI Stick is its price. It is expected to retail in North America for around $120 to $150. By contrast, a decent HDMI cable can be bought for $20. Unless the price of the Stick comes down many consumers might decide they don't care enough about hiding the wires to justify the cost. On the other hand, if you are someone who doesn't want to have your home theater equipment close to the TV or put wires through your walls, the WHDI Stick might be worth the investment.
In principle the WHDI Stick is a neat device with enough useful applications to justify its existence. Enabling wireless connectivity between multimedia devices is a great idea and the WHDI Stick could be a practical solution in scenarios where cables are undesirable even with the issues I encountered. It's more flexible than USB-based wireless video solutions, produces a better quality picture, can transmit pretty much anything and isn't hindered by the compatibility issues that plague DLNA. With its capacity for future firmware upgrades, it also has lots of potential.
