- Written by Chris Heinonen
- Published on 11 May 2012
The Solutions for the Wireless HDMI Round Up
I tested three different solutions: The Belkin ScreenCast AV 4, the IOGear Wireless 3D Digital Kit, and the DVDO Air. Each product was just a little bit different from each the other models and fit different solutions. The Belkin AV 4 was intended to serve as your HDMI switching station, with 4 HDMI inputs that you can switch between from the included remote, it can make all of your HDMI devices wireless without an additional switcher. The IOGear solution has 2 HDMI inputs, so it can switch between inputs as well, but also includes an HDMI output so it can be used to display the same HDMI source on two displays at once. The DVDO has a single input, so it's meant to be paired with a receiver or processor, and then take the HDMI output from that to be sent to your display or projector.
The solutions also differed in the technology they used. Both Belkin and IOGear went with 5 GHz WHDI-compatible devices. The 5 GHz Wi-Fi spectrum is often far cleaner with less interference than the 2.4 GHz spectrum, and can allow faster transfer speeds. Both also use 4 antennas to transmit and a 40 MHz bandwidth so they are capable of up to 600 megabits per second. This is more than enough to handle a 1080p signal at Blu-ray or HDTV bitrates, which are compressed, but not a fully uncompressed signal. These wireless speeds were not available just a couple of years ago, which is why earlier wireless streaming options didn't really perform well.
The higher frequency also means that it has a lower range than 2.4 GHz so the maximum range is 100 feet with line-of-sight. The DVDO solution uses the far less common 60 GHz frequency spectrum, which is almost completely devoid of any interference. However a frequency this high means that going through walls is simply impossible, as signals will just bounce off. The DVDO is designed to reflect off a single surface, so you can bounce your signal off a wall or ceiling, but otherwise you will need some line-of-sight to make it work. The higher frequency also allows for a maximum data rate of almost 3Gb/sec, or five times faster than the 5 GHz solutions.
All of these solutions promise uncompressed 1080p video and 5.1 audio at the minimum, but there are small differences beyond that. Belkin says they send all their video at YCbCr 4:4:4 uncompressed, so you should try to set your devices to that format, but they only send audio as Dolby Digital or DTS and not the lossless formats. IOGear also promises uncompressed 1080p but also can do lossless audio with 5.1 channels instead of just the lossy formats. Of course delivering lossless audio in addition to lossless video means the IOGear might need a better connection for perfect quality. DVDO is able to move beyond these, promising 7.1 channels of uncompressed audio to go with your uncompressed video, so the compromise with walls does offer more functionality.
Of course the maximum bandwidth of the 5 GHz solutions suggest there would have to be some compression going on, but all of our HD sources are already compressed to save on bandwidth. Using both test patterns and native content, I didn't notice any additional compression artifacts in the images, so there seems to be enough headroom for these to work just fine with our current content.