Now that HD video and audio is well established in nearly all AV installations from the most presentation show reel to the highest level of stage presentation, the next ‘must have’ technology is potentially wireless transmission of signals. Steve Montgomery reports.
Wireless will of course, save every installation considerable cost as well as making every application ridiculously simple to complete and outrageously profitable. It is, without doubt ‘the Holy Grail’ of high tech video installations. Or is it? Will it work; what is the point, what will it actually deliver? The more pertinent questions of: Is it reliable? and whether it makes practical sense are probably ones that we should be asking before taking considering any real applications any further.
It is early days and as ever in this type of industry, there are currently two competing technologies operating on different frequency bands and each vying for supremacy. Each lauded by its own industry body and backed by its own group of manufacturers, although some manufacturers have a foot in both camps. In no specific order: Wireless Home Digital Interface (WHDI) is: “The new wireless High Definition video standard that will change the way people use Audio/Video devices in the home. WHDI's revolutionary video-modem approach enables top-quality and robust wireless uncompressed HD video delivery throughout the home, allowing consumers to connect any source in the home to any display.” It was formed by a consortium of AMIMON, Hitachi, Motorola, Samsung, Sharp, Sony and LG Electronics. Conversely the Wireless HD interface: “Will serve as the first and only global specification to combine uncompressed high-definition video, multi-channel audio, intelligent format and control data, and Hollywood approved standard content protection techniques. For end-users, elimination of cables for audio and video dramatically simplifies home theatre system installation and eliminates the traditional need to locate source devices in the proximity of the display.” This body was the brainchild of a consortium of Broadcom, Intel, LG Electronics, Panasonic, Philips, NEC, Samsung, SiBEAM, Sony and Toshiba.
The inevitable comparison with network delivery of video using compressed packet switching technologies IP will be raised in any consideration of HD video transmission. The wireless 802.11n specification relates to general purpose wireless data delivery. WirelessHD and WHDI are specific to wireless delivery of video, audio and control. 802.11n can be used for streaming of HD video, however due to rate limitations it can only deliver compressed video. Wireless delivery of uncompressed HDTV supports all HD video sources that do not provide compressed video outputs, such as gaming consoles, PC graphics, BD players, DVD players and set-top-boxes. Critically HDCP content protection needs to be accommodated which is not possible in compressed transmission without sequential encoding and decoding at low resolution levels.
This technology is real. “The first generation chipsets received considerable interest, as AMIMON sold over 100,000 chipsets in 2008 and we expect increased demand for the second generation chipsets," said Noam Geri, vice president of marketing and business development for AMIMON. "AMIMON's first generation chipset made wireless HDTV in the home a reality; the second generation WHDI chipset will make mass-market, interoperable standard-based wireless connectivity in every home a reality.” Domestic TVs and Blu-ray players are available from Sony, LG, Hitachi. ABI Research forecasts that the world market for wireless video television installations will rise to 2.5 million by 2013. This in turn, will lead to more products destined for the professional AV market, supplementing devices from the likes of Gefen and Belkin that are already available.
The two wireless formats utilise different technologies to achieve essentially the same thing. According to Meir Feder, Chief Technology Officer, AMIMON: “WHDI is based on Joint Source Channel Coding (JSCC) which separates out the most important elements of a video signal and uses unequal error protection to protect them the most significant bits (MSBs) gets the greatest protection the least significant bits (LSBs) get less, combined with modulation control to allocate remaining channel capacity to send information that is less sensitive, so that JSCC utilizes capacity almost to its fullness, even in a varying bandwidth channel.” The result is that uncompressed HD at up to 1080p/60Hz can be transmitted over a range of 100 feet through walls, with a latency that is less than one millisecond; crucial for interactive applications. WirelessHD supports a technical specification that also tests for interoperability to deliver uncompressed HD audio and video at multi-gigabit rates in the unlicensed 60GHz band within one room at up to 10 metres. All products carrying the WirelessHD logo are required to pass the rigorous compliance and interoperability tests. WirelessHD is supported by SiBEAM’s unique Omnilink 60 adaptive beam steering technology that solves the line of sight challenges previously inherent with 60GHz signals.
This would appear to be very much a process of technology leading applications. In this case chipset availability from high-tech companies albeit ones that are sponsored and supported by large AV corporations, has produced a solution to a requirement. The next stage is for manufacturers to take that technology and apply it to their products. This evolutionary process has yielded two product branches: the first includes the use of these chipsets in AV equipment; displays, Blu-ray players, gaming consoles, set-top boxes and so on. The other opens up new product lines for system components such as wireless HD extenders. Sharp (wireless HDTV), Mitsubishi (wireless HDTV) and Sony (wireless HDTV and dongle) all have products based on AMIMON’s 1st generation chips.
Of greater interest to system integrators are the emerging ranges of wireless transmitter, receiver products that will allow the transmission of HD signals from point to point and are independent of display manufacturer. Marmitek’s GigaVideo800 HDMI can select up to four HDMI/HDCP devices and transmit them over 20 metres to a full HD display using WHDI technology. Melanie Jeuken, Marketing Communications Specialist at Mamitek commented: “It acts as a switching centre for all the HD sources in an installation, transmitting HDMI signals, uncompressed and wirelessly to your TV or projector. The receiver can be located behind your TV, to remove all visible HDMI cables. The IR commands will be transmitted back to the transmitter.”
The Gefen GTV HDMI Extender allows a wireless transmission of high definition video up to 1080p with 5.1 digital audio using 5Ghz technology by Amimon. “A Blu-ray player or set top box that is HDCP compliant can be delivered to one display or projector,” explained Hagai Gefen, President and CEO of Gefen Inc. “For digital signage purposes, one hi-def source can be sent to multiple displays, making it best suited for larger venues with a greater span than previous wireless solutions currently on the market. It operates in two modes: broadcast and unicast. In unicast mode, it delivers a point-to-point wireless transmission that is fully HDCP compliant up to 100 feet (30m) in distance. In broadcast mode, the GefenTV Wireless for HDMI 5Ghz Extender delivers several identical HDTV signals without HDCP compliance. In this mode, individual receivers are connected to each display or projector to transmit the hi-def video at the same distance.”
Whilst wireless transmission does seem like a good idea for some applications, the question of whether it is a sensible option for a particular installation is always open, specifically when considering the fact that some wiring always has to be done at a display point to feed power to the device. Kamran Ahmed, Senior Technology Advisor, Magenta Research voices a note of dissent: “Wireless extension is really only useful for board rooms or very small scale digital signage applications since the range for high definition uncompressed video is limited to about 30m as opposed to 600m for wired copper extension. Of course longer distances are possible but only at much reduced resolutions and/or highly compressed video formats. Most signage applications use a PC or equivalent as a source and have a mixture of video and non-video data so resolution and compression rates are a factor. In addition, wireless solutions are typically very limited in multi-point distribution support i.e. one transmitter can only drive a handful of receivers. Commercial signage applications often require tens, if not hundreds of displays which are far more easily and reliably supported on wired networks.”
It is a proven technology with potential; with significant application opportunities and one that can solve issues for integrators. In time it will become a more common and demanded solution and one that will undoubtedly become mainstream, just as others have before.