Tech Trends '09: HDTV Unplugged Page 2
While acknowledging that most source material comes into the home in compressed form, backers of WHDI say its ability to send uncompressed video most mimics wired connections. That's because compressed video is rarely available at the output of most A/V, gear due to copy protection (compressed video is more susceptible to theft) and to interoperability issues caused by the use of different video codecs. Of course, the counter argument is that since source material is compressed, there's no reason the compressed stream shouldn't be carried all the way to the display.
WHDI's key supporters include Sharp, which is using it in its ultra-slim TVs, and Sony, which incorporates Amimom's chips in its Bravia Link DMX-WL1 wireless system ($800), though it's limited to 1080i video. Non-TV offerings include Belkin's FlyWire ($1,500) and Gefen's GefenTV Wireless for HDMI 5-GHz extender ($900). FlyWire, with support for 1080p/24 video, includes a transmitter, receiver, remote control, and IR repeater. Gefen's system supports 1080p/30 video, 5.1-channel digital surround sound, and 2-channel analog audio.
If CES had any wireless winner, our money's on SiBeam's 60-GHz WiHD, which got a boost when LG, Panasonic, and Toshiba all promised add-on WiHD wireless capability for TVs this year. The technology is backed by a consortium that, in addition to those three companies, includes Broadcom, Intel, NEC, Samsung, and Sony.
At the heart of WiHD is SiBeam's OmniLink60, which sends uncompressed (or lossless) HD video by way of the unlicensed 60-GHz band, at rates up to 4 Gbps over a 30-foot range. Current chip sets support up to 1080p/60 video and 8-channel high-rez audio, but backers say the technology has a theoretical data rate as high as 25 Gbps, making it scalable for the higher resolutions and color depths that will come with next-generation panel technology (such as 4K displays). Like WHDI, it includes support for device control protocols (such as CEC), but it uses another Hollywood-approved copy-protection scheme called the Digital Transmission Content Protection (DTCP) protocol, originally developed for FireWire.
With its more limited range and its inability to pass signals through walls, WiHD is positioned as an in-room technology. (Devices can be hidden out of sight beyond a door, though.) While the 60-GHz spectrum has plenty of bandwidth to handle uncompressed high-def video, it's highly directional, so products have typically required line-of-sight operation. Another sticking point: 60-GHz waves can't pass through water, a major component of human bodies. That means that communication between devices can break down any time someone walks between a transmitter and receiver.
But OmniLink60 uses real-time adaptive "beam-steering" technology to provide non-line-of-sight operation. Employing tiny arrays of antennas, the system automatically surveys the room to find the best transmission path. If a direct path isn't available, it will bounce signals off walls, ceilings, floors, or even other objects. And if a transmission path gets blocked - say, by someone who's walking into the room - the system simply switches to the next best available path with no disruption of the video stream. It can also automatically detect new devices and add them to the in-room network.
Based on CES announcements, LG will offer separate WiHD media boxes for its 55-inch LHX and 47- and 55-inch LH-85 LCD models, as will Panasonic in its ultra-thin Z1 plasmas. Toshiba said it would have a WiHD adapter for its Regza LCD TVs later in the year, and Gefen will support the technology in its GefenTV Wireless for HDMI 60-GHz extender (price to be announced).