The wireless media question

Farpoint Group –

My older daughter, Stephanie, just wrapped up a successful college career at CMU. She did not get an engineering degree, in case you were wondering - she's a pretty good techie, but has her heart set on a career in politics, so it's off to Washington she's gone.

This means that, in addition to losing some pretty hefty college payments, I gain a spare room. And, as my wife knows all too well, a spare room is an invitation for either more space for wireless stuff, or a home theater - or both. OK, both it is. I have wanted to do a fully-wireless home theater for some time, and now's the perfect opportunity to give it a try. Plus, residential media distribution is assumed to be a huge opportunity for many new WLAN and UWB companies. (For examples, see Video54 and Freescale Semiconductor.)

While I'd like to tell you that all is well, I am sorry to report that a fully-wireless home theater mostly can't be done with today's technology. I'll return to the "mostly" part in a moment, but for now, the basics.

It appears that the home entertainment folks are crystallizing around the HDMI (High Definition Multimedia Interface) specification. You can find HDMI connectors on a variety of equipment today, mostly TVs/monitors and DVD players. HDMI is essentially the familiar DVI (Digital Visual Interface) implementation with the addition of eight-channel audio and a new connector. DVI is already popular in the computer world and on some home-entertainment equipment, but it appears that HDMI will be the path forward, at least partially because HDMI can also support copy protection in the form of the High-bandwidth Digital Content Protection (HDCP) specification. Notwithstanding that I'm totally unclear on why content protection should be required between a player and a display, expect the HDMI/HDCP combo to be the basis of home entertainment electronics for some time to come.

And the reason for this is that HDMI is a no-compromise, up-to-5 Gbps, uncompressed channel that can, with the right cables, run for 15 meters over copper, and much longer over fiber. Still, as a wireless guy, my goal was to be able to move video from any source, anywhere in the house, to anywhere else in the house, without running expensive cables all over the place. (Have you checked the prices for cables - any kind of cables, especially those based on new technologies like HDMI? In my next life, I'm going into the cable business. These guys must be cleaning up!)

Alas, it's the uncompressed nature of HDMI that gets in the way. Do the math: 480p EDTV requires about 500 Mbps, and full 1080p will suck down the entire 5 Gbps available on HDMI! There are, as I noted above, no wireless technologies available to us mere mortals today that can do this. I'm expecting 500 Mbps (effective throughput) UWB at some point over the next year, but not in inexpensive HDMI adapters, and not with a range of more than a few meters at that data rate.

So, we have two choices. One is to use wire. But I really wanted to avoid running more coax and renting another cable box, and buying a $250 HDMI cable, so a simple "video sender" would be nice. I'm expecting some based on pre-N MIMO technology at some point, but I've heard there may be legal issues with the Digital Millennium Copyright Act. It's certainly understandable that those developing digital content (and that's effectively all entertainment content today) want to protect their property. But what we have here is fundamentally a cultural issue. I expect to be able to record, for my own use, entertainment content in any form. And the hackers out there will figure out a way to break content encryption techniques with little problem, so let's move on already.

The other option (returning to the "mostly" above) is to compress the video, a standard technique today, and then send this compressed stream wirelessly. Good compression can reduce data volumes by a factor of ten or more, making even high-end video reasonable over wireless within a few years. But will that be acceptable in a home theater DVD application? We won't know until we try. I should note that all of the digital content you get off cable and satellite is already compressed, but it's nowhere near as good as what you can get off a good DVD player with HDMI. (Here, by the way, is the DVD player I use.)

Anyway, a truly wireless, HDTV-quality home entertainment system remains my goal, and I'll keep you posted on my progress. For now, though, it's a wired world.

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