Well, that graph says it all, doesn't it? This is the Windows Media Center Network Performance Tuner in action and it could spell doom for HDTV over WiFi. Let me explain a little. We showed you a video where we streamed high-def content from a Media Center PC to an Xbox 360 via WiFi. Luckily it all worked out, but there's some things you need to know if you plan to go this route.
If you recall, we were demonstrating the Windows Media Extender technology with the Xbox 360 for high-def. I'll say right up front, it works as advertised: you can stream high-definition content to the 360 that's hooked up to an HDTV set. I've been completely impressed with the quality of the streaming; both recorded HD as well as live. The best way to say it: there is no noticeable difference if I'm watching HD via my over-the-air tuner or from the Xbox 360.
So what's the kicker? Bandwidth, baby...bandwidth. Those MPEG-2 streams I used to watch OTA can be up to 19.39 megabits-per-second. If you don't have the pipe for that bandwidth, your video will be choppy, will stutter, or will even be dropped for a time.
"OK," you say, "so for me to do this via WiFi, I need to have fast WiFi capability." You guessed it, but your options are VERY limited if you want to use the Xbox 360 for one reason and one reason only. The WiFi adapter for the unit is capable of the three main 802.11x standards: a, b, and g. Don't even consider the 802.11b network for this purpose. It's fine for Xbox Live, but the 11 Mbps speed won't even come close for high-def streaming.
This gives you the 802.11a or 802.11g choices, both of which are advertised at up to 54 Mbps. Sounds plenty fast enough, right? On paper, yes; in practice, not necessarily as evidenced by the graph below. For example: I'm using an 802.11g router in my office. My office is on the second floor of my home and the Xbox 360 is in the room directly below the office. The direct distance between the router and the 360 is roughly 15 feet and there are no metal vents or anything else in the floor between the two. I also have the Linksys Range Extender antennas on the router that boost the signal 7 dbs.
You can see that until I positioned the router antennas "just right" I didn't have a signal stable enough for high-def streaming. Even when I did, I'm cutting it really close as evidenced by hours of actual testing. All it takes is for one of our cats to walk past the 360 and we get a stutter or two (on the video, not on the cats!)
So, what can you do? Well, Microsoft does provide a website that makes some suggestions, but most of these were common sense to me. "Don't hide your router behind a plant" should be a standard rule for WiFi users in general. There were some valid suggestions that might help, however.
First off, if you can use an 802.11a router, you're less likely to have interference from other radio signals. The 802.11a routers run at 5 Ghz, while the 802.11b & g routers run on the 2.4 Ghz spectrum, making them more succeptable to interferance. You can also try different radio channels on your router to see if that helps.
One thing that did help was getting my router out of "mixed mode". Mixed mode provides backwards compatibility for 802.11b routers, but it slows down the network as a whole. Your router configuration may be different, but on my Linksys, it was a simple task to run in the faster "g" mode only. This will prevent devices that have a "b" radio from accessing your network, but it does keep things humming a little faster.
The other thing I did on my own (this wasn't indicated as a tip from Microsoft) was to enable Frame Bursting. Again, your router may not have this function or it may be called something different.
After trying to take advantage of the WiFi streaming for high-def, I'm a little disappointed. As I mentioned, the quality of the video is great, but only when you can see via your network. 802.11 a, b, and g standards for WiFi are getting a little old and tired. Additionally, the real throughput is essentially half of the advertised speed; and that's a best case scenario.
It would have been nice for Microsoft to offer a wireless network adapter with one of the newer WiFi standards, such as Super-G, MIMO, pre-N, etc.... I'm sure they will, but of course then I'll have to shell out more dollars and dump the $99 adapter I bought! In the end, I'll likely go with a wired connection, so watch for updates on the project.
If you have any other suggestions to help speed up the HDTV over WiFi, we're all