Intel Wireless Display: From Your Notebook To The Big Screen

Wireless Display, In Depth

If you read some of the preliminary coverage on Wireless Display, then you undoubtedly saw gripes about lots of latency between the host notebook and client output. This is absolutely the case. According to Intel, the technology was never meant to be interactive (allowing you to play a game on the laptop through the TV, for example). Instead, it enables a “kick back and watch” usage model, compelling you to fire up a television show on Hulu or a PowerPoint presentation and take your hands off of the laptop. Understanding why this is the case requires a little background on what’s happening behind the scenes.

At the heart of this technology you’ll find Intel’s My WiFi and Wireless Display software, running on the notebook. Wireless Display grabs the desktop frame buffer and encodes it at 30 frames per second. In the first software release, the technology supported resolutions of up to 1280x800. But the latest version adds 1366x768 to the list—the native resolution of our Dell Studio test subject. To the video, Intel’s encoder adds two-channel audio, multiplexing it into an MPEG-2 stream transmitted over WiFi to the Netgear adapter using Real Time Streaming Protocol (RTSP). The adapter decodes the stream and renders it out to the HDMI output.

Now, on the television side, extended display identification data (EDID) establishes the compatible display resolution, audio capabilities, and so on of a display device. Netgear’s Push2TV adapter reads that data structure and scales the output accordingly.

The stream itself is variable bitrate. When you’re looking at the desktop, it’s around 6 Mb/s. If you’re playing back video with lots of motion, it scales up to about 9 Mb/s. Audio adds another 1 Mb/s or so. Intel keeps the stream at this level on purpose. You see, the connection between the notebook and adapter employs 802.11g, with theoretical bandwidth of 54 Mb/s. But as with all theoretical throughput rates, the real world is a lot different. Practically, the connection is good for somewhere between 22 and 24 Mb/s. Keeping Wireless Display below 50% of that pipe leaves room for other devices on the Personal Area Network (PAN). Or, the difference can be used to cope with interference.

In addition to enabling the PAN utilizes by Wireless Display, the same Centrino networking module also connects to the Internet over a standard WLAN. Intel’s My WiFi software is the key to making this dual-network scheme possible. It allows the hardware adapter to be timeshared between serving as an access point to the PAN and a client on the WLAN simultaneously. Complex though it might sound, the Wireless Display software component controls the My WiFi SDK, hiding the networking aspect of the PAN. You enter that four-digit security code during initial setup, and that’s it. The network is enabled and disabled based on the presence of the Netgear adapter transparently.

Update: A while back, Nvidia asked me about Intel's plans with regard to the relationship between Wireless Display and its own Optimus technology. Nvidia already claims the two technologies work well together, so I can only assume it's afraid Intel will block the use of Wireless Display on Optimus-enabled notebooks. I asked Intel to weigh in, but was answered back with "we can't comment on other companies' products." In other words, Wireless Display may or may not work with Optimus-enabled platforms moving forward.

Chris Angelini
Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.
  • blashyrkh
    hmm.... First we had computer hacking over wifi. Now we'll have TV signal hacking over wifi!! Hehehe!!!
    Why don't we check what the neighbors are watching!! Oh!! It's home made pron!! Good for me!!

  • SchizoFrog
    blashyrkhhmm.... First we had computer hacking over wifi. Now we'll have TV signal hacking over wifi!! Hehehe!!! Why don't we check what the neighbors are watching!! Oh!! It's home made pron!! Good for me!!/lolJust be careful with the porn... Yo might find it's a lesbian couple in their 70's acting out '2 girls, 1 cup'... *Instant spinal shivers...*
  • taltamir
    what an epic fail... a locked tech that requires you to use an intel laptop with locked software? arrg!

    I wanted this to stream from my desktop to my TV in the other room. Now they tell me that if I want to buy this I have to buy an intel laptop with their "HD" video (lowest performing video card on the market)

    this sucks.
  • JohnnyLucky
    Interesting article.
  • twisted politiks
    getting there, now give me a wireless card for my desktop coupled with an HDMI to wifi plug thing-a-majig to plug into the back of my t.v. so i can do this without buying another computer, adding to my already 5 computers under one roof. honestly, how hard can it be?
  • alexcheng
    Am I to be expecting to see desktop monitors all with wireless connection in another 6 months??? ;0

    But good idea... now I can take my 55" TV to my bathroom! xD
  • huron
    Seems like a nice bonus, but not a real viable option because of all the restrictions. With some nice improvements, this could be a cool technology.
  • cknobman
    I still prefer my Kodak HD MediaServer I picked up for $50 on woot. Streams anything I want from my media server (dvd and bluray if I choose) either wireless or hard line and is connected to my TV via HDMI. Picture so good I cant complain although it did take some tweaking of my network to run smooth. Had to reposition my wireless router to be more central in home. Stupid cheap ass Verizon ActionTek router sucks so I may upgrade to a new router soon.

    Best $50 I ever spent.
  • I stopped reading the article after reading "WoW dailies..."
  • RazberyBandit
    Besides the already mentioned locked tech in Intel laptops, it only has 2-channel audio? That's definitely not what I have in mind when I think of "Home Theater" at all. No thanks.