Like so many modern computing experiences, Miracast is a great idea, implemented almost (but not quite) well enough to be used by mere mortals.
The Miracast standard, maintained by the Wi-Fi Alliance, is designed for mirroring a display and streaming high-definition content (with 5.1 surround sound) between mobile devices and large displays.
In theory, you can wirelessly stream the display from a Miracast-enabled phone or tablet to a Miracast-compatible receiver, such as a TV, with perfect fidelity. If the TV isn’t Miracast-ready, you can plug an adapter into a spare HDMI port.
After pairing the two devices, you can duplicate the display on your handheld device to a much larger screen, allowing you to wirelessly project a PowerPoint presentation to a conference room TV, watch a livestream in your living room, or cue up a music playlist for a party.
(As an aside: If this all sounds familiar, it’s because Apple’s AirPlay and Google’s ChromeCast offer similar features, without the noble promise of standards-based interoperability. AirPlay Mirroring works with Apple TV and iOS devices. ChromeCast does most of its magic through web apps that only run in the Google Chrome browser, and screen mirroring requires an Android 4.2 or later device.)
That’s the theory. In practice, based on my initial experience, I can tell you that Miracast is delightful when it works and maddening when something goes wrong.
Although the Miracast standard is relatively new, the technology behind it is well-tested, and there are an increasing number of compatible devices on the market. Popular adapters include the Netgear PTV3000 Push2TV Wireless Display Adapter, the Actiontec Screenbeam line, and Belkin's Miracast Video Adapter. Miracast support is also built into some TVs and Blu-ray players.
Last weekend, I spread out an assortment of tablets and smartphones, plugged a fresh-from-the-box Belkin Miracast Video Adapter into the nearly new 58-inch Panasonic TV in our living room, and asked my wife for her patience and forbearance as I tested different scenarios.
After plugging the Miracast adapter in to an empty HDMI input and connecting its power input to a USB port on the TV, I tinkered with the device briefly, just long enough to determine that it needed a firmware update. (As it turned out, there was a software update available for the TV as well.)
Updating the embedded code on the Belkin adapter required downloading a firmware file to a local PC and then powering up the device while holding down a button on the tiny HDMI dongle. That replaced the normal “Connect a device” screen with a setup screen on the TV.
Next, I had to use a web browser to connect to the device using its built-in Wi-Fi hotspot (normally hidden and visible only in setup mode) and navigate to a specific IP address to choose the firmware update, which was accompanied by this weird description.
The update hung on the first try but succeeded the second time around. After restarting, I noticed that the onscreen interface was noticeably cleaner and included specific instructions for Windows 8.1 and Android.
A Miracast receiver (in this case, my TV with the Miracast adapter) uses Wi-Fi Direct to turn itself into a special-purpose wireless hotspot. Connecting a Miracast-compatible device to that invisible hotspot allows the device to mirror or extend its display to the larger screen.
To connect a Windows 8.1 device to a Miracast receiver, you use the Project option on the Devices charm. The first time you encounter a Miracast adapter, you're prompted to add it. On subsequent visits, that device should be available as a target for the Project option.
Connecting an Android device involves searching for the equivalent command, which might be buried in the Settings menu or be controlled by an app.
After the connection is made, you can use the touchscreen on a mobile device such as a phone or tablet to control the output.
With that introduction out of the way, how did my assortment of devices fare?