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?
Here's what happened when I tried a variety of PCs and mobile devices with a Miracast-equipped TV.
Windows 8.1 devices
Miracast is a signature feature of Windows 8.1, so one hopes that it would work well with devices running the latest release of Windows. And with one exception, that was true.
I had the best results with the Surface Pro family, starting with the Surface Pro 3 and working backwards through the Surface Pro 2 and original Surface Pro. All three devices connected to the Miracast receiver with a minimum of fuss and played audio and video nearly perfectly, with only occasional, very minor glitches.
Two Acer laptops delivered less satisfying results. The 13-inch Acer S7-392 laptop was able to connect to the Miracast adapter but couldn't stream a high-definition movie from Xbox Video without serious glitching and, eventually, disconnecting. The 11-inch Acer S7-191, despite having all the correct drivers, was completely unable to recognize the wireless display feature. Hours of troubleshooting couldn't make this one work.
Dell's diminutive Venue 8 Pro was a model Miracast citizen, making a rock-solid connection. I had problems setting up a second Venue 8 Pro, which only allowed me to extend the display instead of mirroring it, and also stubbornly refused to switch out of portrait mode. Both problems were resolved with a chipset driver update.
It's worth noting that the Acer and Dell devices are not on Belkin's compatibility list.
Windows RT 8.1 devices
Microsoft's Surface 2, running Windows RT, worked nearly perfectly, connecting to the Miracast adapter immediately and streaming audio and video reliably. I saw occasional minor glitches, but they were only mildly annoying, and the ARM processor was more than powerful enough to handle everything I threw at it.
I also tried delivering a PowerPoint presentation from the Surface 2, with superb results. PowerPoint recognized the external display and switched the device into Presentation Mode, projecting the slides on the external display with my notes and navigation controls on the lightweight tablet. When I exited PowerPoint, it resumed mirroring.
The screen below shows what I saw when I looked at the Surface; my audience saw the full presentation.
I had much less satisfying results with a Nokia Lumia 2520 tablet, also running Windows RT 8.1. Although I know others who have successfully used this device with a Miracast adapter, I couldn't make the connection work. After a few seconds of trying, the adapter simply reported "Connection failed."
Android and Kindle Fire OS devices
I had two Android devices available for Miracast testing. Alas, neither one is on Belkin's compatibility list for the Miracast adapter.
Dell's Venue 8, which is physically nearly identical to the Venue 8 Pro, runs the latest version of Android (KitKat), but doesn't include the necessary options under the Display command in Settings. I tried several third-party Miracast apps for Android and was occasionally able to see the remote display but couldn't connect to it.
The low-cost Moto G phone, also running Android KitKat, experienced identical issues.
Had I been using a more powerful (and expensive) Android device, such as the Moto X or any Samsung Galaxy device running Android 4.2.2 or later, I probably would have had better results.
If you're thinking of using this device, check that compatibility list carefully. According to Belkin, Google's Nexus 7 and Nexus 10 tablets do not support Miracast and will not work. Likewise, there are workarounds and potential gotchas for a host of devices that are on the list.
Two Kindle Fire HDX devices, on the other hand, are both listed as fully compatible, and I had no problems connecting with them. Both the seven-inch and 8.9-inch tablets offered Wireless Display options under the Settings menu and played content from Amazon Instant Video and Amazon Music without any issues.
The bottom line
The promise of Miracast is the ability to connect any standards-compliant device to a Miracast receiver quickly and easily. In my testing, I found enough differences in device support to recommend caution before relying on Miracast.
You'll have best results with devices that are certified as compatible, including the entire Surface family and most high-end Android devices.
For my household, Miracast will be mostly an entertainment option, projecting YouTube videos and the occasional webcast to a larger screen. I would also recommend this setup for a corporate conference room or a classroom, where the Miracast adapter could be permanently attached to a large-screen display. As long as employees (or students and teachers) have compatible devices, this is the ideal way to deliver a PowerPoint presentation.