What is Miracast and Why Should I Care?

miracast 2

Miracast is a wireless display standard designed for mirroring a smartphone, tablet, or PC’s screen to a television without requiring any physical HDMI cables. It’s becoming more widespread with each passing day.

The Roku 3 and Roku Streaming Stick recently gained support for Miracast. Amazon’s Fire TV and Fire TV stick also do Miracast. Microsoft it even selling two Miracast dongles of its own, for some reason.

Miracast is Like a Wireless HDMI Cable

Miracast is a standard that hopes to one day banish the need for HDMI cables. Rather than physically connecting your laptop, smartphone, or tablet to a TV like you would with an HDMI cable, Miracast provides a wireless standard that allows devices to discover each other, connect to each other, and mirror the contents of their screen wirelessly.

Unlike protocols like Apple’s AirPlay (on the Apple TV) and Google’s Chromecast (on the Chromecast and Android TV devices), Miracast is designed to be a cross-platform standard. Check out our comparison of AirPlay, Miracast, WiDi, Chromecast, and DLNA to understand the differences between all these different protocols.

Miracast functions exclusively as a “screen mirroring” protocol. So, if you wanted to start a Netflix video on your phone and play it via Miracast, you’d have to leave your phone’s screen on the whole time. Everything on your phone’s screen would be mirrored on the TV.

Because it’s all about screen mirroring and doesn’t have the “smarts” you see in protocols like AirPlay and Chromecast, which can hand-off streaming to another device and display a different interface on one device’s screen, Miracast can best be thought of like a wireless HDMI cable.

roku screen mirroring beta

Which Operating Systems and Devices Support Miracast

Computers running Windows 8.1 and phones running Windows Phone 8.1 can stream to Miracast devices. Android phones and tablets running Android 4.2 or newer can also stream to Miracast devices. Amazon’s Fire OS is built on top of Android, so it also supports Miracast.

Linux PCs will require some sort of unsupported hack to do this, Chromebooks don’t have native Miracast support, and Apple’s Macs and iOS devices support AIrPlay and not this open standard. It’s basically Windows and Android only, for now.

As we mentioned above, the Roku 3 and Roku Streaming Stick are now Miracast-compatible. Microsoft sells two of their own Miracast receivers, named the Microsoft Screen Sharing for Lumia Phones (HD-10) and the Microsoft Wireless Display Adapter. Amazon’s Fire TV has Miracast integrated, and so does their new Fire TV Stick — a $39 device with Miracast support built in. There are also many other dedicated Miracast receivers you can buy.

In theory, Miracast should become increasingly widespread, even being integrated into TVs themselves so you can easily wirelessly stream to them.

roku streaming stick now supports miracast

Miracast Problem 1: It’s Only Screen Mirroring

Miracast is a great idea in theory. It should be open standard for wireless display streaming that every manufacturer can implement, allowing devices to just work with each other. It would be great to be able to walk into a hotel room and easily mirror your device’s screen on its TV, or walk into an office and wirelessly connect to a TV so you could give a presentation without messing with cables. Miracast promises to banish the HDMI cable.

In practice, even if Miracast worked perfectly, the core design would still be a problem. Banishing the HDMI cable is nice, but Miracast doesn’t have the “smarts” competing protocols offer. Both Apple’s AirPlay and Google’s Chromecast can mirror a device’s screen — yes, a Chromecast can even mirror your Windows desktop and all your running applications. However, they can also be smarter.

For example, you could open the Netflix app on your phone, locate a movie you want to watch, and tap the Chromecast button. Your phone would then tell the Chromecast to play the video, and the CHromecast would connect to the web and stream it directly. You could then set your phone down and it would go to sleep. With Miracast, your phone’s screen would have to stay powered-on and streaming the video for the entire length of the Netflix movie, draining its battery.

These protocols also allow you to display something different on your device’s screen and on your TV. So you could watch a Netflix video and view the playback controls only on your phone, so they wouldn’t get in the way on the TV. Or, you could play a video game and view only the game world on the screen, with a separate set of controls on your phone. With Miracast, you can’t have separate controls on your phone — your TV just mirrors everything on your phone’s display.

Miracast could be a good solution for replacing HDMI cables with a wireless protocol, but it’s inconvenient for many of the things people use Chromecast and AirPlay for in the living room.

Miracast Problem 2: It’s Unreliable and Often Doesn’t Work

But here’s the biggest problem with Miracast. It’s an open standard and Miracast-certified devices are supposed to communicate just fine with other Miracast-certified devices. However, they often don’t. If you look at help pages for devices like the Roku 3, you’ll often see a list of devices that have been tested to work with the receiver. This shouldn’t be necessary if it was a proper standard — you don’t need to check if your model of phone or laptop is compatible with your Wi-Fi router, after all.

Time and time again, both coordinated tests and people trying to use Miracast in the real world have struggled to make it work. We tried getting Miracast working on a Roku 3 after enabling the new Screen Sharing feature and were unable to, both with a Nexus 4 running Android 4.4.4 and a Surface Pro 2 running Windows 8.1. Both are officially approved devices Roku says will work, but they all hang on a “Connecting” message before timing out without any helpful status messages.

This shouldn’t be because of a problem with our Wi-Fi network, as Miracast is supposed to use Wi-Fi Direct. This means Miracast devices can even work where no Wi-Fi network is present — the devices connect directly to each other, bypassing the standard Wi-Fi network and wireless router.


MIracast is nice in theory, but it’s also just a wireless HDMI cable. In many situations, you’re often just better off plugging in an HDMI cable rather than dealing with the potential connection problems and streaming glitches.

A new generation of Miracast receivers and Miracast-capable operating systems could potentially solve these problems and turn MIracast into a standard that works well. We can only hope that will happen.

Image Credit: Sam Churchill on Flickr, John Biehler on Flickr

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 11/6/14
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