When Amazon recently launched the 4K Fire TV, it arrived with a marketing campaign touting all of its noteworthy features, including something called screen mirroring with Miracast.
But Fire TV isn't the only device with Miracast, which is a wireless display and video streaming standard. Miracast is supported across a wide range of televisions, sticks, dongles, and set-top boxes. It lets you duplicate whatever you see on the screen of one device onto a different device's display - without an HDMI cable or network connection.
If you think Miracast sounds a lot like Google's Chromecast or Apple's AirPlay, you're both right and wrong. All three technologies work similarly, but they're also vastly different. To help clear the confusion and make things easier to digest, we've explained how Miracast works and what makes it unique.
What is Miracast?
Miracast is an industry-wide standard that allows a mobile device, for instance, to discover and connect to another device, such as a television, in order to mirror the contents of its screen to the television's display. It acts like a wireless HDMI cable and is a cross-platform solution, so it's not limited to one brand or ecosystem.
Here's some background on Miracast: The Wi-Fi Alliance, which is a 17-year-old network of hundreds of companies from around the globe that collectively enforce standards for the Wi-Fi brand, established Miracast as a solution or standard for displaying multimedia between devices, without cables or a network connection.
Miracast is built upon Wi-Fi Direct, a technology that enables two devices to form a direct, peer-to-peer Wi-Fi connection so that they can automatically discover and connect without a wireless router. Miracast doesn't rely on your home's network and instead creates its own, allowing data to pipe freely between paired devices.
Miracast is largely considered a response or an alternative to Apple’s AirPlay. Support for the standard is currently built into Android 4.2+ and Windows 8.1+ so that Android smartphones and Windows tablets and laptops can wirelessly mirror their screen contents to Miracast-compatible receivers (like televisions, streaming sticks, and set-top boxes).
How does Miracast work?
Starting off with the technical stuff: Miracast employs the H.264 codec in order to mirror video in 1080p as well as 5.1 surround sound audio. It also has a DRM layer so that a Miracast-supported mobile device is able to mirror copyright-protected content, such as DVDs and music, from its screen to a Miracast-compatible receiver.
Miracast, as we mentioned earlier, is just like a wireless HDMI cable. Without the hassle of using a cable to connect two devices, Miracast can take whatever you see on one device and duplicate that in real-time on another display in high definition and with audio. It also does this without relying on your home's Wi-Fi network.
Miracast has one major pitfall: let's say, for instance, you're watching a movie on an Android device and want to use Miracast to mirror the movie to your television. Miracast will pair both devices, if they support the standard, but it'll require your Android device to stay awake. If it goes to sleep, your television will go dark.
Miracast could also drain your Android device's battery life while mirroring. It's strictly a screen-mirroring protocol and therefore unlike AirPlay and Chromecast, which are both smart enough to hand over the streaming. They allow for multitasking so that you can use your mobile device for other purposes while mirroring.
Is Miracast different from Chromecast and AirPlay?
Yes. But let's take a step back.
Remember... HDMI allows you to connect nearly any device to another display, but it has long required a wired connection in the form of a HDMI cable. Although Miracast banishes the need for a HDMI cable, it's not alone. There is a variety of competing wireless standards and protocols available.
Google's Chromecast and Apple's AirPlay are just two of many alternatives to Miracast. Chromecast is an affordable dongle that plugs into your television's HDMI port and uses the Discover-And-Launch protocol. With this setup, you can open an app like Netflix on your Android or iOS device and command the app to stream video to your Chromecast.
Chromecast, which requires a internet connection from a local wireless router, will then display the video on your television's display, but while that content streams from your mobile device to a television, you're still free to use your mobile device for other purposes and can even control playback of the stream from your mobile device.
Chromecast also has a feature that lets you duplicate your desktop or a Chrome tab onto your television's display. Chromecast therefore doesn't just mirror the contents of your mobile device's screen, and it allows for multitasking on your mobile device while it is working. Thus, many critics have claimed Chromecast is "smarter" than Miracast.
AirPlay allows you to stream video from an iOS device or a Mac to an Apple TV. It can display your Mac’s desktop on a television, for instance. It can also take video playing in an iPhone app and stream it to your television, while letting you use playback controls on your iPhone, and it can even mirror your iPad's screen onto your television.
Apple’s wireless display standard is therefore smart enough to stream the content you want to see and display, but it's unfortunately limited to Apple devices. You can't use AirPlay to stream from a Windows laptop, and so on.
Which devices use Miracast?
All Android phones and tablets running Android 4.2 or newer support Miracast and can mirror to Miracast-compatible receivers, and that includes Amazon’s Fire OS, because it's a version of Android. All computers running Windows 8.1 or newer and all phones running Windows Phone 8.1 or newer can also mirror to Miracast-compatible receivers.
A number of new televisions support Miracast, making them Miracast-compatible receivers. Miracast technology is still relatively new, so television makers, such as Sony, LG, and Panasonic, are still in the process of integrating Miracast into their sets. If you don't own a Miracast-ready television, you can still get your hands on another type of receiver.
Retailers like Amazon and Best Buy sell a range of inexpensive Miracast-compatible receivers, such as the Roku and Roku Streaming Stick. Microsoft sells Microsoft Screen Sharing for Lumia Phones (HD-10) and the Microsoft Wireless Display Adapter, while Amazon’s Fire TV and the Fire TV Stick come with built-in Miracast support as well.
It's important to note the Wi-Fi Alliance doesn’t require Miracast-supported devices to carry the “Miracast” brand name. Manufacturers can call their Miracast implementations whatever they want, making it hard to quickly identify if a device is Miracast-ready. Here are examples of Miracast being called other names:
- LG's "SmartShare"
- Samsung's "AllShare Cast"
- Sony's "Screen mirroring"
- Panasonic's "Display mirroring"
You can view a complete list of Miracast-ready televisons, sticks, dongles, and set-top boxes here. You should check the user-guide for each device for more specific instructions on how to establish a Miracast connection.
Want to know more?
Check out the Wi-Fi Alliance's website to learn more about Miracast.