When it comes to playing content from one device to another, most assume HDMI or even VGA is the way to go. Isn't there a well-supported standard for wireless displays? Not exactly…
There's a huge range of standards currently battling for dominance over the market, even today. There's Apple's AirPlay, Google Cast (used in their Chromecast dongle), DLNA and Miracast, for example. Here's a quick explanation of each.
Apple's wireless display standard is AirPlay. It allows the streaming of content from a Mac, iPhone or iPad to the Apple TV. AirPlay currently has two main modes - streaming or mirroring.
Mirroring allows you to display a copy of your screen, be it on your iPhone, iPad or Mac, to the TV connected to your Apple TV. Hence the term mirroring. With streaming, you can start a song, video or even certain games and have them play on the TV instead of your device.
The device can then be used as a remote control instead of using the TV's remote. AirPlay is designed so that the playback controls (volume, scrubbing, etc) only display on your device - never on the TV.
AirPlay's biggest drawback is that it only works on Apple systems. If you own a device that isn't part of Apple's expensive ecosystem, you'll want a different alternative.
DLNA (Digital Living Network Alliance)
While DLNA is the most widely accepted standard (most smart TVs, smartphones, etc. can use DLNA), it's also a huge mess. Every manufacturer of DLNA devices uses their own version of the standard, and the user interface displayed on your TV varies greatly.
DLNA uses the Universal Plug and Play (uPnP) standard, but only has one function: play content from one device on another. This could mean streaming music from your iPhone to your speakers, or a video to your TV. There are also DLNA-enabled storage devices, commonly known as a NAS (network-attached storage) which can be used as media servers for storing content. This lets you use your smartphone, for example, to stream content from your NAS to your TV, freeing up space on your smartphone or tablet.
On non-Apple devices, DLNA playback devices will commonly be targeted with the "Play To" command (with VLC Media Player - our favorite media player for Windows & Mac, you would right-click while playing a movie and choose "Play To" then choose the DLNA device).
DLNA is an aging standard, and it's biggest drawback is that you can only stream local content. If you're watching a YouTube video, for example, you'll want need a different alternative.
Chromecast is a relatively new device that uses the Google Cast standard. When Android version 4.2 was launched, Google promised a device that connected to your TV's HDMI port, and allow wireless display, initially thought to use Miracast. The huge number of problems with Miracast forced Google to create a new standard.
Chromecast allows two modes - streaming and mirroring, just like Apply TV.
Streaming on the Chromecast is different, however: when you play a YouTube video on your smartphone and choose Chromecast as a display, Chromecast connects to the internet and streams the video itself. You can then control playback as usual on your smartphone. Chromecast doesn't stream content from your smartphone directly, saving precious bandwidth.
Mirroring on the Chromecast is also slightly different: you can mirror your computer's desktop to Chromecast, or the contents of a Google Chrome browser tab.
Miracast is an industry standard that sounds great on paper, but fails in practice. The largest issue is that manufacturers aren't required to use the term Miracast - Panasonic uses "Display Mirroring", Sony calls it "Screen Mirroring" and Samsung calls it "AllShare Cast", for example. This causes a huge deal of confusion, and most Miracast-enabled device owners don't actually know their device supports it!
While thousands of Miracast receivers are sold today, they rarely play nice with other Miracast-enabled devices from a different manufacturer. The standard has completely fallen apart and isn't much of a "standard" anymore.
The biggest drawback to Miracast, apart from the mess of incompatibilities? It only offers "dumb mirroring". Unlike Apple TV, which hides your playback controls on the TV, Miracast shows everything - playback controls, battery life, signal and wi-fi reception, etc. When Miracast does work, it's ugly.
What's the best option? It depends. AirPlay is the easiest to set up, and has virtually no errors. If you're an Apple adopter, that's the way to go. Chromecast is a cheaper alternative for those that don't own Apple devices. If you already own a smartphone and smart-TV you'll likely already have DLNA, in which case a DLNA-compatible app is required to stream content.