| Developer | Apple Inc. |
|---|---|
| Release date | September 1, 2010; November 22, 2010 for iOS systems |
| Website | apple.com/itunes/airplay |
AirPlay (previously called AirTunes when it was for audio only[1]) is a proprietary protocol stack/suite developed by Apple Inc. that allows wireless streaming of audio, video, and photos, together with related metadata between devices. Originally only implemented in Apple's software and devices, Apple has licensed the audio-streaming portion of the AirPlay protocol stack as a third-party software component technology to manufacturer partners for them to use in their products in order to be compatible with Apple's iDevices.
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AirTunes was originally released on June 7, 2004.[2]
The enhancements to the AirTunes technology and the subsequent name change to AirPlay were announced by Steve Jobs at the iPod event on September 1, 2010 and explained thus:
“Now, what is AirPlay? You know what AirTunes is… listen to music from all over your house from your mobile device,” said Jobs. We’re changing the name of AirTunes to AirPlay, and it’s not just music anymore. You can stream all kinds of media anywhere in your house."[1]
In 2011 at the WWDC 2011, Apple CEO Steve Jobs announced AirPlay Mirroring as a feature in iOS 5 where the user can stream the screen from an iPad 2 to a HDTV wirelessly and securely without the need of cables.[3][4]
Devices currently implementing AirPlay are of two categories: the devices that send audiovisual content, and the devices receiving the content and render it on display and/or speakers :
As of iOS 4.3, third-party apps may also send compatible audio and video streams over AirPlay.[5] The iTunes Remote app for iOS can be used to control media playback and select streaming devices.[6]
AirPlay wireless technology (receiver mode) will be integrated into speaker docks, AV receivers, and stereo systems from companies such as Marantz, Bowers & Wilkins, Pioneer, and Denon.[7] Song titles, artists, album names, elapsed and remaining time, and album artwork can appear on AirPlay-enabled speakers with graphical displays.
Several third-party implementations of AirPlay are available:
AirPlay allows an Apple TV or AirPort-enabled computer with the iTunes music player to send a stream of music to multiple (three to six, in typical conditions) stereos connected to an AirPort Express or Apple TV.[13]
Speakers attached to an AirPort Express or Apple TV can be selected from within the "Remote" iPhone/iPod Touch application, allowing full AirPlay compatibility[14] (see "Remote control" section below).
The AirTunes part of the AirPlay protocol stack uses UDP for streaming audio and is based on the RTSP network control protocol.[15] The streams are encrypted with AES, requiring the receiver to have access to the appropriate private key to decrypt the streams.[16]
AirPlay Mirroring is a slightly different technology that allows specific content to be broadcast from a variety of iOS devices and iTunes to an Apple TV 2, the inner workings of the protocols that AirPlay Mirroring has not yet fully been discovered, nor reversed-engineered like with AirTunes and standard AirPlay video.[17]
The AirPort Express' streaming media capabilities use Apple's Remote Audio Output Protocol (RAOP), a proprietary variant of RTSP/RTP. Using WDS-bridging,[18] the AirPort Express can allow AirPlay functionality (as well as Internet access, file and print sharing, etc.) across a larger distance in a mixed environment of wired and up to 10 wireless clients.
The AirPlay protocol (then known as AirTunes and was for audio-only) was reverse-engineered by Jon Lech Johansen in 2004.[16]
On April 8, 2011, James Laird reverse-engineered and released the private key used by the Apple AirPort Express to decrypt incoming audio streams.[19] The release of this key means that third-party software and devices modified to use the key will be able to decrypt and playback or store AirPlay streams.[20] Laird released ShairPort as an example of an audio-only software receiver implementation of AirPlay.[21]