AirPlay
| Developer | Apple Inc. |
|---|---|
| Type | Wireless Media Streaming |
| 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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[edit] History
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]
[edit] Implementations
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 :
- AirPlay sender devices include computers running iTunes and iOS devices such as iPhones, iPods, and iPads running iOS 4.2 or greater, as well as computers running Mac OS X Mountain Lion, which is scheduled for release in summer 2012.
- AirPlay receiver devices include the AirPort Express (that has an audio output through a jack connector), the Apple TV, and third party 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:
- senders enabling non-Apple software to send media to AirPlay-enabled speakers: Rogue Amoeba's Airfoil for Mac OS X and Windows, Plethra's audio|acacia (currently in beta)[8], axStream (formerly oAEP) for Windows, qTunes (Java, open source)[9], JustePort for Windows, and raop_play for Linux. PulseAudio (the default sound system used on most desktop Linux distributions) also has support allowing virtually any Linux audio application to use AirPlay devices.
- receivers enabling non-Apple software to receive media from AirPlay-enabled devices: AirServer[10] by Pratik Kumar, BananaTV[11] & AirPlayer by Erica Sadun, Shairport for Windows by Franck Friemel, Airfoil Speakers by Rogue Amoeba, AirMediaPlayer by Apostolos Georgiadis, AirReceiver[12] by Florian Pflug and Aerodrom [13] for Windows and Windows Media Center by funkyf@ctory development, and the NewTek HD line of TriCasters[14], XBMC adds with 11.0 Eden Beta[15].
[edit] AirPort
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.[16]
Speakers attached to an AirPort Express or Apple TV can be selected from within the "Remote" iPhone/iPod Touch application, allowing full AirPlay compatibility[17] (see "Remote control" section below).
[edit] Protocols
The AirTunes part of the AirPlay protocol stack uses UDP for streaming audio and is based on the RTSP network control protocol.[18] The streams are transcoded using the Apple Lossless codec with 44100 Hz and 2 channels and encrypted with AES, requiring the receiver to have access to the appropriate private key to decrypt the streams.[19]
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.[20]
The AirPort Express' streaming media capabilities use Apple's Remote Audio Output Protocol (RAOP), a proprietary variant of RTSP/RTP. Using WDS-bridging,[21] 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.
[edit] Reverse engineering AirTunes and AirPlay
When the protocol was known as AirTunes, it was reverse-engineered by Jon Lech Johansen in 2004.[19]
On April 8, 2011, James Laird reverse-engineered and released the private key used by the Apple AirPort Express to decrypt incoming audio streams.[22] 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.[23] Laird released ShairPort as an example of an audio-only software receiver implementation of AirPlay.[24]
[edit] See also
- AirPort
- Time Capsule (Apple)
- iOS (Apple)
- Apple TV
- iDevice
- iTunes
- Zero configuration networking
- Apple Sleep Proxy Service (Bonjour Sleep Proxy)
- Digital Living Network Alliance
- Universal Plug and Play
[edit] Notes
- ^ a b Brownlee, John (September 1, 2010). "September iPod Event: In iOS 4.2, AirTunes Becomes AirPlay". Cult of Mac. Cultomedia. http://www.cultofmac.com/september-ipod-event-in-ios-4-2-airtunes-becomes-airplay/57429. Retrieved April 11, 2011.
- ^ Apple Unveils AirPort Express for Mac & PC Users
- ^ Apple - iOS5 - AirPlay Mirroring for iPad 2
- ^ http://www.aorensoftware.com/blog/2011/08/20/exploring-airplay-mirroring-internals/ Exploring Airplay Mirroring Internals
- ^ Rose, Michael. "iOS 4.3 spotlight: AirPlay improvements and 720p playback". TUAW. AOL accessdate=May 5, 2011. http://www.tuaw.com/2011/03/09/ios-4-3-spotlight-airplay-improvements-and-720p-playback/.
- ^ "Apple.com - iTunes Remote". http://www.apple.com/itunes/remote/.
- ^ Grobart, Sam (November 22, 2010). "Understanding AirPlay in Apple’s iOS 4.2". The New York Times. http://gadgetwise.blogs.nytimes.com/2010/11/22/understanding-airplay-in-apples-ios-4-2/. Retrieved April 11, 2011.
- ^ "audio|acacia". http://www.plethra.com. Retrieved 28 November 2011.
- ^ "qTunes". http://qTunes.org. Retrieved 19 January 2012.
- ^ "AirServer". http://www.airserverapp.com/. Retrieved 14 February 2012.
- ^ "Banana TV". http://bananatv.net/. Retrieved 14 February 2012.
- ^ "AirReceiver". https://github.com/fgp/AirReceiver/tree/STABLE_1_X. Retrieved 10 June 2011.
- ^ "Aerodrom". http://funky-factory.blogspot.com/. Retrieved 08 September 2011.
- ^ "NewTek TriCaster". http://www.newtek.com. Retrieved 1 October 2011.
- ^ "XBMC 11.0 Beta Changelog". http://xbmc.supsec.org/releases/11.0-Eden_beta1-changelog.txt. Retrieved 31 December 2011.
- ^ "Apple TV: Using AirPlay". Apple. 2008-11-20. http://support.apple.com/kb/HT3291. Retrieved 2009-03-12.
- ^ Apple.com- iTunes Remote
- ^ Donenfeld, Jason A.. "AirTunes 2 Protocol". ZX2C4. http://git.zx2c4.com/Airtunes2/about/. Retrieved April 11, 2011.
- ^ a b Hanselmann, Michael (December 16, 2008). "Add Remote Audio Output Protocol stream output plugin". vlc-devel mailing list. http://mailman.videolan.org/pipermail/vlc-devel/2008-December/054010.html.
- ^ http://www.aorensoftware.com/blog/2011/08/20/exploring-airplay-mirroring-internals/ Exploring Airplay Mirroring Internals
- ^ Apple WDS Setup
- ^ Laird, James (April 8, 2011). "RAOP/Airtunes". vlc-devel mailing list. http://mailman.videolan.org/pipermail/vlc-devel/2011-April/079616.html.
- ^ Cheng, Jacqui (April 11, 2011). "ShairPort emulates AirPort Express to receive AirPlay streams". Ars Technica. http://arstechnica.com/apple/news/2011/04/shairport-emulates-airport-express-to-receive-airplay-streams.ars. Retrieved April 11, 2011.
- ^ Laird, James (April 11, 2011). "ShairPort 0.02 released". http://mafipulation.org/blagoblig/2011/04/08#shairport. Retrieved April 11, 2011.
