AirPlay

From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about the software. For the radio term, see Airplay. For other uses, see Airplay (disambiguation).
AirPlay
Developer Apple Inc.
Type Wireless Media Streaming
Release date September 1, 2010; November 22, 2010 for iOS systems
Website apple.com/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.

Contents

History [edit]

[icon] This section requires expansion. (June 2012)

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 Apple CEO 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]

At WWDC 2011, 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 for cables.[3][4]

Output AirPlay device selection via Remote app for iPhone

Implementations [edit]

There are two types of AirPlay devices: those that send audiovisual content, and those capable of receiving the content and rendering it on displays and speakers.

AirPlay sender devices include computers running iTunes, and iOS devices such as iPhones, iPods, and iPads running iOS 4.2 or greater. OS X Mountain Lion supports display mirroring via AirPlay on systems containing 2nd and 3rd Generation Intel Core processors.[5]

AirPlay receiver devices include AirPort Express (which includes an audio output connector), Apple TV, and third party speakers.

As of iOS 4.3, third-party apps may send compatible audio and video streams over AirPlay.[6] The iTunes Remote app for iOS can be used to control media playback and select streaming devices.[7]

AirPlay wireless technology (receiver mode) is integrated into speaker docks, AV receivers, and stereo systems from companies such as Philips, Marantz, Bowers & Wilkins, Pioneer, and Denon.[8] Song titles, artists, album names, elapsed and remaining time, and album artwork can appear on AirPlay-enabled speakers with graphical displays.

Third-party software implementations [edit]

Senders/Receivers enabling non-Apple software to send/receive media to AirPlay-enabled devices:

AirPlay senders
Name Media type OS Vendor
Beamer[9] video only, supports common codecs OS X Tupil
Airfoil[10] audio only OS X, Windows Rogue Amoeba
acacia[11] audio only (currently[when?] in beta) Plethra
axStream[12] (formerly oAEP) audio only Windows
qTunes[13] audio only Java open source
JustePort[14] audio only Windows
raop_play[15] audio only Linux
PulseAudio audio only Linux, default sound system used on most desktop distributions, supports allowing virtually any audio application to use some (no UDP) AirPlay devices
forked-daapd audio only Linux
AirParrot[16] OS X or Windows screen mirroring OS X (10.6.8+), Windows (XP+) Squirrels
HUDTube Video Player[17] OS X Macoscope sp. z o.o.
AirFlick[18] OS X Erica Sadun
Porthole[19] audio only OS X Danger Cove
AirPlay receivers
Name Media type OS Vendor
AirServer[20] audio, video, photos, screen mirroring OS X as well as Windows, although it currently has a more limited feature set than on OS X. AirServer
BananaTV[21] does not support iOS 5 or newer Discontinued as of November 2011
casualShare[22] video, photos OS X Joris Suppers
AirPlayer[23] video only Erica Sadun
ShairPort[24] audio only OS X, Windows & Linux James Laird
Airfoil Speakers Rogue Amoeba
Android HiFi audio only Android 2.2+ Android-HiFi
AirMediaPlayer[25] Windows Apostolos Georgiadis
AirReceiver[26] audio only (Java) Florian Pflug
Aerodrom[27] audio, video, photos Windows, Windows Media Center funkyf@ctory development
TriCaster (XD models)[28] (hardware) NewTek
Reflector[29] iOS (iPhone 4S+, iPad 2+) screen mirroring X (10.6.8+) or Windows (XP+) Squirrels
XBMC[30] audio, video, photos Windows, OS X, Linux, iOS, Android
Freebox AirMedia photos, audio and videos Linux on freebox TV set-top-box and broadband router Free/Iliad
Totem Media Player optional plug-in Linux
Airtight[31] Google TV Google Play
AirBubble audio only Android Bubblesoft
AirFloat[32] audio only iOS (removed from App Store[33]) The Famous Software Company

AirPort [edit]

Main article: 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.[34]

Speakers attached to an AirPort Express or Apple TV can be selected from within the "Remote" iPhone/iPod Touch application, allowing full AirPlay compatibility[35] (see "Remote control" section below).

Protocols [edit]

The AirTunes part of the AirPlay protocol stack uses UDP for streaming audio and is based on the RTSP network control protocol.[36] The streams are transcoded using the Apple Lossless codec with 44100 Hz and 2 channels encrypted with AES, requiring the receiver to have access to the appropriate private key to decrypt the streams.[37] The stream is buffered for approximately 2 seconds before playback begins, resulting in a small delay before audio is output after starting an AirPlay stream.[38]

AirPlay Mirroring [edit]

AirPlay Mirroring is a slightly different technology that allows specific content to be broadcast from a variety of iOS devices and iTunes to a second generation Apple TV. The exact composition of the protocols that AirPlay Mirroring uses have not yet fully been discovered, nor reverse-engineered.[4] An unofficial AirPlay protocol specification is available, though.[39]

Supported hardware:[1]

  • iMac (Mid 2011 or newer)
  • Mac mini (Mid 2011 or newer)
  • MacBook Air (Mid 2011 or newer)
  • MacBook Pro (Early 2011 or newer)
  • Apple TV (Late 2010 or newer)

The AirPort Express' streaming media capabilities use Apple's Remote Audio Output Protocol (RAOP), a proprietary variant of RTSP/RTP. Using WDS-bridging,[40] 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.

Reverse engineering AirTunes and AirPlay [edit]

When the protocol was known as AirTunes, it was reverse-engineered by Jon Lech Johansen in 2004.[37]

On April 8, 2011, James Laird reverse-engineered and released the private key used by the Apple AirPort Express to decrypt incoming audio streams.[41] The release of this key means that third-party software and devices modified to use the key will be able to decrypt and play back or store AirPlay streams.[42] Laird released ShairPort as an example of an audio-only software receiver implementation of AirPlay.[43]

See also [edit]

Notes [edit]

  1. ^ a b Brownlee, John (September 1, 2010). "September iPod Event: In iOS 4.2, AirTunes Becomes AirPlay". Cult of Mac. Cultomedia. Retrieved April 11, 2011. 
  2. ^ "Apple Unveils AirPort Express for Mac & PC Users". Apple.com. June 7, 2004. Retrieved April 12, 2012. 
  3. ^ "iOS5 – AirPlay Mirroring for iPad 2". Apple. Retrieved April 12, 2012. 
  4. ^ a b http://www.aorensoftware.com/blog/2011/08/20/exploring-airplay-mirroring-internals/ Exploring Airplay Mirroring Internals
  5. ^ "About AirPlay Mirroring in OS X Mountain Lion". Apple. Retrieved 6 August 2012. 
  6. ^ Rose, Michael. "iOS 4.3 spotlight: AirPlay improvements and 720p playback". TUAW. AOL. Retrieved May 5, 2011. 
  7. ^ "Apple.com – iTunes Remote". 
  8. ^ Grobart, Sam (November 22, 2010). "Understanding AirPlay in Apple’s iOS 4.2". The New York Times. Retrieved April 11, 2011. 
  9. ^ "Beamer for Mac - Play any movie file directly via Apple TV". Tupil. Retrieved May 18, 2012. 
  10. ^ "Airfoil | Select Your Operating System". Rogue Amoeba. Retrieved April 12, 2012. 
  11. ^ "Multimedia Distribution & Automation". Plethra. Retrieved April 12, 2012. 
  12. ^ "Airport Express Streamer (oAEP)". Oaep.codeplex.com. Retrieved April 12, 2012. 
  13. ^ "qTunes". Retrieved January 19, 2012. 
  14. ^ "Jon Lech Johansen's blog". Nanocr.eu. February 22, 1999. Retrieved April 12, 2012. 
  15. ^ "Apple Airport Express Client Player". Raop-play.sourceforge.net. December 16, 2005. Retrieved April 12, 2012. 
  16. ^ "AirParrot". 
  17. ^ "Free your videos from the browser with HUDTub!". Hudtu.be. Retrieved April 12, 2012. 
  18. ^ "Index of /ftp/AirPlay". Ericasadun.com. Retrieved April 12, 2012. 
  19. ^ "Porthole". 
  20. ^ "AirServer". Retrieved February 14, 2012. 
  21. ^ "Banana TV". Retrieved February 14, 2012. 
  22. ^ "casualShare". Retrieved January 9, 2013. 
  23. ^ "AirPlayer". ericasadun.com. Retrieved April 12, 2012. 
  24. ^ "ShairPort". James Laird. Retrieved 26 March 2013. 
  25. ^ "Technology and Science: AirMediaPlayer for Windows". Apogeorgiadis.blogspot.com.au. Retrieved April 12, 2012. 
  26. ^ "AirReceiver". Retrieved June 10, 2011. 
  27. ^ "Aerodrom". Retrieved March 26, 2013. 
  28. ^ "NewTek TriCaster". Retrieved October 1, 2011. 
  29. ^ "Reflector". 
  30. ^ "XBMC 11.0 Eden Changelog". Retrieved April 9, 2012. 
  31. ^ "Airtight is Airplay for Your Google TV". Retrieved March 6, 2012. 
  32. ^ "AirFloat – Turn your iPhone into an AirPlay speaker!". 
  33. ^ "AirFloat has been removed from App Store". 
  34. ^ "Apple TV: Using AirPlay". Apple. November 20, 2008. Retrieved March 12, 2009. 
  35. ^ "iTunes Remote". Apple.com. September 13, 2011. Retrieved April 12, 2012. 
  36. ^ Donenfeld, Jason A. "AirTunes 2 Protocol". ZX2C4. Retrieved April 11, 2011. 
  37. ^ a b Hanselmann, Michael (December 16, 2008). "Add Remote Audio Output Protocol stream output plugin". http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=bc9a84781306ab22d2facc636a2f82eb6ba2abd3.
  38. ^ "Preventing audio delays while watching videos with Airfoil". Rogue Amoeba. Retrieved Aug 18, 2012. 
  39. ^ "Unofficial AirPlay Protocol Specification". nto.github.com. May 29, 2012. Retrieved May 29, 2012. 
  40. ^ "Apple WDS Setup". Support.apple.com. February 11, 2011. Retrieved April 12, 2012. 
  41. ^ Laird, James (April 8, 2011). "RAOP/Airtunes". vlc-devel mailing list. http://mailman.videolan.org/pipermail/vlc-devel/2011-April/079148.html.
  42. ^ Cheng, Jacqui (April 11, 2011). "ShairPort emulates AirPort Express to receive AirPlay streams". Ars Technica. Retrieved April 11, 2011. 
  43. ^ Laird, James (April 11, 2011). "ShairPort 0.02 released". Archived from the original on April 27, 2011. Retrieved April 11, 2011. 
Retrieved from "http://en.wikipedia.org/w/index.php?title=AirPlay&oldid=556233755"