AirPlayis aproprietarywirelesscommunication protocolstack/suitedeveloped byApple Inc.that allows thestreamingofmultimediaand device screens, together with relatedmetadata,between compatible devices. Originally implemented only in Apple's own software and hardware, the company has since licensed the AirPlay protocol stack to third-party manufacturers and it has been implemented on devices such astelevision setsandhome audiosystems. AirPlay works through either a directpeer-to-peerconnection between devices or through an infrastructurelocal network.[2]
 Logos of AirPlay 2 AirPlay video (left) and AirPlay audio (right) | |
| Developer | Apple Inc. |
|---|---|
| Type | Wireless media streaming |
| Release date |
|
| Website | apple |
History
editIn 2004, Apple introducedAirTunes[3]as a new feature ofiTunes4.6. It allowed music streaming over a network to anAirPort Express,which was equipped with a3.5 mmanalog-digital audio jack for speakers or other audio devices. In 2010, Apple introduced a new iteration of the AirTunes technology, now called AirPlay, as part ofiOS 4.2.It supported audio and now video streaming to theApple TV,and later added screen-mirroring and eventually support for a broad range of 3rd-party AirPlay-compatible speakers and AV equipment.
Apple announced AirPlay 2 at its annualWWDCconference on June 5, 2017. It was scheduled for release along withiOS 11in the third quarter of 2017, but was delayed until June 2018.[4][5]Compared to the original version, AirPlay 2 improves buffering; adds streaming audio to stereo pairs of speakers (e.g. stereo pairs of individual HomePods; AirPlay and its predecessor, AirTunes have always been stereo);[6]allows audio to be sent to multiple devices in different rooms;[7]and control by Control Center, the Home app, or Siri,[8]functionality that was only available previously usingiTunesundermacOSorWindows.[9]
| History of AirPlay | |
|---|---|
| 2004 | Launch as AirTunes for iTunes and AirPort Express |
| 2010 | Launch on iOS 4 as AirPlay |
| 2018 | AirPlay 2 launch on iOS 11.4 |
| 2021 | macOS Monterey (12) includes receiver capability on compatible Macs |
Senders
edit
AirPlay sender devices include computers runningiTunes,andiOS devicessuch asiPhones,iPods,andiPadsrunningiOS4.2 or greater, and devices can send AirPlay over Wi-Fi or ethernet.OS X Mountain Lionsupports display mirroring via AirPlay on systems containing 2nd generation Intel Core processors or later.[10]
In 2016,HTCreleased the"10", also known as "One M10",an Android phone with Apple AirPlay streaming.[11]
As of iOS 4.3, third-party apps like ApowerMirror,[12]AirServer, and Reflector may send compatible audio and video streams over AirPlay.[13]TheiTunes Remoteapp on iOS can be used to control media playback and select AirPlay streaming receivers for iTunes running on a Mac or PC.[14]
As of macOS 10.14, there is nopublic APIfor third-party developers to integrate AirPlay 2 into their macOS apps. However, there are third-party streamers such asAirfoil.In May 2019, a third-party developer released a macOS app that can stream audio using AirPlay 2.[15]The app includes a helper tool called "AirPlay Enabler" that usescode injectionto bypass restrictions to the AirPlay 2private APIon macOS.[16]
Receivers
editAirPlay receiver devices includeApple TV,HomePod,third-party speakers and the discontinuedAirPort Express,which included a combined analog and opticalS/PDIFaudio output connector. Compatible devices can receive AirPlay over wi-fi or ethernet. Some open-source projects have reverse-engineered the audio part of the protocol, enabling any computer to be turned into an AirPlay receiver for audio.[17]
However, because not all third-party receivers implement Apple's DRM encryption, some media, such as iTunes Store's own rights-protected music (Apple's own "FairPlay"encryption),YouTube,andNetflix,cannot stream to those devices or software. On Apple TV, starting with firmware 6.0, the DRM scheme is enforced: devices without it cannot be used.[18]
AirPlay wireless technology is integrated into speaker docks, AV receivers, and stereo systems from companies such asNaim,Bose,Yamaha,Philips,Marantz,Onkyo,Bowers & Wilkins,Pioneer,Sony,Sonos,McIntosh,Denon,[19]andBang & Olufsen.[20]Song titles, artists, album names, elapsed and remaining time, and album artwork can appear on AirPlay-enabled speakers with graphical displays. Often these receivers are built to only support the audio component of AirPlay, much like AirTunes.
Bluetooth devices (headsets, speakers) that support theA2DPprofile also appear as AirPlay receivers when paired with an iOS device, although Bluetooth is a device-to-device protocol that does not rely on a wireless network access point.
During the January 2019 Consumer Electronics Show (CES) in Las Vegas, television makers Samsung, LG, Vizio, and Sony announced they would be producing sets with built-in AirPlay 2 receiving capability.[21]LG announced that television models that are AirPlay 2-enabled will include the 2019 OLED, NanoCell SM9X, UHD UM7X, and LG NanoCell SM8X models.[22]
In September 2020,Rokuadded AirPlay 2 support as part of the 9.4 update on select 4K Roku devices. In April 2021, the 10.0 update added support for more Roku TVs and Players.[23]
DuringWWDC 2021,Apple announced thatmacOS Montereywould include AirPlay receiver compatibility for compatible Macs.
Protocols
editAirPlay and AirTunes can work over alocal network(LAN), through eitherWi-FiorEthernet,or (since 2017) directly to each other usingWi-Fi Direct,allowing devices to connect without a central LAN.[24]This method ofpeer-to-peerconnecting is now preferred by AirPlay, but Apple notes that the protocol establishes a connection "using the method that’s the most responsive".[2]
The AirTunes part of the AirPlay protocol stack usesUDPfor streaming audio and is based on theReal Time Streaming Protocol.[25]The streams are transcoded using theApple Losslesscodec with 44100 Hz and 2 channels symmetrically encrypted withAES,requiring the receiver to have access to the appropriate key to decrypt the streams.[26]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.[27]
The protocol supports metadata packets that determine the final output volume on the receiving end. This makes it possible to always send audio data unprocessed at its original full volume, preventing sound quality deterioration due to reduction inbit depthand thus sound quality which would otherwise occur if changes in volume were made to the source stream before transmitting. It also makes possible the streaming of one source to multiple targets each with its own volume control, and for volume adjustments to be applied instantly, instead of being delayed by the 2 second buffer period. The AirPort Express' streaming media capabilities use Apple'sRemote Audio Output Protocol(RAOP), a proprietary variant ofRTSP/RTP.UsingWDS-bridging,[28]the AirPort Express can allow AirPlay functionality (as well as Internet access,fileandprint sharing,etc.) across a larger distance in a mixed environment of wired and up to 10 wireless clients.
AirPlay Mirroring
editAtWWDC 2011,Steve Jobs,then CEO ofApple Inc.,announced AirPlay Mirroring as a feature iniOS 5where the user can stream the screen from aniPad 2to anHDTVwirelessly and securely without the need for cables.[29][30]
AirPlay is a different technology from AirPlay Mirroring, as the former allows specific content formats to be streamed, while the latter allows the whole screen to be broadcast from a variety of iOS devices and iTunes to an Apple TV (2nd Gen or later). The exact composition of the protocols that AirPlay Mirroring uses have not yet fully been discovered, or reverse-engineered.[30]However, an unofficial AirPlay protocol specification is available.[31]Supported hardware (when using OS X Mountain Lion or later) includes any 2011 or later iMac, Mac mini, MacBook Air, MacBook Pro, or the Mac Pro (late 2013 or newer).[32]
Reverse engineering
editWhen the protocol was known as AirTunes, it wasreverse-engineeredbyJon Lech Johansenin 2008.[26]
On April 8, 2011, James Laird reverse-engineered and released the private key used by the AppleAirPort Expressto decrypt incoming audio streams.[33]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.[34]Laird released ShairPort as an example of an audio-only software receiver implementation of AirPlay.[35]Soon more followed and in 2012 the first AirPlay audio and video receiver for PC came with a product called AirServer.[36][37]
An open-source AirPlay mirroring server (receiver) known asRPiPlayis available for theRaspberry PiandDesktop Linuxoperating systems. The author describes it as being based on dsafa22's Android mirroring server, which was in turn based on Juho Vähä-Herttua's ShairPlay.[38]
With Shairport Sync,[39]there is an implementation that supports AirPlay and parts of AirPlay 2 that runs on Linux and FreeBSD and works well on embedded devices such as Raspberry Pis or OpenWrt-powered routers.
See also
editNotes
edit- ^"Apple Unveils AirPort Express for Mac & PC Users".Apple.com.June 7, 2004. Archived fromthe originalon March 29, 2011.RetrievedApril 12,2012.
- ^ab"Use AirPlay with Apple devices".Apple Support.RetrievedJuly 15,2024.
- ^Brownlee, John (September 1, 2010)."September iPod Event: In iOS 4.2, AirTunes Becomes AirPlay".Cult of Mac.RetrievedApril 21,2024.
- ^"Apple unveils iOS 11 with P2P Apple Pay transfers, a new sound for Siri, AirPlay 2, more".AppleInsider.June 5, 2017.RetrievedApril 21,2024.
- ^"iOS 11.4 brings stereo pairs and multi-room audio with AirPlay 2".Apple.com.May 29, 2018.RetrievedMay 29,2018.
- ^"iOS 11.4 brings stereo pairs and multi-room audio with AirPlay 2".Apple Newsroom.RetrievedMay 9,2019.
- ^"AirPlay 2 FAQ: What it is, how it works, and which devices support it".Macworld.RetrievedJune 22,2018.
- ^"iOS 11 brings new features to iPhone and iPad this fall".Apple.com.RetrievedJune 6,2017.
- ^"Use AirPlay to stream content from iTunes on your computer".Apple Support.RetrievedJune 30,2017.
- ^"About AirPlay Mirroring in OS X Mountain Lion".Apple.com.RetrievedAugust 6,2012.
- ^"HTC's 10 is the first Android phone with Apple AirPlay streaming".Engadget.April 12, 2016.
- ^"ApowerMirror".Apowersoft.RetrievedSeptember 10,2017.
- ^Rose, Michael."iOS 4.3 spotlight: AirPlay improvements and 720p playback".TUAW.AOL.RetrievedMay 5,2011.
- ^"iTunes Remote".Apple.com.Archived fromthe originalon September 13, 2010.
- ^"Optimus Player".Optimus Player.May 7, 2019.RetrievedMay 8,2019.
- ^Mo, Darren (May 7, 2019)."A helper tool that enables Optimus Player to stream audio using AirPlay 2".GitHub.RetrievedMay 9,2019.
- ^"How-To: Turn your Raspberry Pi into a AirPlay receiver to stream music from your iPhone".Raspberry Pi HQ.July 27, 2013.RetrievedApril 21,2024.
- ^Kafasis, Paul (September 20, 2013)."Warning on Apple TV version 6.0".Under the Microscope.Rogue Amoeba.RetrievedApril 21,2024.
- ^Grobart, Sam (November 22, 2010)."Understanding AirPlay in Apple's iOS 4.2".The New York Times.RetrievedApril 21,2024.
- ^"Bang & Olufsen unveils Playmaker wireless audio bridge, makes sure AirPlay and DLNA speak Danish".Engadget.RetrievedJune 12,2019.
- ^"At CES 2019, Apple finally sets iTunes, AirPlay loose".CNET.RetrievedJanuary 12,2019.
- ^Rossignol, Joe (March 5, 2019)."LG's Latest Smart TVs Will Receive AirPlay 2 Update in Mid 2019".MacRumors.RetrievedApril 2,2019.
- ^"How do I use AirPlay and HomeKit with my Roku streaming device?".Rokuwebsite.RetrievedNovember 2,2020.
- ^Bell, Killian."AirPlay no longer requires a Wi-Fi network in iOS 8".RetrievedApril 21,2024.
- ^Donenfeld, Jason A."AirTunes 2 Protocol".ZX2C4.RetrievedApril 21,2024.
- ^abHanselmann, Michael (December 16, 2008)."Add Remote Audio Output Protocol stream output plugin"(Mailing list).
- ^"Preventing audio delays while watching videos with Airfoil".Rogue Amoeba.RetrievedAugust 18,2012.
- ^"Apple WDS Setup".Apple.com.February 11, 2011.RetrievedApril 12,2012.
- ^"iOS5 – AirPlay Mirroring for iPad 2".Apple.com.Archived fromthe originalon September 23, 2011.RetrievedApril 12,2012.
- ^ab"Exploring Airplay Mirroring Internals".Aoren.August 20, 2011.
- ^"Unofficial AirPlay Protocol Specification".nto.github.com.May 29, 2012.RetrievedMay 29,2012.
- ^"About AirPlay Mirroring in OS X".Apple.com.RetrievedJanuary 13,2015.
- ^Laird, James (April 8, 2011)."RAOP/Airtunes".vlc-devel(Mailing list).
- ^Cheng, Jacqui (April 11, 2011)."ShairPort emulates AirPort Express to receive AirPlay streams".Ars Technica.RetrievedApril 11,2011.
- ^Laird, James (April 11, 2011)."ShairPort 0.02 released".Archived fromthe originalon April 27, 2011.RetrievedApril 11,2011.
- ^"Wireless Mirroring from iPad to PC Now a Reality with AirServer".Learning in Hand.May 5, 2012.RetrievedApril 21,2024.
- ^"History".AirServer.RetrievedApril 21,2024.
- ^"RPiPlay: Authors".GitHub.March 30, 2023.
- ^"Shairport Sync".GitHub.May 6, 2023.
