AirPlay
Encyclopedia
AirPlay 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 implemented only 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 other manufacturer partners for them to use in their products in order to be compatible with Apple's iDevice
s.
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:
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.
As of iOS 4.3, third-party apps may also send compatible audio and video streams over AirPlay. The iTunes Remote app for iOS can be used to control media playback and select streaming devices.
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
. 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:
-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.
Speakers attached to an AirPort Express or Apple TV can be selected from within the "Remote" iPhone/iPod Touch application, allowing full AirPlay compatibility (see "Remote control" section below).
for streaming audio and is based on the RTSP network control protocol. The streams are encrypted with AES
, requiring the receiver to have access to the appropriate private key to decrypt the streams.
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.
The AirPort Express' streaming media capabilities use Apple's Remote Audio Output Protocol (RAOP), a proprietary variant of RTSP/RTP
. Using WDS
-bridging, 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.
by Jon Lech Johansen
in 2004.
On April 8, 2011, James Laird reverse-engineered and released the private key used by the Apple AirPort Express
to decrypt incoming audio streams. 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. Laird released ShairPort as an example of an audio-only software receiver implementation of AirPlay.
Proprietary protocol
In telecommunications, a proprietary protocol is a communications protocol owned by a single organization or individual.-Enforcement:Proprietors may enforce restrictions through patents and by keeping the protocol specification a trade secret...
stack/suite
Protocol stack
The protocol stack is an implementation of a computer networking protocol suite. The terms are often used interchangeably. Strictly speaking, the suite is the definition of the protocols, and the stack is the software implementation of them....
developed by Apple Inc. that allows wireless streaming
Streaming media
Streaming media is multimedia that is constantly received by and presented to an end-user while being delivered by a streaming provider.The term "presented" is used in this article in a general sense that includes audio or video playback. The name refers to the delivery method of the medium rather...
of audio, video, and photos, together with related metadata between devices. Originally implemented only in Apple's software and devices, Apple has licensed the audio-streaming portion of the AirPlay protocol stack as a third-party software component
Third-party software component
In computer programming, a third-party software component is a reusable software component developed to be either freely distributed or sold by an entity other than the original vendor of the development platform...
technology to other manufacturer partners for them to use in their products in order to be compatible with Apple's iDevice
IDevice
iDevice in its widest sense, is an unofficial general term that can refer to any mobile electronic devices marketed by Apple Inc. that start with "i" or more specifically any mobile devices that use the iOS operating system, which includes:* iPad* iPhone...
s.
History
AirTunes was originally released on the 7th June 2004.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:
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.
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 iTunesITunesiTunes is a media player computer program, used for playing, downloading, and organizing digital music and video files on desktop computers. It can also manage contents on iPod, iPhone, iPod Touch and iPad....
; and iDeviceIDeviceiDevice in its widest sense, is an unofficial general term that can refer to any mobile electronic devices marketed by Apple Inc. that start with "i" or more specifically any mobile devices that use the iOS operating system, which includes:* iPad* iPhone...
s such as iPhoneIPhoneThe iPhone is a line of Internet and multimedia-enabled smartphones marketed by Apple Inc. The first iPhone was unveiled by Steve Jobs, then CEO of Apple, on January 9, 2007, and released on June 29, 2007...
s, iPodIPodiPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...
s, and iPadIPadThe iPad is a line of tablet computers designed, developed and marketed by Apple Inc., primarily as a platform for audio-visual media including books, periodicals, movies, music, games, and web content. The iPad was introduced on January 27, 2010 by Apple's then-CEO Steve Jobs. Its size and...
s running iOS 4.2 or greater. - 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. The iTunes Remote app for iOS can be used to control media playback and select streaming devices.
AirPlay wireless technology (receiver mode) will be integrated into speaker docks, AV receivers, and stereo systems from companies such as Marantz
Marantz
Marantz is a company that develops and sells upper-mid range to high-end audio products.The first Marantz audio product was designed and built by Saul B. Marantz in his home in Kew Gardens, New York...
, Bowers & Wilkins
Bowers & Wilkins
Bowers & Wilkins is a British loudspeaker company that produces mid-range through reference quality hi-fi and home theater speakers. The company name is often abbreviated to just B&W.Joe Atkins is current owner and chairman...
, Pioneer
Pioneer
A pioneer is a soldier employed to perform engineering tasks. The term is in principle similar to sapper.Pioneers were originally part of the Artillery branch of European armies. Their primary job was to assist other Arms in tasks such as construction of field fortifications or military camps...
, and Denon
Denon
is a Japanese electronics company that was involved in the early stages of development of digital audio technology, while specializing in the manufacture of high-fidelity professional and consumer audio equipment. For many decades, Denon was a brand name of Nippon-Columbia, including the Nippon...
. 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 AmoebaRogue AmoebaRogue Amoeba Software, LLC is a Macintosh software company that produces audio software, specializing in applications for audio capture. Rogue Amoeba's best-known products are Audio Hijack and Audio Hijack Pro. The Audio Hijack programs allow for users to capture and record audio from any program...
's Airfoil for Mac OS XMac OS XMac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
and WindowsMicrosoft WindowsMicrosoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
, Plethra's audio|acacia (currently in beta), axStream (formerly oAEP) for Windows, JustePort for Windows, and raop_play for LinuxLinuxLinux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
. PulseAudioPulseAudioPulseAudio is a cross-platform, networked sound server commonly used on the Linux-based and FreeBSD operating systems.PulseAudio runs under Microsoft Windows, Mac OS X, and POSIX-compliant platforms, such as Linux and FreeBSD...
(the default sound system used on most desktop LinuxLinuxLinux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
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: AirPlayer by Erica Sadun, Shairport for Windows by Franck Friemel, Airfoil Speakers by Rogue AmoebaRogue AmoebaRogue Amoeba Software, LLC is a Macintosh software company that produces audio software, specializing in applications for audio capture. Rogue Amoeba's best-known products are Audio Hijack and Audio Hijack Pro. The Audio Hijack programs allow for users to capture and record audio from any program...
, AirMediaPlayer by Apostolos Georgiadi, AirReceiver by Florian Pflug and Aerodrom by funkyf@ctory development, and the NewTek HD line of TriCasters.
AirPort
AirPlay allows an Apple TV or AirPortAirPort
AirPort and AirPort Extreme are local area wireless networking products from Apple Inc. based on the IEEE 802.11 standard ....
-enabled computer with the iTunes
ITunes
iTunes is a media player computer program, used for playing, downloading, and organizing digital music and video files on desktop computers. It can also manage contents on iPod, iPhone, iPod Touch and iPad....
music player to send a stream
Streaming media
Streaming media is multimedia that is constantly received by and presented to an end-user while being delivered by a streaming provider.The term "presented" is used in this article in a general sense that includes audio or video playback. The name refers to the delivery method of the medium rather...
of music to multiple (three to six, in typical conditions) stereos connected to an AirPort Express or Apple TV.
Speakers attached to an AirPort Express or Apple TV can be selected from within the "Remote" iPhone/iPod Touch application, allowing full AirPlay compatibility (see "Remote control" section below).
Protocols
The AirTunes part of the AirPlay protocol stack uses UDPUser Datagram Protocol
The User Datagram Protocol is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol network without requiring...
for streaming audio and is based on the RTSP network control protocol. The streams are encrypted with AES
Advanced Encryption Standard
Advanced Encryption Standard is a specification for the encryption of electronic data. It has been adopted by the U.S. government and is now used worldwide. It supersedes DES...
, requiring the receiver to have access to the appropriate private key to decrypt the streams.
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.
The AirPort Express' streaming media capabilities use Apple's Remote Audio Output Protocol (RAOP), a proprietary variant of RTSP/RTP
Real-time Transport Protocol
The Real-time Transport Protocol defines a standardized packet format for delivering audio and video over IP networks. RTP is used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications, television services and...
. Using WDS
Wireless Distribution System
A wireless distribution system is a system enabling the wireless interconnection of access points in an IEEE 802.11 network. It allows a wireless network to be expanded using multiple access points without the traditional requirement for a wired backbone to link them...
-bridging, 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
The AirPlay protocol (then known as AirTunes and was for audio-only) was reverse-engineeredReverse engineering
Reverse engineering is the process of discovering the technological principles of a device, object, or system through analysis of its structure, function, and operation...
by Jon Lech Johansen
Jon Lech Johansen
Jon Lech Johansen , also known as DVD Jon, is a Norwegian programmer famous for his work on reverse engineering data formats....
in 2004.
On April 8, 2011, James Laird reverse-engineered and released the private key used by the Apple AirPort Express
AirPort Express
The AirPort Express is a simplified and compact AirPort Extreme base station. It allows up to 10 networked users, and includes a feature called AirTunes...
to decrypt incoming audio streams. 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. Laird released ShairPort as an example of an audio-only software receiver implementation of AirPlay.
See also
- AirPortAirPortAirPort and AirPort Extreme are local area wireless networking products from Apple Inc. based on the IEEE 802.11 standard ....
- Time Capsule (Apple)Time Capsule (Apple)The Time Capsule is a wireless network-attached storage device combined with a wireless residential gateway router made by Apple Inc. It is described as a "Backup Appliance", designed to work in tandem with the Time Machine backup utility, introduced in Mac OS X 10.5 "Leopard".The device includes a...
- iOS (Apple)
- Apple TV
- iDeviceIDeviceiDevice in its widest sense, is an unofficial general term that can refer to any mobile electronic devices marketed by Apple Inc. that start with "i" or more specifically any mobile devices that use the iOS operating system, which includes:* iPad* iPhone...
- iTunesITunesiTunes is a media player computer program, used for playing, downloading, and organizing digital music and video files on desktop computers. It can also manage contents on iPod, iPhone, iPod Touch and iPad....
- Zero configuration networking
- Apple Sleep Proxy Service (Bonjour Sleep Proxy)
- Digital Living Network AllianceDigital Living Network AllianceThe Digital Living Network Alliance is a non-profit collaborative trade organization established by Sony in June 2003, and has more than 250 member companies in the mobile, consumer electronics, PC, and service provider industries...
- Universal Plug and PlayUniversal Plug and PlayUniversal Plug and Play is a set of networking protocols for primarily residential networks without enterprise class devices that permits networked devices, such as personal computers, printers, Internet gateways, Wi-Fi access points and mobile devices to seamlessly discover each other's presence...