| Apple Lossless Audio Codec | |
|---|---|
| Developer | Apple |
| Initial release | April 28, 2004; 21 years ago (2004-04-28) |
| Stable release | October 28, 2011; 14 years ago (2011-10-28) |
| Type | Audio codec |
| License | Apache License 2.0 |
| Website | alac |
| Repository | |
| Filename extension | |
|---|---|
| Developed by | Apple Inc. |
| Type of format | Losslessaudio |
| Contained by | MPEG-4 Part 14 |
| Open format? | Yes |
| Free format? | Yes |
TheApple Lossless Audio Codec (ALAC,/əˈlæk/), also known asApple Lossless, orApple Lossless Encoder (ALE), is anaudio coding format, and its referenceaudio codec implementation, developed byApple forlossless data compression of digitalmusic. After initially keeping itproprietary from its inception in 2004, in late 2011 Apple made the codec availableopen source androyalty-free. Traditionally, Apple has referred to the codec asApple Lossless, though more recently, c.a. 2017, it has begun to use the abbreviated termALAC when referring to the codec.[1][2]
ALAC data is frequently stored within anMP4container with thefilename extension.m4a. This extension is also used by Apple forAAC (which is alossy format) in an MP4 container (same container, different audio encoding). ALAC can also be used by the.CAF file type container, though this is much less common.
ALAC supports up to 8 channels of audio at 16, 20, 24 and 32 bit depth with a maximum sample rate of 384 kHz.
ALAC also does not use anyDRM scheme;[dubious –discuss] but by the nature of the MP4container, it is feasible that DRM could be applied to ALAC much in the same way it is applied to files in other QuickTime containers.
According to Apple, audio files compressed with its lossless codec will use up "about half the storage space" that the uncompressed data would require. Testers using a selection of music have found that compressed files are about 40% to 60% the size of the originals depending on the kind of music, which is similar to other lossless formats.[3][4]
ALAC has been measured to require around four times as much CPU power to decode thanFLAC does,[5] with implications for battery life on limited-power devices. Still, the format has been recommended for olderiPod devices based on claims of lower power usage.[6]
Partly because of the use of an MP4 container, ALAC does not contain integrated error checking.[7]
ALAC is not a variant ofAAC (which is alossy format), but rather an unrelated lossless format that useslinear prediction (similar to other lossless codecs).
Thedata compression software for encoding into ALAC files, Apple Lossless Encoder, was introduced into the Mac OS XCore Audio framework on April 28, 2004, together with theQuickTime 6.5.1 update, thus making it available iniTunes since version 4.5 and above, and its replacement, the Music application.[8] The codec is also used in theAirPort andAirPlay implementation.
David Hammerton andSerafina Brocious analyzed andreverse engineered the codec without any documents on the format. On March 5, 2005, Hammerton published a simpleopen source decoder written in theC programming language on the basis of the work.[9]
The Apple Lossless Encoder (and decoder) were released as open source software under theApache License version 2.0 on October 27, 2011.[10][11][12]
On May 17, 2021, Apple announced that they would begin offering lossless audio inApple Music in June 2021, with all lossless music being encoded using ALAC.[13]
All current iOS devices can play ALAC encoded files.
However, in theiOS 9.3.6 (13G37) update, which was released on July 22, 2019, afteriOS 9.3.5 (13G36) on August 25, 2016,[relevant?] as the last update for theiPhone 4S and aimed at fixing security issues, etc., there was still a bug with the ALAC codec inMusic app.This issue involved songs with the ALAC codec being synced internally to the phone byiTunes (known asApple Music as of June 3, 2019), and when playing that song/album, the album cover from another album (in a non-ALAC format) would be displayed.[citation needed]
The open source librarylibavcodec incorporates both a decoder and an encoder for the ALAC format, which means thatmedia players based on that library (includingVLC media player andMPlayer, as well as many media center applications forhome theater computers, such asPlex,Kodi, andBoxee) are able to play ALAC files.
The introduction ofBlackBerry OS 10 in 2013 made it possible to play the ALAC Audio Codec.Earlier,BlackBerry OS 7 in 2011 had enabled the playback ofFLAC onBlackBerry phones.
As of 2015,Windows 10 includes support for ALAC encoding and decoding, thereby enabling other media players to use it, e.g.Windows Media Player when ripping CDs or theSpotify desktop client for playback of local .m4a files.The library was subsequently optimized for ARM processors and included inRockbox.[clarification needed]
Foobar2000 will play ALAC files as willJRiver Media Center and BitPerfect.
Lossless music via ALAC was added toApple Music in June 2021, at no additional cost for all subscribers. The maximum fidelity for lossless music on Apple Music is 24-bit at 192 kHz.[14]
If you have songs encoded in ALAC, WAV, or AIFF formats, we create an AAC 256 Kbps version and upload it to iCloud so that it can be played on all of your other devices.
We create AAC 256Kbps versions of songs that are encoded in ALAC, WAV, or AIFF formats and add the AAC version to iCloud Music Library.
Apple Music will also make its catalog of more than 75 million songs available in Lossless Audio. Apple uses ALAC (Apple Lossless Audio Codec) to preserve every single bit of the original audio file. This means Apple Music subscribers will be able to hear the exact same thing that the artists created in the studio.
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