View source for Software:Apple Lossless Audio Codec

{{Short description|Audio codec format}}
{{Infobox software
| name = Apple Lossless Audio Codec
| logo = 
| screenshot = 
| caption = 
| author = 
| developer = [[Company:Apple Inc.|Apple Inc.]]
| released = {{start date and age|2004|April|28}}
| latest_release_version = {{Start date and age|2011|10|28}}
| latest_release_date = 
| latest preview version = 
| latest preview date = 
| operating_system = <!-- Do not forget your source -->
| genre = [[Audio codec]]
| license = [[Software:Apache License|Apache License]] 2.0
| website = {{URL|http://alac.macosforge.org}}
}}
{{Infobox file format
| name = 
| logo =
| screenshot =
| caption =
| extension = .m4a [[Core Audio Format|.caf]]
| mime =
| type code =
| uniform type =
| magic =
| owner = [[Company:Apple Inc.|Apple Inc.]]
| type = Lossless data compression, [[Audio file format|audio file format]]
| container for =
| contained by = [[MPEG-4 Part 14]]
| extended from =
| extended to =
| standard =
}}
The '''Apple Lossless Audio Codec''' ('''ALAC'''), also known as '''Apple Lossless''', or '''Apple Lossless Encoder''' ('''ALE'''), is an [[Audio coding format|audio coding format]], and its reference [[Audio codec|audio codec]] implementation, developed by [[Company:Apple Inc.|Apple Inc.]] for lossless data compression of digital [[Physics:Music|music]]. After initially keeping it [[Proprietary format|proprietary]] from its inception in 2004, in late 2011 Apple made the codec available [[Open-source software|open source]] and royalty-free. Traditionally, Apple has referred to the codec as ''Apple Lossless'', though more recently it has begun to use the abbreviated term ''ALAC'' when referring to the codec.<ref name=ALAC-term-1>{{cite web|title=Subscribe to iTunes Match|url=https://support.apple.com/en-us/HT204146|publisher=Apple Inc|access-date=May 31, 2017|date=May 8, 2017|quote=If you have songs encoded in ALAC, WAV, or AIFF formats, we create an AAC 256Kbps version and upload it to iCloud so that it can be played on all of your other devices.}}</ref><ref name=ALAC-term-2>{{cite web|title=Access your music collection on all of your devices with Apple Music|url=https://support.apple.com/en-us/HT205919|publisher=Apple Inc|access-date=May 31, 2017|date=May 12, 2017|quote=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.}}</ref>

==Codec==
Apple Lossless supports up to 8 channels of audio at 16, 20, 24 and 32 bit depth with a maximum sample rate of 384kHz. 

ALAC and FLAC has identical quality.<ref>{{Cite web|last=Inc|first=Coppertino|date=2017-07-23|title=The difference between FLAC vs. ALAC explained|url=https://vox.rocks/resources/flac-vs-alac|access-date=2021-10-21|website=VOX Player|language=en}}</ref><ref>{{Cite web|last=info@pooraudiophile.com|date=2013-07-18|title=What's the Difference Between FLAC vs ALAC Lossless for audiophile recordings?|url=https://www.pooraudiophile.com/2013/07/difference-between-flac-vs-alac-recordings.html|url-status=live|access-date=2021-10-21|website=Poor Audiophile|language=en-us|quote=From an audio perspective, there’s no difference between FLAC or ALAC files that are recorded at the same sampling rate. That’s ultimately the case because all FLAC or ALAC files are compressed versions of a “lossless” original, which means that the original file, when compressed in either format to make it smaller to store and transmit, doesn’t lose any of its quality when it’s played on your system}}</ref> 

Apple Lossless data is frequently stored within an [[MPEG-4 Part 14|MP4]] container with the [[Filename extension|filename extension]] ''.m4a''. This extension is also used by Apple for lossy AAC audio data in an MP4 container (same container, different audio encoding). The codec can also be used by the [[Core Audio Format|.CAF]] file type container, though this is much less common.

Apple Lossless is not a variant of [[Advanced Audio Coding|AAC]] (which is a [[Lossy compression|lossy]] format), but rather a distinct{{Clarify|reason=distant lossless format in what way?|date=July 2021}} lossless format that uses [[Linear prediction|linear prediction]]; similar to other lossless codecs.  

ALAC also does not use any [[Engineering:Digital rights management|DRM]] scheme; but by the nature of the MP4 container, it is feasible that DRM could be applied to ALAC much in the same way it is applied to files in other QuickTime containers.{{fact|date=April 2015}}

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.<ref name="ALAC-space1">{{cite web|url=http://wiki.hydrogenaud.io/index.php?title=Lossless_comparison#Comparison_Table|title=Lossless comparison - HydrogenAudio Knowledgebase|publisher=HydrogenAudio|date=July 27, 2011|access-date=June 27, 2012}}</ref><ref name="ALAC-space2">{{cite web|url=http://www.mcelhearn.com/an-overview-of-apple-lossless-compression-results/|title=An Overview of Apple Lossless Compression Results|publisher=Kirkville|first=Kirk|last=McElhearn|date=November 5, 2011|access-date=June 27, 2012}}</ref> 

Compared to some other formats,{{Clarify|reason=which formats|date=July 2021}} it requires less computing to decode. Therefore, it is suitable for a limited-power devices, such as older [[Software:IOS|iOS]] devices.<ref>{{cite book|url=http://my.safaribooksonline.com/book/audio/30000lti00201/internet-delivery-formats/ch12lev1sec3|title=The Mastering Engineer's Handbook: The Audio Mastering Handbook, Second Edition|at=Chapter 12. Internet Delivery Formats &gt; Lossless Codecs |isbn=978-1-59863-449-5 |first=Bobby |last=Owsinski|publisher=Thomson Course Technology PTR|date=December 26, 2007 |access-date=January 15, 2012}}</ref><ref name="Rockbox-comparison">{{cite web|url=http://www.rockbox.org/wiki/CodecPerformanceComparison|title=CodecPerformanceComparison|publisher=RockBox|date=July 28, 2013|access-date=November 29, 2014}}</ref>

Partly because of the use of an MP4 container, Apple Lossless does not contain integrated error checking.<ref>{{cite web|url=http://www.hydrogenaud.io/forums/index.php?s=&showtopic=33226&view=findpost&p=862031|title=Which is the best lossless codec? – Hydrogenaudio Forums|publisher=Hydrogenaudio|date=April 1, 2014|access-date=June 30, 2014}}</ref>

==History==
The [[Data compression|data compression]] software for encoding into ALAC files, Apple Lossless Encoder, was introduced into the Mac OS X [[Software:Core Audio|Core Audio]] framework on April 28, 2004 together with the [[Software:QuickTime|QuickTime]] 6.5.1 update, thus making it available in [[Software:ITunes|iTunes]] since version 4.5 and above, and its replacement, the Music application.<ref name="MW info 1">{{Cite web|title=QuickTime 6.5.1 adds Lossless Encoder, improves AAC|url=http://www.macworld.com/article/1031552/quicktime.html|website=Macworld|access-date=2016-01-24|date=2004-04-28}}</ref> The codec is also used in the [[Engineering:AirPort|AirPort]] and [[Engineering:AirPlay|AirPlay]] implementation.

David Hammerton and Cody Brocious analyzed and [[Reverse engineering|reverse engineered]] the codec without any documents on the format. On March 5, 2005, Hammerton published a simple [[Open-source software|open source]] decoder written in the [[C (programming language)|C programming language]] on the basis of the work.<ref name="ALAC-reverse">{{cite web|year=2004|title=ALAC|url=http://craz.net/programs/itunes/alac.html|url-status=dead|archive-url=https://web.archive.org/web/20120620124229/http://craz.net/programs/itunes/alac.html|archive-date=June 20, 2012|access-date=June 27, 2012|publisher=Crazney.net}}</ref>

The Apple Lossless Encoder (and decoder) were released as open source software under the [[Software:Apache License|Apache License]] version 2.0 on October 27, 2011.<ref name="Apache-license">{{cite web|url=http://alac.macosforge.org|title=Apple Lossless Audio Codec|publisher=MacOS Forge|date=October 27, 2011|access-date=October 29, 2011}}</ref><ref name="Apache-ars">{{cite web|last=Foresman|first=Chris|title=After seven years, Apple open sources its Apple Lossless Audio Codec|url=https://arstechnica.com/apple/news/2011/10/after-seven-years-apple-open-sources-its-apple-lossless-audio-codec.ars|publisher=Ars Technica|date=October 28, 2011|access-date=October 29, 2011}}</ref><ref name="Apache-3">{{cite web|url=http://h-online.com/-1368212|archive-url=https://web.archive.org/web/20120515214941/http://www.h-online.com/open/news/item/Apple-open-sources-its-ALAC-lossless-audio-codec-1368212.html|archive-date=15 May 2012|title=Apple open sources its ALAC lossless audio codec|first=Chris|last=von Eitzen|publisher=The H|date=October 28, 2011|access-date=October 29, 2011}}</ref> 

On May 17, 2021, Apple announced that they would begin offering lossless audio in [[Software:Apple Music|Apple Music]] in June 2021, with all lossless music being encoded using ALAC.<ref>{{cite web |title=Apple Music announces Spatial Audio and Lossless Audio |url=https://www.apple.com/newsroom/2021/05/apple-music-announces-spatial-audio-and-lossless-audio/ |website=Apple Newsroom |quote=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.}}</ref>

== Apple support for lossless formats ==
Other lossless codecs, such as FLAC and [[Software:Shorten (file format)|Shorten]], are not natively supported by Apple's [[Software:ITunes|iTunes]] nor the later [[Software:Music|Music app]] (either the macOS or Windows versions) or by [[Engineering:List of iOS devices|iOS device]]s running [[Software:IOS 10|iOS 10]] or below. In order to be played through the iTunes and Music app on iOS, audio files using these lossless codecs may be converted via various [[Finance:Third-party source|third-party]] tools into ALAC-encoded files with no change in fidelity. 

Third-party applications are available from the [[Software:App Store (iOS)|App Store]] to play such files without converting them. Devices running [[Software:IOS 11|iOS 11]] or above do support FLAC playback natively, through the [[Software:Files (Apple)|Files]] application only.<ref name="MR info 1">{{Cite web|date=June 6, 2017|title=iOS 11 lets you play FLAC audio files straight from your iPad and iPhone|url=https://thenextweb.com/apple/2017/06/06/ios-11-flac-audio-iphone-ipad/|access-date=August 25, 2020|website=The Next Web}}</ref> The method of importing the files to the Apple device varies between applications, including Files, as there is currently no official support for doing so.<ref>{{Cite web|last=Harris|first=Mark|date=March 2, 2020|title=How to Play FLAC Files on the iPhone|url=https://www.lifewire.com/can-flac-files-be-played-on-the-iphone-2438627|access-date=August 25, 2020|website=Lifewire}}</ref>

=== Metadata ===
Users of the iTunes or Music app applications who wish to use a lossless format which supports [[Metadata|metadata]] (unlike [[WAV]]/[[Audio Interchange File Format|AIFF]] or other PCM-type formats, where [[WAV#Metadata|metadata is usually ignored]]) must use ALAC.<ref>{{cite web|last=Hammerton|first=David|date=March 1, 2005|title=Re: Apple Lossless Audio Codec: Issues surrounding the release of my code|url=http://article.gmane.org/gmane.comp.video.ffmpeg.devel/19686|url-status=dead|archive-url=https://web.archive.org/web/20070221052210/http://article.gmane.org/gmane.comp.video.ffmpeg.devel/19686|archive-date=February 21, 2007|access-date=November 5, 2006|publisher=Gmane}}</ref> 

==Software==
All current iOS devices can play Apple Lossless encoded files. 


As of 2015, [[Software:Windows 10|Windows 10]] includes support for Apple Lossless encoding and decoding, thereby enabling other media players to use it, e.g. [[Software:Windows Media Player|Windows Media Player]] when ripping CDs or the [[Software:Spotify|Spotify]] desktop client for playback of local .m4a files. 

The library was subsequently optimized for ARM processors and included in [[Software:Rockbox|Rockbox]].{{Clarify|reason=which library|date=July 2021}} 

[[Software:Foobar2000|Foobar2000]] will play Apple Lossless files as will [[Software:JRiver Media Center|JRiver Media Center]] and BitPerfect.

Lossless music via ALAC was added to [[Software:Apple Music|Apple Music]] in June 2021, at no additional cost for all subscribers. The maximum fidelity for lossless music on Apple Music is 24-bit at 192kHz.<ref>{{cite web |title=Apple Music announces Spatial Audio and Lossless Audio |url=https://www.apple.com/newsroom/2021/05/apple-music-announces-spatial-audio-and-lossless-audio/ |website=Apple Newsroom |access-date=17 May 2021}}</ref>

==See also==
*[[Audio Interchange File Format]] (AIFF)
*[[Comparison of audio coding formats]]
*Free Lossless Audio Codec (FLAC)
*[[Software:Monkey's Audio|Monkey's Audio]]
*[[Software:TTA (codec)|TTA]]
*[[Software:WavPack|WavPack]]
*[[Software:Windows Media Audio 9 Lossless|Windows Media Audio 9 Lossless]]

==References==
{{reflist|colwidth=50em}}

==External links==
*[http://alac.macosforge.org ALAC Project] at MacOSForge
*[http://alac.macosforge.org/trac/browser/trunk/ReadMe.txt ALAC] technical features at MacOSForge
*[https://web.archive.org/web/20110329002415/http://www.apple.com/itunes/features/#importing ALAC] importing at [[Company:Apple Inc.|Apple]]
*[https://kirkville.com/an-overview-of-apple-lossless-compression-results ALAC compression rates for different types of music] article by Kirk McElhern

{{Compression formats}}
{{Compression Software Implementations}}

[[Category:Free audio codecs]]
[[Category:Lossless audio codecs]]
[[Category:Open formats]]
[[Category:Software using the Apache license]]

{{Sourceattribution|Apple Lossless Audio Codec}}