Editing Apple Lossless Audio Codec (section)

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

ALAC also does not use any [[digital rights management|DRM]] scheme;{{dubious|Apple Lossless with Apple Music and DRM|date=February 2022}} but by the nature of the MP4 [[container format (digital)|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.

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>

ALAC has been measured to require around four times as much CPU power to decode than FLAC does,<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> with implications for battery life on limited-power devices. Still, the format has been recommended for older [[iPod]] devices based on claims of lower power usage.<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|archive-date=September 8, 2011|archive-url=https://web.archive.org/web/20110908014656/http://my.safaribooksonline.com/book/audio/30000lti00201/internet-delivery-formats/ch12lev1sec3|url-status=dead}}</ref>

Partly because of the use of an MP4 container, ALAC 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>

ALAC is not a variant of [[Advanced Audio Coding|AAC]] (which is a [[Lossy compression|lossy]] format), but rather an unrelated lossless format that uses [[linear prediction]] (similar to other lossless codecs).