Editing Advanced Audio Coding (section)

====iTunes and iPod====
In April 2003, [[Apple Inc.|Apple]] brought mainstream attention to AAC by announcing that its [[iTunes]] and [[iPod]] products would support songs in MPEG-4 AAC format (via a [[firmware]] update for older iPods). Customers could download music in a closed-source [[digital rights management]] (DRM)-restricted form of 128&nbsp;kbit/s AAC (see [[FairPlay]]) via the [[iTunes Store]] or create files without DRM from their own CDs using iTunes. In later years, Apple began offering music videos and movies, which also use AAC for audio encoding.

On May 29, 2007, Apple began selling songs and music videos from participating record labels at higher bitrate (256&nbsp;kbit/s cVBR) and free of DRM, a format dubbed "iTunes Plus" . These files mostly adhere to the AAC standard and are playable on many non-Apple products but they do include custom iTunes information such as [[album artwork]] and a purchase receipt, so as to identify the customer in case the file is leaked out onto [[peer-to-peer]] networks. It is possible, however, to remove these custom tags to restore interoperability with players that conform strictly to the AAC specification. As of January 6, 2009, nearly all music on the USA regioned iTunes Store became DRM-free, with the remainder becoming DRM-free by the end of March 2009.<ref>
{{cite web
| url=http://www.macworld.com/article/137946/2009/01/itunestore.html
| title=iTunes Store goes DRM-free
| access-date=2009-02-10
| last=Cohen
| first=Peter
| date=2010-05-27
| work=Macworld
| publisher=Mac Publishing
| archive-url= https://web.archive.org/web/20090218092311/http://www.macworld.com/article/137946/2009/01/itunestore.html| archive-date= 18 February 2009 | url-status= live}}</ref>

iTunes offers a "Variable Bit Rate" encoding option which encodes AAC tracks in the [[Average bitrate|Constrained Variable Bitrate]] scheme (a less strict variant of ABR encoding); the underlying QuickTime API does offer a true VBR encoding profile however.<ref>{{cite web
| url=https://wiki.hydrogenaud.io/index.php?title=Apple_AAC#afconvert
| title=Apple AAC
| access-date=2021-11-22
| publisher=[[Hydrogenaudio]]
| url-status= live|archive-url=https://web.archive.org/web/20211123040120/https://wiki.hydrogenaud.io/index.php?title=Apple_AAC#afconvert|archive-date=2021-11-23}}</ref>

As of September 2009, Apple has added support for [[HE-AAC]] (which is fully part of the MP4 standard) only for radio streams, not file playback, and iTunes still lacks support for true VBR encoding.