Editing Audio Units

{{Short description|API for audio software in macOS and iOS}}

[[File:Audio Units colour logo.svg|thumb|right|]]

'''Audio Units''' ('''AU''') are a system-level [[Plug-in (computing)|plug-in]] architecture provided by [[Core Audio]] in [[Apple Inc.|Apple]]'s [[macOS]] and [[iOS]] operating systems.  Audio Units are a set of [[application programming interface]] (API) services provided by the [[operating system]] to generate, process, receive, or otherwise manipulate streams of audio in near-real-time with minimal latency. It may be thought of as Apple's architectural equivalent to another popular plug-in format, [[Steinberg]]'s [[Virtual Studio Technology]] (VST).

Because of the many similarities between Audio Units and VST, several commercial and free wrapping technologies are available (e.g. [https://code.google.com/p/symbiosis-au-vst/ Symbiosis] and [[FXpansion]] [http://www.fxpansion.com/index.php?page=5 VST-AU Adapter]). [[Celemony Software]] and [[PreSonus]] have also developed the [[Audio Random Access]] (ARA) extension, which works for both AU and [[Virtual Studio Technology|VST]], allowing greater integration between the [[Audio plug-in|plug-ins]] and [[Digital audio workstation|DAW]] software.<ref>{{Cite web|url=http://www.kvraudio.com/news/celemony-introduces-ara-audio-random-access---extension-for-plug-in-interfaces-17543|title=Celemony introduces ARA Audio Random Access - Extension for Plug-in Interfaces|website=KVR Audio|date=27 October 2011 |language=en|access-date=2018-06-05}}</ref>

== Use ==
Audio Units allows sound file [[audio time stretching and pitch scaling]] (e.g., timestretch), [[sample rate]] conversion, and streaming over a [[local area network]]. It also comes with a set of AU plug-ins such as EQ filters, dynamic processors, delay, reverb, and a Soundbank Synthesizer Instrument.
<!-- Deleted image removed: [[Image:AppleAU.jpg|thumb|250px|right|AUDelay, an Apple AU plug-in included in OS X]] -->

AU are used by Apple applications such as [[GarageBand]], [[Soundtrack Pro]], [[Logic Express]], [[Logic Pro]], [[Logic Pro X]], [[Final Cut Pro]], [[MainStage]] and most 3rd party audio software developed for [[macOS]] such as [[Ableton Live]], Amadeus Pro, [[Ardour (software)|Ardour]], [[Audio Hijack]], [[DaVinci Resolve]], [[Digital Performer]], [[Gig Performer]], [[REAPER]], and [[Studio One (software)|Studio One]].

== Competing technologies ==
*[[Avid Technology|Avid]]'s Avid Audio eXtension (a successor to the RTAS format)
*[[Digidesign]]'s [[Real Time AudioSuite]] (now obsolete)
*[[LADSPA]] and [[Disposable Soft Synth Interface]] (DSSI) for [[Linux]]
*[[LV2]] (crossplatform successor to LADSPA)
*[[Microsoft]]'s [[DirectX]]
*[[Steinberg]]'s [[Virtual Studio Technology]]

==References==
<references />

{{CoreFoundation}}
{{OS X}}

[[Category:Music software plugin architectures]]
[[Category:macOS APIs]]