Audio Interchange File Format: Difference between revisions

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{{Short description|File format family}}

{{Redirect-acronym|AIFF|[[All India Football Federation]]}}{{more citations needed|date=January 2016}}{{Infobox file format

{{Redirect|AIFC|the Astana International Financial Centre|Astana International Financial Centre}}

{{more citations needed|date=January 2016}}

{{Infobox file format

| name = Audio Interchange File Format <br>(AIFF)

| icon =

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| uniform type = public.aiff-audio<br />public.aifc-audio

| magic =

| owner = [[Apple Inc.|Apple]]

| released = {{start date and age|1988|01|21|df=yes}}<ref name="aiff-spec">{{citation |url=httphttps://www-.mmsp.ece.mcgill.ca/Documents/AudioFormats/AIFF/Docs/AIFF-1.3.pdf |title=Audio Interchange File Format, A Standard for Sampled Sound Files, Version 1.3 |format=PDF |author=Apple Computer, Inc. |date=1989-01-04 |access-date=2010-03-21}}</ref><!-- {{Start date|YYYY|dd|mm|df=yes}} -->

| latest release version = 1.3

| latest release date = {{Start date and age|1989|01|04|df=no}}<!-- {{Start date and age|YYYY|dd|mm|df=yes}} --><br />AIFF-C / {{Start date and age|1991|07|df=yes}}<ref name="aiff-spec2">{{cite web |url=httphttps://www-.mmsp.ece.mcgill.ca/Documents/AudioFormats/AIFF/AIFF.html |title=Audio File Format Specifications - AIFF / AIFF-C Specifications |author=P. Kabal |publisher=McGill University |date=2005-03-15 |access-date=2010-03-21}}</ref>

| genre = [[audioAudio file format]], [[container format (digital)|container format]]

| container for =

| contained by =

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In addition to audio data, AIFF can include [[Loop (music)|loop]] point data and the musical note of a [[sampling (music)|sample]], for use by hardware samplers and musical applications.

The file extension for the standard AIFF format is '''<code>.aiff'''</code> or '''<code>.aif'''</code>. For the compressed variantsformat itthe ispreferred supposedsuffix to beis '''<code>.aifc'''</code>, but .aiffaudio orapplications .aifsupporting arethe acceptedformat asalso wellallow by<code>.aiff</code> audioor applications supporting the format<code>.aif</code>.

==AIFF on macOS==

{{Original research|section|date=March 2009}}

With the development of the OS X operating system now known as [[macOS]] operating system, Apple created a new type of AIFF which is, in effect, an alternative [[little-endian]] byte order format.<ref>[{{Cite web |date=2008-10-29 |title=Speech Synthesis Manager - OS X Manual |url=https://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man1/say.1.html Mac OS X Reference|url-status=dead Library]<|archive-url=https://web.archive.org/web/20091128075236/ref><ref>[https://developer.apple.com/iphonemac/library/documentation/musicaudioDarwin/ConceptualReference/CoreAudioOverviewManPages/SupportedAudioFormatsMacOSXman1/SupportedAudioFormatsMacOSXsay.1.html |archive-date=2009-11-28 |website=Apple}}</ref><ref>{{Cite web |date=2008-11-13 |title=Supported Audio File and Data Formats in Mac OS X] |url=https://developer.apple.com/iphone/library/documentation/musicaudio/Conceptual/CoreAudioOverview/SupportedAudioFormatsMacOSX/SupportedAudioFormatsMacOSX.html |url-status=dead |archive-url=https://web.archive.org/web/20090523155253/https://developer.apple.com/iphone/library/documentation/musicaudio/Conceptual/CoreAudioOverview/SupportedAudioFormatsMacOSX/SupportedAudioFormatsMacOSX.html |archive-date=2009-05-23 |website=Apple}}</ref>

Because the AIFF architecture has no provision for alternative byte order, Apple used the existing AIFF-C compression architecture, and created a "pseudo-compressed" codec called '''sowt''' ('''twos''' spelled backwards). The only difference between a standard AIFF file and an AIFF-C/sowt file is the byte order; there is no compression involved at all.<ref name='"RF04'">{{cite web |date=1995-05-01 |title=Technical Q&A QTMRF04: QuickTime Sound | url=https://developer.apple.com/mac/library/archive/qa/qtmrf/qtmrf04.html | publisherurl-status=Applelive |archive-url=https://web.archive.org/web/20220705133320/https://developer.apple.com/library/archive/qa/qtmrf/qtmrf04.html |archive-date=19952022-07-05-01 | access-date=2009-11-09 |website=Apple |publisher=}}</ref>

Apple uses this new little-endian AIFF type as its standard on macOS. When a file is imported to or exported from [[iTunes]] in "AIFF" format, it is actually AIFF-C/sowt that is being used. When audio from an audio CD is imported by dragging to the macOS Desktop, the resulting file is also an AIFF-C/sowt. In all cases, Apple refers to the files simply as "AIFF", and uses the "<code>.aiff"</code> extension.

For the vast majority of users this technical situation is completely unnoticeable and irrelevant. The sound quality of standard AIFF and AIFF-C/sowt are identical, and the data can be converted back and forth without loss. Users of older audio applications, however, may find that an AIFF-C/sowt file will not play, or will prompt the user to convert the format on opening, or will play as static.

All traditional AIFF and AIFF-C files continue to work normally on macOS (including on the new Intel-based hardware), and many third-party audio applications as well as hardware continue to use the standard AIFF big-endian byte order.

==AIFF Apple Loops==

Apple has also created another recent extension to the AIFF format in the form of Apple Loops<ref>{{cite web |title=Logic Studio - Plug-ins & Sounds |url=https://www.apple.com/logic-pro/plugins-and-sounds/ |titleurl-status=Logic Studiolive |archive- Plugurl=https://web.archive.org/web/20130720011337/http://www.apple.com/logic-ins & Soundspro/plugins-and-sounds |publisherarchive-date=Apple2013-07-20 |access-date=2010-04-30 |website=Apple |publisher=}}</ref> used by [[GarageBand]] and [[Logic Pro]], which allows the inclusion of data for pitch and tempo shifting by an application in the more common variety, and [[MIDI]]-sequence data and references to GarageBand playback instruments in another variety.

Apple Loops use either the <code>.aiff</code> (or <code>.aif</code>) or <code>.caf</code> extension regardless of type.

==Data format==

An AIFF file is divided into a number of chunks.<ref>[http{{Cite web |last=Kabal |first=Peter |date=2017-09-20 |title=Audio File Format Specifications |url=https://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/AIFF/AIFF.html Audio|url-status=live File|archive-url=https://web.archive.org/web/20220724201945/https://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/AIFF/AIFF.html Format|archive-date=2022-07-24 Specifications]|website=MMSP Lab, ECE, McGill University}}</ref> Each chunk is identified by a ''chunk ID'' more broadly referred to as [[FourCC]].

Types of chunks found in AIFF files:

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==Metadata==

AIFF files can store [[metadata]] in Name, Author, Comment, Annotation, and Copyright chunks. An [[ID3v2 tag]] chunk can also be embedded in AIFF files, as well as an Application Chunk with [[Extensible Metadata Platform]] (XMP) data in it.<ref>{{cite web |date=November 18, 2013 |title=AIFF Tagging |url=http://aifftagging.blogspot.com |url-status=live |archive-url=https://web.archive.org/web/20220407031344/https://aifftagging.blogspot.com/ |archive-date=2022-04-07}}</ref>

==Common compression types==

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{| class="wikitable sortable"

|+AIFF-C common compression types<ref name="aiff-spec" /><ref>{{cite web |url=http://shoko.calarts.edu/~tre/AIFFC/comptype.html |title=AIFF-C Compression Types and Names |author=Tom Erbe |year=1999 |access-date=2010-03-21 |archive-url=https://web.archive.org/web/20060620002145/http://shoko.calarts.edu/~tre/AIFFC/comptype.html |archive-date=2006-06-20}}</ref><ref>{{cite web |date=2005-05-09 |title=AIFF-hul Module |url=http://hul.harvard.edu/jhove/aiff-hul.html |title=JSTOR/Harvard Object Validation Environment - AIFF-hul Module |date=2005-05-09 |access-date=2010-03-21 |url-status=dead |archive-url=https://web.archive.org/web/20100629090032/http://hul.harvard.edu/jhove/aiff-hul.html |archive-date=2010-06-29 |access-date=2010-03-21 |website=JSTOR/Harvard Object Validation Environment}}</ref>

|-

! Compression type

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| ALAW

| [[CCITT]] G.711 A-law

| 8-bit ITU-T G.711 A-law (64 &nbsp;kbit/s)

| SGI

|-

| ULAW

| CCITT G.711 u-law

| 8-bit ITU-T G.711 μ-law (64 &nbsp;kbit/s)

| SGI

|-

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| Square-Root-Delta

| Big-endian

| 3DO (Panasonic) / MACMac (Apple)

|}

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==External links==

*[https://web.archive.org/web/20071219035740/http://www.cnpbagwell.com/aiff-c.txt Audio Interchange File Format AIFF-C -– Draft 08/26/91 -– Apple Computer, Inc.] -– (archive.org backup)

*[https://web.archive.org/web/20171118222232/http://www-mmsp.ece.mcgill.ca/documents/audioformats/aiff/aiff.html AIFF / AIFC Sound File Specifications -– Draft 17/11/17] -– (archive.org backup)

{{Compression formats}}