Editing High-Efficiency Advanced Audio Coding (section)

==Standards==
HE-AAC profile was first standardized in ISO/IEC 14496-3:2001/Amd 1:2003.<ref name="ISO 2003"/> HE-AAC v2 profile (HE-AAC with Parametric Stereo) was first specified in ISO/IEC 14496-3:2005/Amd 2:2006.<ref name="mpeg4audio-n7016" /><ref name="ISO 14496-3:2005/Amd.2"/><ref name="embedded">{{cite web|title=Audio compression gets better and more complex |url=http://www.embedded.com/columns/specialreports/164300682?_requestid=60812 |author=Mihir Mody |publisher=Embedded.com |date=2005-06-06 |access-date=2009-10-13 }}{{dead link|date=November 2016 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The Parametric Stereo coding tool used by HE-AAC v2 was standardized in 2004 and published as ISO/IEC 14496-3:2001/Amd 2:2004.<ref name="parametric"/><ref name="3gpp26401"/>

The current version of the MPEG-4 Audio (including HE-AAC standards) is published in ISO/IEC 14496-3:2009.

Enhanced aacPlus is required audio compression format in [[3GPP]] technical specifications for [[3G]] [[UMTS]] multimedia services and should be supported in [[IP Multimedia Subsystem]] (IMS), [[Multimedia Messaging Service]] (MMS), [[Multimedia Broadcast Multicast Service|Multimedia Broadcast/Multicast Service]] (MBMS) and Transparent end-to-end Packet-switched Streaming Service (PSS).<ref>ETSI (2009-04) [http://www.3gpp.org/ftp/Specs/html-info/26234.htm ETSI TS 126 234 V8.2.0 (2009-04); 3GPP TS 26.234; Transparent end-to-end Packet-switched Streaming Service (PSS); Protocols and codecs] {{webarchive|url=https://web.archive.org/web/20081201093237/http://www.3gpp.org/ftp/specs/html-info/26234.htm |date=2008-12-01 }} Page 58. Retrieved on 2009-06-02.</ref><ref>ETSI (2009-01) [http://www.3gpp.org/ftp/Specs/html-info/26140.htm ETSI TS 126 140 V8.0.0 (2009-01); 3GPP TS 26.140; Multimedia Messaging Service (MMS); Media formats and codes] {{webarchive|url=https://web.archive.org/web/20081206062526/http://www.3gpp.org/ftp/Specs/html-info/26140.htm |date=2008-12-06 }} Page 11. Retrieved on 2009-06-02.</ref><ref>ETSI (2009-01) [http://www.3gpp.org/ftp/Specs/html-info/26141.htm ETSI TS 126 141 V8.0.0 (2009-01); 3GPP TS 26.141; IP Multimedia System (IMS) Messaging and Presence; Media formats and codecs] {{webarchive|url=https://web.archive.org/web/20081007213730/http://www.3gpp.org/ftp/Specs/html-info/26141.htm |date=2008-10-07 }} Page 10. Retrieved on 2009-06-02.</ref><ref name="3gpp-26346">{{cite web | title=ETSI TS 126 346 V8.3.0 (2009-06); 3GPP TS 26.346; Multimedia Broadcast/Multicast Service (MBMS); Protocols and codecs | url=http://www.3gpp.org/ftp/Specs/html-info/26346.htm | page=85 | author=3GPP | author-link=3GPP | publisher=[[ETSI]] | year=2009 | access-date=2009-10-13 | url-status=live | archive-url=https://web.archive.org/web/20081004163354/http://www.3gpp.org/FTP/Specs/html-info/26346.htm | archive-date=2008-10-04 }}</ref> HE-AAC version 2 was standardized under the name Enhanced aacPlus by [[3GPP]] for 3G UMTS multimedia services in September 2004 (3GPP TS 26.401).<ref name="3gpp-26401">{{cite web | title=3GPP TS 26.401 - General audio codec audio processing functions; Enhanced aacPlus general audio codec; General description | url=http://www.3gpp.org/ftp/Specs/html-info/26401.htm | author=3GPP | publisher=3GPP | year=2004 | access-date=2009-10-13 | url-status=live | archive-url=https://web.archive.org/web/20081004163359/http://www.3gpp.org/FTP/Specs/html-info/26401.htm | archive-date=2008-10-04 }}</ref>

HE-AAC and HE-AAC v2 audio coding for [[Digital Video Broadcasting|DVB]] applications is standardized by TS 101 154.<ref>ETSI TS 101 154 v1.5.1: Specification for the use of Video and Audio Coding in Broadcasting Applications based on the [[MPEG transport stream|MPEG-2 Transport Stream]]</ref><ref name="etsi-101-154">{{cite web | title=TS 101 154 version 1.9.1 - Digital Video Broadcasting (DVB); Specification for the use of Video and Audio Coding in Broadcasting Applications based on the MPEG-2 Transport Stream | url=http://webapp.etsi.org/workprogram/Report_WorkItem.asp?wki_id=30945 | author=ETSI | publisher=ETSI | date=2009-03-31 | access-date=2009-10-13 | url-status=live | archive-url=https://archive.today/20130414175722/http://webapp.etsi.org/WorkProgram/Report_WorkItem.asp?WKI_ID=30945 | archive-date=2013-04-14 }}</ref> AacPlus v2 by Coding Technologies<ref name="CT-whitepaper">{{cite web|url=http://www.codingtechnologies.com/products/assets/CT_aacPlus_whitepaper.pdf |title=Archived copy |access-date=2007-01-29 |url-status=dead |archive-url=https://web.archive.org/web/20061026031407/http://www.codingtechnologies.com/products/assets/CT_aacPlus_whitepaper.pdf |archive-date=2006-10-26 }}</ref> is also standardized by the [[European Telecommunications Standards Institute|ETSI]] as TS 102 005 for Satellite services to Handheld devices (DVB-SH) below 3&nbsp;GHz.

In December 2007, Brazil started broadcasting terrestrial DTV standard called International [[ISDB-Tb]] that implements video coding H.264 with audio AAC-LC on main program (single or multi) and video H.264 with audio HE-AACv2 in the 1Seg mobile sub-program.

===Versions===
The following is the summary of the different versions of HE-AAC:
{|class="wikitable"
! Version
! Common trade names
! Codec feature
! Standards
|----
| HE-AAC v1
 | aacPlus v1, eAAC, AAC+, CT-aacPlus
 | AAC-LC + SBR
 | ISO/IEC 14496-3:2001/Amd 1:2003
|----
| HE-AAC v2
 | aacPlus v2, eAAC+, AAC++, Enhanced AAC+
 | AAC-LC + SBR + PS
 | ISO/IEC 14496-3:2005/Amd 2:2006
|----
| [[Unified Speech and Audio Coding|xHE-AAC]]
 | aacPlus v2, eAAC+, AAC++, Enhanced AAC+
 | AAC-LC + SBR + PS + [[Unified Speech and Audio Coding|USAC]]
 | ISO/IEC 23003-3:2012/Amd 2:2012<br><ref>{{cite web|url=https://www.iis.fraunhofer.de/en/ff/amm/broadcast-streaming/xheaac.html|title=xHE-AAC|website=Fraunhofer Institute for Integrated Circuits IIS|access-date=3 January 2021}}</ref>
|}

* '''LC''' means ''[[Advanced Audio Coding#Modular encoding|low complexity]]''
* '''SBR''' means ''[[spectral band replication]]''
* '''PS''' means ''[[parametric stereo]]''
* '''USAC''' means ''[[unified speech and audio coding]]''