Editing High-Efficiency Advanced Audio Coding (section)

==Perceived quality==
Testing indicates that material decoded from 64&nbsp;kbit/s HE-AAC does not quite have similar audio quality to material decoded from MP3 at 128&nbsp;kbit/s using high quality encoders.<ref>{{cite web|url=http://www.rjamorim.com/test/64test/results.html|title=Results of 64kbit/s Listening Test|date=23 June 2007|access-date=3 May 2018|url-status=bot: unknown|archive-url=https://web.archive.org/web/20070623042116/http://www.rjamorim.com/test/64test/results.html|archive-date=23 June 2007}}</ref><ref>{{cite web|url=http://www.hydrogenaud.io/forums/index.php?showtopic=50888|title=Multiformat Listening Test @ 48 kbps - FINISHED|website=www.hydrogenaud.io|access-date=3 May 2018|url-status=live|archive-url=https://web.archive.org/web/20140708014541/http://www.hydrogenaud.io/forums/index.php?showtopic=50888|archive-date=8 July 2014}}</ref><ref>{{cite web|url=http://www.hydrogenaud.io/forums/index.php?showtopic=35438|title=80 kbps personal listening test (summer 2005)|website=www.hydrogenaud.io|access-date=3 May 2018|url-status=live|archive-url=https://web.archive.org/web/20140708054803/http://www.hydrogenaud.io/forums/index.php?showtopic=35438|archive-date=8 July 2014}}</ref><ref>{{cite web|url=http://forum.hardware.fr/hardwarefr/VideoSon/MP3-WMA-AAC-OGG-qualite-kbit/s-evaluation-sujet-84950-1.htm|title=MP3 – WMA – AAC – OGG – qualité à 96 kbps (évaluation) - Traitement Audio - Video & Son - FORUM HardWare.fr|website=forum.hardware.fr|access-date=3 May 2018|url-status=live|archive-url=https://archive.today/20120715145608/http://forum.hardware.fr/hardwarefr/VideoSon/MP3-WMA-AAC-OGG-qualite-kbit/s-evaluation-sujet-84950-1.htm|archive-date=15 July 2012}}</ref> The test, taking bitrate distribution and [[RMSD]] into account, is a tie between [[mp3PRO]], HE-AAC and [[Ogg Vorbis]].

Further controlled testing by [[3GPP]] during their revision 6 specification process indicates that HE-AAC and HE-AAC v2 provide "Good" audio quality for music at low bit rates (e.g., 24&nbsp;kbit/s).

In 2011, a public listening test<ref>{{cite web|url=http://people.xiph.org/~greg/opus/ha2011/|title=Hydrogen audio 2011 multiformat listening test unofficial results page|website=people.xiph.org|access-date=3 May 2018|url-status=live|archive-url=https://web.archive.org/web/20120725215759/http://people.xiph.org/~greg/opus/ha2011/|archive-date=25 July 2012}}</ref> comparing the two best-rated HE-AAC encoders at the time to [[Opus (audio format)|Opus]] and Ogg Vorbis indicated that Opus had statistically significant superiority at 64&nbsp;kbit/s over all other contenders, and second-ranked Apple's implementation of HE-AAC as statistically superior to both Ogg Vorbis and Nero HE-AAC, which were tied for third place.

[[MPEG-2]] and MPEG-4 AAC-LC decoders without SBR support will decode the AAC-LC part of the audio, resulting in audio output with only half the sampling frequency, thereby reducing the audio bandwidth. This usually results in the high-end, or [[Treble (sound)|treble]], portion of the audio signal missing from the audio product.