Editing Spectral band replication (section)

== History and use ==
A Swedish company [[Coding Technologies]] (acquired by [[Dolby Laboratories|Dolby]] in 2007) developed and pioneered the use of SBR in its MPEG-2 [[Advanced Audio Coding|AAC]]-derived codec called aacPlus, which first appeared in 2001. This codec was submitted to MPEG and formed the basis of MPEG-4 [[High-Efficiency Advanced Audio Coding|High-Efficiency AAC]] (HE-AAC), standardized in 2003.<ref>{{cite web | title=Bandwidth extension, ISO/IEC 14496-3:2001/Amd 1:2003 | url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=38148 | author=ISO | publisher=ISO | year=2003 | accessdate=2009-10-13}}</ref> [[Lars Liljeryd]], Kristofer Kjörling, and Martin Dietz received the [[IEEE Masaru Ibuka Consumer Electronics Award]] in 2013 for their work developing and marketing HE-AAC.<ref name=ieee-award>{{cite web |title=IEEE Masaru Ibuka Consumer Electronics Award |url=http://www.ieee.org/about/awards/bios/ibuka_recipients.html |archive-url=https://web.archive.org/web/20100408000509/http://www.ieee.org/about/awards/bios/ibuka_recipients.html |url-status=dead |archive-date=April 8, 2010 |website=IEEE.org |accessdate=7 July 2015}}</ref><ref name=ieee-interview>{{cite web |title=Interview with Martin Dietz, Kristofer Kjörling, and Lars Liljeryd |url=https://www.youtube.com/watch?v=i-eKbP_K2Sg |website=YouTube |accessdate=7 July 2015}}</ref> Coding Technologies' SBR method has also been used with [[Windows Media Audio|WMA]] 10 Professional to create WMA 10 Pro LBR, and with [[MP3]] to create [[mp3PRO]].

HE-AAC which uses SBR is used in broadcast systems like [[DAB+]], [[Digital Radio Mondiale]] (including [[xHE-AAC]]), [[HD Radio]], and [[XM Satellite Radio]].<ref>{{cite web | title = XM Radio – Fast Facts | url = http://sounds.xmradio.com/about/fast-facts/sound.xmc | accessdate = February 8, 2010 | archive-date = November 15, 2006 | archive-url = https://web.archive.org/web/20061115191347/http://sounds.xmradio.com/about/fast-facts/sound.xmc | url-status = dead }}</ref>

If the player is not capable of using the side information that has been transmitted alongside the "normal" compressed audio data, it may still be able to play the "baseband" data (e.g. sampled at 22.05&nbsp;kHz instead of 44.1&nbsp;kHz) as usual, resulting in a dull (since the high frequencies are missing), but otherwise mostly acceptable sound. This is, for example, the case if an mp3PRO file is played back with MP3 software incapable of utilizing the SBR information.

Opus's [[CELT]] part performs ''spectral folding'' on the MDCT bin level, making it a far less advanced but lower-delay technique compared to SBR.<ref name="ValinAES135">{{cite web |author1=Jean-Marc Valin |author2=Gregory Maxwell |author3=Timothy B. Terriberry |author4=Koen Vos |title=High-Quality, Low-Delay Music Coding in the Opus Codec |url = http://jmvalin.ca/papers/aes135_opus_celt.pdf |website=www.xiph.org |publisher=Xiph.Org Foundation|access-date=19 August 2014 |location = New York, NY |page=2 |date=October 17–20, 2013 |archive-url=https://web.archive.org/web/20180714000735/http://jmvalin.ca/papers/aes135_opus_celt.pdf|archive-date=14 July 2018|url-status=dead}}</ref>

[[Dolby Digital Plus]] (E-AC3) performs ''Spectral Extension'' (SPX). SPX reduces high-frequency components to metadata and is similar to E-AC3 multichannel coupling calculation.<ref>{{cite web |last1=Andersen |first1=Robert Loring |last2=Crockett |first2=B. |last3=Davidson |first3=G. |last4=Davis |first4=Mark |last5=Fielder |first5=L. |last6=Turner |first6=Stephen C. |last7=Vinton |first7=M. |last8=Williams |first8=P. |title=Introduction to Dolby Digital Plus, an Enhancement to the Dolby Digital Coding System |url=https://www.dolby.com/us/en/technologies/aes-convention-paper-intro-to-dolby-digital-plus.pdf |archive-url=https://web.archive.org/web/20161119192949/https://www.dolby.com/us/en/technologies/aes-convention-paper-intro-to-dolby-digital-plus.pdf |url-status=dead |archive-date=2016-11-19 |website=Journal of The Audio Engineering Society |date=1 October 2004}}</ref> [[Dolby AC-4]] expands the technique to Advanced Spectral Extension (A-SPX), with the option of interleaving with regular, non-extended data in time or frequency domain. As a result, SPX can be selective disabled for difficult portions.<ref>{{cite web |title=Dolby® AC-4: Audio delivery for next-generation entertainment services |url=https://professional.dolby.com/siteassets/technologies/dolbt_atmos_ac-4_whitepaper.pdf}}</ref>