Editing Mp3PRO (section)

{{Short description|Obsolete variant of the MP3 audio format}}
{{lowercase|title=mp3PRO}}
'''mp3PRO''' is an unmaintained proprietary [[audio data compression|audio compression]] [[codec]] that combines the [[MP3]] audio format with the [[spectral band replication]] (SBR) compression method. At the time it was developed it could reduce the size of a [[stereo]] MP3 by as much as 50% while maintaining the same relative quality.<ref name=geekcom>{{cite web|title=mp3PRO–the new MP3|url=http://www.geek.com/news/mp3pro-the-new-mp3-544624/|website=geek.com|accessdate=9 December 2015|date=9 January 2001|archive-date=29 July 2017|archive-url=https://web.archive.org/web/20170729180335/https://www.geek.com/news/mp3pro-the-new-mp3-544624/|url-status=dead}}</ref> This works, fundamentally, by discarding the higher half of the frequency range and algorithmically replicating that information while decoding.

The technology behind SBR was developed by the former Swedish company [[Coding Technologies]] AB (acquired by [[Dolby Laboratories]] in 2007) in the late 1990s. It was included in their MPEG-2 [[Advanced Audio Coding|AAC]] derived codec aacPlus, which would later be standardized as MPEG-4 [[High-Efficiency Advanced Audio Coding|HE-AAC]]. Thomson Multimedia (now [[Technicolor SA]]) licensed the technology and used it to extend the MP3 format, for which they held patents, hoping to also extend its profitable lifetime. This was released as mp3PRO in 2001.<ref name=extreme-hackman>{{cite web|last1=Hachman|first1=Mark|title=MP3Pro Audio Specification Debuts|url=http://www.extremetech.com/extreme/49252-mp3pro-audio-specification-debuts|website=ExtremeTech|accessdate=9 December 2015|date=15 June 2001}}</ref><ref>{{cite web|title=mp3PRO licensing|url=http://mp3licensing.com/mp3/mp3pro.html|accessdate=27 December 2014}}</ref>

It was originally claimed that mp3PRO files were compatible with existing MP3 decoders, and that the SBR data could simply be ignored. The reality was that MP3 players lacking specific mp3PRO decoding capability experienced a significant reduction in audio quality when playing mp3PRO files as only the lower half of the original frequency range is available.<ref name=sbrexp>{{cite web|title=SBR Explained|url=http://codtech.vhost.noris.net/products/sbr.htm|website=Coding Technologies|accessdate=9 December 2015|archive-url=https://web.archive.org/web/20141227081352/http://codtech.vhost.noris.net/products/sbr.htm|archive-date=27 December 2014|url-status=dead}}</ref><ref>{{cite web|title=Playing MP3 Pro file under Linux|url=http://users.softlab.ece.ntua.gr/~ttsiod/mp3pro.html|accessdate=27 December 2014}}</ref>

mp3PRO development has been abandoned.{{when|date=December 2015}} The format was never standardized and there is no publicly available reference source code or documentation in existence. A [[Thomson Demo mp3PRO Player|very old software encoder/player]] exists, but is not maintained.<ref>{{cite web|title=mp3 Demo software download|url=http://www.mp3prozone.com/download.htm|accessdate=27 December 2014|archive-date=2 November 2007|archive-url=https://web.archive.org/web/20071102083211/http://www.mp3prozone.com/download.htm|url-status=dead}}</ref> Nero's Soundtrax application, bundled in the [[Nero Multimedia Suite]], is capable of encoding and decoding this format into several others. Some versions of the outdated [[MusicMatch Jukebox]] player (which will still run even on Windows 10 x64) were able to decode and encode this format, too. In the early 2000s, mp3PRO was usable in several portable music players and in popular music software,<ref>{{cite web|title=mp3PRO Products|url=http://www.mp3prozone.com/products.htm|accessdate=27 December 2014}}</ref> but its market share has deteriorated rapidly. The codec itself is largely surpassed in quality and efficiency, as well as device and application support, by modern codecs like AAC and its HE-AAC variants which employ the same SBR method.