View source for Windows Media Audio

{{Short description|Audio data compression technology}}
{{Infobox file format
| icon = 
| extension = .wma
| owner = [[Microsoft]]
| genre = [[Audio file format|Audio]]
| container for =
| contained by =
| extended from =
| extended to =
| standard =
| released = {{start date and age|1999|08|17}}<ref name="wmt4-release"/>
| free = No
| open = No
| website = {{web archive|url=https://web.archive.org/web/20080211194317/http://www.microsoft.com/windowsmedia|title=microsoft.com/windowsmedia}}
}}
'''Windows Media Audio''' ('''WMA''') is a series of [[audio codec]]s and their corresponding [[audio coding format]]s developed by [[Microsoft]]. It is a [[Proprietary software|proprietary]] technology that forms part of the [[Windows Media]] framework. Audio encoded in WMA is stored in a [[digital container format]] called [[Advanced Systems Format]] (ASF).

WMA consists of four distinct codecs. The original WMA codec, known simply as ''WMA'', was conceived as a competitor to the popular [[MP3]] and [[RealAudio]] codecs.<ref>{{cite web |author=Smith, Tony |title=Microsoft readies MP3-killer digital music format |website=[[The Register]] |date=1999-03-12 |url=https://www.theregister.co.uk/1999/03/12/microsoft_readies_mp3killer_digital_music/ |access-date=2007-08-16 |url-status=live |archive-url=https://web.archive.org/web/20080321023436/http://www.theregister.co.uk/1999/03/12/microsoft_readies_mp3killer_digital_music/ |archive-date=2008-03-21 }}</ref><ref name="RealNetworks MSAudio Analysis">{{cite web |title=Analysis of the Microsoft Audio Codec |url=https://www.real.com/msaudio/ |url-status=live |archive-url=https://web.archive.org/web/20070818112312/https://www.real.com/msaudio/ |archive-date=2007-08-18 |access-date=2007-08-16 |publisher=RealNetworks}}</ref> ''WMA Pro'', a newer and more advanced codec, supports [[Surround sound|multichannel]] and [[high-resolution audio]].<ref name="Windows Media 9 Series Whitepaper">{{cite web |title=Windows Media 9 Series Capabilities and Benefits Overview |url=https://www.cse.dmu.ac.uk/~hoi/mult2003/week6/WinMedia9WhitePaper.doc |url-status=dead |archive-url=https://web.archive.org/web/20070928022928/https://www.cse.dmu.ac.uk/~hoi/mult2003/week6/WinMedia9WhitePaper.doc |archive-date=2007-09-28 |access-date=2007-08-16 |publisher=International Narcotics Control Board |format=DOC}}</ref> A [[Lossless compression|lossless codec]], ''WMA Lossless'', compresses audio data without loss of audio fidelity (the regular WMA format is [[lossy compression|lossy]]).<ref name="Windows Media 9 Series Whitepaper" /> ''WMA Voice'', targeted at voice content, applies compression using a range of low [[bit rate]]s.<ref name="Windows Media 9 Series Whitepaper" /> 

==Development history==
The first WMA [[codec]] was based on earlier work by [[Henrique Malvar]] and his team which was transferred to the Windows Media team at Microsoft.<ref name="Henrique Malvar brazilmax.com">{{cite web |author=Hinchberger, Bill |date=2001-09-09 |title=Riding the Malvar Wave |url=https://www.brazilmax.com/news.cfm/tborigem/fe_business/id/3 |url-status=dead |archive-url=https://web.archive.org/web/20071013004451/https://www.brazilmax.com/news.cfm/tborigem/fe_business/id/3 |archive-date=2007-10-13 |access-date=2007-08-16}}</ref> Malvar was a senior researcher and manager of the Signal Processing Group at [[Microsoft Research]],<ref name="Microsoft Research Henrique Malvar">{{cite web |url=http://research.microsoft.com/aboutmsr/presskit/malvar/ |title=Press Kit: Henrique Malvar |publisher=Microsoft Research |access-date=2007-08-16 |archive-url=https://web.archive.org/web/20070825181638/http://research.microsoft.com/aboutmsr/presskit/malvar/ |archive-date=2007-08-25 }}</ref> whose team worked on the ''MSAudio'' project.<ref>{{cite web |url=http://research.microsoft.com/ccsp/ |title=Communication, Collaboration, and Signal Processing |publisher=Microsoft Research |access-date=2007-08-16 |archive-url = https://web.archive.org/web/20070717203523/http://research.microsoft.com/ccsp/ <!-- Bot retrieved archive --> |archive-date = 2007-07-17}}</ref> The first finalized codec was initially referred to as ''MSAudio 4.0''.<ref>{{cite press release |url=http://www.microsoft.com/presspass/press/1999/apr99/wmtdwnldpr.mspx |title=Microsoft Windows Media Technologies Gains Support for Downloadable Music from Top Music Sites, Independent Labels, Popular Bands And Innovative Developers |publisher=Microsoft PressPass |access-date=2007-08-16 |url-status=dead |archive-url=https://web.archive.org/web/20071024025133/http://www.microsoft.com/presspass/press/1999/apr99/wmtdwnldpr.mspx |archive-date=2007-10-24 }}</ref><ref>{{cite web |author=Barry, Richard |title=MS Audio 4.0 will eat MP3... |date=1999-04-14 |url=http://news.zdnet.co.uk/emergingtech/0,1000000183,2071559,00.htm |access-date=2007-08-16 |archive-url=https://web.archive.org/web/20070930205652/http://news.zdnet.co.uk/emergingtech/0,1000000183,2071559,00.htm |archive-date=2007-09-30 }}</ref> It was later officially released as ''Windows Media Audio'',<ref name="wmt4-release">{{cite press release |title=Windows Media Technologies 4 Delivers Cutting-Edge CD-Quality Audio On the Internet |url=https://www.microsoft.com/presspass/press/1999/Aug99/WM4Lnchpr.mspx |url-status=dead |archive-url=https://web.archive.org/web/20071024030506/https://www.microsoft.com/presspass/press/1999/Aug99/WM4Lnchpr.mspx |archive-date=2007-10-24 |access-date=2007-08-16 |publisher=Microsoft PressPass}}</ref> as part of Windows Media Technologies 4.0. Microsoft claimed that WMA could produce files that were half the size of equivalent-quality MP3 files;<ref name="Microsoft TechNet MS Windows Media Technologies Features">{{cite web |url=http://www.microsoft.com/technet/archive/netshow/evaluate/features.mspx?mfr=true |title=MS Windows Media Technologies Features |publisher=Microsoft TechNet |access-date=2007-08-16 |url-status=dead |archive-url=https://web.archive.org/web/20071024193445/http://www.microsoft.com/technet/archive/netshow/evaluate/features.mspx?mfr=true |archive-date=2007-10-24 }}</ref> Microsoft also claimed that WMA delivered "near CD-quality" audio at 64&nbsp;kbit/s.<ref name="Microsoft TechNet MS Windows Media Technologies Features"/> The former claim however was rejected by some [[audiophile]]s<ref name="EDN Internet Radio">{{cite web |title=The Internet-audio (r)evolution |url=http://www.edn.com/index.asp?layout=article&articleid=CA46537 |access-date=2007-08-16 |quote=some audiophiles challenge Microsoft's claims regarding WMA's quality |url-status=dead |archive-url=https://web.archive.org/web/20071010050058/http://www.edn.com/index.asp?layout=article&articleid=CA46537 |archive-date=2007-10-10 }}</ref> and both claims have been refuted through publicly-available [[Codec listening test|codec listening tests]]. [[RealNetworks]] also challenged Microsoft's claims regarding WMA's superior audio quality compared to RealAudio.<ref name="RealNetworks MSAudio Analysis"/>

Newer versions of WMA became available: ''Windows Media Audio 2'' in 1999,<ref name="Broadcom">{{cite web|url=http://www.broadcom.com/products/software/mobmm_audiocodecs.php|title=Broadcom Corporation: Audio Codecs|url-status=dead|archive-url=https://web.archive.org/web/20070608015446/http://www.broadcom.com/products/software/mobmm_audiocodecs.php|archive-date=2007-06-08|access-date=2007-05-30}}</ref> ''Windows Media Audio 7'' in 2000,<ref>{{cite web |url=http://www.microsoft.com/presspass/press/2000/Apr00/NABWMT7pr.mspx |title=Microsoft Announces Windows Media Technologies 7 |publisher=Microsoft |access-date=2007-08-16 |url-status=dead |archive-url=https://web.archive.org/web/20071024031413/http://www.microsoft.com/presspass/press/2000/Apr00/NABWMT7pr.mspx |archive-date=2007-10-24 }}</ref> ''Windows Media Audio 8'' in 2001,<ref>{{cite web |url=http://www.cdrinfo.com/Sections/News/Details.aspx?NewsId=1232 |title=Microsoft Releases Windows Media Audio and Video 8 |publisher=CDRInf |access-date=2007-08-16 |url-status=live |archive-url=https://web.archive.org/web/20070926232302/http://www.cdrinfo.com/Sections/News/Details.aspx?NewsId=1232 |archive-date=2007-09-26 }}</ref> and ''Windows Media Audio 9'' in 2003.<ref name="Windows Media 9 Series Whitepaper"/> Microsoft first announced its plans to license WMA technology to third parties in 1999.<ref>{{cite web |url=http://www.microsoft.com/presspass/press/1999/may99/wmtsupppr.mspx |title=Microsoft Wins Major ISV Support for Windows Media Technologies 4.0 |publisher=Microsoft PressPass |access-date=2007-08-16 |url-status=dead |archive-url=https://web.archive.org/web/20070912233437/http://www.microsoft.com/presspass/press/1999/may99/wmtsupppr.mspx |archive-date=2007-09-12 }}</ref> Prior to [[Windows XP]], WMA files were primarily streamed using the Windows Media Source Filter ([[DirectShow]] codec), later being removed in Windows Vista with the addition of Media Foundation.<ref>{{Cite web|last=|first=|title=Windows Media Source Filter - Win32 apps|url=https://docs.microsoft.com/en-us/windows/win32/directshow/windows-media-source-filter|access-date=2021-11-30|website=docs.microsoft.com|language=en-us}}</ref> Although earlier versions of [[Windows Media Player]] played WMA files, support for WMA file creation was not added until the seventh version.<ref>{{cite web |author=Thurrott, Paul |title=SuperSite for Windows Media Player 7 Review |date=2005-04-30 |url=http://www.winsupersite.com/reviews/wmp7.asp |access-date=2007-08-16 |url-status=dead |archive-url=https://web.archive.org/web/20070818152206/http://www.winsupersite.com/reviews/wmp7.asp |archive-date=2007-08-18 }}</ref> In 2003, Microsoft released new audio codecs that were not compatible with the original WMA codec. These codecs were ''Windows Media Audio 9 Professional'',<ref name="Windows Media 9 Series Whitepaper"/> ''Windows Media Audio 9 Lossless'',<ref name="Windows Media 9 Series Whitepaper"/> and ''Windows Media Audio 9 Voice''.<ref name="Windows Media 9 Series Whitepaper"/>

All versions of WMA released since version 9.0{{Snd}}namely 9.1, 9.2, and 10{{Snd}}have been backwards compatible with the original v9 decoder and are therefore not considered separate codecs. The sole exception to this is the WMA 10 Professional codec whose Low Bit Rate (LBR) mode is only backwards compatible with the older WMA Professional decoders at a half sampling rate (similar to how HE-AAC is backwards compatible with AAC-LC). Full fidelity decoding of WMA 10 Professional LBR bitstreams requires a WMA version 10 or newer decoder.

==Container format==
{{Main|Advanced Systems Format}}

A WMA file is in most circumstances contained in the [[Advanced Systems Format]] (ASF), a [[Proprietary software|proprietary]] Microsoft [[Container format (digital)|container format]] for [[digital audio]] or [[digital video]].<ref>{{cite web |url=http://support.microsoft.com/kb/284094 |title=The Difference Between ASF and WMV/WMA Files |publisher=Microsoft |access-date=2007-08-16 |url-status=live |archive-url=https://web.archive.org/web/20070819113435/http://support.microsoft.com/kb/284094 |archive-date=2007-08-19 }}</ref> The ASF container format specifies how [[Metadata (computing)|metadata]] about the file is to be encoded, similar to the [[ID3]] tags used by MP3 files. Metadata may include song name, track number, artist name, and also [[audio normalization]] values. This container can optionally support [[digital rights management]] (DRM) using a combination of [[elliptic curve cryptography]] key exchange, [[Data Encryption Standard|DES]] block cipher, a custom block cipher, [[RC4 cipher|RC4]] stream cipher and the [[SHA-1]] hashing function. See [[Windows Media DRM]] for further information.

Since 2008 Microsoft has also been using WMA Professional in its Protected Interoperable File Format (PIFF) based on the [[ISO base media file format|ISO Base Media File Format]] and most commonly used for Smooth Streaming, a form of adaptive bitrate streaming over HTTP. Related industry standards such as DECE [[UltraViolet (system)|UltraViolet]] and [[MPEG-DASH]] have not standardized WMA as a supported audio codec, deciding in favor of the more industry-prevalent MPEG and Dolby audio codecs.

==Codecs==
Each WMA file features a single audio track in one of the four sub-formats: WMA, WMA Pro, WMA Lossless, or WMA Voice. These formats are implemented differently from one another, such that they are technically distinct and mutually incompatible; that is to say, a device or software compatible with one sub-format does not therefore automatically support any of the other codecs. Each codec is further explained below.

===Windows Media Audio===
'''Windows Media Audio''' (WMA) is the most common codec of the four WMA codecs. The colloquial usage of the term ''WMA'', especially in marketing materials and device specifications, usually refers to this codec only. The first version of the codec released in 1999 is regarded as WMA 1. In the same year, the [[bit stream]] syntax, or [[compression algorithm]], was altered in minor ways and became WMA 2.<ref name="Broadcom"/> Since then, newer versions of the codec have been released, but the decoding process remained the same, ensuring compatibility between codec versions.<ref name="Broadcom"/> WMA is a lossy audio codec based on the study of [[psychoacoustics]]. Audio signals that are deemed to be imperceptible to the human ear are encoded with reduced resolution during the compression process.

WMA can encode audio signals sampled at up to 48&nbsp;[[kHz]] with up to two discrete channels ([[stereo]]). WMA 9 introduced [[variable bit rate]] (VBR) and [[average bit rate]] (ABR) coding techniques into the MS encoder although both were technically supported by the original format.<ref name="Broadcom"/> WMA 9.1 also added support for low-delay audio,<ref name="Low-Delay Audio">{{cite web |url=http://msdn2.microsoft.com/en-us/library/aa390496.aspx |title=Windows Media Format 11 SDK Low-Delay Audio |publisher=Microsoft MSDN |access-date=2007-08-16 |url-status=live |archive-url=https://web.archive.org/web/20071024183517/http://msdn2.microsoft.com/en-us/library/aa390496.aspx |archive-date=2007-10-24 }}</ref> which reduces [[Latency (engineering)|latency]] for encoding and decoding.

Fundamentally, WMA is a transform coder based on [[modified discrete cosine transform]] (MDCT), somewhat similar to [[Advanced Audio Coding|AAC]], [[Cook Codec|Cook]] and [[Vorbis]]. The bit stream of WMA is composed of superframes, each containing 1 or more frames of 2048 samples. If the bit reservoir is not used, a frame is equal to a superframe. Each frame contains several blocks, which are 128, 256, 512, 1024, or 2048 samples long after being transformed into the frequency domain via the MDCT. In the frequency domain, masking for the transformed samples is determined, and then used to requantize the samples. Finally, the [[floating point]] samples are decomposed into coefficient and exponent parts and independently [[Huffman coding|huffman coded]]. Stereo information is typically [[Joint stereo#M/S stereo coding|mid/side]] coded. At low bit rates, [[line spectral pairs]] (typically less than 17&nbsp;kbit/s) and a form of noise coding (typically less than 33&nbsp;kbit/s) can also be used to improve quality.

Like AAC and Ogg Vorbis, WMA was intended to address perceived deficiencies in the MP3 standard. Given their common design goals, the three formats ended up making similar design choices. All three are pure transform codecs. Furthermore, the MDCT implementation used in WMA is essentially a superset of those used in Ogg and AAC such that WMA iMDCT and windowing routines can be used to decode AAC and Ogg Vorbis almost unmodified. However, quantization and stereo coding is handled differently in each codec. The primary distinguishing trait of the WMA Standard format is its unique use of 5 different block sizes, compared to MP3, AAC, and Ogg Vorbis which each restrict files to just two sizes. WMA Pro extends this by adding a 6th block size used at 88.2/96&nbsp;kHz sampling rate.

Certified [[PlaysForSure]] devices, as well as a large number of uncertified devices, ranging from portable hand-held music players to set-top [[DVD player]]s, support the playback of WMA files. Most PlaysForSure-certified online stores distribute content using this codec only. In 2005, [[Nokia]] announced its plans to support WMA playback in future Nokia handsets.<ref name="nokia">{{cite web|url=http://www.microsoft.com/presspass/press/2005/feb05/02-14NokiaCollaborationPR.mspx|title=Microsoft and Nokia Collaborate to Help Ensure Consumers Can Enjoy Digital Music Anywhere|website=[[Microsoft]]|url-status=dead|archive-url=https://web.archive.org/web/20070831104239/http://www.microsoft.com/presspass/press/2005/feb05/02-14NokiaCollaborationPR.mspx|archive-date=2007-08-31|access-date=2007-08-15}}</ref> In the same year, an update was made available for the [[PlayStation Portable]] (version 2.60) which allowed WMA files to be played on the device for the first time.<ref name="PSP Review">{{cite web |author=Carnoy, David |title=Sony PSP review |date=2005-03-23 |url=http://reviews.cnet.co.uk/gamesconsoles/0,139102149,39188324,00.htm |access-date=2007-08-16 |url-status=dead |archive-url=https://web.archive.org/web/20070810200119/http://reviews.cnet.co.uk/gamesconsoles/0,139102149,39188324,00.htm |archive-date=2007-08-10 }}</ref>

===Windows Media Audio Professional===
[[Image:WMA10ProOptions.PNG|thumb|Screenshot of Windows Media Encoder 9 Series, displaying new encoding options for Windows Media Audio 10 Professional.]]
'''Windows Media Audio Professional''' (WMA Pro) is an improved lossy codec closely related to WMA standards. It retains most of the same general coding features, but also features improved entropy coding and quantization strategies as well as more efficient stereo coding. Notably, many of the WMA standard's low bitrate features have been removed, as the core codec is designed for efficient coding at most bitrates. Its main competitors include [[Advanced Audio Coding|AAC]], [[HE-AAC]], [[Vorbis]], Dolby Digital, and DTS. It supports 16-bit and 24-bit sample bit depth, sampling rates up to 96&nbsp;kHz, and up to eight discrete channels ([[7.1|7.1 channel surround]]).<ref name="Windows Media Audio 9 Professional">{{cite web |url=http://www.microsoft.com/windows/windowsmedia/forpros/codecs/audio.aspx#WindowsMediaAudio9Professional |title=Windows Media Audio Codecs: Windows Media Audio 9 Professional |publisher=Microsoft |access-date=2007-08-16 |url-status=live |archive-url=https://web.archive.org/web/20070901193343/http://www.microsoft.com/windows/windowsmedia/forpros/codecs/audio.aspx#WindowsMediaAudio9Professional |archive-date=2007-09-01 }}</ref> WMA Pro also supports [[dynamic range compression]], which reduces the volume difference between the loudest and quietest sounds in the audio track. According to Microsoft's Amir Majidimehr, WMA Pro could theoretically go beyond 7.1 surround sound and support "an unlimited number of channels"; however, Microsoft chose to limit its current capability to eight (7.1 discrete channels).<ref name="winsupersite">{{cite web|url=http://www.winsupersite.com/reviews/wm9series.asp|title=Paul Thurrott's SuperSite for Windows: Windows Media 9 Series reviewed|url-status=dead|archive-url=https://web.archive.org/web/20070528090443/http://www.winsupersite.com/reviews/wm9series.asp|archive-date=2007-05-28|access-date=2007-06-24}}</ref>

The codec's bit stream syntax was frozen at the first version, WMA 9 Pro.<ref name="wmav9series">{{cite web|url=http://download.microsoft.com/download/6/f/c/6fc03c60-5d5b-42c0-bcce-5e184fa56741/2_Audio_Video.ppt|title=Windows Media Audio & Video 9 Series|url-status=dead|archive-url=https://web.archive.org/web/20070928022926/http://download.microsoft.com/download/6/f/c/6fc03c60-5d5b-42c0-bcce-5e184fa56741/2_Audio_Video.ppt|archive-date=2007-09-28|access-date=2007-08-08}}</ref> Later versions of WMA Pro introduced low-bit rate encoding, low-delay audio,<ref name="wmalowdelay">{{cite web|url=http://msdn2.microsoft.com/en-us/library/aa390496.aspx|title=Low-Delay Audio|website=msdn2.microsoft.com|access-date=30 April 2018|url-status=live|archive-url=https://web.archive.org/web/20080417175047/http://msdn2.microsoft.com/en-us/library/aa390496.aspx|archive-date=17 April 2008}}</ref> frequency interpolation mode,<ref name="streamingmedia.com Windows Media Best Practices">{{cite web |author=Smith, Tony |title=Best Practices for Windows Media Encoding |date=2007-02-21 |url=http://www.streamingmedia.com/article.asp?id=9510&page=2&c=4 |access-date=2007-08-16 |archive-url=https://web.archive.org/web/20070831100606/http://www.streamingmedia.com/article.asp?id=9510&page=2&c=4 |archive-date=2007-08-31 |url-status=dead }}</ref> and an expanded range of [[sampling rate]] and [[Audio bit depth|bit-depth]] encoding options. A WMA 10 Pro file compressed with frequency interpolation mode comprises a WMA 9 Pro track encoded at half the original sampling rate, which is then restored using a new compression algorithm.<ref name="edn">{{cite web|url=http://www.edn.com/index.asp?layout=article&articleid=CA6391444&industryid=22043|title=Voices: Microsoft's Amir Majidimehr: a window to the world of digital media - 11-23-2006 - EDN|url-status=dead|archive-url=https://web.archive.org/web/20070430153905/http://www.edn.com/index.asp?layout=article&articleid=CA6391444&industryid=22043|archive-date=2007-04-30|access-date=2007-06-07}}</ref> In this situation, WMA 9 Pro players which have not been updated to the WMA 10 Pro codec can only decode the lower quality WMA 9 Pro stream. Starting with WMA 10 Pro, eight channel encoding starts at 128&nbsp;kbit/s, and tracks can be encoded at the native audio CD resolution (44.1&nbsp;kHz, 16-bit), previously the domain of WMA Standard.

Despite a growing number of supported devices and its superiority over WMA, WMA Pro still has little hardware and software support. Some notable exceptions to this are the [[Microsoft Zune]] (limited to stereo),<ref name="zunefaq">{{cite web|url=http://www.zune.net/en-us/support/howto/start/providecontent.htm|title=Zune.net: How-To - Provide Content for Zune|url-status=live|archive-url=https://web.archive.org/web/20070819115547/http://www.zune.net/en-us/support/howto/start/providecontent.htm|archive-date=2007-08-19}}</ref> [[Xbox 360]],<ref name="xboxfaq">{{cite web|url=http://blogs.msdn.com/xboxteam/default.aspx|title=Spring '07 Video Playback FAQ|url-status=dead|archive-url=https://web.archive.org/web/20080213124920/http://blogs.msdn.com/xboxteam/default.aspx|archive-date=2008-02-13|access-date=2007-08-08}}</ref> [[Windows Mobile]]-powered devices with Windows Media Player 10 Mobile,<ref name="winmobilefaq">{{cite web|url=http://www.microsoft.com/windows/windowsmedia/player/windowsmobile/faq.aspx|title=Windows Media Player Mobile FAQ|website=[[Microsoft]]|url-status=live|archive-url=https://web.archive.org/web/20070914112132/http://www.microsoft.com/windows/windowsmedia/player/windowsmobile/faq.aspx|archive-date=2007-09-14}}</ref> newer [[Gigabeat|Toshiba Gigabeat]] and [[Motorola]] devices,<ref name="msmotorolawmapro">{{cite web|url=http://www.microsoft.com/presspass/press/2006/feb06/02-13MotorolaMSCollabPR.mspx|title=Motorola and Microsoft Plan to Bring More Choice to Mobile Music Fans|website=[[Microsoft]]|url-status=dead|archive-url=https://web.archive.org/web/20071024172933/http://www.microsoft.com/presspass/press/2006/feb06/02-13MotorolaMSCollabPR.mspx|archive-date=2007-10-24|access-date=2018-12-06}}</ref><ref name="digitallifestyles">{{cite web|url=http://digital-lifestyles.info/2006/02/13/motorola-dis-apple-expect-more-microsoft-music-phones-3gsm/|title=Motorola Dis Apple, Expect More Microsoft Music Phones: 3GSM|url-status=dead|archive-url=https://web.archive.org/web/20070927230600/http://digital-lifestyles.info/2006/02/13/motorola-dis-apple-expect-more-microsoft-music-phones-3gsm/|archive-date=2007-09-27|access-date=2007-08-08}}</ref> and devices running recent versions of the [[Rockbox]] alternative firmware.<ref name="rockbox">{{cite web |title=New WMA Audio Codecs |url=https://www.rockbox.org/wiki/NewWMAAudioCodecs |url-status=live |archive-url=https://web.archive.org/web/20110106054756/https://www.rockbox.org/wiki/NewWMAAudioCodecs |archive-date=2011-01-06}}</ref> In addition, WMA Pro is a requirement for the [[WMV HD]] certification program.<ref name="wmvhd">{{Cite web|url=https://www.bing.com/?form=HPFBBK&ssd=20230121_0800&mkt=en-ID|title=Info|website=Bing}}</ref> On the software side, [[Verizon]] utilizes WMA 10 Pro for its V CAST Music Service,<ref name="verizonwmapro">{{cite web|url=http://www.microsoft.com/presspass/press/2006/jan06/01-05WMVCASTPR.mspx|title=Verizon Wireless Chooses Microsoft Windows Media to Power Its New V CAST Music Service|website=[[Microsoft]]|url-status=dead|archive-url=https://web.archive.org/web/20070615201708/http://www.microsoft.com/presspass/press/2006/jan06/01-05WMVCASTPR.mspx|archive-date=2007-06-15|access-date=2018-12-06}}</ref> and [[Windows Media Player|Windows Media Player 11]] has promoted the codec as an alternative to WMA for copying audio CD tracks.<ref name="winvistawmp11">{{cite web|url=http://www.microsoft.com/windows/products/windowsvista/features/details/mediaplayer11.mspx|title=Windows Vista Features Explained Windows Media Player 11|website=[[Microsoft]]|url-status=live|archive-url=https://web.archive.org/web/20070913180242/http://www.microsoft.com/windows/products/windowsvista/features/details/mediaplayer11.mspx|archive-date=2007-09-13}}</ref> WMA Pro is supported in Silverlight as of version 2 (though only in stereo mode). In the absence of the appropriate audio hardware, WMA Pro can automatically [[Downmixing|downmix]] multichannel audio to stereo or [[Monophonic sound|mono]], and 24-bit resolution to 16-bit during playback.

A notable example of WMA Pro being used instead of WMA Standard is the NBC Olympics website which uses WMA 10 Pro in its low-bitrate mode at 48 kbit/s.{{Citation needed|date=April 2021}}

===Windows Media Audio Lossless===
[[File:5 1 channels (surround sound) label.svg|thumb|Label for 5.1 surround sound, the maximum channels supported in the format.]]

As part of the Windows Media 9 series, Microsoft introduced '''Windows Media Audio Lossless''' in early 2003, a [[Data compression#Audio|lossless]] audio format sharing the .wma file extension as its lossy counterparts. It is designed to store a digital audio stream (such as a [[Compact Disc Digital Audio|CD-Audio]] track) at some fraction of the original. Each sample in a channel can be encoded at up to 24 bits, at a rate of 96 KHz, with up to 6 discrete channels (for [[5.1 surround sound]]). The container is also said to have dynamic range compression control. Like WMA Pro, the WMA Lossless decoder can perform downmixing when capable audio hardware is not present.{{Citation needed|date=May 2010}} While the details of the format have never been publicly documented, it has been reverse-engineered for use on non-Microsoft platforms by the open source [[FFmpeg]] project. Only 16-bit WMA files are supported as of 2012.{{needs update|date=May 2025}}

Designed for archival purposes,<ref name="Windows Media Audio 9 Lossless">{{cite web |url=http://www.microsoft.com/windows/windowsmedia/forpros/codecs/audio.aspx#WindowsMediaAudio9Lossless |title=Windows Media Audio Codecs: Windows Media Audio 9 Lossless |publisher=Microsoft |access-date=2007-08-16 |url-status=live |archive-url=https://web.archive.org/web/20070901193343/http://www.microsoft.com/windows/windowsmedia/forpros/codecs/audio.aspx#WindowsMediaAudio9Lossless |archive-date=2007-09-01 }}</ref> it competed with [[ATRAC]] Advanced Lossless, [[Dolby TrueHD]], [[DTS-HD Master Audio]], [[Shorten (file format)|Shorten]], [[Monkey's Audio]], [[FLAC]], [[Apple Lossless]], and [[WavPack]]. Since late 2011,<ref name=Apache-license>{{cite web|url=http://alac.macosforge.org|title=Welcome to the Apple Lossless Audio Codec Project|work=Apple Lossless Audio Codec|publisher=MacOS Forge|date=October 27, 2011|access-date=October 29, 2011|url-status=live|archive-url=http://archive.wikiwix.com/cache/20160615225151/http://alac.macosforge.org/|archive-date=June 15, 2016}}</ref><ref name=Apache-ars>{{cite web|last=Foresman|first=Chris|title=After seven years, Apple open sources its Apple Lossless Audio Codec|url=https://arstechnica.com/apple/news/2011/10/after-seven-years-apple-open-sources-its-apple-lossless-audio-codec.ars|website=Ars Technica|date=October 28, 2011|access-date=October 29, 2011|url-status=live|archive-url=https://web.archive.org/web/20111029123807/http://arstechnica.com/apple/news/2011/10/after-seven-years-apple-open-sources-its-apple-lossless-audio-codec.ars|archive-date=October 29, 2011}}</ref><ref name=Apache-3>{{cite web|url=http://h-online.com/-1368212|archive-url=https://web.archive.org/web/20120515214941/http://www.h-online.com/open/news/item/Apple-open-sources-its-ALAC-lossless-audio-codec-1368212.html |archive-date=15 May 2012|title=Apple open sources its ALAC lossless audio codec|first=Chris|last=von Eitzen|publisher=[[The H]]|date=October 28, 2011|access-date=October 29, 2011}}</ref> the last three have the advantage of having [[open source software|open source]] encoders, no licensing costs, and availability on nearly any [[operating system]]. The typical compression ratio for music varies between 1.7:1 and 3:1.<ref name="Windows Media Audio 9 Lossless"/><ref name="extremetech">{{cite web|url=http://www.extremetech.com/article2/0,1558,1560783,00.asp|title=ExtremeTech Audio Codec Quality Shootout|url-status=live|archive-url=https://web.archive.org/web/20110607190304/http://www.extremetech.com/article2/0,1558,1560783,00.asp|archive-date=2011-06-07}}</ref><ref>{{cite web |url=http://members.home.nl/w.speek/comparison.htm |title=Comparison of lossless audio compressors |access-date=2010-11-25 |url-status=dead |archive-url=https://web.archive.org/web/20101125045330/http://members.home.nl/w.speek/comparison.htm |archive-date=2010-11-25 }}</ref> It compresses an audio CD to a range of 206 to 411&nbsp;MB, at bit rates of 470 to 940&nbsp;kbit/s.

Like WMA Standard, WMA Lossless was adopted by a few online distribution stores in the mid-2000s.<ref name="businessweek">{{cite web|url=http://www.businessweek.com/technology/content/jun2005/tc2005062_3663_tc024.htm|title=Is This Digital Music's Future|url-status=dead|archive-url=https://web.archive.org/web/20070715011626/http://www.businessweek.com/technology/content/jun2005/tc2005062_3663_tc024.htm|archive-date=2007-07-15}}</ref><ref name="microsoftwmpstores">{{cite web|url=http://www.microsoft.com/windows/windowsmedia/player/stores.aspx|title=Online Stores in Windows Media Player|website=[[Microsoft]]|url-status=live|archive-url=https://web.archive.org/web/20070727062708/http://www.microsoft.com/windows/windowsmedia/player/stores.aspx|archive-date=2007-07-27}}</ref> Hardware support for the codec became available on the first-party [[Zune 4, 8, 16|Zune 4, 8]], [[Zune 30|30]], [[Zune 80|80, 120]] (with firmware version 2.2 or later), and [[Zune HD|HD]] portable media players and the [[Xbox 360]].<ref name="xboxfaq"/> Third-party support emerged in the Cowon A3,<ref>{{cite web|url=https://techcaption.com/what-is-windows-audio-endpoint-builder-service/ |title=What is Windows Audio Endpoint Builder service And How To Start/Stop It |website=techcaption.com |author=Tushar |date=July 2019}}</ref> Cowon S9, [[Bang & Olufsen]] Serenata,<ref>{{usurped|1=[https://web.archive.org/web/20070930231119/http://www.serenatamobile.com/ Article title]}}</ref> Sony Walkman NWZ-A and NWZ-S series, Toshiba Gigabeat S and V models, Toshiba T-400, the Meizu M3, and [[Best Buy]]-exclusive Insignia NS-DV, Pilot, and Sport music players. The Logitech Squeezebox Touch was also updated to support the format natively; previously it was added through transcoding. [[Windows Mobile]]-powered devices with Windows Media Player 10 Mobile,<ref name="winmobilefaq"/> and Windows Phone (version 8 and above) also included playback support for the format.

===Windows Media Audio Voice===
'''Windows Media Audio Voice''' (WMA Voice) is a lossy audio codec that competes with [[Speex]] (used in Microsoft's own [[Xbox Live]] online service<ref>Ralph Giles of [[Xiph.org]] explained that Xbox Live uses Speex for voice compression in the June 6, 2005 interview on [[LugRadio]]: {{cite web |url=http://www.lugradio.org/episodes/29 |title=Linux radio show - LugRadio |access-date=2007-10-10 |url-status=live |archive-url=https://web.archive.org/web/20071014210527/http://lugradio.org/episodes/29 |archive-date=2007-10-14 }}</ref>), [[ACELP]], and other codecs. Designed for low-bandwidth, voice playback applications,<ref name="Windows Media Audio 9 Voice">{{cite web |url=http://www.microsoft.com/windows/windowsmedia/forpros/codecs/audio.aspx#WindowsMediaAudio9Voice |title=Windows Media Audio Codecs: Windows Media Audio 9 Voice |publisher=Microsoft |access-date=2007-08-16 |url-status=live |archive-url=https://web.archive.org/web/20070901193343/http://www.microsoft.com/windows/windowsmedia/forpros/codecs/audio.aspx#WindowsMediaAudio9Voice |archive-date=2007-09-01 }}</ref> it employs low-pass and high-pass filtering of sound outside the human speech frequency range to achieve higher compression efficiency than WMA. It can automatically detect sections of an audio track containing both voice and music and use the standard WMA compression algorithm instead.<ref name="wmav9series"/> WMA Voice supports up to 22.05&nbsp;kHz for a single channel (mono) only.<ref name="Windows Media Audio 9 Voice"/> Encoding is limited to [[constant bit rate]] (CBR) and up to 20&nbsp;kbit/s. The first and only version of the codec is WMA 9 Voice.

Windows Mobile-powered devices with Windows Media Player 10 Mobile have native support for WMA 9 Voice playback.<ref name="winmobilefaq"/> In addition, [[BBC World Service]] has employed WMA Voice for its [[Internet radio]] streaming service.<ref name="roku">{{cite web|url=http://www.rokulabs.com/products_soundbridge_internet.php|title=Roku - SoundBridge Internet Radio|url-status=dead|archive-url=https://web.archive.org/web/20070816182910/http://www.rokulabs.com/products_soundbridge_internet.php|archive-date=2007-08-16|access-date=2007-08-08}}</ref>

==Sound quality==
:''See [[codec listening test#Results|codec listening test]] for a table of double-blind listening test results.''

Microsoft claims that audio encoded with WMA sounds better than MP3 at the same bit rate; Microsoft also claims that audio encoded with WMA at lower bit rates sound better than MP3 at higher bit rates.<ref name="wmmusic">{{cite web|url=http://www.microsoft.com/windows/windowsmedia/music/default.aspx|title=Windows Media: Music|website=[[Microsoft]]|url-status=live|archive-url=https://web.archive.org/web/20060415235414/http://www.microsoft.com/windows/windowsmedia/music/default.aspx|archive-date=2006-04-15}}</ref> [[Double blind]] listening tests with other lossy audio codecs have shown varying results, from failure to support Microsoft's claims about its superior quality to supremacy over other codecs. One independent test conducted in May 2004 at 128&nbsp;kbit/s showed that WMA was roughly equivalent to [[LAME]] MP3; inferior to AAC and Vorbis; and superior to [[ATRAC3]] (software version).<ref name="rjamorim">{{cite web|last=Amorim|first=Roberto|url=http://www.rjamorim.com/test/multiformat128/results.html|archive-url=https://web.archive.org/web/20090123124822/http://rjamorim.com/test/multiformat128/results.html |archive-date=2009-01-23|title=Results of Multiformat at 128&nbsp;kbit/s public Listening Test}}</ref>

Some studies concluded:
*At [http://www.rjamorim.com/test/32&nbsp;kbit/s/results.html 32&nbsp;kbit/s],{{Dead link|date=August 2019 |bot=InternetArchiveBot |fix-attempted=yes }} WMA Standard was noticeably better than LAME MP3, but not better than other modern codecs in a collective, independent test in July 2004.
*At [http://www.hydrogenaud.io/forums/index.php?showtopic=50888 48&nbsp;kbit/s] {{Webarchive|url=https://web.archive.org/web/20140708014541/http://www.hydrogenaud.io/forums/index.php?showtopic=50888 |date=2014-07-08 }}, WMA 10 Pro was ranked second after [[Nero AG|Nero]] HE-AAC and better than WMA 9.2 in an independent listening test organized and supported by Sebastian Mares and Hydrogenaudio Forums in December 2006. This test, however, used CBR for WMA 10 Pro and VBR for the other codecs.
*At [http://www.microsoft.com/windows/windowsmedia/forpros/codecs/comparison.aspx 64&nbsp;kbit/s], WMA Pro outperformed Nero HE-AAC in a listening test commissioned by Microsoft but independently performed by the [[National Software Testing Labs]] in 1999. Out of 300 participants, "71% of all listeners indicated that WMA Pro was equal to or better than HE AAC."{{citation needed|reason=No working link to the actual study|date=January 2016}} However, a September 2003 public listening test conducted by Roberto Amorim found that listeners preferred 128&nbsp;kbit/s MP3 to 64&nbsp;kbit/s WMA audio with greater than 99% [[Confidence interval|confidence]].
*At [http://www.hydrogenaud.io/forums/index.php?showtopic=35438 80&nbsp;kbit/s] {{Webarchive|url=https://web.archive.org/web/20140708054803/http://www.hydrogenaud.io/forums/index.php?showtopic=35438 |date=2014-07-08 }} and [http://forum.hardware.fr/hardwarefr/VideoSon/MP3-WMA-AAC-OGG-qualite-kbit/s-evaluation-sujet-84950-1.htm 96&nbsp;kbit/s], WMA had lower quality than HE-AAC, [[AAC-LC]], and Vorbis; near-equivalent quality to MP3, and better quality than [[Musepack|MPC]] in individual tests done in 2005.
*At [https://web.archive.org/web/20100214134736/http://www.listening-tests.info/mf-128-1/results.htm 128&nbsp;kbit/s], there was a four-way tie between aoTuV Vorbis, LAME MP3, WMA 9 Pro and AAC in a large scale test in January 2006, with each codec sounding close to the uncompressed music file for most listeners.
*At [https://web.archive.org/web/20070927173254/http://www.edn.com/article/CA307865.html 768&nbsp;kbit/s], WMA 9 Pro delivered full-spectrum response at half the bit rate required for [[DTS (sound system)|DTS]] in a comparative test done by [[EDN (magazine)|EDN]] in October 2003. The test sample was a 48&nbsp;kHz, 5.1 channel surround audio track.

===Criticism of claimed quality===
Microsoft's claims of WMA sound quality have frequently drawn complaints. "Some audiophiles challenge Microsoft's claims regarding WMA's quality", according to a published article from EDN.<ref name="EDN Internet Radio"/> Another article from MP3 Developments wrote that Microsoft's claim about CD-quality audio at 64&nbsp;kbit/s with WMA was "very far from the truth".<ref>{{cite web |url=http://www.mp3developments.com/article4.php |title=Lossy Audio Formats |publisher=MP3Developments |access-date=2007-08-16 |url-status=live |archive-url=https://web.archive.org/web/20070815110114/http://www.mp3developments.com/article4.php |archive-date=2007-08-15 }}</ref> At the early stages of WMA's development, a representative from RealNetworks claimed that WMA was a "clear and futile effort by Microsoft to catch up with [[RealAudio]] 8".<ref>{{cite web |url=http://www.streamingmedia.com/article.asp?id=6637 |title=Codec Rivalry Spurs Development |publisher=streamingmedia.com Codec |access-date=2007-08-16 |archive-url=https://web.archive.org/web/20071015090021/http://streamingmedia.com/article.asp?id=6637 |archive-date=2007-10-15 |url-status=dead }}</ref>

Microsoft has sometimes claimed that the sound quality of WMA at 64&nbsp;kbit/s equals or exceeds that of MP3 at 128&nbsp;kbit/s (both WMA and MP3 are considered near-[[Transparency (data compression)|transparent]] at 192&nbsp;kbit/s by most listeners). In a 1999 study funded by Microsoft, [[National Software Testing Laboratories]] (NSTL) found that listeners preferred WMA at 64&nbsp;kbit/s to MP3 at 128&nbsp;kbit/s (as encoded by [[MusicMatch Jukebox]]).<ref>[http://www.microsoft.com/windows/windowsmedia/compare/audiocompare.aspx Microsoft's summary of the study] {{webarchive|url=https://web.archive.org/web/20071024035924/http://www.microsoft.com/windows/windowsmedia/compare/audiocompare.aspx |date=2007-10-24 }}. [http://www.nstl.com/reports/Final%20MSAudio%20Report.pdf Full report from NSTL] {{webarchive|url=https://web.archive.org/web/20071128082513/http://www.nstl.com/reports/Final%20MSAudio%20Report.pdf |date=2007-11-28 }}.</ref> 

Both MP3 and WMA encoders have undergone active development and improvement for many years, so their relative quality may change over time.

==Players==
Apart from Windows Media Player, most of the WMA compression formats can be played using [[ALLPlayer]], [[VLC media player]],<ref name="vlc">{{cite web |url=http://www.videolan.org/vlc/features.php?cat=audio |title=VLC playback Features |author=VideoLAN team |access-date=2010-01-03 |url-status=dead |archive-url=https://web.archive.org/web/20100103042927/http://www.videolan.org/vlc/features.php?cat=audio |archive-date=2010-01-03 }}</ref> [[Media Player Classic]],<ref name=mpc-hc>{{cite web|title=Media Player Classic - Player Features|url=https://mpc-hc.sourceforge.net/media-player-features.html|access-date=2011-08-17|url-status=live|archive-url=https://web.archive.org/web/20110816013457/http://mpc-hc.sourceforge.net/media-player-features.html|archive-date=2011-08-16}}</ref> [[MPlayer]], [[RealPlayer]], [[Winamp]], [[Zune Software]] (with certain limitations&mdash;DSP plugin support and DirectSound output is disabled using the default WMA plugin),{{Citation needed|date=March 2012}} and many other software media players. The Microsoft Zune media management software supports most WMA codecs, but uses a variation of [[Windows Media DRM]] which is used by PlaysForSure.

The [[FFmpeg]] project has reverse-engineered and re-implemented the WMA codecs to allow their use on [[POSIX]]-compliant operating systems such as [[Linux]]. The [[Rockbox]] project further extended this codec to be suitable for embedded cores, allowing playback on portable MP3 players and cell phones running open source software. RealNetworks has announced plans to support playback of DRM-free WMA files in RealPlayer for Linux.<ref name="newsdotcom">{{cite web|last1=Shankland|first1=Stephen|title=Real to plug Windows media support into Linux|url=http://www.cnet.com/news/real-to-plug-windows-media-support-into-linux-1/|website=[[CNET]]|publisher=[[CBS Interactive]]|access-date=5 April 2016|date=17 August 2006|url-status=live|archive-url=https://web.archive.org/web/20160424152726/http://www.cnet.com/news/real-to-plug-windows-media-support-into-linux-1/|archive-date=24 April 2016}}</ref> On the [[Mac (computer)|Macintosh]] platform, Microsoft released a [[PowerPC]] version of Windows Media Player for [[Mac OS X]] in 2003,<ref name="wmp9mac">{{cite web|url=http://www.microsoft.com/mac/downloads.aspx?pid=download&location=/mac/download/misc/winmp_osx.xml&secid=80&ssid=8&flgnosysreq=True|title=Windows Media Player 9 for Mac OS X|website=[[Microsoft]]|url-status=live|archive-url=https://web.archive.org/web/20070821192229/http://www.microsoft.com/mac/downloads.aspx?pid=download&location=%2Fmac%2Fdownload%2Fmisc%2Fwinmp_osx.xml&secid=80&ssid=8&flgnosysreq=True|archive-date=2007-08-21}}</ref> but further development of the software has ceased. Microsoft currently endorses the third-party [[Flip4Mac]] WMA, a [[QuickTime]] component that allows Macintosh users to play WMA files in any player that uses the QuickTime framework.<ref name="flip4mac">{{cite web|url=http://www.microsoft.com/mac/otherproducts/otherproducts.aspx?pid=windowsmedia|title=Important information for Windows Media Player for Mac users|website=[[Microsoft]]|url-status=live|archive-url=https://web.archive.org/web/20070822133715/http://www.microsoft.com/mac/otherproducts/otherproducts.aspx?pid=windowsmedia|archive-date=2007-08-22}}</ref> Flip4Mac, however, does not currently support the Windows Media Audio Voice codec.<ref name="flip4macwmavoice">{{cite web|url=http://forum.telestream.net/forum/messageview.aspx?catid=9&threadid=3052|title=Flip4Mac forum post discussing WMA Voice support|url-status=dead|archive-url=https://web.archive.org/web/20090701100022/http://forum.telestream.net/forum/messageview.aspx?catid=9&threadid=3052|archive-date=2009-07-01|access-date=2010-01-26}}</ref>

The core [[Android (operating system)|Android platform]] does not itself support WMA, but there is third-party WMA software for Android devices.<ref>{{cite web | author=Cooper | title=Three Methods of How to Play WMA on Android | website=WonderFox| url=https://www.videoconverterfactory.com/tips/play-wma-on-android.html | date=27 February 2023}}</ref>

WMA format can be played on almost all Windows Mobile and later Windows Phone devices.

==Encoders==
There are many proprietary and [[Open-source software|open source]] software packages that can export audio in WMA format, including amongst many others Windows Media Player, [[Windows Movie Maker]], [[Microsoft Expression Encoder]], [[Sony Sound Forge]], [[GOM Player]], [[RealPlayer]],<ref name="realplayerwma">{{cite web|url=http://real.custhelp.com/cgi-bin/real.cfg/php/enduser/std_adp.php?p_faqid=3746&p_created=&p_sid=F*jLGDIi&p_lva=1085180089&p_sp=4494&p_li=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MTA3JnBfcHJvZHM9MywxMSZwX2NhdHM9JnBfcHY9Mi4xMSZwX2N2PSZwX3NlYXJjaF90eXBlPWFuc3dlcnMuc2VhcmNoX25sJnBfcGFnZT0xJnBfc2VhcmNoX3RleHQ9Y29weSBDRCBXTUE*cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MTgmcF9wcm9kcz0zLDExJnBfY2F0cz0mcF9wdj0xLjM7Mi51MCZwX2N2PSZwX3NlYXJjaF90eXBlPWFuc3dlcnMuc2VhcmNoX25sJnBfcGFnZT0xJnBfc2VhcmNoX3RleHQ9V01B&p_prod_lvl1=3&p_prod_lvl2=11&tabName=tab0&p_topview=1|title=RealPlayer Customer Support: What formats can I use to record tracks from a CD with RealPlayer?}}{{Dead link|date=August 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> [[Adobe Premiere Pro]],<ref name="premiere">[http://kb.adobe.com/selfservice/viewContent.do?externalId=332612 Supported file formats in Adobe Premiere Pro 2.0] {{webarchive|url=https://web.archive.org/web/20071013122312/http://kb.adobe.com/selfservice/viewContent.do?externalId=332612 |date=2007-10-13 }},</ref> [[Adobe Audition]],<ref name="audition">{{cite web|url=http://kb.adobe.com/selfservice/viewContent.do?externalId=329174|title=Supported file formats (Adobe Audition 2.0)|url-status=dead|archive-url=https://web.archive.org/web/20071015002521/http://kb.adobe.com/selfservice/viewContent.do?externalId=329174|archive-date=2007-10-15|access-date=2007-08-08}}</ref> [[Adobe Soundbooth]], and [[VLC media player]].<ref name="soundbooth">{{cite web|url=http://kb.adobe.com/selfservice/viewContent.do?externalId=kb401643|title=Soundbooth CS3 supported file formats|url-status=live|archive-url=https://web.archive.org/web/20071015002526/http://kb.adobe.com/selfservice/viewContent.do?externalId=kb401643|archive-date=2007-10-15}}</ref> [[Microsoft Office OneNote]] supports encoding in all WMA codecs,<ref name="onenote">{{cite web|url=http://support.microsoft.com/kb/837846|title=General information about the audio functionality in OneNote 2003|url-status=live|archive-url=https://web.archive.org/web/20071024201509/http://support.microsoft.com/kb/837846|archive-date=2007-10-24}}</ref> and [[Windows Media Encoder]] supports all available bit rate and resolution options as well.

==Digital rights management==
{{Main|Windows Media DRM}}
The WMA codecs are most often used with the ASF container format, which has an optional DRM facility. Windows Media DRM, which can be used in conjunction with WMA, supports time-limited music subscription services such as those offered by unlimited download services, including MTV's [[URGE]], [[Napster]], [[Rhapsody (online music service)|Rhapsody]], [[Yahoo! Music Unlimited]], and [[Virgin Digital]]. Windows Media DRM, a component of PlaysForSure and [[Windows Media Connect]], is supported on many modern portable audio devices and streaming media clients such as [[Roku]], [[SoundBridge]], [[Xbox 360]], and [[Wii]]. Players that support the WMA format but not Windows Media DRM cannot play DRM-protected files.

==See also==
*[[Windows Media Video]] – a video file format and codec developed by Microsoft
*[[WAV]]
*[[JPEG XR|JPEG XR / HD Photo]] – an image file format and codec developed by Microsoft
*[[Surround sound]]
*[[Timeline of audio formats]]
*[[Comparison of audio coding formats]]

==References==
{{Reflist|30em}}

==External links==
* {{web archive|url=https://web.archive.org/web/20080211194317/http://www.microsoft.com/windowsmedia|title=Official website}}

{{Compression formats}}
{{Authority control}}

[[Category:Audio codecs]]
[[Category:Audio file formats]]
[[Category:Microsoft proprietary codecs]]
[[Category:Windows audio]]