View source for Adaptive Multi-Rate Wideband

{{Short description|Wideband speech audio coding standard}}
{{Infobox technology standard
|title=G.722.2
|long_name=Wideband coding of speech at around 16&nbsp;kbit/s using Adaptive Multi-Rate Wideband (AMR-WB) 
|image=
|caption=
|status= In force
|year_started=2002
|version=(08/18)
|version_date=August 2018
|preview=
|preview_date=
|organization= [[ITU-T]]
|committee= [[ITU-T Study Group 16]]
|base_standards=
|related_standards=
|abbreviation=
|domain=[[telecommunication]]
|license=Freely available
|website=https://www.itu.int/rec/T-REC-G.722.2
}}
'''Adaptive Multi-Rate Wideband''' ('''AMR-WB''') is a [[patent]]ed [[Wideband audio|wideband]] [[speech coding|speech]] [[audio coding standard]] developed based on [[Adaptive Multi-Rate audio codec|Adaptive Multi-Rate]] encoding, using a similar methodology to [[algebraic code-excited linear prediction]] (ACELP). AMR-WB provides improved speech quality due to a wider speech bandwidth of 50–7000&nbsp;Hz compared to [[narrowband]] speech coders which in general are optimized for [[Plain old telephone service|POTS]] wireline quality of 300–3400&nbsp;Hz. AMR-WB was developed by [[Nokia]]<ref>{{cite web |title=Nokia Research Center: AMR-WB and the Nokia Voice Experience - Istanbul |url=http://research.nokia.com/news/12097 |archive-url=https://web.archive.org/web/20130210012744/http://research.nokia.com/news/12097 |archive-date=2013-02-10 |url-status=dead}}</ref> and VoiceAge and it was first specified by 3GPP.<ref>{{cite web |title=G.722.2: Wideband coding of speech at around 16 kbit/s using Adaptive Multi-Rate Wideband (AMR-WB) |url=https://www.itu.int/rec/T-REC-G.722.2/ |url-status=live |archive-url=https://web.archive.org/web/20210614081446/https://www.itu.int/rec/T-REC-G.722.2/ |archive-date=2021-06-14 |access-date=2021-12-14 |website=ITU Telecommunication Standard Sector}}</ref>

AMR-WB is codified as G.722.2, an [[ITU-T]] standard speech codec, formally known as ''Wideband coding of speech at around 16&nbsp;kbit/s using Adaptive Multi-Rate Wideband (AMR-WB)''. G.722.2 AMR-WB is the same codec as the [[3GPP]] AMR-WB. The corresponding 3GPP specifications are TS 26.190 for the speech codec<ref>{{cite web |title=Specification # 26.190: Speech codec speech processing functions; Adaptive Multi-Rate - Wideband (AMR-WB) speech codec; Transcoding functions |url=https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1424 |website=3GPP Portal |publisher=3GPP |access-date=2021-12-14}}</ref> and TS 26.194 for the Voice Activity Detector.<ref>{{cite web |title=Specification # 26.194: Speech codec speech processing functions; Adaptive Multi-Rate - Wideband (AMR-WB) speech codec; Voice Activity Detector (VAD) |url=https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1428 |website=3GPP Portal |publisher=3GPP |access-date=2021-12-14}}</ref>

The AMR-WB format has the following parameters:<ref>{{cite web |title=Wideband Speech Coding Standards and Applications |url=http://www.voiceage.com/media/WidebandSpeech.pdf |archive-url=https://web.archive.org/web/20071013214817/http://www.voiceage.com/media/WidebandSpeech.pdf |archive-date=2007-10-13 |access-date=2012-02-22 |url-status=dead}}</ref>
* Frequency bands processed: 50–6400&nbsp;Hz (all modes) plus 6400–7000&nbsp;Hz (23.85&nbsp;kbit/s mode only)
* Delay frame size: 20&nbsp;ms
* Look ahead: 5&nbsp;ms
* AMR-WB codec employs a bandsplitting filter; the one-way delay of this filter is 0.9375&nbsp;ms<ref>{{cite web |title=Specification # 26.976: Performance characterization of the Adaptive Multi-Rate Wideband (AMR-WB) speech codec; Chapter 25: Transmission Delay |url=https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1509 |website=3GPP Portal |publisher=3GPP |access-date=2021-12-14}}</ref>
* Complexity: 38 [[Weighted Million Operations Per Second|WMOPS]], RAM 5.3&nbsp;kilowords
* [[Voice activity detection]], [[discontinuous transmission]], [[comfort noise generator]]
* Fixed point: bit-exact [[C (programming language)|C code]]
* Floating point: under work

A common [[file extension]] for the AMR-WB file format is <code>.awb</code>. There also exists another storage format for AMR-WB that is suitable for applications with more advanced demands on the storage format, like random access or synchronization with video. This format is the 3GPP-specified [[3GP]] [[container format (digital)|container format]], based on the [[ISO base media file format]].<ref>{{Cite IETF |title=RTP Payload Format and File Storage Format for the Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs |rfc=4867 |sectionname=AMR and AMR-WB Storage Format |section=5 |page=35 }}</ref> 3GP also allows use of AMR-WB bit streams for stereo sound.

==AMR modes==
AMR-WB operates, like [[Adaptive Multi-Rate|AMR]], with nine different bit rates. The lowest bit rate providing excellent speech quality in a clean environment is 12.65&nbsp;kbit/s. Higher bit rates are useful in background noise conditions and for music. Also, lower bit rates of 6.60 and 8.85&nbsp;kbit/s provide reasonable quality, especially when compared to narrow-band codecs.

The frequencies from 6.4&nbsp;kHz to 7&nbsp;kHz are only transmitted in the highest bitrate mode (23.85&nbsp;kbit/s), while in the rest of the modes the decoder generates sounds by using the lower frequency data (75–6400&nbsp;Hz) along with random noise (in order to simulate the high frequency band).<ref>Kuo, Sen M., Bob H. Lee, and Wenshun Tian. Real-Time Digital Signal Processing: Fundamentals, Implementations and Applications. John Wiley & Sons, 2013.</ref>

All modes are sampled at 16&nbsp;kHz (using 14-bit resolution) and processed at 12.8&nbsp;kHz.

The bit rates are the following:

* Mandatory multi-rate configuration
** 6.60&nbsp;kbit/s (used for circuit switched [[GSM]] and [[UMTS]] connections; should only be used temporarily during bad radio connections and is not considered [[Wideband audio|wideband]] speech)
** 8.85&nbsp;kbit/s (used for circuit switched GSM and UMTS connections; should only be used temporarily during bad radio connections and is not considered [[Wideband audio|wideband]] speech; provides quality equal to [[G.722]] at 48&nbsp;kbit/s for clean speech)
** 12.65&nbsp;kbit/s (main anchor bitrate; used for circuit switched GSM and UMTS connections; offers superior audio quality to AMR at and above this bit rate; provides quality equal to or better than G722 at 56&nbsp;kbit/s for clean speech)
* Higher bitrates for speech in adverse background noise environments, combined speech and music, and multi-party conferencing.
** 14.25&nbsp;kbit/s
** 15.85&nbsp;kbit/s
** 18.25&nbsp;kbit/s
** 19.85&nbsp;kbit/s
** 23.05&nbsp;kbit/s (not targeted for full-rate GSM channels)
** 23.85&nbsp;kbit/s (provides quality equal to G.722 at 64&nbsp;kbit/s for clean speech; not targeted for full-rate GSM channels)
Notes: "The codec mode can be changed every 20 ms in 3G WCDMA channels and every 40 ms in GSM/GERAN channels. (For Tandem Free Operation interoperability with GSM/GERAN, mode change rate is restricted in 3G to 40 ms in AMR-WB encoders.)" <ref>3GPP [http://www.3gpp.org/DynaReport/26976.htm 3GPP TS 26.976 – Performance characterization of the Adaptive Multi-Rate Wideband (AMR-WB) speech codec; Chapter 4.2 ] Retrieved on 2014-04-10.</ref>

==Configurations for 3GPP==
When used in mobile phone networks, there are three different configurations (combinations of bitrates) that may be used for voice channels:

* Configuration A (Config-WB-Code 0): 6.6, 8.85, and 12.65&nbsp;kbit/s (Mandatory multi-rate configuration)
* Configuration B (Config-WB-Code 2): 6.6, 8.85, 12.65, and 15.85&nbsp;kbit/s
* Configuration C (Config-WB-Code 4): 6.6, 8.85, 12.65, and 23.85&nbsp;kbit/s

This limitation was designed to simplify the negotiation of bitrate between the handset and the base station, thus vastly simplifying the implementation and testing. All other bitrates can still be used for other purposes in mobile phone networks, including multimedia messaging, streaming audio, etc.

==Deployment==
AMR-WB has been standardized by a mobile phone manufacturer consortium for future usage in networks such as [[UMTS]]. Its speech quality is high, but older networks will have to be upgraded to support a wideband codec.{{Citation needed|date=February 2009}}

In October 2006, the first AMR-WB tests were conducted in a deployed network by T-Mobile in Germany, in cooperation with Ericsson.<ref>{{cite web|url=http://www.slashphone.com/74/5630.html |title=T-Mobile and Ericsson conduct world's first field trial with AMR Wideband - SlashPhone.com |access-date=2006-11-26 |url-status=usurped |archive-url=https://web.archive.org/web/20070929045642/http://www.slashphone.com/74/5630.html |archive-date=2007-09-29 }}</ref><ref>{{Cite web |url=http://www.t-mobile.de/unternehmen/presse/0,1807,17596-_,00.html |title=T-Mobile press release (in German) |access-date=2006-11-20 |archive-url=https://web.archive.org/web/20070212091243/http://www.t-mobile.de/unternehmen/presse/0,1807,17596-_,00.html |archive-date=2007-02-12 |url-status=dead }}</ref>

In 2007 an end-to-end AMR-WB TrFO capable 3G & VoIP product line was commercially released by [[Nokia Siemens Networks|NSN]] (M13.6 [[Network switching subsystem|MSS]], U3C [[Media gateway|MGW]]). AMR-WB TFO support was commercially released in 2008 (M14.2, U4.0). End-to-end TFO/TrFO negotiation and mid-call optimization (e.g. on [[handover]], [[Call forwarding|CF]] or [[Call transfer|CT]] events) was released in 2009 (M14.3, U4.1).

In late 2009, [[Orange UK]] announced that it would be introducing AMR-WB on its network in 2010.<ref>{{Cite web |url=http://newsroom.orange.co.uk/2009/12/31/orange-to-launch-mobile-hd-voice-in-2010-a-new-standard-for-the-uk-telecoms-industry/ |title=Orange newsroom |access-date=2009-12-31 |archive-url=https://web.archive.org/web/20100104032426/http://newsroom.orange.co.uk/2009/12/31/orange-to-launch-mobile-hd-voice-in-2010-a-new-standard-for-the-uk-telecoms-industry/ |archive-date=2010-01-04 |url-status=dead }}</ref><ref>Orange to launch mobile HD Voice in 2010</ref> In France [[Orange S.A.]] and SFR are using AMR-WB format on their 3G+ networks since the end of summer 2010.

WIND Mobile in Canada launched HD Voice (AMR-WB) on its 3G+ network in February, 2011. WIND Mobile also announced that several handsets will support HD Voice (AMR-WB) in the first half of 2011,<ref>{{Cite web|date=2018-12-04|title=CNW {{!}} WIND MOBILE ANNOUNCES SUCCESSFUL 4G LIVE TRIAL|url=https://www.newswire.ca/news-releases/wind-mobile-announces-successful-4g-live-trial-507591171.html|url-status=dead|archive-url=https://web.archive.org/web/20181204031118/https://www.newswire.ca/news-releases/wind-mobile-announces-successful-4g-live-trial-507591171.html|archive-date=2018-12-04|access-date=2022-01-25|website=CNW}}</ref> with the first one being Alcatel Tribe.<ref>WIND Mobile press release, Feb 3, 2011</ref>

In January 2013, T-Mobile became the first GSM/UMTS based network in the US to enable AMR-WB.<ref>http://www.anandtech.com/show/6594/tmobile-announces-amrwb-hd-voice-calls-active-on-its-network T-Mobile Announces AMR-WB (HD Voice) Calls Active on its Network</ref>

In Feb 2013, Chunghwa Telecom became the first GSM/UMTS based network in  Taiwan to enable AMR-WB.
<ref>[https://archive.today/20130418194156/http://www.ithome.com.tw/itadm/article.php?c=78703]</ref>

In August 2013 the AMR-WB standard was introduced in Ukraine by Kyivstar.
<ref>{{cite web |url=http://www.telecompaper.com/news/kyivstar-launches-hd-voice--960156 |title = Kyivstar launches HD Voice - Telecompaper}}</ref>

[[Nokia]] developed<ref>{{Cite web|date=2004-07-21|title=Nokia - Ready for deployment: First wideband speech codec for 3G CDMA2000 networks - Press Releases - Press - About Nokia|url=http://press.nokia.com/PR/200407/953215_5.html|url-status=dead|archive-url=https://web.archive.org/web/20070817040405/http://press.nokia.com/PR/200407/953215_5.html|archive-date=2007-08-17|access-date=2022-01-25|website=Nokia.com}}</ref> the [[VMR-WB]] format for [[CDMA2000]] networks, which is fully interoperable with 3GPP AMR-WB. AMR-WB is also a widely adapted format in mobile handsets for ringtones.<ref>{{Cite web|date=2003-03-11|title=Nokia - Nokia transforms the mobile music experience with the Nokia 3300 - Press Releases - Press - About Nokia|url=http://press.nokia.com/PR/200303/894893_5.html|url-status=dead|archive-url=https://web.archive.org/web/20030605165656/hittp://press.nokia.com/PR/200303/894893_5.html|archive-date=2003-06-05|access-date=2022-01-25|website=Nokia.com}}</ref>

The AMR wideband speech format shall be supported in [[3G]] multimedia services when [[Wideband audio|wideband]] speech working at 16&nbsp;kHz sampling frequency is supported. This requirement is defined in 3GPP technical specifications for [[IP Multimedia Subsystem]] (IMS), [[Multimedia Messaging Service]] (MMS) and Transparent end-to-end Packet-switched Streaming Service ([[3GPP PSS|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] 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] 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] Page 10. Retrieved on 2009-06-02.</ref> In 3GPP specifications is AMR-WB format also used in 3GP container format.

==Licensing==
{{missing information|section|pricing|date=February 2021}}
The patent for AMR expired in 2024.<ref>{{Cite patent|number=US7403892B2|title=AMR multimode codec for coding speech signals having different degrees for robustness|gdate=2008-07-22|invent1=Sjoberg|invent2=Bruhn|inventor1-first=Johan|inventor2-first=Stefan|url=https://patents.google.com/patent/US7403892B2/en}}</ref> Previously G.722.2 was licensed by VoiceAge Corporation.<ref name="voiceage-profile">{{cite web |publisher=Industry Canada – ic.gc.ca |url=http://www.ic.gc.ca/app/ccc/srch/nvgt.do?lang=eng&prtl=1&sbPrtl=&estblmntNo=234567018545&profile=cmpltPrfl&profileId=1861&app=sold |title=VoiceAge Corporation – Complete Profile |date=2008-03-13 |access-date=2009-09-11 |archive-url=https://web.archive.org/web/20111026213610/http://www.ic.gc.ca/app/ccc/srch/nvgt.do?lang=eng&prtl=1&sbPrtl=&estblmntNo=234567018545&profile=cmpltPrfl&profileId=1861&app=sold |archive-date=2011-10-26 |url-status=dead }}</ref><ref name="voiceage-pool">{{cite web|publisher=ecplaza.net |url=http://www.ecplaza.net/news/0/27878/voiceage_announces_the.html |title=VoiceAge Announces the Creation of a Patent Pool for AMR-WB/G.722.2 Speech Compression Standards |date=2009-07-21 |access-date=2009-09-11 |url-status=dead |archive-url=https://web.archive.org/web/20110723105055/http://www.ecplaza.net/news/0/27878/voiceage_announces_the.html |archive-date=2011-07-23 }}</ref><ref name="voiceage-press">{{cite web|author=VoiceAge Corporation |publisher=VoiceAge Corporation |url=http://www.voiceage.com/news42.php |title=VoiceAge Announces the Creation of a Patent Pool for AMR-WB/G.722.2 Speech Compression Standards |date=2009-07-21 |access-date=2009-09-11 |url-status=dead |archive-url=https://web.archive.org/web/20100128094308/http://www.voiceage.com/news42.php |archive-date=2010-01-28 }}</ref><ref name="voiceage-licamrwb">{{cite web |author=VoiceAge Corporation |publisher=VoiceAge Corporation |url=http://www.voiceage.com/licamrwb.php |title=Licensing for AMR-WB/G.722.2 |access-date=2009-09-11}}</ref>

==Tools==
For encoding and decoding AMR-WB, an open-source library named [[OpenCORE]] exists. The OpenCORE codec can be used in [[FFmpeg|ffmpeg]].

For encoding, another open-source library exists as well, provided by [[VisualOn]]. It is included in the [[Android (operating system)|Android]] mobile operating system.

==See also==
* [[Enhanced Voice Services]] (EVS)
* [[Adaptive Multi-Rate]] (AMR)
* [[Extended Adaptive Multi-Rate – Wideband]] (AMR-WB+)
* [[Half Rate]]
* [[Full Rate]]
* [[Enhanced full rate|Enhanced Full Rate]] (EFR)
* [[G.722]]
* [[G.722.1]]
* [[3GP]]
* [[Comparison of audio coding formats]]
* [[RTP audio video profile]]
* [[Wideband audio]]

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

==External links==
* [https://www.itu.int/rec/T-REC-G.722.2/ ITU-T Recommendation G.722.2 (AMR-WB) – technical specification]
* [http://www.3gpp.org/ftp/Specs/html-info/26190.htm Adaptive Multi-Rate – Wideband (AMR-WB) speech codec; Transcoding functions; 3GPP TS  26.190 – 3GPP technical specification]
* [http://www.3gpp.org/ftp/Specs/html-info/26194.htm Adaptive Multi-Rate – Wideband (AMR-WB) speech codec; Voice Activity Detector (VAD); 3GPP TS  26.194 – 3GPP technical specification]
* [http://www.3gpp.org/ftp/Specs/html-info/26171.htm Adaptive Multi-Rate – Wideband (AMR-WB) speech codec; General description; 3GPP TS 26.171 – 3GPP technical specification]
* [http://www.3gpp.org/ftp/Specs/html-info/26-series.htm 3GPP codecs specifications; 3G and beyond / GSM, 26 series]
* {{IETF RFC|4867|link=no}} – RTP Payload Format and File Storage Format for the Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs
* {{IETF RFC|4281|link=no}} – The Codecs Parameter for "Bucket" Media Types
* [https://web.archive.org/web/20080216034113/http://mobilesociety.typepad.com/mobile_life/2006/12/deep_inside_the.html Deep Inside the Network, Episode 2: AMR-WB – Skype-like Audio Quality for Mobile Networks]
* [https://web.archive.org/web/20071013214817/http://www.voiceage.com/media/WidebandSpeech.pdf Wideband Speech Coding Standards and Applications]
* [http://www.3gpp.org/ftp/tsg_sa/TSG_SA/TSGS_17/Docs/PDF/SP-020422.pdf 3GPP – Technical Specification Group Services and System Aspects]
* [http://www.itu.int/itudoc/itu-t/com16/implgd/old/g7222-ig.pdf ITU-T Implementors' Guide for G.722.2]
* [http://www.gsacom.com/downloads/pdf/GSA_Mobile_HD_Voice_report_200212.php4 Report on Mobile HD Voice using AMR Wideband, as of 20th of Feb 2012]

{{Compression formats}}

[[Category:Audio codecs]]
[[Category:Speech codecs]]
[[Category:Wideband codecs]]
[[Category:ITU-T recommendations]]
[[Category:ITU-T G Series Recommendations]]