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Enhanced Voice Services

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Enhanced Voice Services (E5VS)
Internet media typeaudio/EVS
Developed byFraunhofer,JVCKenwood,Nippon Telegraph and Telephone,NTT Docomo,Panasonic,Ericsson
Type of formatLossyaudio
Standard3GPP TS 26.441, 26.442

Enhanced Voice Services(EVS) is asuperwidebandspeechaudio coding standardthat was developed forVoLTEandVoNR.It offers up to 20 kHz audio bandwidth and has high robustness to delay jitter and packet losses due to its channel aware coding[1]and improvedpacket lossconcealment.[2]It has been developed in3GPPand is described in3GPP TS 26.441.The application areas of EVS consist of improved telephony and teleconferencing, audiovisual conferencing services, and streaming audio. Source code of both decoder and encoder in ANSI C is available as3GPP TS 26.442and is being updated regularly. Samsung uses the term HD+ when doing a call using EVS.

History[edit]

Work on EVS was started in 2007. The standardization process lasted from 2010 to 2014, being completed in December 2014 with 3GPP Release 12.[3]The codec was developed collaboratively among chipset, handset and infrastructure manufacturers as well as operators and technology providers.[4]

GSMArequires EVS for their HD Voice+ Logo Licensing Program.[5]

The six patent holders areFraunhofer IIS,JVC Kenwood,Nippon Telegraph and Telephone,NTT Docomo,Panasonic,andEricsson.[6]Other contributors includedHuawei,Nokia,Orange,Qualcomm,Samsung Electronics,VoiceAge, andZTE Corporation.[4]Apatent poolfor EVS has been listed byMPEG LA.[7]

Technology[edit]

EVS employs similar concepts to its predecessors, such asAMR-WB,to which it retains backward-compatibility. It switches between speech and audio compression modes depending on the content, usingACELPandMDCT.

The following features are present in EVS:[8]

  • source-controlledvariable bit-rate(SC-VBR)
  • voice/sound activity detector (VAD)
  • comfort noise generation (CNG)
  • error concealment(EC) for packet loss in networks
  • channel-aware mode to improve frame/packet error resilience
  • jitter buffermanagement (JBM)

Input sampling rates for EVS can be 8, 16, 32, and 48 kHz. It supports the following bitrates (in kbps) for different bandwidths:[8]

  • Narrowband (NB): 5.9, 7.2, 8, 9.6, 13.2, 16.4, 24.4
  • Wideband (WB): 5.9, 7.2, 8, 9.6, 13.2, 13.2 channel-aware, 16.4, 24.4, 32, 48, 64, 96, 128 (6.6 ~ 23.85 for AMR-WB IO)
  • Super-wideband (SWB): 9.6, 13.2, 13.2 channel-aware, 16.4, 24.4, 32, 48, 64, 96, 128
  • Fullband (FB): 16.4, 24.4, 32, 48, 64, 96, 128

Bitrates can be switched every 20 ms.[3]

Subjective listening testsconducted by Nokia concluded that EVS offers significantly improved quality overAMRandAMR-WBat all operating points.[3]

Adoption[edit]

Operators which have launched EVS poweredVoLTEservices include:[9][failed verification]


As of 2024 there are about 200 models from different smartphones manufacturers supporting EVS, including:[9]

Interoperability[edit]

Inter-carrier interoperability is a problem, as calls are by default routed over narrowband connections which downgrades the voice to narrowband quality instead of EVS andHD Voiceeven if the individual phones and carrier networks all support EVS.[11]Thus, users are encouraged to switch from phone calls to pure VoIP apps such asFaceTime,Google Duo,WhatsApp,Facebook Messenger,and/orTelegramwhen voice call quality remains poor despite good network connectivity.[12]

Licensing[edit]

EVS, like AMR-WB and AMR-WB+, incorporates severalpatents.As with those two codecs, VoiceAge Corporation is in charge of the licensing[13]and offers RAND pricing[14]

See also[edit]

References[edit]

  1. ^Atti, V.; Sinder, D. J.; Subasingha, S.; Rajendran, V.; Dewasurendra, D.; Chebiyyam, V.; Varga, I.; Krishnan, V.; Schubert, B. (2015-04-01). "Improved error resilience for volte and VoIP with 3GPP EVS channel aware coding".2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP).pp. 5713–5717.doi:10.1109/ICASSP.2015.7179066.ISBN978-1-4673-6997-8.S2CID17443373.
  2. ^Lecomte, J.; Vaillancourt, T.; Bruhn, S.; Sung, H.; Peng, K.; Kikuiri, K.; Wang, B.; Subasingha, S.; Faure, J. (2015-04-01). "Packet-loss concealment technology advances in EVS".2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP).pp. 5708–5712.doi:10.1109/ICASSP.2015.7179065.ISBN978-1-4673-6997-8.S2CID11693594.
  3. ^abcThe 3GPP Enhanced Voice Services (EVS) codec.Nokia white paper.
  4. ^abEnhanced Voice Services (EVS) Codec.Fraunhofer Technical Paper, 2015
  5. ^"HD Voice".Future Networks.Retrieved2020-05-10.
  6. ^"Licensors Included in the EVS Patent Portfolio License".MPEG LA.Retrieved10 July2019.
  7. ^MPEG LA Facilitating Development of Enhanced Voice Services Patent Pool LicenseArchived2016-03-09 at theWayback Machine.MPEG LA News Release, 20.01.2016
  8. ^abJärvinen, Kari."Enhanced Voice Services Codec for LTE".3GPP.
  9. ^ab"EVS".Fraunhofer Institute for Integrated Circuits IIS.Retrieved2020-05-10.
  10. ^https://www.howardforums.com/threads/att-evs.1918271/
  11. ^Segan, Sascha (April 2018)."How to Make Your Cell Phone Calls Sound Better".PCMAG.
  12. ^"What to Do If Your Smartphone's Voice Call Quality Sucks".Lifehacker.13 April 2018.Retrieved29 December2022.
  13. ^"VoiceAge EVS".voiceageevs.com.
  14. ^"RAND pricing".voiceageevs.com.

External links[edit]

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