Enhanced Voice Services

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Enhanced Voice Services (EVS)
Developed byFraunhofer, JVC Kenwood, Nippon Telegraph and Telephone, NTT Docomo, Panasonic, Ericsson
Type of formatAudio
Standard3GPP TS 26.441

Enhanced Voice Services (EVS) is a superwideband speech audio coding standard. 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 improved packet loss concealment.[2] It has been developed in 3GPP and is described in 3GPP TS 26.441. The application areas of EVS consist of improved telephony and teleconferencing, audiovisual conferencing services, and streaming audio.

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] The six patent holders are Fraunhofer IIS, JVC Kenwood, Nippon Telegraph and Telephone, NTT Docomo, Panasonic, and Ericsson.[5] Other contributors included Huawei, Nokia, Orange, Qualcomm, Samsung Electronics, VoiceAge, and ZTE Corporation.[4]

A patent pool for EVS has been listed by MPEG LA.[6]

Technology[edit]

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

The following features are present in EVS:[7]

  • source-controlled variable 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 buffer management (JBM)

Input sampling rates for EVS can be 8, 16, 32, and 48 kHz. It supports the following bitrates (in kbps) for different bandwidths:[7]

  • 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 tests conducted by Nokia concluded that EVS offers significantly improved quality over AMR and AMR-WB at all operating points.[3]

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): 5713–5717. doi:10.1109/ICASSP.2015.7179066. ISBN 978-1-4673-6997-8.
  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): 5708–5712. doi:10.1109/ICASSP.2015.7179065. ISBN 978-1-4673-6997-8.
  3. ^ a b c The 3GPP Enhanced Voice Services (EVS) codec. Nokia white paper.
  4. ^ a b Enhanced Voice Services (EVS) Codec. Fraunhofer Technical Paper, 2015
  5. ^ "Licensors Included in the EVS Patent Portfolio License". MPEG LA. Retrieved 10 July 2019.
  6. ^ MPEG LA Facilitating Development of Enhanced Voice Services Patent Pool License. MPEG LA News Release, 20.01.2016
  7. ^ a b Järvinen, Kari. "Enhanced Voice Services Codec for LTE". 3GPP.

External links[edit]