We optimize the quality of calls by using the Opus codec for audio on Webex Calling. Opus is supported by most clients on the Webex Calling platform and, where possible, is the main codec used for audio calls.

G.711 is the universal codec. We do not support calls with only G.729 codec. If only G.729 is included in codec list, there may be some call flows that will not work correctly. Therefore, all invites should include the G.711 codec.

Opus is supported by the Webex App client as well as all Multiplatform Phones. Opus is not currently supported by analog telephone adapters and DECT phones on the Webex Calling platform. Opus is also not supported by most PSTN providers and for this reason, G.711 is generally used.

The Opus codec is supported in the following call flows:

  • Webex App (desktop) <—> Webex App (desktop)

  • Multiplatform Phone <—> Multiplatform Phone

  • Multiplatform Phone <—> Webex App (desktop)

  • Multiplatform Phone <—> Auto Attendant

  • Multiplatform Phone <—> Voicemail

  • Webex App (desktop) <—> Auto Attendant

  • Webex App (desktop) <—> Voicemail

Each codec consumes roughly the same level of bandwidth, which is 70-80kbps for each audio stream. We recommend that customers allow for 100kbps per audio stream that they want to support on their network, keeping in mind that an internal enterprise requires two audio streams (200kbps).