Transcoding

Last Updated : Dec 18, 2023 |

Transcoding translates a media stream encoded by using one codec into a media codec encoded by using another codec. Avaya SBC performs transcoding when the inbound and outbound entities have incompatible codecs. The Session Description Protocol (SDP) offer contains information about the codecs that the device sending the message prefers. The device that receives the message responds to the SDP offer by using the set of codecs that the receiving device supports.

To enable the transcoding feature, you must go to Network & Flows > Advanced Options, click the Feature Control tab, and select the Transcoding check box.

By providing transcoding, Avaya SBC:

  • Optimizes bandwidth availability by enforcing the use of different compression codecs.

  • Normalizes traffic in the network to a single codec.

  • Reduces the usage of multimedia resource function processors and media gateways to support a large number of codecs.

Avaya SBC supports audio transcoding and transcoding for trunk deployments. All transcoded calls are anchored to Avaya SBC. If a call has both audio and video lines, Avaya SBC only transcodes the audio. Video calls that require transcoding are converted to audio calls.

Note:

FAX transcoding is not supported.

Supported transcoding capacities

Server name

Maximum transcoded sessions

Maximum non-transcoded sessions

HP DL360 G8

200

6000

Dell R320

200

6000

Dell R620

200

6000

Dell R630

1000

10000

HP DL360 G9

1000

10000

These capacities vary from codec to codec because, depending on the codec algorithm, the processing CPU cycles differ for each media stream. The estimated capacities are with G711 and G729 codecs and are based on the 180 second hold/talk time.

Codecs supported for transcoding

The following codecs are supported for transcoding:

  • G711

  • G711A

  • G711MU

  • G711U

  • G722

  • G726-32

    This codec is available only when AMS Offloading is enabled.

  • G729

  • G729AB

  • H224

  • H264/SVC

  • OPUS Constrained Narrow Band

  • OPUS Narrow Band

  • OPUS Wide Band

  • PCMA

  • PCMU

  • AMR-WB

  • AMR-NB

The following codecs are supported specifically for Teams:

  • G711A

  • G711U

  • G722

  • G729

  • OPUS

Any codecs not listed here that are used for calls passing through Avaya SBC do not receive any transcoding treatment from Avaya SBC and are simply relayed through the system.

Note:

Avaya SBC does not support the SILK codec, and it can be filtered if required.