1. Configuration Guide
  2. Transcoding
  3. AMR-NB and AMR-WB Specifications
  4. AMR AMR-WB Payload Type Mapping

AMR AMR-WB Payload Type Mapping

When the Oracle® Enterprise Session Border Controller connects endpoints that choose AMR with different dynamic payload types but equivalent AMR parameters, payload type remapping can be handled by the local network processor rather than using transcoding resources. In prior releases, the system transcoded all AMR-to-AMR calls or all AMR-WB-to-AMR-WB calls when the Offer/Answer differed only in the assignment of dynamic payload types, or in the values assigned to certain AMR/AMR-WB parameters.

The decision to transcode is based entirely upon a comparison of the SDP Offer presented by the session initiator and the SDP Answer returned by the session responder. Transcoding is NOT REQUIRED when all of the following conditions are met.

  • The offer/answer codecs are identical.
  • The offer/answer payload formats (specified by the AMR/AMR-WB octet-align parameter) are identical.
  • The offer/answer mode-sets (specified by the AMR/AMR-WB mode-set parameter) are identical or intersect.

To use this feature you must create appropriate media profiles (examples given below) and codec policies. You must also enable the audio-payload-type-mapping option in the media-manager-config.

Note:

On a per-call basis, if AMR/AMR-WB payload mapping is invoked, the system can not also perform RFC 2833 to SIP INFO/H.323 UII payload translation. If a call starts with RFC 2833 translation and per a call change AMR/AMR-WB payload mapping, the system prioritizes the AMR/AMR-WB action and ceases RFC 2833 translation.