Communication of codec information

摘要

The invention relates to a method for communicating codec related information between a first mobile communication device (UE1) and a second mobile communication device (UE2) via a network. The codec related information relates to operational modes of an adaptive multi-rate (AMR) codec. The information is transmitted by the first mobile communication device (UE1) to the second mobile communication device (UE2) in a form of a binary mask in an SDP (Session Description Protocol) body (33) of a SIP (Session Initiation Protocol) INVITE message (31), a value of 1 indicating the operational modes which are supported by the first mobile communication device (UE1). In the event that the network does not support at least one of the operational modes that the codec related information indicates as being supported the network modifies the codec related information accordingly.