A system for providing telecommunication service between users, includes a
first network, a second network, a gateway. The first network is capable
of communicating media in at least one encoding format. The second
network is capable of communicating media in at least one format. In
operation, the gateway receives a call setup message from the first
network, the call setup message signaling for a media channel for
transporting media between a first device and a second device. The
gateway identifies a first encoding format for the media communicated
with the first network. The gateway also determines a second encoding
format for the media in the media channel communicated with the second
network. If the first encoding format and the second encoding format are
different, the gateway modifies transcoding information in the call setup
message, the transcoding information indicating a number of transcoding
points on the media channel.