Audio Codec Conversion

Codec conversion takes place when an intermediary device such as a Media Gateway is providing translation services for two endpoints that support disparate sets of Codecs. For example, one endpoint may support GSM encoding of audio and the other only G.711 or Speex encoding. Unless an intermediary translator is involved, these two devices cannot directly establish an RTP audio channel. The intermediary device essentially translates audio from the Codec being used by one endpoint to a Codec that can be understood by the other. Audio Codec conversion may also take place if the inherent latency or Quality-of-Service (QoS) properties of the transport network on either side of the intermediary device requires a lighter-weight Codec.