The responsibilities of WG4 (Codec) include the following items:
Development and maintenance of specifications for speech, audio, video, and multimedia codecs, as required to enable services specified for 3G terminals and systems.
Guidance to other 3GPP groups concerning required QoS parameters and other system implications, including channel coding requirements, imposed by different multimedia codecs in both circuit-switched and packet-switched environments.
Speech, audio, video, and multimedia quality evaluation (including new evaluation methods, testing, verification, characterisation, selection criteria)
End-to-end performance, including terminal characteristics, of speech, audio, video, and multimedia services.
Interoperability aspects with existing mobile and fixed networks from the codec point of view.
In conducting its work, the Codec WG will strive to specify the best possible technical solutions at the same time as considering the planned global use of the codecs and the flexibility needs imposed by different regional requirements and preferences, including possible differences in quality/capacity trade-offs.