The present document introduces the set of default codecs for packet switched conversational multimedia applications within 3GPP IP Multimedia Subsystem. Visual and sound communication are specifically addressed. The intended applications are assumed to require low-delay@ real-time functionality. The present document is applicable@ but not limited@ to services such as PS video telephony and Push to talk over Cellular (PoC) as well as Combined CS and IMS services (CSI). For Multimedia Telepphony Service for IMS (MTSI)@ all media handling@ including codecs@ is defined in TS 26.114 [50]. This specification does not apply for MTSI. The applicability of this specification to GERAN is FFS.