The European Broadcasting Union (EBU) has defined the standard EBU Tech 3326 to describe the minimal interoperablity requirements of an audio codec. EBU Tech 3326 is based on a couple of IETF RFCs such as those of RTP und SIP. RTP is used for transmitting the audio codec, SIP helps to establish the call.
All modern audio codecs support the EBU Tech 3326 standard and thus work well together will Sipcast.Net.