RTP payload formats

The Real-time Transport Protocol (RTP) specifies a general-purpose data format and network protocol for transmitting digital media streams on Internet Protocol (IP) networks.

The details of media encoding, such as signal sampling rate, frame size and timing, are specified in an RTP payload format.

The format parameters of the RTP payload are typically communicated between transmission endpoints with the Session Description Protocol (SDP), but other protocols, such as the Extensible Messaging and Presence Protocol (XMPP) may be used.

RFC 3551, entitled RTP Profile for Audio and Video (RTP/AVP), specifies the technical parameters of payload formats for audio and video streams.

Applications should always support PCMU (payload type 0); previously, DVI4 (payload type 5) was also recommended, but this was removed in 2013 by RFC 7007.