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.
The technical parameters of payload formats for audio and video streams are standardised. The standard also describes the process of registering new payload types with IANA.
Payload formats and types for text messaging are defined in the following specifications:
Payload formats and types for MIDI are defined in the following specifications:
Payload formats and types for audio and video are defined in the following specifications:
Payload identifiers 96âÂÂ127 are used for payloads defined dynamically during a session. It is recommended to dynamically assign port numbers, although port numbers 5004 and 5005 have been registered for use of the profile when a dynamically assigned port is not required.
Applications should always support PCMU (payload type 0). Previously, DVI4 (payload type 5) was also recommended, but this was removed in 2013.