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.

Audio and video payload types

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

The standard also describes the process of registering new payload types with IANA; additional payload formats and payload types are defined in the following specifications:

• RFC 3551, Standard 65, RTP Profile for Audio and Video Conferences with Minimal Control
• RFC 4856, Media Type Registration of Payload Formats in the RTP Profile for Audio and Video Conferences
• RFC 3190, RTP Payload Format for 12-bit DAT Audio and 20- and 24-bit Linear Sampled Audio
• RFC 6184, RTP Payload Format for H.264 Video
• RFC 3640, RTP Payload Format for Transport of MPEG-4 Elementary Streams
• RFC 6416, RTP Payload Format for MPEG-4 Audio/Visual Streams
• RFC 2250, RTP Payload Format for MPEG1/MPEG2 Video
• RFC 7798, RTP Payload Format for High Efficiency Video Coding (HEVC)
• RFC 2435, RTP Payload Format for JPEG-compressed Video
• RFC 4587, RTP Payload Format for H.261 Video Streams
• RFC 2658, RTP Payload Format for PureVoice Audio Video
• RFC 4175, RTP Payload Format for Uncompressed Video
• RFC 7587, RTP Payload Format for the Opus Speech and Audio Codec
• RFC 9134, RTP Payload Format for JPEG XS

Payload identifiers 96–127 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 by RFC 7007.

Text messaging payload

• RFC 4103, RTP Payload Format for Text Conversation

MIDI payload

• RFC 6295, RTP Payload Format for MIDI
• RFC 4696, An Implementation Guide for RTP MIDI

See also

• Session Initiation Protocol
• H.323
• Comparison of audio coding formats

References

External links

• IANA assignments of Real-Time Transport Protocol (RTP) Parameters