Closing the RTP Payload Format Media Types Registry
updates
- rfc-8088 — How to Write an RTP Payload Format
Extracted elements (8)
The origins of the 'RTP Payload Format Media Types' registry are unknown: RFC 4855 was cited as providing maintenance instructions but contains no such text, and no other specification establishing the registry was found. It was likely created via email correspondence or at an Area Director's request, so there is no known specification requiring an update upon closure.
The 'RTP Payload Format Media Types' registry was closed because it served no functional purpose beyond tracking which media types have RTP payload formats, and authors frequently omitted registration there without any practical impact. The canonical 'Media Types' registry already provides the necessary collision avoidance and specification reference functions.
RFC 8088 Section 7.4 previously mandated dual registration in both the 'Media Types' registry and the 'RTP Payload Format Media Types' registry. RFC 9751 removes that dual-registration requirement, updating the IANA Considerations guidance in RFC 8088 to reference only the 'Media Types' registry. The Informational status of RFC 8088 is unaffected.
New RTP payload format authors must register their media type only in the IANA 'Media Types' registry (https://www.iana.org/assignments/media-types/). Registration in the now-closed 'RTP Payload Format Media Types' registry is no longer required or possible.
Before closure, 17 previously missing RTP payload format media types were added to the 'RTP Payload Format Media Types' registry, including audio/opus (RFC 7587), video/VP8 (RFC 7741), video/AV1, video/HEVC (RFC 7798), video/VVC (RFC 9328), video/EVC (RFC 9584), application/flexfec (RFC 8627), and others.
The IANA 'RTP Payload Format Media Types' registry has been closed to future registrations by RFC 9751. The registry note was updated to state it is redundant because all RTP payload formats are already part of the 'Media Types' registry.
Two existing entries in the 'RTP Payload Format Media Types' registry were updated before closure: audio/MP4A-LATM and video/MP4V-ES, both now referencing RFC 6416.
RFC 9751 has no security considerations, as it defines only an administrative rule change (closing a redundant IANA registry and updating registration guidance).