Internet-Draft Close RTP Payload Formats Registry October 2024
Westerlund Expires 10 April 2025 [Page]
Workgroup:
AVTCORE
Internet-Draft:
draft-ietf-avtcore-rtp-payload-registry-04
Updates:
8088 (if approved)
Published:
Intended Status:
Standards Track
Expires:
Author:
M. Westerlund
Ericsson

Closing the RTP Payload Format Media Types IANA Registry

Abstract

It has been observed that specifications of new Real-time Transport Protocol (RTP) payload formats often forget to specify registration of the format's media type in the IANA registry "RTP Payload Formats Media Types" as recommended by RFC 8088. In practice this has no real impact. One reason is that the Media Types registry is the crucial registry to register any Media Type to establish the media type used to identified the format in various signaling usage.

This document resolves the situation by first updating the RTP Payload Format Media Type registry to include all the known RTP payload formats at the time of writing, then it closes this IANA Registry for any future registration. Beyond instructing IANA to close this registry, the instructions to authors in RFC 8088 are updated to reflect this.

About This Document

This note is to be removed before publishing as an RFC.

Status information for this document may be found at https://datatracker.ietf.org/doc/draft-ietf-avtcore-rtp-payload-registry/.

Discussion of this document takes place on the AVTCORE Working Group mailing list (mailto:avt@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/avt/. Subscribe at https://www.ietf.org/mailman/listinfo/avt/.

Source for this draft and an issue tracker can be found at https://github.com/gloinul/draft-ietf-avtcore-rtp-payload-registry.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 10 April 2025.

1. Introduction

It has been observed that specifications of new Real-time Transport Protocol (RTP) payload formats often forget to specify registration of the format's media type in the IANA registry "RTP Payload Formats Media Types" [RTP-FORMATS] as recommended by [RFC8088]. In practice this has no real impact. This registry is not used for any purpose other than to track which media types actually have RTP payload formats. That purpose could be addressed through other means.

The Media Types registry [MEDIA-TYPES] is the crucial registry to register any Media Type to establish the media type used to identify the format in various signalling usages, to avoid collisions, and to reference their specifications.

To resolve this situation, this document performs the following actions. First, it updates the registry to include known RTP payload formats at the time of writing. Then, it closes the IANA Registry for RTP Payload Formats Media Types for future registration. Beyond instructing IANA to close this registry, the instructions to authors in [RFC8088] are updated so that registration in the closed registry is no longer mentioned.

It is unclear how the "RTP Payload formats Media Types" [RTP-FORMATS] registry came into existence. The registry references [RFC4855] as the instructions for this registry. However, reviewing that RFC we have been unable to find any text that defines its purpose and rules. Further attempts to find how the registry was created have failed to find any reference to its creation. It is likely this was created based on email or AD request. Thus, there is no known existing specification for this registry that needs to be updated when closing the registry.

2. Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. Update to How To Write an RTP Payload Format

How to write an RTP Payload format [RFC8088] mandates in its section on IANA Considerations (Section 7.4) that RTP Payload formats shall register in RTP Payload Format media types:

"Since all RTP payload formats contain a media type specification, they also need an IANA Considerations section. The media type name must be registered, and this is done by requesting that IANA register that media name. When that registration request is written, it shall also be requested that the media type is included under the "RTP Payload Format media types" sub-registry of the RTP registry (http://www.iana.org/assignments/rtp-parameters)."

This paragraph is changed to the following:

"Since all RTP payload formats contain a media type specification, they also need an IANA Considerations section. The media type name must be registered, and this is done by requesting that IANA register that media name in the Media Types registry (https://www.iana.org/assignments/media-types/media-types.xhtml)."

Thus removing the need to register in the "RTP Payload Format media types".

4. IANA Considerations

IANA is requested to add the following missing RTP Payload types to the "RTP Payload Format Media Types" registry [RTP-FORMATS].

Table 1: Payload Types to Register in RTP Payload Format Media Types
Media Type Sub Type Clock Rate (Hz) Channels (audio) Reference
application flexfec     RFC8627
audio EVRCNW 16000   RFC6884
audio EVRCNW0 16000   RFC6884
audio EVRCNW1 16000   RFC6884
audio aptx     RFC7310
audio opus 48000   RFC7587
audio G711-0     RFC7650
audio flexfec     RFC8627
text flexfec     RFC8627
text ttml+xml     RFC8759
video VP8 90000   RFC7741
video AV1 90000   [AV1-Media-Type]
video HEVC 90000   RFC7798
video smpte291     RFC8331
video VVC 90000   RFC9328
video EVC 90000   RFC9584
video flexfec     RFC8627

IANA is requested to update the following RTP Payload types in the "RTP Payload Format Media Types" registry [RTP-FORMATS].

Table 2: Payload Types to update in RTP Payload Format Media Types
Media Type Sub Type Clock Rate (Hz) Channels (audio) Reference
audio MP4A-LATM     RFC6416
video MP4V-ES 90000   RFC6416

IANA is further requested to close the "RTP Payload Format Media Types" registry [RTP-FORMATS] for any further registrations. IANA should add the following to the existing note for the registry:

"This registry has been closed as it was considered redundant as all RTP Payload formats are part of the Media Types registry (https://www.iana.org/assignments/media-types/media-types.xhtml). For further motivation see (RFC-TBD1)."

In addition it is requested that the existing note of "RTP Payload Format Media Types" registry [RTP-FORMATS] is changed in the following way:

OLD: Registration procedures and a registration template can be found in [RFC4855].

NEW: It was previously stated that registration procedures and a registration template can be found in [RFC4855]. This is not actually the case as discussed by [RFC-TBD1].

RFC-Editor Note: Please replace RFC-TBD1 with the RFC number of this specification and then remove this note.

5. Security Considerations

This document has no security considerations as it defines an administrative rule change.

6. References

6.1. Normative References

[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC8088]
Westerlund, M., "How to Write an RTP Payload Format", RFC 8088, DOI 10.17487/RFC8088, , <https://www.rfc-editor.org/info/rfc8088>.
[RTP-FORMATS]
"IANA's registry for RTP Payload Format Media Types", , <https://www.iana.org/assignments/rtp-parameters/rtp-parameters.xhtml#rtp-parameters-2>.
[MEDIA-TYPES]
"IANA's registry for Media Types", , <https://www.iana.org/assignments/media-types/media-types.xhtml>.
[AV1-Media-Type]
"IANA Media Type Entry for video/AV1", , <https://www.iana.org/assignments/media-types/video/AV1>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.

6.2. Informative References

[RFC4855]
Casner, S., "Media Type Registration of RTP Payload Formats", RFC 4855, DOI 10.17487/RFC4855, , <https://www.rfc-editor.org/info/rfc4855>.

Appendix A. Acknowledgments

The author likes to thank Jonathan Lennox, Zaheduzzaman Sarker, Bernard Aboba, Elwyn Davies, Wes Hardaker, and Hyunsik Yang for review and editorial fixes.

Author's Address

Magnus Westerlund
Ericsson