Request for Publication Document: RTP Payload Format for Versatile Video Coding (VVC) Link: https://datatracker.ietf.org/doc/html/draft-ietf-avtcore-rtp-vvc Intended Status: Proposed Standard Document Shepard: Bernard Aboba (1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header? Proposed Standard. (2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections: Technical Summary: This document describes the RTP payload format for ITU-T Recommendation H.266, also know as Versatile Video Coding (VVC). The RTP payload format, which is applicable to video conferencing, video streaming and high-bitrate entertainment-quality video, allows for packetization of Network Abstraction Layer (NAL) units in an RTP packet payload as well as fragmentation of a NAL unit into multiple RTP packets. Similar to earlier hybrid-video-coding-based standards, including HEVC, the following basic video coding design is employed by VVC. A prediction signal is first formed by either intra- or motion- compensated prediction, and the residual (the difference between the original and the prediction) is then coded. The gains in coding efficiency are achieved by redesigning and improving almost all parts of the codec over earlier designs. In addition, VVC includes several tools to make the implementation on parallel architectures easier. Finally, VVC includes temporal, spatial, and SNR scalability as well as multiview coding support. VVC inherits the basic systems and transport interfaces designs from HEVC and AVC. These include the NAL-unit-based syntax structure, the hierarchical syntax and data unit structure, the supplemental enhancement information (SEI) message mechanism, and the video buffering model based on the hypothetical reference decoder (HRD). The scalability features of VVC are conceptually similar to the scalable variant of HEVC known as SHVC. Working Group Summary: The VVC payload specification resembles the RTP payload specification for HEVC (RFC 7798), so discussion in the WG focused on the differences between the VVC and HEVC codecs and the impact on the RTP payload format. Compared with HEVC, the VVC RTP payload specification has simplified transmission modes. While HEVC supported SRST, MRST and MRMT transmission modes, VVC only supports SRST, which has been the most commonly implemented transmission mode for H.264/SVC and HEVC. As a result, the VVC RTP payload specification does not require the tx-mode parameter, and the number of SDP optional parameters has been reduced. The VVC RTP payload specification also has removed discussion of the Slice Loss Indication (SLI) and Reference Picture Selection Indication (RPSI) Feedback Messages, both of which are rarely implemented with modern codecs. In addition to these and other simplifications, the WG discussed support for the Framemarking RTP header extension and concluded that it need not be supported by the VVC RTP payload specification. Document Quality: Are there existing implementations of the protocol? Have a significant number of vendors indicated their plan to implement the specification? Are there any reviewers that merit special mention as having done a thorough review, e.g., one that resulted in important changes or a conclusion that the document had no substantive issues? If there was a MIB Doctor, YANG Doctor, Media Type or other expert review, what was its course (briefly)? In the case of a Media Type review, on what date was the request posted? There are existing implementations of the VVC (H.266) encoder and decoder, including the VVC Test Model. See: https://jvet.hhi.fraunhofer.de/ There is a prototype implementation of the VVC RTP payload specification covering the mandatory and some optional features of the media plane. There is no known implementation of the SDP signaling. So far, there have not been any interop events relating to the VVC RTP payload specification. There have been no MIB Doctor, Yang Doctor, Media Type or other expert reviews. Personnel: Who is the Document Shepherd? Who is the Responsible Area Director? Document Shepherd is Bernard Aboba. Responsible AD is Murray Kucherawy. (3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG. I have reviewed draft -14. Previously, I had reviewed draft-10 and provided comments here: https://mailarchive.ietf.org/arch/msg/avt/CNYVIC_3T9VQxpm6r8dnctvFiaU/ The authors responded to my comments: https://mailarchive.ietf.org/arch/msg/avt/5U2GmOLMCwR6cYgCaC8O1iQjKbo/ (4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed? The specification has not been reviewed by the SDP Directorate. (5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place. The document does not raise any unique security, AAA, DNS, DHCP, XML or internationalization issues. (6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here. The VVC RTP payload specification has made a considerable effort to reduce the number of optional features, including transmission modes and SDP parameters. This simplification should address some of the interoperability issues encountered with the HEVC and H.264/SVC RTP payload specifications. That said, we are still early in the implementation cycle and no interoperability testing has been done. In the past, organizations such as IMTC developed profiles as well as producing test suites and organizing interop events. However, the IMTC (since merged into MEF) has no current plans to update the HEVC RTP profile for VVC: https://www.mef.net/wp-content/uploads/2020/09/IMTC1016_22034_1.pdf (7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why? On March 8, a request for author confirmation was posted to the mailing list: https://mailarchive.ietf.org/arch/msg/avt/s4qv9h6osUBw9GCMux8cSRu1tJM/ A response was received from each of the authors: Shuai Zhao: https://mailarchive.ietf.org/arch/msg/avt/z-squBK_9cc1Ebtb5ZUoVANmw6Q/ Stephan Wenger: https://mailarchive.ietf.org/arch/msg/avt/_LBJVphT1RRtHCR-p3Mvi1Opu8Y/ Yago Sanchez de la Fuente: https://mailarchive.ietf.org/arch/msg/avt/sDovNWZ5CZ-z7mwnv6ygZFJk7x8/ Ye-Kui Wang: https://mailarchive.ietf.org/arch/msg/avt/s6rJHDcLHq9pgyGZGrBFqx6jxvs/ Miska Hannuksela: https://mailarchive.ietf.org/arch/msg/avt/hn0YMTDYVrqmNVjmvs1kBS1XgEY/ (8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures. Multiple IPR declarations have been filed: https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-avtcore-rtp-vvc WG discussion on whether to proceed to publication was requested on March 8, 2022: https://mailarchive.ietf.org/arch/msg/avt/vH-1ZgsF0EMBqIUy64apLQqLl78/ The issue will also be raised during IETF 113. So far, no objections have been received. (9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it? WG consensus behind this document appears solid. A summary of the second WGLC is here: https://mailarchive.ietf.org/arch/msg/avt/g5uv_hrfZtPJmJFEWQaHKDwHFqY/ 7 responses to the WGLC announcement were received. Of the responses, 6 favored publication "as is" and 1 provided comments. There were no objections. *"As is"* Stephan Wenger: https://mailarchive.ietf.org/arch/msg/avt/354RgFgb4EWmQFsFNSC41LDls4M/ Sanchez de la Fuente: https://mailarchive.ietf.org/arch/msg/avt/S8cY3yBtFmbCYc6n8JrfZ_iddxg/ Ye-Kui Wang: https://mailarchive.ietf.org/arch/msg/avt/9p3ziA8t9d06U7wnCU5qiNd933A/ Shuai Zhao: https://mailarchive.ietf.org/arch/msg/avt/3nKG5jR_phMtHBECrjHwgf7am5Q/ Miska Hannuksela: https://mailarchive.ietf.org/arch/msg/avt/3Kb2VCLGUQLwsPeL8pUW2YhWIXg/ Thomas Schierl: https://mailarchive.ietf.org/arch/msg/avt/XCzdnL3uonjTZMkgWGdlIhAyCyg/ *Comments provided:* Mach Chen: https://mailarchive.ietf.org/arch/msg/avt/PWJ2ZsBwolsHxGiWu-wwfIAOX38/ Response from Stephan: https://mailarchive.ietf.org/arch/msg/avt/u40nDpFsD7JveHLu-mkW5wi-PH8/ Response from Mach: https://mailarchive.ietf.org/arch/msg/avt/3b2FktXkhYzx3Cd1tXKFUh4J_K0/ Response from Stephan: https://mailarchive.ietf.org/arch/msg/avt/rdl9D3lJzGUZg9z9lXPrqlWgA4A/ The authors addressed the comments in draft -14. (10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.) No appeal threats or extreme discontent expressed. (11) Identify any ID nits the Document Shepherd has found in this document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough. An ID nits run on -14 discloses 0 errors, 0 flaws and 1 warning: idnits 2.17.00 (12 Aug 2021) /tmp/idnits1001/draft-ietf-avtcore-rtp-vvc-14.txt: /tmp/idnits1001/draft-ietf-avtcore-rtp-vvc-14.txt(3591): Found non-ascii character (Ã) in position 10. Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- == There is 1 instance of lines with non-ascii characters in the document. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- -- The document date (25 February 2022) is 19 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Looks like a reference, but probably isn't: '0' on line 1390 'transmission order), AbsDon[0] is set equal to DON[0]....' -- Possible downref: Non-RFC (?) normative reference: ref. 'ISO23090-3' -- Possible downref: Non-RFC (?) normative reference: ref. 'VSEI' -- Possible downref: Non-RFC (?) normative reference: ref. 'VVC' Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 5 comments (--). (12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, YANG Doctor, media type, and URI type reviews. The document contains no MIBs or YANG modules and does not define URI types. It does define a media type. (13) Have all references within this document been identified as either normative or informative? Yes. (14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion? There are references to non-IETF documents, such as the VVC specification: https://www.itu.int/rec/T-REC-H.266 There are no normative references to documents not ready for advancement or in an unclear state. However, there is one Informative reference that appears improperly formatted, to [CABAC]. (15) Are there downward normative references references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure. No. (16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary. The publication of this document will not change the status of any existing RFCs. (17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126). The document requests allocation of a new media type in Section 7.1. AFAICT the request is consistent with the rest of the document. (18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries. No new IANA registries are established by the document. (19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, YANG modules, etc. No formal languages used. (20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342? No YANG modules.