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Shepherd writeup

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(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. This is the proper type of RFC as this document adds
normative requirements for implementations that wish to support ambisonics in
the Ogg Opus format described by RFC 7845, and also updates RFC 7845 (if

(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 defines an extension to the Opus audio codec to encapsulate coded
ambisonics using the Ogg format. It also contains updates to RFC 7845 to
reflect necessary changes in the description of channel mapping families.

Working Group Summary

There were no particularly controversial aspects of this draft, and consensus
on all decisions was generally easy to reach.

Document Quality

The format has been implemented in the open-source libopus library (using an
experimental mapping family identifier), with support included in the
opus-tools package. Several significant vendors have indicated a plan to
implement the specification, including Gooogle, Mozilla, and the open source
VideoLAN and FFmpeg projects. Mark Harris performed a particularly thorough
review, and motivated many of the necessary updates to RFC 7845. In addition,
the updates to the "Opus Channel Mapping Families" IANA registry were reviewed
by the original authors of RFC 7845 (which created that registry).


  Who is the Document Shepherd? Who is the Responsible Area

Document Shepherd: Timothy B. Terriberry
Responsible Area Director: Ben Campbell

(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 been involved with this document since it was first brought to the IETF,
and even originally recommended to the authors that the work be brought here. I
have reviewed all of the revisions in detail, and as an author of the original
RFC 7845 and a developer of the libopus open-source project, I believe that the
proposed format is technically sound and explained in sufficient detail to
enable other implementations. I believe this document is ready for publication.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?


(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.

This document has no AAA, DNS, DCHP, XML, or internationalization components,
and I believe that it raises no new security or operation complexity issues
beyond those of RFC 7845. Therefore we have not sought such review.

(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.

I have no specific concerns or issues.

(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.

I have received confirmation from Jan Skoglund. Michael Graczyk has left
Google, who was employing him to work on this draft, and I have been
unsuccessful in contacting him. However, Jan Skoglund was his boss at Google
and believes that any and all appropriate IPR disclosures have already been

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR

The following IPR disclosure has been filed:

There has been no discussion on the mailing list. Since the application has
been offered with Royalty-Free, Reasonable and Non-Discriminatory terms, and
only relates to one specific aspect of one possible method for encoding, we do
not anticipate any issues.

(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?

I believe that all of the active WG members, which includes all of those who
participated in the standardization RFC 7845, as well as several additional
members who joined to participate in the standardization of this format
understand and agree with this document.

(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 appeals or other indications of extreme discontent have been threatened or

(11) Identify any ID nits the Document Shepherd has found in this
document. (See and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be

No ID nits were identified.

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

This document does not define a new MIB, media type, or URI type.

(13) Have all references within this document been identified as
either normative or informative?


(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?


(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.


(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.

This document updates RFC 7845. RFC 7845 is listed on the title page header, in
the abstract, and is discussed in the introduction.

(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 5226).

I confirm that all protocol extensions that the document makes are associated
with the appropriate reservations in an IANA registry, and that the referenced
IANA registry has been clearly identified. This document does not create any
new IANA registries.

(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.


(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, etc.

No sections of the document are written in a formal language.