Shepherd writeup

Proto writeup below.

(1.a) Who is the Document Shepherd for this document? Has the Document
Shepherd personally reviewed this version of the document and, in
particular, does he or she believe this version is ready for
forwarding to the IESG for publication?

Jonathan Rosenberg is the Document Shepherd and has personally reviewed
this version of the document and believes it is ready for publication.

(1.b) Has the document had adequate review both from key WG members
and from key non-WG members? Does the Document Shepherd have any
concerns about the depth or breadth of the reviews that have been

The document has received good discussion by the group. It has been
reviewed top to bottom by the co-chairs of the group, who have focused
on breadth. However, the details of the algorithms, include parameters,
have not received deep review by anyone in the group outside of the
small author team. This is not unexpected given the technical depth of
the work and the domain expertise required to understand the nuances of
all aspects of the codec.

(1.c) Does the Document Shepherd have concerns that the document needs
more review from a particular or broader perspective, e.g., security,
operational complexity, someone familiar with AAA,
internationalization or XML?

No. The document is very narrowly focused on speech coding, and has no
interactions with areas outside of this space.

(1.d) Does the Document Shepherd have any specific concerns or issues
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. Has an IPR disclosure related to this
document been filed? If so, please include a reference to the
disclosure and summarize the WG discussion and conclusion on this

The CODEC working group is, in general, a contentious area of work. Much
of this is in the area of intellectual property. The ADs need to be
aware that IPR declarations have been made against this
specification. They are:


Broadcom, Xiph and Skype/Microsoft have all revised their IPR
declarations throughout the process; the above represents the most
recent set.

The Qualcomm declaration is the most concerning; it does not provide a
royalty-free grant. Achieving RF has been a goal of the activity. None
of the participants in the working group appear to work for, or
represent Qualcomm. The chairs have advised the group that the IETF
cannot take positions on validity of IPR claims, and that individuals
must make their own determinations on this matter. The AD should be
aware that one of the participants from Xiph did post on the list his
belief that, after analysis, none of the patents listed in the Qualcomm
declaration apply to Opus

The Huawei declaration is very recent - posted on March 12, 2012. There
has not been any discussion of this on the list. The chairs have decided
to proceed with publication requested, and give the working group the
opportunity to complain during IETF LC if they so wish. Informally, a
few participants have indicated that they do not believe this IPR
impacts Opus.

Some working group members had concerns (expressed privately to the
chairs) about the nature of the RF grants made by Skype; specifically
around termination clauses under conditions of lawsuit. These clauses
have been modified in the most recent disclosure above

The working group was explicitly pointed to all of these disclosures and
was asked whether they wish to proceed given the nature of the
disclosures and their terms. The chairs believe there has been consensus
to proceed based on the IPR declarations made at the time of WGLC. The
only thing that has changed since the consensus call was an updated
Microsoft/Skype license that provides more liberal terms (as well as
availability under the original terms), and the Huawei statement.

The document has also been the source of commentary from external
standards body, most notably ITU, 3gpp and ISO/MPEG. Numerous liaison
statements have been exchanged back and forth. The chairs advised these
groups of our progress throughout the process, and also explicitly asked
for feedback as part of the last call process. The majority of the
comments expressed concerns on the testing process followed by the IETF,
which lacks the rigor typically seen in more formalized ITU
processes. That said, the group itself has consensus that the document
should be published.

(1.e) 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?

The document has had two WGLC. The first was on 8 July 2011. The second
was on 21 October 2011. Comments were received by the group after both
of these WGLC. The chairs believe there is good consensus behind the
document, particularly around the technology. There are several vocal
participants who continue to express dissatisfaction over the testing
and codec validation associated with the work. There is also a
participant who has expressed dissatisfaction with the applicability of
the Qualcomm IPR and has asked for loosening decoder conformance
definitions to comply. The chairs believe there was not consensus for
such changes.

(1.f) 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 entered into the ID

No appeals have been threatened. As noted above, disagreements have
taken place primarily in the areas of testing and validation, and around
IPR and compliance. We do not see those as outside of the normal scope
of disagreement that is common within a working group.

(1.g) Has the Document Shepherd personally verified that the document
satisfies all ID nits? (See the Internet-Drafts Checklist and Boilerplate checks are not
enough; this check needs to be thorough. Has the document met all
formal review criteria it needs to, such as the MIB Doctor, media type
and URI type reviews?

Yes, idnits has been run and generated no errors. No MIB, media type or
URI reviews are required.

(1.h) Has the document split its references into normative and
informative? 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 strategy for their completion?
Are there normative references that are downward references, as
described in [RFC3967]? If so, list these downward references to
support the Area Director in the Last Call procedure for them

Yes. The document is intended for proposed standard. It has a single
normative reference, RFC2119. All others are informative.

(1.i) Has the Document Shepherd verified that the document IANA
consideration section exists and is consistent with the body of the
document? If the document specifies protocol extensions, are
reservations requested in appropriate IANA registries? Are the IANA
registries clearly identified? If the document creates a new registry,
does it define the proposed initial contents of the registry and an
allocation procedure for future registrations? Does it suggest a
reasonable name for the new registry? See [RFC5226]. If the document
describes an Expert Review process has Shepherd conferred with the
Responsible Area Director so that the IESG can appoint the needed Expert
during the IESG Evaluation?

There is no IANA consideration.

(1.j) Has the Document Shepherd verified that sections of the document
that are written in a formal language, such as XML code, BNF rules,
MIB definitions, etc., validate correctly in an automated checker?

The document contains the source-code for the reference implementation,
in uuencoded format. The chairs have verified that the code from
draft-ietf-codec-opus-11 extracts and compiles on a recent version of
OSX 10.8.

(1.k) 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:

This document specifies a speech and audio codec designed for usage on
the Internet.

Technical Summary
  Relevant content can frequently be found in the
  abstract and/or introduction of the document. If not, this may be an
  indication that there are deficiencies in the abstract or

The abstract conveys the technical summary well:

This document defines the Opus interactive speech and audio codec.  Opus
is designed to handle a wide range of interactive audio applications,
including Voice over IP, videoconferencing, in-game chat, and even live,
distributed music performances. It scales from low bitrate narrowband
speech at 6 kb/s to very high quality stereo music at 510 kb/s. Opus
uses both linear prediction (LP) and the Modified Discrete Cosine
Transform (MDCT) to achieve good compression of both speech and music.

Working Group Summary
  Was there anything in WG process that is worth
  noting? For example, was there controversy about particular points or
  were there decisions where the consensus was particularly rough?

The chairs believe there is good consensus behind the document,
particularly around the technology. There has not been any significant
disagreement on any of the technical aspects of the codec. However, the
working group has left the detailed specification work to the small
author team. There are several vocal participants who continue to
express dissatisfaction over the testing and codec validation associated
with the work. The WG chairs do not believe that there was consensus to
make these changes.

This document has been the subject of a number of IPR declarations.


The WG has had an opportunity to review these disclosures in Last Call
and has opted to proceed with document publication.

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, 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 is an existing implementation - the reference implementation which
is included in the appendix of the document and has been maintained by
the authors of the specification. One of the authors developed several
independent decoder implementations in order to help validate the
specification. There are no known alternative encoder
implementations. There are no significant reviewers worth noting beyond
the author team.

The codec has gone through a great degree of testing that demonstrates
its quality. Test results can be found at:

  Who is the Document Shepherd for this document?  Who is the
  Responsible Area Director?

Shepherd: Jonathan D. Rosenberg, Ph.D. <>
Responsible AD: Robert Sparks <>