Re: [codec] WG Review: Internet Wideband Audio Codec (codec)

[Cullen Jennings <[e-mail]>]

Before the IESG sent the proposed CODEC charter out for community review, we received some concerns about  this proposed charter. I had hoped these would be discussed during the WG charter review. I'm raising these issues now to make sure that the IESG has an opportunity to hear from the whole community.  As a starting point for the discussion, I am providing some of my own thoughts on these issues.

1) The charter should allow for the proposed WG to decide to select an existing codec 

My read of the current charter is that selecting an existing codec is allowed, and this would be a very good outcome.  This topic has been discussed in the past; my recollection is that people that have expressed opinions on existing codecs also believe that it would be a good thing for the WG to be able to choose an existing one as long as it meets the goals. If there is something that needs to be clarified in the proposed charter to make this clear, please help by suggesting wording.

2) Some people have proposed the WG should be chartered in three stages. (1) get consensus on the requirements, (2) see if an existing codec meets the requirements, and (3) specify a new codec only if none are found in stage 2. Initially the WG would be chartered for (1) and when that was done it would be re-charted for (2) and so on. 

We have received excellent liaison about existing codecs and their IPR status and many of the participants on the list have a reasonable knowledge of the currently available codecs. I have not heard people making strong arguments that one of the existing codecs meets the requirements and goals that the list seems to be converging on.  The key issues here is that even *after* codec work is started, the WG still needs to be able to choose an existing codec as the IPR status of existing codec. Specifically if some patent holders of one of the existing codecs decided to make the codec royalty free, the WG very well could choose to abandon ongoing work and choose the existing codec. Also as the work evolves, participants will get better information about the quality of any codec being developed and this may change the consensus regarding the need to develop a new codec. Given all of these, chartering in multiple stages seems to add to the process burden and does not seem to have a strong benefit in producing a better final outcome one way or the other. 

3) There should be a only a single codec coming out of the proposed WG and forbid more than one

Most codecs of this type end of having various algorithm parameter values in the payload that make it hard to enforce something like this. Various codec experts have explained to me that it is easy to make a codec where one of the bits ends up selecting which coding technique to use. Adding constraints like this is likely to just create incentives for a WG to do patchwork designs to work around process constraints. In the end, I suspect we need to rely on the WG consensus process to cause the correct thing to happen. 

4) Some people suggested that the WG needs to demonstrate the codec is superior to all existing codecs in ways other than just IPR considerations

I observe it is unlikely that a codec that tries to avoid any modern IPR would end up being better in all other ways to codecs that incorporated modern advances in codec design that are patented. My current read of the input from the list discussion and BOFs is that that the bulk of the participants do not view this as a needed to meet the envisioned use cases.  

5) The WG should have consensus that any codec they select is not IPR encumbered or is royalty free.

The IETF IPR policy attempts to get relevant information from the participants of the a WG about IPR associated with contributions.  This allows the WG to make informed decisions when deciding on mechanisms. All chartered WGs must work within the current IETF IPR rules.  The proposed codec WG is no exception, and this has been very clearly stated in the BOFs and other discussions about this work.  BCP 79 says the IETF "will take no position on the validity or scope of  any such IPR claims".

Thanks, Cullen <RAI AD>





On Dec 23, 2009, at 9:15 , IESG Secretary wrote:

> A new IETF working group has been proposed in the Real-time Applications
> and Infrastructure Area.  The IESG has not made any determination as yet.
> The following draft charter was submitted, and is provided for
> informational purposes only.  Please send your comments to the IESG
> mailing list ([e-mail]) by January 20, 2010.
> 
> Internet Wideband Audio Codec (codec)
> -------------------------------------------------------------------------
> Last Modified: 2009-12-17
> 
> Proposed Chair(s):
> * TBD
> 
> Real-time Applications and Infrastructure Area Director(s):
> * Robert Sparks <[e-mail]>
> * Cullen Jennings <[e-mail]>
> 
> Real-time Applications and Infrastructure Area Advisor:
> * Cullen Jennings <[e-mail]>
> 
> Mailing Lists:
> General Discussion: [e-mail]
> To Subscribe: [e-mail]
> In Body: subscribe
> Archive: https://www.ietf.org/mailman/listinfo/codec
> 
> Description of Working Group
> Problem Statement
> 
> According to reports from developers of Internet audio applications and
> operators of Internet audio services, there are no standardized,
> high-quality audio codecs that meet all of the following three
> conditions:
> 
> 1. Are optimized for use in interactive Internet applications.
> 
> 2. Are published by a recognized standards development organization
> (SDO) and therefore subject to clear change control.
> 
> 3. Can be widely implemented and easily distributed among application
> developers, service operators, and end users.
> 
> There exist codecs that provide high quality encoding of audio
> information, but that are not optimized for the actual conditions of the
> Internet; according to reports, this mismatch between design and
> deployment has hindered adoption of such codecs in interactive Internet
> applications.
> 
> There exist codecs that can be widely implemented and easily
> distributed, but that are not standardized through any SDO; according to
> reports, this lack of standardization and clear change control has
> hindered adoption of such codecs in interactive Internet applications.
> 
> There exist codecs that are standardized, but that cannot be widely
> implemented and easily distributed; according to reports, the presence
> of various usage restrictions (e.g., in the form of requirements to pay
> royalty fees, obtain a license, enter into a business agreement, or meet
> other special conditions imposed by a patent holder) has hindered
> adoptions of such codecs in interactive Internet applications.
> 
> According to application developers and service operators, an audio
> codec that meets all three of these would: (1) enable protocol
> designers to more easily specify a mandatory-to-implement codec in
> their protocols and thus improve interoperability; (2) enable
> developers to more easily easily build innovative, interactive
> applications for the Internet; (3) enable service operators to more
> easily deploy affordable, high-quality audio services on the Internet;
> and (4) enable end users of Internet applications and services to enjoy
> an improved user experience.
> 
> Objectives
> 
> The goal of this working group is to develop a single high-quality audio
> codec that is optimized for use over the Internet and that can be widely
> implemented and easily distributed among application developers, service
> operators, and end users.  Core technical considerations include, but
> are not necessarily limited to, the following:
> 
> 1. Designing for use in interactive applications (examples include, but
> are not limited to, point-to-point voice calls, multi-party voice
> conferencing, telepresence, teleoperation, in-game voice chat, and live
> music performance)
> 
> 2. Addressing the real transport conditions of the Internet as
> identified and prioritized by the working group
> 
> 3. Ensuring interoperability with the Real-time Transport Protocol
> (RTP), including secure transport via SRTP
> 
> 4. Ensuring interoperability with Internet signaling technologies such
> as Session Initiation Protocol (SIP), Session Description Protocol
> (SDP), and Extensible Messaging and Presence Protocol (XMPP); however,
> the result should not depend on the details of any particular signaling
> technology
> 
> Optimizing for very low bit rates (typically below 2.4 kbps) and for
> non-interactive audio is out of scope because such work might
> necessitate specialized optimizations.
> 
> Although the codec produced by the working group might be used as a
> mandatory-to-implement technology by designers of particular Internet
> protocols, it is explicitly not a goal of the working group to produce a
> codec that will be mandated for use across the entire IETF or Internet
> community nor would their be any expectation that this would be the only
> mandatory-to-implement codec.
> 
> The goal of the working group is to produce only one codec.  Based on
> the working group's analysis of the design space, the working group
> might determine that it needs to produce more than one codec, or a codec
> with multiple modes; however, it is not the goal of working group to
> produce more than one codec, and to reduce confusion in the marketplace
> the working group shall endeavor to produce as few codecs as possible.
> 
> In completing its work, the working group should collaborate with other
> IETF working groups to complete particular tasks.  These might include,
> but would not be limited to, the following:
> 
> - Within the AVT WG, define the codec's payload format for use with the
>  Real-time Transport Protocol (RTP).
> 
> - Collaborate with working groups in the Transport Area to identify
>  important aspects of packet transmission over the Internet.
> 
> - Collaborate with working groups in the Transport Area to understand
>  the degree of rate adaptation desirable, and to reflect that
>  understanding in the design of a codec that can adjust its
>  transmission in a way that minimizes disruption to the audio.
> 
> - Collaborate with working groups in the RAI Area to ensure that
>  information about and negotiation of the codec can be easily
>  represented at the signaling layer.
> 
> The working group will inform the ITU-T (Study group 16) of each new
> revision of working group drafts, with the intent of submitting the
> completed codec RFC for co-publication by the ITU-T if the ITU-T finds
> that appropriate. The working group will communicate detailed
> description of the requirements and goals to other SDOs including the
> ITU-T, 3GPP, and MPEG to help determine if existing codecs meet the
> requirements and would therefore enable co-publication of an existing
> standard at the IETF. The working group will also continue to discuss
> with other standards bodies to determine if it becomes possible to
> satisfy the IETF requirements through a new or revised standard at other
> bodies.
> 
> Suggested Codec Standardization Guidelines and Requirements for
> achieving the foregoing objectives are provisionally outlined in
> draft-valin-codec-guidelines and draft-valin-codec-requirements
> respectively; these documents will form the starting point for working
> toward consensus and, if accepted as work items of the working group,
> will be refined by the working group in accordance with the usual IETF
> procedures.
> 
> A codec that can be widely implemented and easily distributed among
> application developers, service operators, and end users is preferred.
> Many existing codecs that might fulfill some or most of the technical
> attributes listed above are encumbered in various ways.  For example,
> patent holders might require that those wishing to implement the codec
> in software, deploy the codec in a service, or distribute the codec in
> software or hardware need to request a license, enter into a business
> agreement, pay licensing fees or royalties, or attempt to adhere to
> other special conditions or restrictions.
> 
> Because such encumbrances have made it difficult to widely implement and
> easily distribute high-quality audio codecs across the entire Internet
> community, the working group prefers unencumbered technologies in a way
> that is consistent with BCP 78 and BCP 79.  In particular, the working
> group shall heed the preference stated in BCP 79: "In general, IETF
> working groups prefer technologies with no known IPR claims or, for
> technologies with claims against them, an offer of royalty-free
> licensing."  Although this preference cannot guarantee that the working
> group will produce an unencumbered codec, the working group shall
> attempt to adhere to the spirit of BCP 79.  This preference does not
> explicitly rule out the possibility of adapting encumbered technologies;
> such decisions will be made in accordance with the rough consensus of
> the working group.
> 
> Deliverables
> 
> 1. A set of Codec Standardization Guidelines that define the work
> processes of the working group. This document shall be Informational.
> 
> 2. A set of technical Requirements. This document shall be
> Informational.
> 
> 3. Specification of a codec that meets the agreed-upon requirements, in
> the form of an Internet-Draft that defines the codec algorithm along
> with source code for a reference implementation.  The text description
> of the codec shall indicate which components of the encoder and decoder
> are mandatory, recommended, and optional.  It is envisioned that this
> document shall be a Proposed Standard document.
> 
> Milestones
> 
> Mar-2010: WGLC on Codec Standardization Guidelines
> May-2010: Codec Standardization Guidelines to IESG (Informational)
> May-2010: WGLC on Requirements
> Jul-2010: Requirements to IESG (Informational)
> Dec-2010: Freeze codec structure
> Jun-2011: Finalize codec parameters
> Jul-2011: WGLC on codec specification
> Oct-2011: Submit codec specification to IESG (Standards Track)
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