Subject: [codec] Updated Guidelines Draft

From: Jean-Marc Valin <[email-masked]>
Date: Thu, 04 Mar 2010 22:13:41 -0500

Hi everyone,

I've just submitted an updated version of the guidelines draft: 
http://tools.ietf.org/html/draft-valin-codec-guidelines-03
I've done my best to address the comments that were made about -02, 
realigning the draft with the approved WG charter and reflecting the 
fact that the WG has now been created. I hope this addresses at least 
some of the concerns about the previous version.

Cheers,

	Jean-Marc

---

From: yusuke hiwasaki <[email-masked]>
Date: Mon, 08 Mar 2010 19:15:08 +0900

Hi,

We have observed the creation of new codec group in IETF and in
particular the discussions on the WG guidelines document, which was
just updated. We would like to offer some comments on it, based on our
experience in ITU-T SG16/WP3 audio standardization work.

1) Comment about IETF perception on other SDOs works (section 6.
  "Relationship with Other SDOs and section 1. Introduction"):

   Many organizations have addressed application of codecs over IP and
   the Internet, so we realize the following statement, although
   trying to be balanced, is tricky: "To the extent that codec work at
   the IETF differs from work at other SDOs, it will focus on issues
   that are specific to the Internet, including robustness to packet
   loss and other aspects of packet transmission over the
   Internet. etc..." We would suggest to simply state what the Codec
   WG will do, thus simplifying the language as follows: "The IETF
   Codec WG will focus on issues that are specific to the Internet,
   including robustness to packet loss and other aspects of packet
   transmission over the Internet. etc..." There has been long since
   other SDOs, including ITU-T, that also take into account aspects of
   packet transmission over the Internet, including robustness to
   packet losses.

2) Comments on the Introduction:

   Operators and vendors who participate to ITU-T meetings have
   successfully deployed VoIP services making use of some of ITU-T
   standardized codec (e.g. G.729, G.711, G.722, ...). We believe the
   Introduction would be more informative if reformulated, as there
   are well-known counter examples of codecs not being IPR
   "unencumbered" while being widely deployed and easily distributed
   (e.g. ITU-T G.729, 3GPP EFR).

3) Comment about PLC specification (section 4. "Requirements
   Conformance"):

   The current texts reads: "The packet loss concealment (PLC)
   algorithm needs not be normative." As Internet communications are
   prone to packet losses, the PLC algorithm is of crucial importance
   for the quality. For this reason, ITU-T has standardized the PLC
   algorithms to ensure consistent quality for all users in adverse
   conditions (see for example ITU-T G.718 and ITU-T G.729.1). We
   think it is needed to have at least a PLC algorithm example
   solution (most preferably in fixed point) specified as part of the
   solution (under the same IPR regime),with test vectors and its
   performance must be well characterized, especially if this is
   considered as a main feature of this Internet codec.

4) Comment and suggestion about the usage of objective/subjective
   measurements (section 3 "Evaluation, Testing, and
   Characterization"):

   In ITU-T WP3/16 audio coding standardisation work, prior to using
   any kind of subjective/objective measurements (e.g. P.800, BS.1116,
   BS.1285, PESQ and PEAQ), we liaise with ITU-T SG12 and/or ITU-R
   WP6C to validate whether the usage of such methodologies and test
   plan design are appropriate, because it is important that those
   evaluations are scruitinized by a third party. SG12 is the experts
   group that specialize in quality assessment methodologies and test
   plans, both subjective and objective, We STRONGLY recommend IETF to
   liaise with ITU-T SG12 on appropriate testing methodologies and
   test plans for conversational codecs.

Just before closing, a comment that applies to the Requirements
document. Maybe it could be also noted that, at the expected time of
completion of the IETF Codec WG work, intellectual property rights of
various codecs defined by a number of SDOs (and that are already
widely deployed) will have expired or would soon after. This could be
mentioned in section 5 of the guidelines and such codecs (e.g. ITU-T
G.729, ITU-T G.728) could be also added as reference codecs in the
section 4 of the requirements document.

Cheers,

yusuke on behalf of Herve, Jon, Paul and Claude
--
============
Yusuke Hiwasaki, NTT Cyber Space Labs.
[email-masked]
Tel: +81-422-59-4815 (Fax: +81-422-60-7811)

At Thu, 04 Mar 2010 22:13:41 -0500,
Jean-Marc Valin wrote:
> _______________________________________________
> codec mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/codec

---

From: Jean-Marc Valin <[email-masked]>
Date: Mon, 08 Mar 2010 15:56:19 -0500

Hi Yusuke,

Thanks a lot for taking the time to go through the drafts. I just submitted
a revised guidelines draft (-04) to address the comments you sent. More below:

>    packet transmission over the Internet, including robustness to

I used the text you suggested.

>    (e.g. ITU-T G.729, 3GPP EFR).

That text was actually removed from the previous version (03) since other
people felt it just wasn't needed at all anymore.

>    considered as a main feature of this Internet codec.

I've tried to make it clearer what is meant here, though I think there's
probably more editing to do on that topic. The idea is for the reference
implementation to provide the best PLC algorithm we have at the time the
codec is specified. At the same time, I think we want to allow implementers
to further improve the quality of the PLC later on while still being
compliant with the specification. That's what I meant by "need not be
normative". Again, I think the revised text is a bit clearer, but it still
needs improvement.

>    test plans for conversational codecs.

A recommendation to liaise with SG12 was added to the evaluation section.

> section 4 of the requirements document.

I think it's a good idea to have a look into the technology used in these
older codecs to see what bits parts of them can be reused safely. That's
probably a good topic for our IPR advisor.

Thanks again,

	Jean-Marc

---

From: Koen Vos <[email-masked]>
Date: Mon, 08 Mar 2010 15:46:00 -0800

We've updated the SILK draft:
http://www.ietf.org/id/draft-vos-silk-01.txt

It now includes an appendix with the complete SILK fixed-point source  
code. Some more work to be done on the codec description.

We're working hard to make the source code available at  
https://developer.skype.com/silk/ in a more convenient format.

Also, we will also soon provide details about Skype's patent licensing terms.

Thanks,
Koen, Karsten, Soren

---

From: Jean-Marc Valin <[email-masked]>
Date: Mon, 08 Mar 2010 19:05:16 -0500

Hi guys,

This is great news! Thanks for all the effort you're putting into this. 
I'm going to try this new codec in the next few minutes...

Cheers,

	Jean-Marc

---

From: "Julian Spittka" <[email-masked]>
Date: Fri, 12 Mar 2010 17:22:06 -0800

SILK source code in a more convenient format is now available on
https://developer.skype.com/silk/.

The package also includes documentation and test vectors/tools.

Julian.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Koen Vos
Sent: Monday, March 08, 2010 3:46 PM
To: [email-masked]
Subject: [codec] new SILK draft

Also, we will also soon provide details about Skype's patent licensing
terms.

Thanks,
Koen, Karsten, Soren

---

From: Jean-Marc Valin <[email-masked]>
Date: Fri, 12 Mar 2010 21:13:46 -0500

> https://developer.skype.com/silk/.

Thanks, that'll be useful.

 > The package also includes documentation and test vectors/tools.

You mean you didn't want to include test vectors in the I-D? :-)

Cheers,

	Jean-Marc

---

From: "Christian Hoene" <[email-masked]>
Date: Thu, 18 Mar 2010 09:30:02 +0100

Hi,
		
attached some of my scanned comments about the latest draft. Sorry, I am too lazy to transfer them to ASCII...
In addition, I have the following comments:
- I am not sure whether future tense shall be used in the document. 
- Also, I like to repeat my comments made in the mail http://www.ietf.org/mail-archive/web/codec/current/msg01145.html
because, currently, the relationships with other SDOs and IETF WGs is somewhat scattered throughout the document. A little bit more
structure would be clearly helpful.
- Stephan: Do you think it makes sense to annotate the source code or the algorithmic description with reference to (old)
publications? This would make it easier to search for parts that might be covered by IPRs.
- Question to the Chairs regarding Working procedures: Is it possible to open add to the Trac/Wiki Webpage SVN support for all
having a password? Technically, it should be straight forward...

Having comments this document, I suggest to accept the document as working group item.

With best regards,

 Christian

---------------------------------------------------------------
Dr.-Ing. Christian Hoene
Interactive Communication Systems (ICS), University of Tübingen 
Sand 13, 72076 Tübingen, Germany, Phone +49 7071 2970532 
http://www.net.uni-tuebingen.de/

>From: [email-masked] [mailto:[email-masked]] On Behalf Of Jean-Marc Valin
>Sent: Monday, March 08, 2010 9:56 PM
>To: yusuke hiwasaki
>Cc: Paul Coverdale; [email-masked]; Jean-Marc Valin
>Subject: Re: [codec] Updated Guidelines Draft
>
>Hi Yusuke,
>