Re: [rtcweb] Input to Video Codec Selection

Gaelle Martin-Cocher <> Fri, 01 March 2013 22:22 UTC

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From: Gaelle Martin-Cocher <>
To: Magnus Westerlund <>
Thread-Topic: [rtcweb] Input to Video Codec Selection
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Date: Fri, 01 Mar 2013 22:21:42 +0000
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Subject: Re: [rtcweb] Input to Video Codec Selection
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Dear All,

Further to Magnus email, while I assume there might not be "something new" to learn at the meeting, I believe the below requested clarifications on existing information would be useful.  Implementers should clearly know which license they can pick or get when it comes to VP8 and by which groups.  I believe answers in advance of the meeting would help the discussion at the meeting.

Questions 1 & 2:
It is assumed that in  the case of choosing VP8, RTCWeb would reference  the informational RFC 6386.
Q1: Is there an intent to move that RFC to the standard track at a point in time?
Q2: Would that change the rule of "who" is obliged to make an IPR declaration?

Question 3:
The IPR disclosure was made on the draft 2 of draft-bankoski-vp8-bitstream-02" as per
Draft 3 and onward contains the copyright license and the additional IP rights grant. 
Q3: Is the initial IPR disclosure still valid? 

Question 4:
The informational RFC 6386 contains the decoder code and some piece of encoder code.
Though the IP rights grant mentioned in the RFC is offered against:

   "This implementation" means the copyrightable works distributed by
   Google as part of the WebM Project."

Q4: As such the  IP rights grant does not seem to apply to the RFC itself or to an implementation of the code contained in the RFC.  Should that be corrected or is that the intent?

Question 5:
The additional IP grant is applied to a particular implementation (namely the WebM VP8 code) without modifications. 
Any derivative work either:
- produced from the reference code in WebM (that is a possible optimized version of it); or
- produced from the RFC text or the code provided within the RFC (while not using the WebM code)
does not have the benefit of the additional IP grant. 
In other words a conformant implementation does not necessarily have the benefit of the additional IP grant.
I am not confident that the VP8 code can be used "as is" for certain platforms. I would think that the code might need some modification to provide the desired performance. In other words, it should be clear that those implementers would not necessarily receive the benefit of that grant.
If the answer to Q3 is negative, then there is no IP license statement at all that applies to a "conformant implementation of the RFC" (aka a derivative work).
If the answer to Q3 is positive, it is not clear  how to reconcile the declaration inside the RFC and the declaration that is attached to the the RFC draft for implementers that would not modify the code.
Q5: Can this be clarified or confirmed?

Question 6:
The IPR disclosure in IETF is different than the IPR statement made in MPEG (see document sent by Harald earlier). 
Q6: the differences in license statement and IP grant referring to WebM code are rather confusing. Can it be clarified which license, copyright, grant are provided for RFC 6386?

In conclusion, before advancing this draft, or considering it as a candidate for RTCWeb,  consistency and clarity should be ensured between the IPR grant associated with the IETF draft, the IPR grants within the IETF draft document itself, the IPR grant given for MPEG, and any IPR grant given in connection with the WEBM project for this same work.  Otherwise, the IPR status of the work that is undertaken is indeterminate, and likely will not produce a result that will be useful.  

Thank you!


-----Original Message-----
From: [] On Behalf Of Magnus Westerlund
Sent: Friday, March 01, 2013 9:23 AM
Subject: [rtcweb] Input to Video Codec Selection


I hope everyone, especially Google, now have provided whatever input they have into the Video Codec discussion and selection. It is important that everyone has the possibility to evaluate the input in good time prior to the meeting. It is especially important if one might require legal or other support when evaluating the proposals or additional information, which might apply for IPR, as an example.

To be extremely blunt, we don't want anyone revealing new input material during the presentations in Orlando. These presentations is only intended to provide a summary of the most important aspects from the proponents side.

The RTCWEB WG chairs

Magnus Westerlund
Ted Hardie
Cullen Jennings

rtcweb mailing list

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