Subject: [rtcweb] Spencer Dawkins' Yes on draft-ietf-rtcweb-video-05: (with COMMENT)

From: "Spencer Dawkins" <[email-masked]>
Date: Tue, 09 Jun 2015 10:54:21 -0700

Spencer Dawkins has entered the following ballot position for
draft-ietf-rtcweb-video-05: Yes

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COMMENT:
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Thank you for producing this document. I'm only mildly familiar with this
level of detail, and the document was clear, with pointers when I needed
them. I'm honored to ballot Yes.

I did have one question. In this text:

   Implementations MAY send and act upon "User data registered by Rec.
   ITU-T T.35" and "User data unregistered" messages.  Even if they do
   not act on them, implementations MUST be prepared to receive such
   messages without any ill effects.

Is that a usual thing to say? Perhaps it is, but I thought that might be
understood.

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From: Adam Roach <[email-masked]>
Date: Tue, 09 Jun 2015 15:21:52 -0500

> Is that a usual thing to say? Perhaps it is, but I thought that might be

This text is the result of a specific recommendation from Stefan Wenger, 
who has far more familiarity with what H.264 implementors are likely to 
get wrong than I do. His suggestion (to the RTCWEB mailing list, 
November 24, 2014) was:

> MAY:
> User data T.35 registered, and user data unregistered
> Especially the latter you see occasionally for proprietary extensions.
> It's a good idea to advise implementers that a bitstream may contain that
> kind of stuff, even if they don't act on it. 

Given Stefan's specific mention of this as a potential issue, I'm 
inclined to leave it in unless someone can provide a reasonable argument 
that it causes harm.

/a