Re: [Gen-art] Genart telechat review of draft-ietf-payload-rtp-ttml-03

James Sandford <> Tue, 15 October 2019 10:17 UTC

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From: James Sandford <>
To: Russ Housley <>, "" <>
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Thread-Topic: Genart telechat review of draft-ietf-payload-rtp-ttml-03
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Date: Tue, 15 Oct 2019 10:17:07 +0000
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Subject: Re: [Gen-art] Genart telechat review of draft-ietf-payload-rtp-ttml-03
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Thank you for the further feedback. 

In an earlier draft we had the second paragraph of section 7.1 elsewhere in the document. I believe it was in section which discusses, amongst other things, how the TTML document timing relates to the RTP timestamps. We concluded that the document was easier to understand when all of the information related to clock rate was in the one section. If this goes against convention, I'm happy to move the second paragraph to another part of the document. But from the position of making the document easy to understand, leaving the information in one place might be best.

With regards to <CODE BEGINS> <CODE ENDS>, I understand that these are defined in the TLP for the purpose of identifying Code Components that aren't already one of the types listed in the accompanying Code Components document and that the Code Components document includes XML. I also see in this thread that the CODE BEGINS notation is seen as optional . I would prefer to not use the CODE BEGINS notation as, at a glance, it looks quite similar to XML itself and may be confusing. Furthermore, the understanding of the meaning of the CODE BEGINS notation requires the reader to read the TLP which already clearly specifies that XML is considered a Code Component. I believe that, in this case, CODE BEGINS is redundant and would make the document more confusing rather than less. 


James Sandford
R&D Project Engineer

BBC Research and Development
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From: Russ Housley via Datatracker []
Sent: 11 October 2019 18:40
Subject: Genart telechat review of draft-ietf-payload-rtp-ttml-03

Reviewer: Russ Housley
Review result: Ready with Nits

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

For more information, please see the FAQ at

Document: draft-ietf-payload-rtp-ttml-03
Reviewer: Russ Housley
Review Date: 2019-10-11
IETF LC End Date: 2019-10-10
IESG Telechat date: 2019-10-17

Thank you for addressing my comments on the previous version of this

Summary: Ready with Nits

Major Concerns:


Minor Concerns:



My guess is that the second paragraph in Section 7.1 uses "should"
because it is asking implementors to think about these things when
selecting a clock rate.  I expected this section to be talking about
the payload format parameters, not implementation considerations.  I
am not sure, but this paragraph might be more impactful elsewhere.

In section and, should the blocks of XML be
enclosed between '<CODE BEGINS>' and '<CODE ENDS>' lines to make it
very clear that the Simplified BSD License applies here?