Re: [rmcat] Roman Danyliw's Discuss on draft-ietf-rmcat-eval-criteria-12: (with DISCUSS and COMMENT)

Roman Danyliw <> Wed, 18 March 2020 23:18 UTC

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From: Roman Danyliw <>
To: Joerg Ott <>, The IESG <>
CC: "" <>, "" <>, "" <>, Martin Stiemerling <>, "" <>, Colin Perkins <>
Thread-Topic: Roman Danyliw's Discuss on draft-ietf-rmcat-eval-criteria-12: (with DISCUSS and COMMENT)
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Date: Wed, 18 Mar 2020 23:18:39 +0000
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Subject: Re: [rmcat] Roman Danyliw's Discuss on draft-ietf-rmcat-eval-criteria-12: (with DISCUSS and COMMENT)
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Hi Joerg!

Thanks for the update.  -13 addresses my DISCUSS points.  One non-blocking comment on a COMMENT inline ...


-----Original Message-----
From: iesg <> On Behalf Of Joerg Ott
Sent: Monday, March 9, 2020 3:56 PM
To: Roman Danyliw <>rg>; The IESG <>
Cc:;;; Martin Stiemerling <>om>;; Colin Perkins <>
Subject: Re: Roman Danyliw's Discuss on draft-ietf-rmcat-eval-criteria-12: (with DISCUSS and COMMENT)

Dear Roman,

thanks much for your comments.  I just posted an updated draft (-13) to address those.  See below.

> ----------------------------------------------------------------------
> ----------------------------------------------------------------------
> Section 5.2.  Per “Sample video test sequences are available at: 
> [xiph-seq] and [HEVC-seq].  The following two video streams are the 
> recommended minimum for
> testing: Foreman and FourPeople.”, these test sequences seems underspecified.
> ** Is the “recommended” here intended to be normative?  There is no 
> RFC2119 boiler plate in this document to guide the parsing of the text.

Recommended is recommended as per English language and it not used as a verb but as an adjective, indicating a suggestion.

> ** From the text, there wasn’t much precision in where to find these 
> recommended videos (Foreman and FourPeople).  At the url pointed to by 
> [HEVC-seq], I found the filenames “FourPeople_1280x720_60.yuv” and 
> “foreman15_4000.yuv”, is that them?

This is fixed in the rev now, also the link that disappeared is removed.

> ** Is it expected for
> to 
> be 0 bytes?  I tried on 03/03/2020 at ~0950 EST

The broken link is gone now.  Both videos can be found in a single place now.  It is clearer specified where to find them.

> ** Give that that one of the recommended urls doesn’t work even before 
> this draft is published, I have great reservation with keeping a 
> normative “recommended” to such external repositories.  However, 
> providing pointers to repositories of “sample video test sequences” makes sense to me and is helpful.

Should be addressed by now.

> ----------------------------------------------------------------------
> ----------------------------------------------------------------------
> ** Section 3.1.  The purpose of this log isn’t clear.  What is the 
> relationship of it to the metrics described in the previous section?  
> Where does it fit into the measurement workflow?  Is this constructed 
> on a per packet capture file basis?

Added a clarifying sentence:

These data should suffice to compute the media-encoding independent metrics described above.  Use of a common log will allow simplified post-processing and analysis across different implementations.

> ** References:
> -- Section 3.  Consider adding a citation for tcpdump and wireshark


> -- Section 4.4.  Consider adding a citation for the “Bilbert-Elliot” 
> model

We got this comment also from Mirja, to which I replied:

I could include a reference here for Gilbert-Elliot such as:

[Roman]  Since it would be informative, I don't think it would hurt to add this citation.

However, this not mandatory text and the second part of the sentence is even less specific and does (deliberately) not give a specific example.  We don't want to create any prejudice here beyond random losses.  The Internet changes, after all.

In order to avoid this being a showstopper here (we don't have enough hour tonight for another rev round, I am adding this in now.  Please provide feedback if this is really needed.  I could still remove it in two weeks when I-D submission reopens.

> ** Editorial:
> -- Section 3.  Recommend explicitly spelling out PCAP as packet capture.

This is spelled out in brackets; since this also refers to a commonly used file format, I would keep it as is.

> -- Section 4.5. s/is is/is/


Thanks much,