[video-codec] Roman Danyliw's Discuss on draft-ietf-netvc-requirements-09: (with DISCUSS and COMMENT)

Roman Danyliw via Datatracker <noreply@ietf.org> Wed, 12 June 2019 01:24 UTC

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Subject: [video-codec] Roman Danyliw's Discuss on draft-ietf-netvc-requirements-09: (with DISCUSS and COMMENT)
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Roman Danyliw has entered the following ballot position for
draft-ietf-netvc-requirements-09: Discuss

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DISCUSS:
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(1) I worry that the level of detail in the in the Compression Performance
Evaluation (Section 4.1) is insufficient for implementation.  Specifically:

(a) Per “Initially, for the codec selected as a reference one (e.g., HEVC or
VP9), a set of 10 QP quantization parameter) values should be specified (in a
separate document on Internet video codec testing) and corresponding quality
values should be calculated.”

-- How should a set of QPs be specified?

--How should the quality values be calculated?

-- What does the text “(in a separate document on Internet video codec
testing)” mean?

(b) Per “A list of video sequences that should be used for testing as well as
the 10 QP values for the reference codec are defined in a separate document ",
what document is that?  Is it draft-ietf-netvc-testing?

(2) Per the Security Considerations Section (Section 5)

-- What does “codec implementation (for both an encoder and a decoder) should
cover the worst case of computational complexity, memory bandwidth, and
physical memory size” mean?

-- Please add additional language that codec should be written in a defensive
style as they will be processing untrusted input.


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COMMENT:
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(1) There is something odd about the document formatting – the title and the
first author last name in the footer is wrapped in “< … >”

(2) It would be helpful to forward reference that acronyms are explained in
Appendix A.

(3) This draft uses the words should and must to prescribe action.  Why wasn’t
RFC2119 cited to explain these words?

(4) Section 2.0.  A reference to explain “YCbCr 4:2:0” would be helpful

(5) Section 2.1. Per “high encoder complexity” and “decoding complexity”, I
initiate read that as a qualitative measure.  However, the text says “up to 10x
and more” so that implies some quantitative measure.  What is that?

(6) Section 2.1.  Expand QP values on first use

(7) Section 2.x.  The language around content doesn’t appear to be consist. 
For example:

-- Section 2.1, Internet Video Streaming says “movies, TV-series and shows, and
animation.”

-- Section 2.2, IPTV says “television content”

-- Section 2.5, Screen casting says “business presentations …, animation
(cartoons), gaming content, data visualization, …, virtual desktop
infrastructure (VDI), screen/desktop sharing and collaboration, supervisory
control and data acquisition (SCADA) display, automotive/navigation display,
cloud gaming, factory automation display, wireless display, display wall,
digital operating room (DiOR), etc.

What the difference between Section 2.1’s animation and Section 2.5’s cartoons?

What’s the different between Section 2.1’s “movies, TV series …” and Section
2.2’s “television content”?

(8) Section 2.5.  The sentence “Currently, …” is very challenging to parse as
it includes inline “i.e.,” and “etc”.

(9) Section 2.5.  Per “powerpoint, word documents”, these are specific
Microsoft products.  I recommend using more generic names.

(10) Section 4.  I found it confusing that an evaluation methodology was in a
requirements document.  I would have expected it in the draft-ietf-netvc-testing

(11) Section 4.1.  VP9 needs a reference.

(12) Section 6.  I don’t think this entire section is necessary.

(13) Editorial Nits:
-- Section 3.  Style nit.  s/chapter/section/

-- Section 4.1. Typo.  s/computged/computed