Minutes IETF102: netvc
minutes-102-netvc-01

NETVC Workgroup Meeting Minutes
IETF 102 - Montreal, CA
2018-Jul-19 15:50-17:50 EDT/UTC-4
https://datatracker.ietf.org/doc/minutes-102-netvc

Chairs: Mo Zanaty, Matthew Miller
Area Director: Adam Roach

Agenda:
Administrivia and Requirements (draft-ietf-netvc-requirements) - chairs
Testing and Evaluation Criteria (draft-ietf-netvc-testing) - Thomas Daede
xvc Video Codec Update (draft-samuelsson-netvc-xvc) - Jonatan Samuelsson
Thor/AV1 Update/Comparisons (draft-fuldseth-netvc-thor) - Steinar Midtskogen
Future Work/Direction Discussion - chairs

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Administrivia and Requirements
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Drafts: https://tools.ietf.org/html/draft-ietf-netvc-requirements
Slides: https://datatracker.ietf.org/doc/slides-102-netvc-chair-slides

Milestones for requirements and testing drafts are a little bit late but still
doable.

First two can be hit with slight adjustments:

April 2018 - Requirements
July 2018 - Testing

But the big problem is the last three milestones which are lacking a single
merged codec candidate and reference codebase.

July 2018 - Codec Specification
July 2018 - Single Reference implementation
Dec 2018 - Storage Format

Will discuss further at the end of the session.

Requirements draft had minor changes to profiles. No further changes expected.
Chairs will issue a last call for comments on the list.

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Test and Evaluation Criteria
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Drafts: https://tools.ietf.org/html/draft-ietf-netvc-testing
Slides:
https://datatracker.ietf.org/doc/slides-102-netvc-draft-ietf-netvc-testing

Adam Roach (as AD): Next step is writing up and asking for publication?

Thomas Daede: Yes

Matt Miller (as chair): Chairs were planning on asking for last call either
this week or right after this week.

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xvc Video Codec Update
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Drafts: https://tools.ietf.org/html/draft-samuelsson-netvc-xvc
Slides: https://datatracker.ietf.org/doc/slides-102-netvc-xvc-video-codec-update

Slide 5:

Mo Zanaty: The RF baseline profile was an interesting development.  That seems
to make this much closer to the charter, my major question is how did you
arrive at the subset of tools to define the RF baseline.  And what, if any, IPR
vetting was done to have confidence in that list.

Jonatan Samuelsson: We have done a limited analysis of the IPR situation.  We
are focused more on finding the toolset that gives good performance and seem to
be generally well known from a certain time back.  We have not done a thorough
IPR analysis. It is more relying on our process for dealing with licensing
issues when they arrive.  If we were to discover that actually there was
someone who had a patent on a tool which we would not be able to provide under
RF terms, then instead of using 25 tools, we would only use 24 after removing
or disabling the patent-encumbered tool.

Mo Zanaty: So the tools you have enabled is a rough stab at a set of tools that
will perform good enough, and that you think will not have any issues.

Jonatan Samuelsson: Yes.  We were trying to find a good balance between the
risk and performance, that is a good question.

Slide 7:

Jonathan Lennox: Can the royalty-free baseline be directly compared to other
codecs?  The draft only includes a comparison with full xvc?

Jonatan Samuelsson: I didn't include it in the slides, or have the results. 
But we do have the runs on our AWCY instance [they don't need to do any new
runs, it's just a matter of picking which pairs you compare].

Slide 9:

Thomas Daede: I was looking at the codebase and couldn't find the baseline
profile.  Is that included in the reference encoder?

Jonatan Samuelsson: Yes, you should be able to run with -profile and set it to
1 instead of 0.

Thomas Daede: Okay that is probably why I didn't see it, thanks.

Mo Zanaty: The JS version of the decoder that you have on the demo page.  Can
you give more detail on how that was developed?  Was it using WASM or
Emscripten?  Is it based on the reference code or something else?

Jonatan Samuelsson: It is based on the reference code.  It is using Emscripten.

Mo Zanaty: You are not using ASM.js or WebAssembly?

Jonatan Samuelsson: Yes ASM.js

Mo Zanaty: So you are using the old version.  I am asking because there are
some results in Steinar's presentation and there is a question of is it good
enough to use. Can you decode high resolution, like 1080p?

Jonatan Samuelsson: What we have is 360p because we think that is what is safe
for all players.  We are single threaded and you might want to run
multi-threaded if you do 1080p.

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Thor/AV1 Update and Comparisons
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Drafts: https://tools.ietf.org/html/draft-fuldseth-netvc-thor
Slides:
https://datatracker.ietf.org/doc/slides-102-netvc-thorav1-updatecomparisons

Slide 4:

Jonathan Lennox: The one thing I'd say is it is probably worth sending the list
of SIMD instructions you want to the people doing the SIMD project so they know
what people will actually use if they defined it.

Steinar Midtskogen: Actually the SIMD library in Thor is using that.

Jonathan Lennox: I would actually suggest asking the guy behind me (Tim
Terriberry) who works for a browser company.

Tim Terriberry: Yes, there are people working on the SIMD for WebAssembly.

Steinar Midtskogen: Do you know if that is floats or integers?

Tim Terriberry: Yes, it will support both but just 32-bit integers which I
suspect is not what you want.

Steinar Midtskogen: Yes.

Tim Terriberry: The question I have is. If you are going to make a codec that
you change on the fly as you see fit, what is the point of standardizing it in
a working group like this?

Steinar Midtskogen: You would standardize how you do it by sending that byte
code.

Mo Zanaty: The chairs have had some discussion on this point, esp. with the AD.
 The majority of that work would not be done here.  It would be shard across a
bunch of groups in ECMA, W3C, IETF, etc.  You may need some umbrella effort to
integrate the work.  You may need IETF work to bind the codec to IETF standards
like RTP, RTCWEB, etc.  What NETVC could do is very vague.

Tim Terriberry: I think that not just me, but a lot of other people would like
to see something less vague, and what you would actually need is a different
charter.

Mo Zanaty: Yes, it definitely is not in charter.

Slide 7:

Mo Zanaty: Jonatan, I suspect the numbers you were presenting were with the
maximum compression.

Jonatan Samuelsson: Yes we were using the highest compression.

Slide 9:

Jonatan Samuelsson: Just for clarification, when you compare xvc and thor, was
that with the RF?

Steinar Midtskogen: Yes, that was with the 51 tools disabled as specified in
the draft, no other changes.

Jonatan Samuelsson: One comment on the SIMD, there is a little bit of SIMD in
xvc as well, when it comes to interpolation filtering for example. [slide
showed now SIMD in xvc]

Mo Zanaty: The core take away is that at the last meeting we asked the xvc
proponents to come up with a RF baseline, and we asked them what the relative
performance to Thor would be, because the Thor team thought they were taking RF
into account and not as an after thought. It seems like the xvc and Thor people
are in agreement on what the performance would be for a RF code base. 
Steinar's testing seems to agree.

Mo Zanaty: The net of it is that the technical requirements are being met.  The
other half of this is what are the IPR concerns with this baseline.  I want to
get a sense of the room as to what the IPR landscape looks like and if others
are comfortable with this approach.

Tim Terriberry: I thank you guys for taking the effort to create the RF
baseline.  I think the level of analysis that has been done has not changed
since the last time.  There are a lot of details here and the details matter. 
As Mo knows from the Thor work it is very difficult to have a degree of
confidence that something really is RF.

Adam Roach (as individual): I share Tim's concerns.

Mo Zanaty (as individual): I think I also share the same concerns.  Speaking
for the work that was done on the Thor team, not the majority but a large chunk
of the effort was getting the IPR story right.  IF we had spent that time on
technical progress instead, we probably would have gotten a better codec out. I
have some concerns about short-circuiting the IPR analysis and doing it in only
a few weeks time.  I don't have a good comfort feeling about publishing a
standard and having people implement that.

Tim Terriberry: I just want to add that, to give some people an idea of what we
are talking about, just on the Mozilla side, the amount of time we spent on the
IPR review for AV1 was on the order of man years.  That doesn't speak for the
other alliance members.  This really does take a lot of effort to get right.

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Future Work/Direction Discussion
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Mo Zanaty (as chair): I think Jonatan has done a good job answering the
questions we had back in March.  He has done a good job coming up with a
technical proposal.  The real concerns are about the IPR story.

We started off this workgroup with two candidates, Thor and Daala.  Both of
those teams have stopped active development on those, there has been a little
bit of work on Thor as Steinar summarized, but has stopped because both of
those teams started working on AV1.

The idea was that AV1 might be published here, but that will be done in a
separate forum.

So while both of those teams are working in this other forum, there will be no
more work done here.  That really leaves just xvc, and the IPR story here does
not have enough confidence to move forward.  I have only heard 3 opinions but
all 3 had low confidence about moving forward.

So that leaves us with a dilemma here, we really don't have any good candidates
to move forward.

We are considering to pause the WG to see what happens with the industry and
other standards bodies like MPEG, but don't anticipate doing something unless
things change.

Adam Roach (as individual): You are speaking about the technical ability to
come up with a standard to publish.  Given that AV1 will be in the market soon,
there is a question of "if this is good or bad".  I would say it is a net
positive that AV1 is out there.  I am sad that the work was not done in an open
standards body, but I am happy that it got done.  Even if we could publish a
codec here, it wouldn't be a good thing.

Mo Zanaty: Adam's comment is that it wouldn't be a good idea to fragment the
market with multiple RF codecs.

Stephen Botzko: I would agree with that.

Tim Terriberry: Pretty much +1.

Mo Zanaty (as chair): Does anyone feel we should be progressing a candidate
while AV1 is in the market?  I am surprised Jonatan is not saying yes.

Jonatan Samuelsson: We are happy to continue pursing xvc, but we want to work
with others.  If there is no interest, we don't want to pursue it.

Adam Roach (speaking as an individual):  I am really pleased to see the
progress in getting this to work in JavaScript, but I don't think this is the
place to progress.  If you need something, work with the W3C to have those ABIs
defined.  There is probably additional work to do around sending JS defined
codecs.  Knobs in WebRTC to get this to work in browsers if you want real-time,
or the audio and video graphics frameworks we have.  So there would be a lot of
work to do there, but most of it is not IETF work.

Jonatan Samuelsson: Okay yes.

Matt Miller (as chair): So what happens now is that we would issue last calls
for the requirements and testing drafts.  And send those to the IESG.  But
after that we would pause for 6 months to see what happens.  No more physical
meetings.

Jonathan Lennox: 6 months is not a unit number of IETF meetings.

Matt Miller (as chair): Lets call it two meeting cycles.

Mo Zanaty (as chair): We would not meet in November and probably not March.  We
may meet in July if needed.  What we are looking for is clarity around AV1 or
MPEG efforts to see if there is a need.

Matt Miller: We are adjourned.

Mo Zanaty: See you in 6 months or never.