See also: IRC log
<scribe> scribe: nigel
group: agenda looks fine
Nigel: Attendance is low today but we'll use the time to make what progress we can
Nigel: Looking at #6 https://github.com/w3c/adpt/pull/6
... Editorial fixes. Closes #4. Also makes any fragment ids
valid.
... First to note is that Cyril raised the issue but hasn't
managed to review the pull request yet.
... In the diff there are some changed dispositions - this is
because I based the branch for this on the branch for
pull
... request #9 so the disposition changes are included in
those.
Matt: This looks fine to me. [approves pull request]
Nigel: Thank you!
...
... The next one is pull request 7, Issue 0005 restructure #7
https://github.com/w3c/adpt/pull/7
Matt: Got that. Yes, this is a
bigger change.
... This is a reordering of the sections rather than the
content?
Nigel: Yes, mainly.
Matt: What was the driver for this change?
Nigel: This was the feedback that
we generated from the previous meeting where we tried to think
about the best
... structure for the document especially for people coming to
it for the first time.
Matt: I remember
... You've added a real world example?
Nigel: The new appendix D is
renamed, the other examples were in other appendices, but I
moved them into the Introduction.
... Section 2.1
... The diff has done something strange to the formatting of
the example includes, the preview does a better job.
Matt: Yes, that makes sense
Nigel: One of the goals we had was to move the more important stuff higher up the document.
Matt: That makes sense.
Nigel: One effect is to move the requirements to the appendix
Matt: This makes sense to me -
I'm impressive we've kept it this small a document!
... [approves]
Nigel: Thank you!
...
... Next is Permit only media timebase #9 https://github.com/w3c/adpt/pull/9
Matt: I said in the issue this
fundamentally makes sense.
... It potentially makes it more of a distribution format than
an archive format.
... Implementers may have a strong view.
Nigel: I was hoping to elicit that view!
Matt: My gut feeling, and talking
with other broadcasters about, say, EBU-TT Part 2 as a way into
EBU-TT, is that
... the ability to support the backwards compatibility remains
very strong. Anything that forces a move away from that
... purity of form may present implementation challenges in the
future.
Nigel: I think I understand.
Matt: If we try to chase
something technically pure here then real world implementers
may have problems if they
... cannot access the out of band data to recalculate any
offsets.
... They may try to introduce their own fields or data to
handle that within the file which may have unintended
... consequences or proliferation in varied practices.
Nigel: That's true.
Matt: If this is used for the
share of data, and everything we have built so far is built on
SMPTE timecode, I don't think
... we ever put any content in before the start of media. In
all practical purposes it doesn't make a difference but it
does
... require knowledge or an assumption about the start of media
and how it relates.
... I don't know what role this group has in proffering
suggestions for good practice operationally.
... We could give guidance about how to deal with this
challenge, and if we don't then people might be creative
... and could come up with different solutions.
Nigel: That's true. I think this
group is perfectly placed to provide informative guidance of
that sort.
... The other observation I would make is that we can start
small and if there's a need to introduce SMPTE later we
... can do that. It's easier than to remove unneeded
features.
Matt: We just need to be sensitive to the trigger for that process.
Nigel: Yes
Matt: We would need to stay on top of when that may need to be revisited, rather than people coming up with creative workarounds.
Nigel: Agreed.
... Given I've talked to 4 members so far who have been able to
live without SMPTE, and nobody has objected, I feel
... we have enough consensus to proceed with the change.
... That takes us to the pull request itself.
... I removed everything to do with clock and smpte timebase
and also noticed that region timing should be removed.
... It was already omitted, so there's no substantive change
for that feature; the prohibition is just made explicit.
Matt: Looks good to me, I will approve this. I will add a note too.
Nigel: Great, thank you.
...
... There's one more: pull request 11 Change DFXP references to
TTML2 profiles https://github.com/w3c/adpt/pull/11
Matt: Just looks like a note in section 4
Nigel: That's correct - the
heritage is a bit of copy and paste from IMSC, which was based
in TTML1, which didn't
... define as many standard profiles as TTML2 does. This work
has to be based on TTML2 so I've changed it to match.
Matt: Looks good to me. [approves]
Nigel: Thank you, I'll merge
those all later.
... Actually just to note I had a message from Peter Spoor
saying he will take a look, and Chris O'Brien also said he
would
... review the changes, so I'll give them a couple of days to
add any more comments before merging them.
https://github.com/w3c/adpt/issues/8
Matt: The reasons for allowing this would need other changes in the specification.
Nigel: For example?
Matt: Say if this is used for
spoken subtitles with multiple voices, then simply permitting
multiple leaf nodes isn't enough.
... We should work through the use case and see what is
needed.
... It is not a current requirement for this document.
Nigel: Good point, we may add
support for that later, potentially.
... Just to note as well that Pilar raised an issue on the
w3c/tt-reqs repo asking for spoken subtitles support,
... and I think the requirement is all about signalling, rather
than content, and I have an action to try to summarise
that
... and get her views on that summary.
...
... Right now, the two commenters are in agreement for this
issue.
... In the absence of any contrary views I will prepare a pull
request to make the change.
https://github.com/w3c/adpt/issues/10
Nigel: Here I'm proposing we
require support for the features in processors but not for them
to be used in documents,
... where usage would be optional.
... It might be a useful output of this group to describe a
best practice in how to use those features, at some point in
the future.
Matt: Agreed
Nigel: We have agreement from the two commenters so far and no contrary views so I will prepare a pull request for this.
Matt: I could support a later slot in the day
Nigel: That would probably be
helpful for folk in Canada or the US, say.
... I feel that we have had low attendance and input so far,
which may be a sign that everyone's happy, but I would
... be more confident if there were a higher volume of
input.
... So I'll look to set up some calls, maybe just a couple, in
May, at different times, to try to give more opportunity
... for participation.
Matt: Makes sense.
Nigel: Thank you, that's an action on me!
Nigel: BBC put out a consultation
about its iPlayer service recently, and RNIB contributed
feedback,
... which is public at:
scribe: I mention this because RNIB states support for a standard format for audio description, which this work is intended to create.
Nigel: Thank you for that - only two of us on the call today but I think we made useful progress. [adjourns meeting]