- From: Nigel Megitt <nigel.megitt@bbc.co.uk>
- Date: Thu, 8 Oct 2015 15:23:19 +0000
- To: "'TTWG'" <public-tt@w3.org>
- Message-ID: <D23C4866.2945C%nigel.megitt@bbc.co.uk>
Thanks to those who attended today's meeting. Minutes can be found at http://www.w3.org/2015/10/08-tt-minutes.html
There's a proposal to extend next week's meeting to 2 hours to close off the remaining IMSC 1 issues as much as possible in advance of TPAC.
In text format:
[1]W3C
[1] http://www.w3.org/
Timed Text Working Group Teleconference
08 Oct 2015
See also: [2]IRC log
[2] http://www.w3.org/2015/10/08-tt-irc
Attendees
Present
nigel, pal, tmichel
Regrets
Andreas, Frans, Mike
Chair
nigel
Scribe
nigel
Contents
* [3]Topics
1. [4]This Meeting
2. [5]Action Items
3. [6]TPAC 2015
4. [7]IMSC stuff...
5. [8]Profiles registry
6. [9]Issues
* [10]Summary of Action Items
__________________________________________________________
<trackbot> Date: 08 October 2015
<scribe> scribe: nigel
This Meeting
nigel: Most of this meeting will be dedicated to closing IMSC 1
pending review issues
... AOB?
... Mike has asked to postpone the incoming liaison from ATSC
issue.
pal: There's also the topic of profile designators - it would
be good to talk about it.
nigel: Great, that's added.
Action Items
Action-421?
<trackbot> Action-421 -- Nigel Megitt to Check with ttml player
manufacturers if they're happy to be listed on our site. -- due
2015-09-24 -- OPEN
<trackbot>
[11]http://www.w3.org/AudioVideo/TT/tracker/actions/421
[11] http://www.w3.org/AudioVideo/TT/tracker/actions/421
nigel: I did contact the manufacturer we discussed and they
said they'd check but haven't yet confirmed.
... Do we have an implementations page?
tmichel: I don't think we have one yet but I'd like to start
one. I think we should have a page
... per technology - one for TTML, one for WebVTT etc.
pal: We have a page for that - remember the contribution from
the Web & TV IG?
nigel: Oh yes, I remember now.
[12]https://www.w3.org/wiki/TimedText/
[12] https://www.w3.org/wiki/TimedText/
[13]https://www.w3.org/wiki/TimedText/EffortsAndSpecifications
is a better URL to use
[13] https://www.w3.org/wiki/TimedText/EffortsAndSpecifications
It's linked from [14]https://www.w3.org/wiki/TimedText under
Timed Text Efforts and Specifications
[14] https://www.w3.org/wiki/TimedText
nigel: I guess we could add it to the group home page too - we
probably should tidy up the
... group page vs wiki home page discrepancy. Having both isn't
especially helpful.
tmichel: In former times we had the CVS hosted home page which
was hard to edit. Now
... the wiki is simpler for people to add information to.
Everyone should be able to add their
... own product if they want to.
nigel: Is it worth an action to redirect from the home page to
the wiki?
tmichel: I'll look into that. There's some information like how
to join on the home page.
nigel: Yes. we'd have to migrate the key information.
tmichel: I'll look into it and propose something.
<scribe> ACTION: tmichel Look into merging the group home page
and the wiki home page and propose something [recorded in
[15]http://www.w3.org/2015/10/08-tt-minutes.html#action01]
<trackbot> Created ACTION-430 - Look into merging the group
home page and the wiki home page and propose something [on
Thierry Michel - due 2015-10-15].
TPAC 2015
nigel: Netflix has just joined the WG and would like to spend
some agenda time on the Thursday
... presenting on their open source TTML2 implementation work.
... I'll add that to the topics/agenda page on the wiki.
tmichel: While we're talking about new participants, SImon from
Opera joined today replacing Philip.
... Simon is the new editor of the WebVTT spec.
IMSC stuff...
action-425?
<trackbot> action-425 -- Thierry Michel to Send a prompt/thank
you to the potential test result contributors for imsc. -- due
2015-10-01 -- OPEN
<trackbot>
[16]http://www.w3.org/AudioVideo/TT/tracker/actions/425
[16] http://www.w3.org/AudioVideo/TT/tracker/actions/425
pal: I've not heard back and am still chasing, so that's still
open. No update despite best efforts.
Profiles registry
pal: Related to Cyril's email earlier today, which came out of
this topic, I think from an
... implementation standpoint he wants users to be able to
signal clearly in a TTML document
... what profiles a document conforms to. In IMSC 1 right now
there's a 'MAY user ttp:profile'
... statement but that's it. Maybe we can add more to IMSC 1 to
encourage people to label
... their documents. The challenge is, as we discussed before,
EBU-TT-D forbids ttp:profile.
... And ttp:profile supports only one profile. So if a document
conforms to both EBU-TT-D and
... IMSC 1 then you should not use ttp:profile but you should
use ebuttm:conformsToStandard
... and list both. If the document is not EBU-TT-D conformant
it probably isn't a bad idea to
... use ttp:profile and also include ebuttm:conformsToStandard
so I'm thinking of adding
... a recommendation to IMSC 1 along those lines.
nigel: I can see the logic to that, yes. It makes sense I
think.
pal: I'd like to be responsive to the request.
nigel: I agree - there's a use case we haven't spent a lot of
time considering that is obviously
... important. I'd like Andreas's and Frans's input on this
specific proposal too, but on the
... surface I think it makes a lot of sense.
... You can recommend using the URI designators.
pal: That would definitely be the recommendation!
... From a tools perspective it would certainly help tools to
determine the document's profile.
nigel: We just need to be careful that
ebuttm:conformsToStandard is indicating document
... conformance in other words the equivalent to TTML2's
ttp:contentProfiles attribute.
... Whereas ttp:profile indicates a processor profile, so we
shouldn't mix the messages there.
pal: I don't know why we hadn't collectively thought about this
before. I think it works in exactly the right way.
nigel: I can see how this would work really well - if an IMSC 1
processor is needed then it's on
... the ttp:profile attribute and if not, because an EBU-TT-D
processor is okay, then it would be
... omitted.
pal: I think we can file an issue for this, especially given
Glenn's email just now proposing that
... IMSC 1 includes a 'should include ttp:profile attribute'
statement, then implement and review
... next week.
... [filing issue right now]
issue-448?
<trackbot> issue-448 -- Add recommendation for ttp:profile and
ebuttm:conformsToStandard -- raised
<trackbot>
[17]http://www.w3.org/AudioVideo/TT/tracker/issues/448
[17] http://www.w3.org/AudioVideo/TT/tracker/issues/448
reopen issue-448
<trackbot> Re-opened issue-448.
pal: I'm going to reply to the thread too.
nigel: I think it's worth pinging back to EBU to check if they
might reopen the discussion on
... whether or not to permit ttp:profile on EBU-TT-D documents.
... Of course if you have a stream of EBU-TT-D documents e.g.
in DASH then this is likely
... to be redundantly repeated data.
pal: Of course the packager could strip it out if it knows the
data won't be needed downstream.
nigel: We may be putting packagers in an uncomfortable
situation of needing to modify the
... samples they're given to wrap up.
pal: True - we're talking about a few bytes though and it's
tiny in comparison with e.g. HTTP headers.
Issues
nigel: Let's go through Pending Reviews...
issue-404?
<trackbot> issue-404 -- Where is #image feature defined? --
pending review
<trackbot>
[18]http://www.w3.org/AudioVideo/TT/tracker/issues/404
[18] http://www.w3.org/AudioVideo/TT/tracker/issues/404
pal: I think this is unambiguous, well specified and can be
closed.
nigel: +1
close issue-404
<trackbot> Closed issue-404.
issue-405?
<trackbot> issue-405 -- why is #nested-span prohibited on image
profile? -- pending review
<trackbot>
[19]http://www.w3.org/AudioVideo/TT/tracker/issues/405
[19] http://www.w3.org/AudioVideo/TT/tracker/issues/405
nigel: This isn't even a proposal to change the spec. It's a
question with an answer.
pal: I think Glenn would have responded if he disagreed.
close issue-405
<trackbot> Closed issue-405.
issue-406?
<trackbot> issue-406 -- #lineBreak-uax14 is never 'used' by a
document? -- pending review
<trackbot>
[20]http://www.w3.org/AudioVideo/TT/tracker/issues/406
[20] http://www.w3.org/AudioVideo/TT/tracker/issues/406
pal: uax14 is mandated for processors in the text profile and
stated as not applicable to document instances.
... The image profile is silent about it.
nigel: Do we permit the profile features to be listed in the
document?
pal: We do. The presence of the profile designator in the
document requires that the processor
... implements uax14. What the spec currently says is the
document constraints. The uax14
... feature is not applicable to constraints on the document.
nigel: There's a niche issue for the text profile: if the
profile features are included then it would
... be an error to state that the #linebreak-uax14 feature is a
'shall not use'.
... That would create a situation where an IMSC 1 text profile
conformant processor should
... reject an IMSC 1 text profile conformant document that
includes this profile feature as
... 'shall not use'.
pal: This is a strange and theoretical case, that applies only
to the uax14 feature.
nigel: We could add a statement that if profile features are
included within a document then
... they shall not conflict with the processor conformance
rules for IMSC 1.
<scribe> ACTION: nigel File issue re profile feature inclusion
in IMSC 1 documents [recorded in
[21]http://www.w3.org/2015/10/08-tt-minutes.html#action02]
<trackbot> Created ACTION-431 - File issue re profile feature
inclusion in imsc 1 documents [on Nigel Megitt - due
2015-10-15].
pal: We could add that to the profile section for document
conformance.
... Going back to issue-406, Glenn suggested to require the
feature. Shall we start the 2 week review clock on this today?
nigel: yes, let's do that.
issue-408?
<trackbot> issue-408 -- Initial value of color -- pending
review
<trackbot>
[22]http://www.w3.org/AudioVideo/TT/tracker/issues/408
[22] http://www.w3.org/AudioVideo/TT/tracker/issues/408
close issue-408
<trackbot> Closed issue-408.
issue-409?
<trackbot> issue-409 -- Font family of default means
monospaceSerif -- pending review
<trackbot>
[23]http://www.w3.org/AudioVideo/TT/tracker/issues/409
[23] http://www.w3.org/AudioVideo/TT/tracker/issues/409
pal: IMSC 1 defines what it means for "default" fontFamily,
i.e. what a processor shall do when
... the fontFamily is set to "default". Glenn points out that
this isn't always the right thing to do.
... My response to that is that authors should not rely on
default. TTML1 doesn't prohibit
... implementations from mapping the default font to a known
one.
nigel: I'm a bit nervous here - Glenn hasn't proposed a
solution, and I don't know why.
... For example we could include a table mapping language to
default font map or reference
... one in e.g. CLDR.
pal: Document authors can make their choice though if default
won't work for them.
nigel: My nervousness here is that we're making a language
market-specific value for default,
... which could make use of default less useful.
... However Glenn knows most about this from those here and he
hasn't picked it up.
pal: We should close this on the basis of no response in over 1
month. It can be reopened if someone is unhappy.
close issue-409
<trackbot> Closed issue-409.
issue-410?
<trackbot> issue-410 -- Constraints on #linePadding and
#multiRowAlign -- pending review
<trackbot>
[24]http://www.w3.org/AudioVideo/TT/tracker/issues/410
[24] http://www.w3.org/AudioVideo/TT/tracker/issues/410
nigel: The problem with SHALL NOT here suggests a syntactic
conformance requirement whereas
... what you mean is that if the attributes are present then
they shall be ignored by implementations.
pal: We don't have Glenn's view on this so it would be uncool
if he doesn't agree.
... Don't forget the problem arose in EBU-TT-D.
nigel: The new EBU-TT Part 1 v1.1 might get us out of that
problem - it defines the features
... and states that they may be used in EBU-TT-D, and fixes the
gaps from the original definition.
<scribe> ACTION: nigel Nigel, pal, andreas and frans to hook up
re changing IMSC 1 EBU-TT feature references to point to
tech3350 v1.1 [recorded in
[25]http://www.w3.org/2015/10/08-tt-minutes.html#action03]
<trackbot> Created ACTION-432 - Nigel, pal, andreas and frans
to hook up re changing imsc 1 ebu-tt feature references to
point to tech3350 v1.1 [on Nigel Megitt - due 2015-10-15].
issue-410: [meeting 2015-10-08] See also Action-432 - it may be
possible to avoid the problem by referencing tech3350 v1.1.
<trackbot> Notes added to issue-410 Constraints on #linePadding
and #multiRowAlign.
nigel: We're out of time so I'll adjourn now.
pal: Maybe we could do 2 hours next week to get through the
remaining issues ahead of TPAC?
nigel: That's fine for me.
pal: I'd like to have gone through all of them - there's one
that may need TPAC discussion.
... Glenn brought up an excellent question about the HRM, in
relation to Arabic, where the
... mapping between code point and glyph is in the majority of
cases is not 1:1 and the shape
... depends on the context. That really messes up the glyph
buffer. I'm researching it.
... The glyph buffer was put in to support e.g. 608, 708 and
Teletext. Hopefully we'll have closed all the others.
nigel: Thanks both. [meeting adjourned]
Summary of Action Items
[NEW] ACTION: nigel File issue re profile feature inclusion in
IMSC 1 documents [recorded in
[26]http://www.w3.org/2015/10/08-tt-minutes.html#action02]
[NEW] ACTION: nigel Nigel, pal, andreas and frans to hook up re
changing IMSC 1 EBU-TT feature references to point to tech3350
v1.1 [recorded in
[27]http://www.w3.org/2015/10/08-tt-minutes.html#action03]
[NEW] ACTION: tmichel Look into merging the group home page and
the wiki home page and propose something [recorded in
[28]http://www.w3.org/2015/10/08-tt-minutes.html#action01]
[End of minutes]
__________________________________________________________
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Received on Thursday, 8 October 2015 15:23:52 UTC