- From: Nigel Megitt <nigel.megitt@bbc.co.uk>
- Date: Thu, 15 May 2014 14:58:50 +0000
- To: TTWG <public-tt@w3.org>
- Message-ID: <CF9A949C.1DB67%nigel.megitt@bbc.co.uk>
Minutes available at: http://www.w3.org/2014/05/15-tt-minutes.html
[1]W3C
[1] http://www.w3.org/
- DRAFT -
Timed Text Working Group Teleconference
15 May 2014
See also: [2]IRC log
[2] http://www.w3.org/2014/05/15-tt-irc
Attendees
Present
nigel._pal, Mike, jdsmith
Regrets
Frans_de_Jong, Glenn_Adams
Chair
nigel
Scribe
nigel
Contents
* [3]Topics
1. [4]MPEG liaison re MIME Codecs parameter
2. [5]F2F planning
3. [6]Issues discussed and raised over the past week
4. [7]Change Proposals
* [8]Summary of Action Items
__________________________________________________________
<trackbot> Date: 15 May 2014
MPEG liaison re MIME Codecs parameter
<scribe> scribeNick: nigel
nigel: Can't cover this topic fully today as we need Glenn and
David to contribute to the conversation, but we can summarise
the state of the debate to date.
mike: I'm concerned that we haven't addressed my email that
described the points of disagreement.
... the thread seems to have evolved towards document
conformance profiles, i.e. documents conform to all of the
profiles that are signalled. Then a decoder only needs to know
that it can support one of the listed profiles
... in order to proceed. This is useful but not sufficient. The
proposal requires registration of the profile, which is fine,
but it doesn't allow 3rd party namespaces to be added and
signalled like the current
... 14496 does. That forces the industry to register all
separate combinations of namespaces. That's not the end of the
world but the discussion hasn't solved that.
nigel: It's a point of dispute in the reflector whether
namespace signalling is needed at all - they're features of
specifications already.
mike: It would be a problem for Ultraviolet if all the features
needed for processing a document can't be defined, e.g. TTML
subset plus image processing subset.
pal: Why can't we delegate that combinatorial logic to the
registration?
mike: Yes that will work for the profiles defines by
Ultraviolet. But it does not solve the problem when the
document contains 608 and 708 data. There's no way to signal
that. Someone would have to register
... the Ultraviolet profile that includes 608 or the one that
includes 708 or the one that includes both.
pal: When you say 608 is that a separate specification?
mike: yes.
pal: So another row in the specification table could contain
m608 and reference that other specification.
mike: Yes. It forces anyone using a combination of namespaces
to register with W3C the combination. There's no concept in the
current proposal to say 'processor needs both X and Y'.
... The proposal is necessary but not sufficient - it would say
'doc conforms to X, Y and Z so if you support any of those you
can decode the document'. This doesn't cover other namespaces
... which would have to be combined and the combination
registered with W3C.
pal: So you'd like a way to signal 'document conforms to A+B or
C or D' to create on the fly new combinations of conformance by
combination.
mike; Right. The argument on the thread was that this allows
custom profiles to be created on the fly. Today that's already
possible in the ISO specs. We were only really dealing with the
unwieldiness of the long strings.
scribe: It's not the end of the world as long as the
registration process is lightweight.
nigel: It would be really helpful Mike if you could point the
discussion to where the requirement for combinations of
profiles comes from in the ISO specs.
mike: It would also be helpful to talk about the registration
process. If the bar is really low then it's much more
compelling to force people to register the combinatorial
profiles they want.
nigel: Describes lightweight process.
mike: Maybe we could codify reasons why a registration may be
rejected, e.g. Not TTML, Already Registered etc.
F2F planning
nigel: It's for me and David to work on the agenda. The goal is
to work on our deliverable of the TTML <--> WebVTT mapping.
Issues discussed and raised over the past week
issue-307?
<trackbot> issue-307 -- Conformance language and processor
profile rather than content profile. -- open
<trackbot>
[9]http://www.w3.org/AudioVideo/TT/tracker/issues/307
[9] http://www.w3.org/AudioVideo/TT/tracker/issues/307
issue-308?
<trackbot> issue-308 -- It is unclear how a document is
associated with a related video object -- open
<trackbot>
[10]http://www.w3.org/AudioVideo/TT/tracker/issues/308
[10] http://www.w3.org/AudioVideo/TT/tracker/issues/308
pal: We're awaiting glenn's input on issue-307.
... I think nigel wanted to think more about 308.
... my action item now is to fix the typo re Related Media
Object.
... I believe the current document does not mandate that a
document be attached to a single frame rate.
nigel: okay I'll review more.
pal: I propose to make the change to Related Video Object
either by defining it or changing it. Then I'll close the issue
and if there's an issue related to frame rate we can open a new
ticket.
mike: Historically we made it 'media object' to be more generic
than video and the link is external to TTML.
pal: my plan is to define Related Video Object as the video
component of the Related Media Object.
nigel: We need to clarify that frameRate in an IMSC document
does not need to be identical to the frame rate of the related
media object.
pal: Would a note be sufficient?
nigel: yes, possibly.
Change Proposals
[11]https://www.w3.org/wiki/TTML/changeProposal002
[11] https://www.w3.org/wiki/TTML/changeProposal002
nigel: I've got a feeling we may need Glenn to review this
before we can close it.
... In fact Glenn has put a note at the bottom showing he's
implemented it so it's for jdsmith to verify that the
implementation meets the expectation.
[12]https://dvcs.w3.org/hg/ttml/rev/c9fd49837446
[12] https://dvcs.w3.org/hg/ttml/rev/c9fd49837446
nigel: that's the change set on TTML2
... The editor's draft for TTML2 is at
[13]https://dvcs.w3.org/hg/ttml/raw-file/default/ttml2/spec/ttm
l2.html
[13] https://dvcs.w3.org/hg/ttml/raw-file/default/ttml2/spec/ttml2.html
jdsmith: I have a question about change proposal 5. It's not
really a change, but a representative way to map to HTML.
... We've reviewed that here, and it's pretty much what we do.
What's the destination for the change?
nigel: It can be an appendix to TTML2, or striped all the way
through TTML2 per feature, or a separate note altogether.
... If the whole world is moving away from XSL-FO towards CSS
then it would make sense to add it throughout TTML2 on a
feature by feature basis.
jdsmith: I could map the rendering to the sections in TTML2.
plh: I think this would be extremely useful.
pal: If it applies equally both to TTML1 and TTML2 it should
not be an appendix to TTML2.
... In that case a separate document would be useful.
plh: I can see it either way. You can use it for TTML1
additionally to TTML2.
nigel: I would prefer it to be striped through TTML2 to
encourage new implementers to start there not at TTML1.
jdsmith: I'll start working on the mapping to sections.
plh: We don't want to overload the editor.
... You could potentially become another editor for this
purpose.
... By the way some features may not be mappable if CSS doesn't
have the features, and it's important to highlight them. That
will probably give rise to a sub-profile of TTML2 that avoids
non-CSS features.
jdsmith: Let me look at the work of striping it through, see
what Glenn thinks and hopefully confirm next week.
<scribe> ACTION: nigel to create a wiki page for the September
F2F with a draft agenda and an 'intention to attend' section.
[recorded in
[14]http://www.w3.org/2014/05/15-tt-minutes.html#action01]
<trackbot> Created ACTION-289 - Create a wiki page for the
september f2f with a draft agenda and an 'intention to attend'
section. [on Nigel Megitt - due 2014-05-22].
plh: We're also looking at setting up an Extensible Web Summit
in Berlin in September just beforehand. This would give people
a good reason to be in Europe around that time.
... The dates aren't final yet - our German office is looking
for a host. The location will be Berlin because on the 13/14th
Sep there's a Javascript conference. Once it's settled I'll
report that back here.
... It may help people to attend.
... On the testing front, there are lots of good movements
there. We have a test suite for WebVTT - I'll add the links to
it to our wiki dashboard. At some point we need to look at what
we can do for TTML.
... The old tests are still valid but we may need to refactor
them so they can be run automatically.
nigel: Change Proposal 26 is our home for this
[15]https://www.w3.org/wiki/TTML/changeProposal026
[15] https://www.w3.org/wiki/TTML/changeProposal026
plh: Waiting until September before diving into the tests will
be really helpful. Any progress with scripting languages and
declarative languages that help automatic testing is good for
us.
Re Codecs we're tentatively scheduled for the 29th.
plh: regrets for the next 2 weeks.
Summary of Action Items
[NEW] ACTION: nigel to create a wiki page for the September F2F
with a draft agenda and an 'intention to attend' section.
[recorded in
[16]http://www.w3.org/2014/05/15-tt-minutes.html#action01]
[End of minutes]
__________________________________________________________
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__________________________________________________________
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Received on Thursday, 15 May 2014 14:59:21 UTC