{Minutes} TTWG Teleconference 2025-01-16

Thanks all for attending today’s TTWG call, the first of 2025. Minutes can be found in HTML format at https://www.w3.org/2025/01/16-tt-minutes.html


In plain text:

   [1]W3C

      [1] https://www.w3.org/


                Timed Text Working Group Teleconference

16 January 2025

   [2]IRC log.

      [2] https://www.w3.org/2025/01/16-tt-irc


Attendees

   Present
          Andreas, Atsushi, Cyril, Gary, Nigel, Pierre

   Regrets
          Chris_Needham

   Chair
          Gary, Nigel

   Scribe
          nigel

Contents

    1. [3]This meeting
    2. [4]IMSC 1.3
         1. [5][WR/ARIB] Character Sets w3c/imsc#544
         2. [6]Refactor the HRM w3c/imsc#586
         3. [7]Update namespace documents w3c/imsc#589
         4. [8]Publication
    3. [9]DAPT
    4. [10]Charter 2025
    5. [11]AOB - Dubtitles
    6. [12]Meeting close

Meeting minutes

  This meeting

   Nigel: Happy New Year everyone, welcome back, hope you had a
   good break from this.
   … Today, we have on the agenda:
   … * DAPT
   … * IMSC 1.3
   … * Charter 2025
   … * AOB: "Dubtitles"
   … Is there anything else anyone wants to cover or make sure we
   get to?

   Pierre: I have an IMSC topic to cover early please

   Nigel: Sure

  IMSC 1.3

    [WR/ARIB] Character Sets [13]w3c/imsc#544

     [13] https://github.com/w3c/imsc/issues/544


   Pierre: [shares screen]
   … ARIB kindly provides a set of characters for use in Japanese
   … One of them is from ARIB STD-B62

   github: [14]w3c/imsc#544

     [14] https://github.com/w3c/imsc/issues/544


   Pierre: It's Table 5-2
   … Additional symbols and characters part 1
   … This table with UCS values - they're all Unicode characters I
   think

   Nigel: Yes they're Unicode code points.

   Pierre: Does Table 5-2 correspond with section 5.5?

   Atsushi: No, even section 5.2 includes additional symbols in
   tables 5-2 and 5-3
   … I may have written somewhere: originally ARIB's definition is
   based on JIS character set.
   … So-called ARIB Gaiji was defined to include characters in
   tables 5-2 and 5-3 that are not in JIS.
   … But at some point the ARIB definition switched from JIS
   encoding system to XXX
   … The last bullet in 5.2 contains characters that were later
   included in Unicode but were "ARIB gaiji" before

   Pierre: So Table 5-2 has nothing to do with section 5.5?

   Atsushi: Nothing

   Pierre: So from the liaison, everything is in Unicode except
   the last bullet which is from Table 5-2.

   Atsushi: It could be possible that there was some correction to
   the submission from ARIB but I would not know.

   Pierre: I will reference Table 5-2 explicitly, thank you.

   SUMMARY: Reference Table 5-2 explicitly

    Refactor the HRM [15]w3c/imsc#586

     [15] https://github.com/w3c/imsc/issues/586


   github: [16]w3c/imsc#586

     [16] https://github.com/w3c/imsc/pull/586


   Pierre: The current version of IMSC includes both the
   definition of the profile and also the HRM
   … that constrains the complexity of IMSC documents.
   … A conformant IMSC document is defined as one that also
   conforms to the HRM.
   … Now the HRM is a separate document, and I think we had
   discussed in the past
   … removing the requirement that an IMSC document conforms to
   the HRM
   … and merely point to it as an additional specification that
   users might want to use.
   … That has two advantages,
   … a. It reduces the strong dependence between the specs
   … b. it matches reality where not every IMSC application checks
   the HRM
   … The goal is to remove the HRM from IMSC 1.3 and the
   suggestion is to also remove conformance
   … as part of the definition of a conformant IMSC document.

   Nigel: I wanted to surface this because I wanted a wider group
   to have visibility, than just me and Pierre.
   … Also, there are other options:
   … 1. Keep the hard requirement
   … 2. Keep the hard requirement but flag that it is likely to be
   softened in the future
   … 3. Change to a SHOULD
   … 4. Change to a MAY

   Pierre: I would not use the term MAY in practice

   Andreas: As a data point, when we defined EBU-TT-D and
   discussed in HbbTV, and wanted to
   … align with IMSC we had long discussions about the HRM and
   whether we include the constraint.
   … We decided not to have this requirement for the HRM.
   … If it is a strict requirement that leaves the possibility to
   have EBU-TT-D documents that do not
   … conform to IMSC I don't think it is a big issue at the moment
   but it is likely to reflect the reality
   … as Pierre is proposing.

   Nigel: So you're in favour of removing the requirement and
   referencing as an option (i.e. 4)

   Andreas: Yes

   Nigel: Any other thoughts?

   Pierre: I would have a different opinion if I thought this
   would go against practice, so there's very little risk here.

   SUMMARY: Remove the hard dependency on IMSC-HRM conformance,
   and reference as an option for users.

    Update namespace documents [17]w3c/imsc#589

     [17] https://github.com/w3c/imsc/issues/589


   github: [18]w3c/imsc#589

     [18] https://github.com/w3c/imsc/pull/589


   Atsushi: Sorry I haven't had time to get to this yet
   … I am not sure what the process is for updating namespace
   documents
   … I will consult the team
   … The document is on github so we can do it with a pull request
   … but the question is what content is required

   Nigel: Would it be something different from what's in the pull
   request?

   Atsushi: No idea actually

   Nigel: OK, I suggest put a comment on the pull request when you
   know

   Atsushi: The process says this is part of CRS publication, but
   we haven't done it for previous IMSC
   … publications so I definitely need to do something for this.

   SUMMARY: Reviews to continue

    Publication

   Nigel: Presumably when we merge pull requests something will
   get published?

   Pierre: I don't know. I do have to change the README too.

   Nigel: I think we need the short code reserved and then
   presumably echidna needs to be configured.
   … I can't remember if we go all the way back to WD or straight
   to CR.
   … There's some bureaucracy to figure out there!
   … Let's take that offline.

   [Pierre drops off the call]

  DAPT

   Nigel: I think we are just waiting for CR publication.
   … Atsushi, are we waiting for anything?

   Atsushi: I pinged Simone for review around year end and will do
   again shortly.
   … In any case 2 months has elapsed since the first request so I
   will talk with plh soon.

   Nigel: So that one HR request is the only thing holding us
   back?

   Atsushi: i18n is finished, so yes, only waiting for Security on
   the Security considerations section.

   Nigel: It's frustrating, can we just go ahead? When will you be
   able to discuss with plh?

   Atsushi: Next Monday or Tuesday. I'm also frustrated!
   … I'm not sure if there is anything I can do.

   Cyril: A question about the security review. Why do we need
   another review when nothing has changed security-wise?

   Atsushi: The W3C Team got a new security lead and activity
   formally started late last year.

   Cyril: OK, we may not have had formal security review but we
   had a long discussion with the security team,
   … that should be mentioned, right?

   Atsushi: That was with the Privacy group?

   Nigel: We put a fingerprint icon on, for sure

   Atsushi: That should be privacy

   Cyril: It's a profile of TTML2 so the security review of TTML2
   applies to the profile.

   Nigel: We do introduce new features that aren't in TTML2.

   Cyril: Should we write down a quick paragraph to help them
   scope the review quickly?

   Nigel: Not a bad idea

   Cyril: I'll draft that

   Nigel: Thank you

   Cyril: Assuming we go to CR at some point, then we have to work
   on the implementation report.
   … Nigel you did work on that already. What needs to be done?
   … Do we need work, or just to get implementations to report
   what they do?

   Nigel: Yes, we need to add the recently added features, if I
   didn't already do that.
   … Also most importantly we need to create a test suite for the
   DAPT features not in TTML2.
   … Then we can add into the implementation report the tests so
   that we can demonstrate
   … the tests that each implementation passes or fails.
   … Then that tells the story of how we have met the CR exit
   criteria

   Cyril: Thinking of at-risk features, they're not new, because
   they're in TTML2, so they
   … won't be part of the implementation report, so how will we
   resolve those issues?

   Nigel: Interesting question.

   Cyril: Implementation feedback, of course, but we will make a
   decision based on implementer feedback?

   Nigel: Yes I think so

   Cyril: We should encourage people to provide feedback on this

   Nigel: I propose we add into the implementation report each at
   risk feature as a row,
   … and then show which implementations implement each feature so
   we can make a clearer decision,
   … even though there's no formal requirement for DAPT-specific
   tests with them.

   Cyril: I think it's a good idea

   Cyril: Hard to tell now, but what is your expectation in terms
   of timeline?
   … Can we publish Rec in 2025.

   Nigel: I expect so, yes.
   … Not sure if I mentioned it yet, but the EBU Eurovox project
   has already implemented a DAPT output.

  Charter 2025

   Nigel: Not much to say except that there has been a
   notification of the new charter work,
   … based on what we did at the end of last year. Thank you
   Atsushi.

   Atsushi: We are now at HR stage.
   … Advanced notice was sent to AC Reps, external parties like
   public-new-work mailing list of W3C.
   … HR should finish within 2 months and we will go to AC review
   right after that.
   … Our changes are not large in terms of text, I don't expect to
   get large amounts of comment from the HR
   … groups or AC.

   Nigel: In other words, we can forget about this for a while!

   Atsushi: Yeah

   Nigel: The only thing is there are some TODOs on it, for
   example when we've published IMSC 1.3
   … in some form then we need to update the links to it.

   Atsushi: For that point, to publish FPWD the spec needs to be
   in the Charter,
   … so I think we should publish the ED for that.

   Nigel: I don't agree, I think it is already in scope of the
   current charter to produce new versions
   … of existing Recs.

   Atsushi: Could be part of Profile of TTML

   Nigel: No doubt, it definitely is!
   … If the next stage is FPWD then that's what I'd like us to do.
   … Anything else on Charter?

   nothing else for now

   Nigel: I will remove this from the ongoing agenda unless you
   want to raise it again, or something comes up.

  AOB - Dubtitles

   Gary: Background: "Dubtitles" are what people have been calling
   subtitles that use the dubbing script
   … for the text. Normally translation subtitles have a different
   timing match to the original audio.
   … With dubtitles the timing matches the dubbing audio.
   … For viewers, sometimes there's a lot of mismatch so it can be
   a frustrating experience.
   … You might hear something in the original audio but then the
   translation cue comes up later or earlier.
   … My question is: is there something we can do technology-wise
   to help reduce the use of dubtitles.
   … One of the issues is likely the cost, where if you only
   generate one thing then it's cheaper than
   … generating a subtitle that matches the original audio and
   then a separate one that matches the dubbing script.
   … I don't know if there's something in DASH or HLS or somewhere
   down the stack that's missing that makes
   … it less likely that people will create both subtitle tracks.

   Cyril: I'm not sure I understand why you want to reduce the use
   of dubtitles?

   Gary: If I'm watching in the original audio then I want
   subtitles that match the timing of the audio.

   Cyril: "captions" in the US

   Gary: Yes. But what's happening is that the timing matches the
   dubbed audio.

   Cyril: In what language?

   Gary: This comes up a lot in anime, where if I try to watch in
   the Japanese original audio but the captions
   … are the English dubbed audio captions.

   Cyril: The problem is the subtitles for English are created
   from the dub instead of the transcribed Japanese?

   Gary: Yes, the main issue is the timing of when the cues are
   shown, which are derived from the dubbed audio.
   … If you're watching in the original Japanese the translation
   cues don't show up when you're expecting
   … based on the Japanese audio.
   … The specific content of the subtitles is less of an important
   issue.
   … The dubbing translation is usually good enough.

   Cyril: That's related to DAPT, where the use case was to avoid
   discrepancies between the dubbed audio
   … and the translated subtitles in the same language.

   Gary: I think it's related, but yes there's weird
   discrepancies.

   Andreas: From my understanding this needs a linkage between the
   audio language and the
   … translated subtitles, and I don't think that exists.
   … You can watch the same video image with any of the audio or
   subtitle languages offered.
   … Right now there's no solution.
   … You could of course use those dubtitles with the dubbed
   version, which should fit.

   Gary: That should be fine because the timing should align in
   that case.

   Cyril: It's also a constraint you can put in the workflows, not
   to create dubs with timing that is too different
   … to the original.

   Gary: It's more complicated because in the dub sometimes there
   are extra lines spoken where there's no
   … dialogue in the original. Then you see extra subtitles when
   nobody is speaking.

   Cyril: Sounds like an annotation to show that an event is not
   in the original language.
   … In DAPT you would have... er, not sure how we support that.

   Nigel: I've got beads of sweat worrying about if we support
   this!

   Cyril: It's like audio description, describing something not
   being spoken.

   Gary: They are spoken, just only in the dubbed audio.

   Cyril: It's an interesting use case. Can we work on a concrete
   example?
   … I would be interested to see content that demonstrates this.
   … Annotating extra subtitles could be done, and the player
   could act on that.

   Andreas: Would a simple solution be to distribute the metadata
   about the source language,
   … so if you combine it with some other audio track then there
   could be problems.
   … It's not just a timing problem, but also about the content,
   because subtitles from the dubbed version
   … used for the original do not match. That's another possible
   issue.

   Gary: Yes, if you know the original language and watch the
   subtitles in that language it's an issue.
   … For the anime example it's not an issue for me, Japanese
   audio and English subtitles,
   … but for dubtitles when the timing matches up it's not an
   issue.
   … When the timing is so different then it makes it hard to
   watch.
   … I agree maybe the issue is, in downstream like DASH and HLS,
   we need a way to associate specific
   … subtitle tracks with specific audio tracks.
   … With DAPT it could be useful if there are these annotations
   already.

   Nigel: I feel that in DAPT we have enough metadata to add the
   annotations but it needs checking.

  Meeting close

   Nigel: Let's adjourn a little over time today, thanks everyone.
   … Next call in 2 weeks.
   … [adjourns meeting]


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