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APA WG comment: semantic layers #524

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michael-n-cooper opened this issue Mar 9, 2020 · 10 comments
Open

APA WG comment: semantic layers #524

michael-n-cooper opened this issue Mar 9, 2020 · 10 comments
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a11y-needs-resolution Issue the Accessibility Group has raised and looks for a response on. a11y-tracker Group bringing to attention of a11y, or tracked by the a11y Group but not needing response. imsc1.3 imscvNEXT
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@michael-n-cooper
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Section C. Forced content This seems like a temporary solution to us. Mightn't it be better to define semantic layers of information so that each layer could be made visible and invisible at runtime as appropriate for the user? For example, the user might want to see either speech-only (subtitles), (parts of subtitles) or some combination of these.

@michael-n-cooper michael-n-cooper added the a11y-needs-resolution Issue the Accessibility Group has raised and looks for a response on. label Mar 9, 2020
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The Timed Text Working Group just discussed APA WG comment: semantic layers, and agreed to the following:

  • SUMMARY: this is a really interesting topic, but we don't think we can make any useful change to IMSC in response to this comment
  • SUMMARY: TTWG suggests this should be the beginning of a conversion with APA and other interested parties
The full IRC log of that discussion <cyril_> Topic: APA WG comment: semantic layers
<cyril_> github: https://github.com//issues/524
<cyril_> nigel: TTML and IMSC permit metadata description to be specified on particular bit of information
<cyril_> ... there is no formal requirement to do anything on that
<cyril_> ... the facility to have layers exist already
<cyril_> ... by using e.g. ttm:role
<cyril_> ... but there is no normative requirement on processor to use it
<cyril_> ... so force content provides a clear mechanism for authors and processors to define a interoperable presentation behavior
<cyril_> pal: "Forced" is a very specific tool for a very specific use case
<cyril_> ... the broader question is how to indicate the semantics of timed text
<cyril_> ... how to get the consistency across the ecosystem but that's beyond the scope of IMSC
<nigel> q?
<cyril_> q?
<nigel> ack cy
<cyril_> ack
<cyril_> SUMMARY: this is a really interesting topic, but we don't think we can make any useful change to IMSC in response to this comment
<cyril_> SUMMARY: TTWG suggests this should be the beginning of a conversion with APA and other interested parties

@gzimmermann
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I think engaging into a conversation with TTWG makes sense. We need to develop meaningful use cases and clearly state the purpose of a semantic layering.

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The Timed Text Working Group just discussed APA WG comment: semantic layers imsc#524, and agreed to the following:

  • SUMMARY: TTWG would like to participate in a joint meeting to progress this, and will make no changes in IMSC 1.2 to try to address this.
The full IRC log of that discussion <nigel> Topic: APA WG comment: semantic layers imsc#524
<nigel> github: https://github.com//issues/524
<nigel> Nigel: I think the proposal here is that we agree to hold a joint meeting with whoever
<nigel> .. wants to attend, and that we will make no change to IMSC 1.2 to address this.
<nigel> Pierre: I guess they're not objecting to deferring this?
<nigel> Nigel: Agreed, that's my reading anyway.
<nigel> SUMMARY: TTWG would like to participate in a joint meeting to progress this, and will make no changes in IMSC 1.2 to try to address this.

@gzimmermann
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I agree. This issue needs more time than we have currently available for IMSC 1.2.
We should arrange for a joint meeting after IMSC 1.2 was published.

@michael-n-cooper michael-n-cooper removed the a11y-needs-resolution Issue the Accessibility Group has raised and looks for a response on. label May 13, 2020
@michael-n-cooper
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APA agrees to defer this to future version.

@michael-n-cooper michael-n-cooper added the a11y-needs-resolution Issue the Accessibility Group has raised and looks for a response on. label May 14, 2020
@michael-n-cooper
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Re-adding a11y-needs-resolution label because of new information about how the horizontal review tracker works, but this is still signed off from APA.

@palemieux palemieux added this to the imsc1.3 milestone Sep 26, 2024
@ruoxiran ruoxiran added the a11y-tracker Group bringing to attention of a11y, or tracked by the a11y Group but not needing response. label Sep 27, 2024
@nigelmegitt
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Discussed in joint call with APA, TTWG and MEIG today 2024-09-27. Further discussion needed; in the meantime, a note pointing to the potential use of DAPT metadata for represents and language source would be helpful.

@palemieux
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I am not excited to introduce additional metadata without a matching track selection algorithm, such as the one specified in Common Manifest.

@nigelmegitt
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Same, as a normative requirement. The idea of the note is to cross-pollinate knowledge of metadata that's available that would be permitted in IMSC, but not required. It formally already is permitted I believe, so this would be informative only.

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The Timed Text Working Group just discussed APA WG comment: semantic layers w3c/imsc#524, and agreed to the following:

  • SUMMARY: Discussed in TTWG call 2025-02-13, more input from APA WG needed to describe the generic scheme they have in mind
The full IRC log of that discussion <nigel> Subtopic: APA WG comment: semantic layers #524
<nigel> github: https://github.com//issues/524
<cpn> Nigel: Am I right that, people have different files for different resources? So the problem moves to the signalling arena
<cpn> Pierre: On the terminal side that's true. But on authoring side, force display, different files for different tracks
<cpn> ... A challenge that's been pointed out is, when you have non forced content on, you have more space so you might change the forced content accordingly
<cpn> ... So there's a creative reason to have separate tracks
<cpn> ... The trend I see is to have separate tracks
<cpn> Nigel: In terms of semantic labelling, this is present in DAPT, so there's a potential production path where DAPT is used as an authoring stage, then the relevant content is extracted from the DAPT layer into a single purpose subtitle or caption track
<cpn> ... then layer on styling as a next step, at which point you have an IMSC document
<cpn> ... I'm nervous about being too prescriptive about arranging production workflows
<cpn> Pierre: It seems an unbounded issue, no concrete proposal, no timeline
<cpn> ... Your note says further discussion needed. So we should either discuss or defer the issue
<cpn> Nigel: The key question seems to be whether some normative statement is needed here
<cpn> ... force display is normative, and clear what the required player behaviour is
<cpn> ... But with an extensible list of layers, what is the player supposed to do?
<cpn> Pierre: force display was created at a time when the selection of a particular experience should be done in the ISMC presentation engine. That turned out not to be a great idea
<cpn> ... So this seems left from a bygone era, rather than being something for the future
<cpn> ... Having separate tracks is an accurate observation
<cpn> Nigel: People who want spoken subtitles, they want indication of the language and to trigger a text to speech system
<cpn> ... We don't have formal semantics for supporting that, but it does get asked for
<cpn> ... Solution to add metadata to allow that information to be tracked. Then it's a player behaviour to decide to speak the translations, but they can also conformantly play the caption track
<cpn> Pierre: There's no impetus today to have a generic system. So address if and when a proposal comes forward for a generic scheme?
<cpn> ... We could respond by saying we don't have use cases that support creating a generic scheme at this point for IMSC 1.3
<cpn> Nigel: You can use ttm:role attribute as generic scheme already. What's missing is to define player semantics
<cpn> Pierre: And for that there's no industry standard. It's been a point of friction
<cpn> ... If APA were to come up with a generic scheme, it might be great
<cpn> Nigel: Yes
<cpn> Nigel: There are two decisions to make. Do we deprecate force-content? Do we reference the ability to label particular subtitles (or parts of) as occupying different roles? And if we do, does APA want to define a specific set?
<cpn> Pierre: I recommend we do nothing, as we don't have concrete use cases?
<cpn> Nigel: Spoken subtitles are in use in parts of Europe now
<cpn> ... They have some additional signalling, I think as part of DVB profile
<cpn> ... Are you saying it would be better to have representation in this group for this?
<cpn> Pierre: Yes. There are definitely use cases, but this is about IMSC specifically
<cpn> Nigel: I can take an action to contact people
<cpn> Pierre: Not sure that would address the APA concerns though, in this issue, as the request is more for a generic system
<cpn> Nigel: And what we have are two very specific systems
<cpn> Pierre: I think the answer is that we don't have the information needed to come up with a generic scheme
<cpn> ... So I suggest going back to APA to say we'll defer it
<nigel> SUMMARY: Discussed in TTWG call 2025-02-13, more input from APA WG needed to describe the generic scheme they have in mind

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a11y-needs-resolution Issue the Accessibility Group has raised and looks for a response on. a11y-tracker Group bringing to attention of a11y, or tracked by the a11y Group but not needing response. imsc1.3 imscvNEXT
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