Audio Description profile of TTML2

[nigelmegitt]

Support the requirements of audio description in a profile of TTML2, based on work currently happening in the Audio Description Community Group's w3c/adpt repository.

[skynavga]

Please add comments describing why a charter revision is needed.

[nigelmegitt]

There is no audio description profile Rec track document in scope or deliverables at the moment, so I think it needs a Charter revision.

[andreastai]

@nigelmegitt Do you imagine the same type as IMSC? Would this be just a subset of TTML or are there any extensions necessary?

[nigelmegitt]

@tairt I'm not sure what you mean by "the same type". I imagine it to be a profile of TTML2, and currently I am not aware of any extensions needed. There's a draft in need of a significant amount of work at https://w3c.github.io/adpt/ which shows the basic approach - there is a list of features, in the same way as there is a list of features for each IMSC profile.

[andreastai]

@nigelmegitt Thanks for clarification.

[andreastai]

I think that the conversation at last TPAC (October 2018) was very interesting. There was f2f session of the community group. It is documented here:

https://lists.w3.org/Archives/Public/public-audio-description/2018Oct/0008.html

Conversations to the browser communities was considered desirable to elaborate the possibility of native browser support. The outcome may have impact on the requirements for clients using the AD document.

[css-meeting-bot]

The Timed Text Working Group just discussed Audio Description profile of TTML2 tt-reqs#4, and agreed to the following:

• RESOLUTION: Accept this requirement for TTWG work in 2019 and add to the 2019 Charter.

The full IRC log of that discussion

<nigel> Topic: Audio Description profile of TTML2 tt-reqs#4
<nigel> github: https://github.com/w3c/tt-reqs/issues/4
<nigel> Nigel: This is for a Rec track profile of TTML2 (or TTML2 2nd Ed) based on the existing work in the AD CG.
<nigel> Andreas: So the idea is first to publish a new document which would be a profile like IMSC is a profile,
<nigel> .. and to make any additions or tweaks in TTML to make it fully compatible.
<nigel> Nigel: Yes
<nigel> Glenn: Another Rec track document basically?
<nigel> Nigel: Yes
<nigel> Glenn: Is there a designated Editor?
<nigel> Andreas: Are we deciding now on the changes to TTML2 or just on this document.
<nigel> Nigel: I'm not sure if there are any tweaks now, it may be that we want only to adjust the range of values
<nigel> .. that, say, tta:gain takes.
<nigel> Pierre: That complicates things significantly.
<nigel> Nigel: I don't think so.
<nigel> Glenn: It pushes it to TTML3. We can make cases for adding values if it was left out by mistake and
<nigel> .. clearly needed to support the functionality that was implied.
<atai> q+
<nigel> Nigel: I don't think so, this is a mistake I think, where the range of tta:gain was discussed but what went
<nigel> .. in the spec was a smaller range.
<nigel> Glenn: That's in a grey area, it sounds like it could be fixed in 2nd Ed.
<nigel> act a
<nigel> s/act a//
<nigel> Andreas: I added to the issue the f2f meeting of the AD CG because there were a lot of interesting ideas.
<nigel> .. I'm not sure how much they would be in scope for the proposed document.
<nigel> ack a
<nigel> Andreas: For example having more on the required processor behaviour.
<nigel> .. It's clearly not in TTML2 yet so the question is if you see this in scope for this new rec track document
<nigel> .. and if it would be more a new module than a new profile.
<nigel> Glenn: It sounds like there may be more impact than just one document here.
<nigel> Nigel: Yes I think so. The semantics are informatively described in TTML2 so we could either make them
<nigel> .. normative and more detailed in TTML2 2nd Ed or make them normative in the profile.
<nigel> Andreas: It would be good to get a harmonised approach with browser manufacturers so they could
<nigel> .. implement the same or a similar concept.
<nigel> .. Also something not in TTML2 is that a processor needs to pause the video if there is not enough time
<nigel> .. for the descriptions.
<nigel> Nigel: That's a good point.
<nigel> Andreas: I want to check that this is in scope of the work.
<nigel> Nigel: Yes the profile could say something about playback behaviour, which is beyond the scope of TTML.
<nigel> .. In terms of the Editor question, at the moment John Birch is editor in the CG, and I can ask if he is able
<nigel> .. to continue that here - he is a member of TTWG. I'd like to make myself an editor but am worried about
<nigel> .. the effort needed to do it, and chair, and look after the live subtitle work.
<nigel> .. We do have an editing opportunity here for anyone who wants to take it on, I think.
<nigel> Pierre: It sounds like we don't have a commitment at this point?
<nigel> Nigel: At the moment John is editor of that profile.
<nigel> .. There was a stated intention in the CG to move this to the TTWG so that won't be a surprise.
<nigel> Pierre: Great.
<nigel> PROPOSAL: Accept this requirement for TTWG work in 2019 and add to the 2019 Charter.
<nigel> Nigel: Any questions or comments before I finalise that?
<nigel> RESOLUTION: Accept this requirement for TTWG work in 2019 and add to the 2019 Charter.
<nigel> Nigel: I've moved the milestone on this issue also.

[nigelmegitt]

2019 Charter revision included Audio Description in scope. This is still work in progress. Removing charter label.