Inheritance model of ttm:role attribute is unclear

[nigelmegitt]

In content elements, e.g. <div> the following text appears:

Any metadata specified by children in the Metadata.class element group applies semantically to the div element and its descendants as a whole.

However, this does not define how metadata specified by Metadata attributes on those content elements apply.

This raises the oddity that the application is specified in a scenario like:

<div>
  <metadata ttm:role="action"/>
  <p>This p has the role set {action}</p>
</div>

but is not specified in this otherwise equivalent seeming scenario:

<div ttm:role="action">
  <p>What is the role set of this p?</p>
</div>

Suggest adding wording that clarifies that metadata attributes on content elements also apply semantically to the element's descendants.

[css-meeting-bot]

The Timed Text Working Group just discussed Inheritance model of ttm:role attribute is unclear w3c/ttml2#1271, and agreed to the following:

• SUMMARY: @nigelmegitt to propose a pull request for this change

The full IRC log of that discussion

<nigel> Subtopic: Inheritance model of ttm:role attribute is unclear #1271
<nigel> github: https://github.com//issues/1271
<cpn> Nigel: role attributes on content elements also apply to descendants
<cpn> ... Glenn agreed on this
<cpn> ... Do we also need more time for this? It might be wording that's obviously missing, that includes attributes in the metadata attributes group
<cpn> ... Proposal is to add attributes to the current definition
<cpn> Cyril: I don't have a strong opinion, so would follow your suggestion. Would it need a new edition of TTML2
<cpn> Nigel: We're in CR anyway, would like to do a new snapshot at some stage
<cpn> s/CR/CR for a new update of TTML2/
<cpn> Nigel: Any objections to me proposing that additional wording?
<nigel> SUMMARY: @nigelmegitt to propose a pull request for this change
<cpn> ... I'll create a pull request