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ebu / ebu-tt-xsd

A public repository with EBU-TT XML Schemas
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ttm:agent only allowed on //tt:head/tt:metadata #6

Open spoeschel opened 5 years ago

spoeschel commented 5 years ago

The element ttm:agent is currently only allowed as child of //tt:head/tt:metadata by the XSD. However TTML doesn't have such a restriction to the tt:head element (as parent of tt:metadata) here.

nigelmegitt commented 5 years ago

This restriction enforces that only significant ttm:agent elements can be created, specified in TTML:

A ttm:agent metadata item is considered to be significant only when specified as a child of the head element or as a child of a metadata element child of the head element.

Note that this is a semantic restriction in TTML rather than a syntactic one, and it would indeed be conformant, though meaningless, to define ttm:agent elements elsewhere.

I would like to keep this schema constraint because I think it is serving a useful purpose.

nigelmegitt commented 5 years ago

I'd be happy to note the divergence from the specification requirements, say in the README, if that would help?

nigelmegitt commented 5 years ago

The resolution to this will depend on ebu/ebu-tt-m-xsd#30.