ISSUE-452: The ttp:profile element is permitted to conflict with the IMSC 1 profile

Profile element may be misused

The ttp:profile element is permitted to conflict with the IMSC 1 profile

State:
CLOSED
Product:
TTML IMSC 1.0
Raised by:
Nigel Megitt
Opened on:
2015-10-09
Description:
This is related to Issue-450 and is filed in response to Action-431.

IMSC 1 permits use of the ttp:profile element via the #profile feature ("MAY be used"). In the text profile in the current editor's draft #lineBreak-uax14 is described as "not applicable to Document Instances".

However in the specific case that a ttp:profile element is used then the #lineBreak-uax14 feature designator can be included in a document instance so in fact it is applicable to the Document Instance.

I had previously been concerned that a contrary feature could be specified, but I see that it is not possible. The closest you can get is.:

<ttp:profile use="http://www.w3.org/ns/ttml/profile/imsc1/text">
<ttp:features xml:base="http://www.w3.org/ns/ttml/feature/">
<ttp:feature value="optional">#lineBreak-uax14</ttp:feature>
</ttp:features>
</ttp:profile>

However any IMSC 1 conformant processor is fine with this so there's no problem there.

It is probably that the resolution to Issue-450 will in passing resolve this issue too, because in order to solve Issue-450 the formulation of the specification will likely need to define document conformance in terms of processor features rather than processor conformance in terms of document features, since the latter don't exist in TTML 1.
Related Actions Items:
Related emails:
  1. {minutes} TTWG Meeting 2015-10-30 (from nigel.megitt@bbc.co.uk on 2015-10-30)
  2. {agenda} TTWG Meeting 2015-10-15 (from nigel.megitt@bbc.co.uk on 2015-10-14)
  3. ISSUE-452 (Profile element may be misused): The ttp:profile element is permitted to conflict with the IMSC 1 profile [TTML IMSC 1.0] (from sysbot+tracker@w3.org on 2015-10-09)

Related notes:

ttp:profile element forbidden.

See https://dvcs.w3.org/hg/ttml/rev/fac9c9ac4e0d

Pierre-Anthony Lemieux, 29 Oct 2015, 00:54:15

[nigel]: [Meeting 2015-10-30] Change agreed as above.

30 Oct 2015, 03:07:36

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David Singer <singer@apple.com>, Nigel Megitt <nigel.megitt@bbc.co.uk>, Chairs, Thierry Michel <tmichel@w3.org>, Philippe Le H├ęgaret <plh@w3.org>, Atsushi Shimono <atsushi@w3.org>, Staff Contacts
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