ISSUE-156: how to specify prohibitions in use of a feature

semantics of missing #feature

how to specify prohibitions in use of a feature

State:

CLOSED

Product:

TTML2

Raised by:

Sean Hayes

Opened on:

2012-02-15

Description:

It has been noted that there is an ambiguity in the way the profile work
A feature set is created in the following way:

The collection of features and extensions of a profile are determined according to the following ordered rules:

initialize the features and extensions of the profile to the empty set;

if a use attribute is present, then augment the profile with the set of features and extensions specified by the referenced baseline profile;

for each ttp:feature and ttp:extension element descendant of the ttp:profile element, using a post-order traversal, merge the specified feature or extension with the features and extensions of the profile, where merging a feature or extension entails replacing an existing feature or extension specification, if it already exists, or adding a new feature or extension specification, if it does not yet exist in the profile;

This process may result in a profile where some features are not mentioned at all. I tis not clear in such a case what the semantics should be, for example whether the missing features are optional or prohibited. As the feature mechanism does not provide a mechanism for prohibiting a feature being processed, and this is a semantic that some groups would like to express, they have adopted this interpretation. We should discuss whether missing implies must not process, in addition we should consider an explicit prohibited value.

We should also consider what it means to apply a profile to players, as opposed to documents.

Related Actions Items:

• ACTION-53 on Glenn Adams to Address or draft CP to resolve ISSUE-156 - due 2012-03-29, closed
• ACTION-54 on Glenn Adams to Clarify behavior regarding processor behavior when encountering feature for which no used or required is indicated - due 2012-03-29, closed

Related emails:

1. Minutes - 2013-07-11 (from glenn@skynav.com on 2013-07-11)
2. RE: TTWG Meeting Minutes March 7, 2013 (from momartin@microsoft.com on 2013-03-07)
3. TTWG Meeting Minutes March 7, 2013 (from momartin@microsoft.com on 2013-03-07)
4. TTWG Agenda March 7, 2013 (from momartin@microsoft.com on 2013-03-07)
5. Re: TTML Agenda for 28/2/13 (from glenn@skynav.com on 2013-02-28)
6. RE: TTML Agenda for 28/2/13 (from mdolan@newtbt.com on 2013-02-28)
7. TTML Agenda for 28/2/13 (from momartin@microsoft.com on 2013-02-28)
8. TTWG Meeting Minutes Feb 28 (from momartin@microsoft.com on 2013-02-28)
9. TTML Agenda for 21/02/13 (from Sean.Hayes@microsoft.com on 2013-02-21)
10. TTWG Meeting Minutes Feb 7, 2013 (from momartin@microsoft.com on 2013-02-14)
11. TTML Agenda for 14/02/13 (from Sean.Hayes@microsoft.com on 2013-02-14)
12. TTWG Meeting Minutes Feb 7, 2013 (from momartin@microsoft.com on 2013-02-07)
13. TTML Agenda for 07/02/13 (from Sean.Hayes@microsoft.com on 2013-02-07)
14. Minutes TTWG Aug 16, 2012 (from momartin@microsoft.com on 2012-08-17)
15. RE: TTML Agenda for 15/8/12 (from momartin@microsoft.com on 2012-08-16)
16. Fwd: TTML Agenda for 15/8/12 (from geoff_freed@wgbh.org on 2012-08-16)
17. Re: TTML Agenda for 15/8/12 (from geoff_freed@wgbh.org on 2012-08-16)
18. TTML Agenda for 15/8/12 (from Sean.Hayes@microsoft.com on 2012-08-16)
19. New ED, Action Items Completed (from glenn@skynav.com on 2012-06-28)
20. {minutes} TTML Agenda for 14/6/12 (from glenn@skynav.com on 2012-06-14)
21. RE: TTML Agenda for 12/4/12 (from geoff_freed@wgbh.org on 2012-04-11)
22. {minutes} TTML Agenda for 5/4/12 (from glenn@skynav.com on 2012-04-05)
23. {minutes} TTML Agenda for 22/3/12 (from glenn@skynav.com on 2012-03-22)
24. Re: {minutes} TTML Agenda for 15/3/12 (from geoff_freed@wgbh.org on 2012-03-15)
25. {minutes} TTML Agenda for 15/3/12 (from glenn@skynav.com on 2012-03-15)
26. [TTWG] Draft Minutes (was: Re: TTML Agenda for 1/3/12) (from glenn@skynav.com on 2012-03-01)
27. Re: TTML Agenda for 23/2/12 (from geoff_freed@wgbh.org on 2012-02-22)
28. Re: TTML Weekly meetings (from glenn@skynav.com on 2012-02-16)
29. ISSUE-156 (semantics of missing #feature): semantics of missing #feature [DFXP 1.0] (from sysbot+tracker@w3.org on 2012-02-15)

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