RE: TTML Agenda for 26/4/12 ISSUE 151

Glenn,

I seek clarification of the following bold (my emphasis) paragraph:

If a value of discontinuous applies, then time expressions must not be converted to real time coordinates, arithmetical operators (addition, multiplication) are not defined on time expressions, and, consequently, any expression of a duration must be considered to be invalid.

Note:

When operating with smpte time base anddiscontinuous marker mode, there is no effective time coordinate space; rather, all time expressions are interpreted as labeled synchronization events (markers), where some external synchronization context emits these events, which, when they correspond with time expressions that denote the same label, cause a temporal interval to begin or end accordingly.

An additional side-effect of operating in discontinuousmode is that time expressions of children have no necessary relationship with time expressions of their temporal container; that is, temporal containers and children of these containers are temporally activated and inactivated independently based on the occurrence of a labeled synchronization (marker) event.
In discontinuous marker mode, would a child <span> within a <p> element require explicit timing (even if they were required to have exactly the same presentation timing)? Or does the above just mean that it is not possible to use relative timings within a child of a temporal container.

i.e. is the following necessary for all the text to appear simultaneously…

<tt:p xml:id=“subtitle1” region=“regionTop” begin=“00:00:00:00” end=“00:00:03:00”>
Beware the <span begin=“00:00:00:00” end=“00:00:03:00” style="greenbackground>Jabberwock</span>, my son!<tt:br/>
The jaws that bite, the claws that catch!
</tt:p>

Best regards,

John

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From: Glenn Adams [mailto:glenn@skynav.com]
Sent: 26 April 2012 05:33
To: Sean Hayes
Cc: public-tt@w3.org
Subject: Re: TTML Agenda for 26/4/12

regrets for tomorrow and next week due to travel and webapps/html f2f meetings; however, i've just posted an updated ED that attempts to address ISSUE-151

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