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RE: beginEnd002: par timeContainer and child with no duration

From: Philippe Le Hegaret <plh@w3.org>
Date: Tue, 16 Dec 2008 09:17:29 -0500
To: "Glenn A. Adams" <gadams@xfsi.com>
Cc: public-tt@w3.org
Message-Id: <1229437049.3114.178.camel@localhost>

Glen,

thank you for going through the specifications.

On Mon, 2008-12-15 at 19:57 -0500, Glenn A. Adams wrote:
> My answer is
> 
> > 3- all paragraphs will end at 20 (and begin at their respective times)
> > because at least one of the children has a resolved duration
> 
> Which is the same as Sean's first response (not his "correction").
> 
> At present, the spec explicitly dictates the following for this example:
> 
> (1) per 7.1.3, body has an implied timeContainer="seq"

ok (although this is related to an issue raised by Sean earlier)

> (2) per 7.1.4, div has an implied timeContainer="par"

ok

> (3) per 10.4 bullet 1, div has an implied dur="indefinite"

But, div is inside the body element, which is a sequential time
container, so per 10.4 bullet 1:
"if the element's parent time container is a sequential time container,
then the implicit duration is equivalent to zero."

So, I would conclude that div has an implied dur="0s"

> (4) per 10.2.4, each p has an implied timeContainer="par" 

ok

> (5) per 10.4 bullet 1, each p has an implied dur="indefinite"

ok

> (6) per 10.4 bullet 1, each anonymous span has an implied
> dur="indefinite"

ok

> (7) per 10.4 and smil2 10.4.1 (by reference), the simple duration of
> each element below is its implicit duration, except for the last p which
> specifies an active duration, i.e., both begin and end;

ok

> (8) per 10.4 and smil2 10.4.1 and 10.4.2 (by reference), the implicit
> duration of a par time container is controlled by its endsync value,
> with a default value of endSync="last" applying to par (since DFXP does
> not explicitly support specification of endsync);

But how do you conclude that the end time of the div (and all its
children) is at 00:00:20? As you mention (8), the implicit duration of a
par time container is controlled by its endsync value, with a default
value of endSync="last" applying to par.

In SMIL 2.1, 10.4.1, we have:
[[
last
        The par, excl, or media element's implicit duration ends with
        the last active end of the child elements. This does not refer
        to the lexical last child, or to the last child to start, but
        rather refers to the last active end of all children that have a
        resolved, definite begin time.
]]

In our case, all paragraph have a resolved begin. Even if they did not
have a begin attribute, their implicit begin would be 0. However, all
but one have an implicit duration of "indefinite" (7). So, when is the
active end of a child with an indefinite implicit duration?

> (9) per 10.4 and smil2 10.4.1 and 10.4.2 (by reference), the implicit
> duration of a seq time container ends with the active end of its last
> child;

Philippe
Received on Tuesday, 16 December 2008 14:17:52 GMT

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