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Re: beginEnd002: par timeContainer and child with no duration

From: Glenn A. Adams <gadams@xfsi.com>
Date: Fri, 19 Dec 2008 16:15:49 +0800
To: Sean Hayes <Sean.Hayes@microsoft.com>
CC: Public TTWG List <public-tt@w3.org>
Message-ID: <C5717935.6F90%gadams@xfsi.com>

OK, now I have gone back and reread all of SMIL2.1ıs Section 10, and taking
your reading below as well as Philippeıs input regarding my earlier
misreading of DFXP 10.4 bullet 1, I think we have a problem in DFXP
regarding the essence of 10.4 bullet 1. In particular, its attempt to define
an implicit duration on body, div, p, and span appears to be problematic and
contradicts various aspects of SMILıs definition of implicit duration for
par and seq time containers. For example, according to that text, the
example below would yield an implicit duration of 0s for div (since itıs
parent is an implied seq time container). In contrast, SMIL would define its
(the div elementıs) implicit duration in terms of it being an implied par
time container. And, as you correctly state, the endsync=²last² semantics
that would apply from SMIL would result in an implicit duration of
indefinite for the div element (since it has children with a resolved begin
time but an unresolved active end time ­ or at least unresolved until the
external time interval of the tt element comes into play).

If I recall, the language of 10.4. bullet 1 was originally intended to
define the implied duration for text, or, more precisely, using DFXP
terminology, the implied duration of an anonymous span. In the case of an
anonymous span, the language of 10.4 bullet 1 seems apropos; however, it
does not seem so for all other cases (body, div, p, span). It seems to me
that in these latter cases, the semantics of SMIL should apply in terms of
each of these being designated as either a par or seq time container. So it
looks to me like we need to rewrite (or abbreviate) this bullet to apply
only to anonymous spans.

G.

On 12/17/08 6:28 AM, "Sean Hayes" <Sean.Hayes@microsoft.com> wrote:

> I agree with your data, however not your analysis; I believe my original
> (corrected) answer is the right one.
> 
> There are I think two ways to read our spec, and neither of them lead to your
> conclusion.
> 
> We explicitly constrain the implicit duration of a seq and par to be
> indefinite, thus, since the endsync behaviour of par is defined by its
> implicit duration, this would imply the endsync behaviour of last is not
> applied. If we wish endsync behaviour we need to change these constraints.
> 
> Notwithstanding that, even if we were to use endsync of "last" for par
> containers, this would reference the child with the last active duration; not
> the last lexical child, so since the rest of the par's have indefinite
> duration these would out last the p ending at 20s. Therefore the implicit
> duration of the div is [0,indefinite) and it would not end, since the last
> active child does not end, and the other p's will remain visible.
> 
> Sean Hayes
> Media Acessibility Strategist
> Accessibility Business Unit
> Microsoft
> 
> Office:  +44 118 909 5867,
> Mobile: +44 7875 091385
> ________________________________________
> From: public-tt-request@w3.org [public-tt-request@w3.org] On Behalf Of Glenn
> A. Adams [gadams@xfsi.com]
> Sent: Monday, December 15, 2008 4:57 PM
> To: Philippe Le Hegaret; public-tt@w3.org
> Subject: RE: beginEnd002: par timeContainer and child with no duration
> 
> 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"
> (2) per 7.1.4, div has an implied timeContainer="par"
> (3) per 10.4 bullet 1, div has an implied dur="indefinite"
> (4) per 10.2.4, each p has an implied timeContainer="par"
> (5) per 10.4 bullet 1, each p has an implied dur="indefinite"
> (6) per 10.4 bullet 1, each anonymous span has an implied
> dur="indefinite"
> (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;
> (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);
> (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;
> 
> Given the above, we can derive the following:
> 
> * implicit duration of Nth p in example is [N,20)
> * implicit duration of div in example is [0,20)
> * implicit duration of body in example is [0,20)
> 
> So, what should appear from the following example (according to the
> spec) is:
> 
> # 00:00:00
> 
> This test counts from 0 to 10 in 10 seconds.
> 0
> 
> # 00:00:01
> 
> This test counts from 0 to 10 in 10 seconds.
> 0
> This test counts from 0 to 10 in 10 seconds.
> 1
> 
> # 00:00:02
> 
> This test counts from 0 to 10 in 10 seconds.
> 0
> This test counts from 0 to 10 in 10 seconds.
> 1
> This test counts from 0 to 10 in 10 seconds.
> 2
> 
> # adds two lines each second until
> # 00:00:10
> 
> This test counts from 0 to 10 in 10 seconds.
> 0
> This test counts from 0 to 10 in 10 seconds.
> 1
> This test counts from 0 to 10 in 10 seconds.
> 2
> This test counts from 0 to 10 in 10 seconds.
> 3
> This test counts from 0 to 10 in 10 seconds.
> 4
> This test counts from 0 to 10 in 10 seconds.
> 5
> This test counts from 0 to 10 in 10 seconds.
> 6
> This test counts from 0 to 10 in 10 seconds.
> 7
> This test counts from 0 to 10 in 10 seconds.
> 8
> This test counts from 0 to 10 in 10 seconds.
> 9
> This test counts from 0 to 10 in 10 seconds.
> 10
> 
> # 00:00:11
> 
> This test counts from 0 to 10 in 10 seconds.
> 0
> This test counts from 0 to 10 in 10 seconds.
> 1
> This test counts from 0 to 10 in 10 seconds.
> 2
> This test counts from 0 to 10 in 10 seconds.
> 3
> This test counts from 0 to 10 in 10 seconds.
> 4
> This test counts from 0 to 10 in 10 seconds.
> 5
> This test counts from 0 to 10 in 10 seconds.
> 6
> This test counts from 0 to 10 in 10 seconds.
> 7
> This test counts from 0 to 10 in 10 seconds.
> 8
> This test counts from 0 to 10 in 10 seconds.
> 9
> This test counts from 0 to 10 in 10 seconds.
> 10
> This test is over.
> 
> # ... continues as above until
> # 00:00:20
> # when all content is removed
> 
> 
>> > -----Original Message-----
>> > From: public-tt-request@w3.org [mailto:public-tt-request@w3.org] On
> Behalf Of Philippe
>> > Le Hegaret
>> > Sent: Tuesday, December 16, 2008 5:44 AM
>> > To: public-tt@w3.org
>> > Subject: beginEnd002: par timeContainer and child with no duration
>> >
>> >
>> > We currently have the test beginEnd002 as follows:
>> > [[
>> >   <body>
>> >     <div>
>> >       <p begin='0s'>This test counts from 0 to 10 in 10
> seconds.<br/>0</p>
>> >       <p begin='1s'>This test counts from 0 to 10 in 10
> seconds.<br/>1</p>
>> >       <p begin='2s'>This test counts from 0 to 10 in 10
> seconds.<br/>2</p>
>> >       <p begin='3s'>This test counts from 0 to 10 in 10
> seconds.<br/>3</p>
>> >       <p begin='4s'>This test counts from 0 to 10 in 10
> seconds.<br/>4</p>
>> >       <p begin='5s'>This test counts from 0 to 10 in 10
> seconds.<br/>5</p>
>> >       <p begin='6s'>This test counts from 0 to 10 in 10
> seconds.<br/>6</p>
>> >       <p begin='7s'>This test counts from 0 to 10 in 10
> seconds.<br/>7</p>
>> >       <p begin='8s'>This test counts from 0 to 10 in 10
> seconds.<br/>8</p>
>> >       <p begin='9s'>This test counts from 0 to 10 in 10
> seconds.<br/>9</p>
>> >       <p begin='10s'>This test counts from 0 to 10 in 10
> seconds.<br/>10</p>
>> >       <p begin='11s' end='20s'>This test is over.</p>
>> >     </div>
>> >   </body>
>> > ]]
>> >
>> > What is the expected behavior?
>> >
>> > 1- give up because the document is not conforming
>> >
>> > 2- only shows the last paragraph from 11 to 20 because the other
>> > paragraphs have unresolved durations (that's the behavior of JW FLV
>> > Media Player)
>> >
>> > 3- all paragraphs will end at 20 (and begin at their respective times)
>> > because at least one of the children has a resolved duration
>> >
>> > 4- the first 11 paragraphs will show for one second each and the last
>> > paragraph will show from 11 to 20 (that's what ccPlayer and Adobe are
>> > doing)
>> >
>> >
>> > Philippe
>> >
>> >
> 
> 
> 
> 
Received on Friday, 19 December 2008 08:16:36 GMT

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