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FW: beginEnd002: par timeContainer and child with no duration

From: Russ Wood <russ.wood@softel.co.uk>
Date: Tue, 16 Dec 2008 14:25:51 -0000
Message-ID: <A367C34D91DC3E43B9FB4ABA401A1363E65545@exchange01.softel.co.uk>
To: <public-tt@w3.org>



-----Original Message-----
From: Russ Wood 
Sent: 16 December 2008 10:56
To: 'Glenn A. Adams'
Subject: RE: beginEnd002: par timeContainer and child with no duration

Subtitle authors like to work without end times in many circumstances,
but that doesn't mean that the concept of "no end time" needs to be
embodied in the file format.  The end time of each subtitle can be
calculated by the authoring station and written into the file.

Russ Wood

-----Original Message-----
From: public-tt-request@w3.org [mailto:public-tt-request@w3.org] On
Behalf Of Glenn A. Adams
Sent: 16 December 2008 03:29
To: Silvia Pfeiffer; Geoff Freed
Cc: Sean Hayes; public-tt@w3.org
Subject: RE: beginEnd002: par timeContainer and child with no duration


I also agree with Silvia, and would oppose the change suggested by
Geoff. The proposed change would be a significant departure from SMIL
timing semantics, which we have tried to maintain.

Geoff, a better way for you to express what you want would be:

<div timeContainer="seq">
<p dur='1s'>This test counts from 0 to 10 in 10 seconds.<br/>0</p>
<p dur='1s'>This test counts from 0 to 10 in 10 seconds.<br/>1</p>
<p dur='1s'>This test counts from 0 to 10 in 10 seconds.<br/>2</p>
<p dur='1s'>This test counts from 0 to 10 in 10 seconds.<br/>3</p>
...
<p dur='1s'>This test counts from 0 to 10 in 10 seconds.<br/>10</p>
<p end='10s'>This test is over.</p>
</div>

G.

> -----Original Message-----
> From: public-tt-request@w3.org [mailto:public-tt-request@w3.org] On
Behalf Of Silvia
> Pfeiffer
> Sent: Tuesday, December 16, 2008 9:41 AM
> To: Geoff Freed
> Cc: Sean Hayes; public-tt@w3.org
> Subject: Re: beginEnd002: par timeContainer and child with no duration
> 
> 
> On Tue, Dec 16, 2008 at 11:51 AM, Geoff Freed <geoff_freed@wgbh.org>
wrote:
> >
> >
> > i agree with sean's explanation, as this is the expected behavior
according to dfxp
> now.  however, when we built ccplayer we implemented things a bit
differently-- that is,
> a caption that has a begin time but no end time or dur will display
until the next
> caption displays.  at that time, the first caption will erase just
before the next
> caption appears.  so in the case of this:
> >
> >      <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>
> >
> > the first caption appears at 1s and is displayed until 2s, at which
time it erases and
> the second caption displays.  at 3s, the second caption erases and the
third caption
> displays.  etc., etc.  in dfxp terms, that equals this:
> >
> >      <p begin='1s' end='2s'>This test counts from 0 to 10 in 10
seconds.<br/>1</p>
> >      <p begin='2s' end='3s'>This test counts from 0 to 10 in 10
seconds.<br/>2</p>
> >      <p begin='3s' end='4s'>This test counts from 0 to 10 in 10
seconds.<br/>3</p>
> >
> >
> > we did things this way because caption software has not always
depended on end times
> to erase captions when the captions are timed to appear sequentially
without pause.
> >
> > doing things the first way means less coding, which is convenient.
i would lobby for
> changing the spec, if it's not a big pain, to permit this behavior not
only because it's
> less work, but also because caption vendors will probably expect to be
able to do things
> this way.
> 
> I respectfully disagree.
> 
> To me, upon first reading the first example, it was clear that this
> would add a new caption every second, but not remove any of the ones
> before. This is a very convenient way of specifying a default end
> value of "this last until the video ends whenever it ends". The best
> means to support this is by not giving an end value and therefore
> allowing it to last "forever". And it allows to have overlapping timed
> text that lasts until the end.
> 
> I think that if you wanted a text removed at a certain time, you'd
> have to provide an end time. Otherwise you are open to all sorts of
> misunderstandings. For example, what would you do with a specification
> like this:
> 
> <p begin='1s'>This test counts from 0 to 10 in 10 seconds.<br/>1</p>
> <p begin='2s' end='4s'>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='3s' end='4s'>This test counts from 0 to 10 in 10
seconds.<br/>4</p>
> 
> Would the third one appear at all?
> 
> Best Regards,
> Silvia.



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Received on Tuesday, 16 December 2008 14:29:58 GMT

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