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Re: Re: questions on simple profile - nested spans

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Wed, 8 Aug 2012 12:33:36 +1000
Message-ID: <CAHp8n2nUd0LN=QKesnGHXySSV8oXDSCj9Rvt2s0FULZx+Gp35A@mail.gmail.com>
To: Sean Hayes <Sean.Hayes@microsoft.com>
Cc: "Goldstein, Glenn" <glenn.goldstein@viacom.com>, "public-tt@w3.org" <public-tt@w3.org>
Thanks, that really clarified it.
Cheers,
Silvia.

On Wed, Aug 8, 2012 at 4:01 AM, Sean Hayes <Sean.Hayes@microsoft.com> wrote:
> The processing happens so that at each time instant T,  the TTML tree is
> pruned to leave only elements temporally active at time T. Then what remains
> gets laid out essentially as if it were HTML for each time T; (the actual
> processing is simplified, because it is possible to compute the set of
> ‘interesting’ times at which something changes). At each interesting time T
> the region is effectively cleared and reflowed.
>
>
>
> In the example the timing is arranged on the <p> and <span>s such that each
> word <span> appears sequentially, and each line <p> is timed to stay visible
> for 11s. So for example at T=24 the top line has expired, and the remaining
> markup would look like:
>
>
>
>  <p >
>
>   <span >with</span>
>
>   <span >word</span>
>
>   <span  >at</span>
>
>   <span  >a</span>
>
>   <span  >time</span>
>
>   <span  >temporal</span>
>
> </p>
>
> <p  >
>
>   <span  >placement</span>
>
> </p>
>
>
>
> The implementation can treat the points T and T+1 as key-frames in an
> animation to smooth the transition, as this is apparently preferred by US
> viewers, in the UK however line-at-a-time jumps are more common.
>
>
>
> From: Silvia Pfeiffer [mailto:silviapfeiffer1@gmail.com]
> Sent: 06 August 2012 17:26
> To: Sean Hayes
> Cc: Goldstein, Glenn; public-tt@w3.org
> Subject: Re: Re: questions on simple profile - nested spans
>
>
>
> I have a question, too.
> http://dvcs.w3.org/hg/ttml/raw-file/tip/ttml10-sdp/Overview.html
>
> The document presents this as an example for rollup captions:
>
> <p region='rollup' begin='00:00:13.000' dur='00:00:11.000'>
>
>   <span begin='00:00:01.000'>rollup</span>
>
>   <span begin='00:00:02.000'>style</span>
>
>   <span begin='00:00:03.000'>caption</span>
>
>   <span begin='00:00:04.000'>support</span>
>
> </p>
>
> <p region='rollup' begin='00:00:17.000' dur='00:00:11.000'>
>
>   <span begin='00:00:01.000'>with</span>
>
>   <span begin='00:00:02.000'>word</span>
>
>   <span begin='00:00:03.000'>at</span>
>
>   <span begin='00:00:04.000'>a</span>
>
>   <span begin='00:00:05.000'>time</span>
>
>   <span begin='00:00:06.000'>temporal</span>
>
> </p>
>
> <p region='rollup' begin='00:00:23.000' dur='00:00:11.000'>
>
>   <span begin='00:00:01.000'>placement</span>
>
>   <span begin='00:00:02.000'>this</span>
>
>   <span begin='00:00:03.000'>could</span>
>
>   <span begin='00:00:04.000'>go</span>
>
> </p>
>
> <p region='rollup' begin='00:00:27.000' dur='00:00:11.000'>
>
>   <span begin='00:00:01.000'>on</span>
>
>   <span begin='00:00:02.000'>all</span>
>
>   <span begin='00:00:03.000'>day</span>
>
> </p>
>
>
> Would you mind explaining how this works?
> I am particularly confused about where the rollup happens. I assume that the
> words within the <p> element are all on the same line, but appear one at a
> time.
>
>
>
> That leads me to the conclusion that each <p> will be rendered on the same
> default position. Does that mean that the <p> elements push each other out
> of the way?
> How does that work technically: when you add a <p> on top of an existing <p>
> in the same location, is it added below and the previous <p> pushed upwards?
>
>
>
> I wasn't able to find that specified in the document. Sorry for my
> ignorance.
>
> Regards,
> Silvia.
>
>
Received on Wednesday, 8 August 2012 02:34:24 GMT

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