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RE: beginEnd002: par timeContainer and child with no duration

From: Geoff Freed <geoff_freed@wgbh.org>
Date: Mon, 15 Dec 2008 19:51:40 -0500
To: Sean Hayes <Sean.Hayes@microsoft.com>, "public-tt@w3.org" <public-tt@w3.org>
Message-id: <E36081A12A13F146AC32D7724B0E8912060C331390@EXCHCCR.wgbh.org>


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.

geoff




________________________________________
From: public-tt-request@w3.org [public-tt-request@w3.org] On Behalf Of Sean Hayes [Sean.Hayes@microsoft.com]
Sent: Monday, December 15, 2008 5:26 PM
To: public-tt@w3.org
Subject: RE: beginEnd002: par timeContainer and child with no duration

Slight update. The last p (the test is over) is removed at 20s. The other p's remain however.

Sean Hayes
Media Accessibility Strategist
Accessibility Business Unit
Microsoft

Office:  +44 118 909 5867,
Mobile: +44 7875 091385


-----Original Message-----
From: public-tt-request@w3.org [mailto:public-tt-request@w3.org] On Behalf Of Sean Hayes
Sent: 15 December 2008 22:17
To: Philippe Le Hegaret; public-tt@w3.org
Subject: RE: beginEnd002: par timeContainer and child with no duration


Assuming the document is surrounded by the appropriate verbiage, then I believe it is conforming. (NB SMIL explicitly disallows 0s, but it is allowed in our spec). Under a seq default for body no output would be produced, assuming we are changing body to be par, then the expected output is shown below.
BTW I'm almost done writing a whole bunch of tests for timing and animation, should be posting these in a few days.

This output is not particularly self explanatory. Each p, being in a par context has indefinite duration. Each one has an onset time one second later than its predecessor.

The expected behaviour is

at time 00:00:00
This test counts from 0 to 10 in 10 seconds.
0

at time 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

at time 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

at time 00:00:03
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

And so on until

at time 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


at time 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.


This then remains onscreen until the outer tt ends (controlled by external forces).


Sean Hayes
Media Accessibility Strategist
Accessibility Business Unit
Microsoft

Office:  +44 118 909 5867,
Mobile: +44 7875 091385


-----Original Message-----
From: public-tt-request@w3.org [mailto:public-tt-request@w3.org] On Behalf Of Philippe Le Hegaret
Sent: 15 December 2008 21:44
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 Tuesday, 16 December 2008 00:53:48 GMT

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