W3C home > Mailing lists > Public > public-tt@w3.org > December 2017

Re: Implicit duration of anonymous spans + error at MediaSeqTiming002.xml?

From: Pierre-Anthony Lemieux <pal@sandflow.com>
Date: Sat, 23 Dec 2017 14:04:35 -0800
Message-ID: <CAF_7JxBZkdFUFW7wx0o4PjQHZKxohvmtOOva_YOFP93D_mgpAg@mail.gmail.com>
To: Glenn Adams <glenn@skynav.com>
Cc: TTWG <public-tt@w3.org>
Ok. Thanks for confirming.

It looks like MediaSeqTiming003.ttml suffers from a similar problem.
The "This text must not appear." appears since the implicit duration
of a 'seq' element ends with the active end of the last child of the
seq (according to SMIL2.1).

Do you concur?

On Sat, Dec 23, 2017 at 11:30 AM, Glenn Adams <glenn@skynav.com> wrote:
>
>
> On Sat, Dec 23, 2017 at 12:26 AM, Pierre-Anthony Lemieux <pal@sandflow.com>
> wrote:
>>
>> Hi all,
>>
>> The discussion at [1] on the implicit duration of singleton spans has
>> prompted me to review the TTML1 and IMSC1 tests.
>>
>> [1] https://github.com/w3c/ttml1/issues/193
>>
>> I am wondering if MediaSeqTiming002.xml might have incorrect guidance.
>> As described at [2], it implies that "default duration for elements in
>> [a seq container] is 0" and that the following should not be rendered:
>>
>> <div timeContainer="seq" dur="20s">
>> ...
>> <p begin="00:00:05:00">This text must not appear.</p>
>> ...
>> </div>
>>
>> Is that correct? Isn't the implicit duration of the <p> indefinite
>> since its anonymous span has an indefinite duration per TTML1?
>
>
> The relevant spec text is in 10.4:
>
>> The implicit duration of an anonymous span is defined as follows: if the
>> anonymous span's parent time container is a parallel time container, then
>> the implicit duration is equivalent to the indefinite duration value as
>> defined by [SMIL 2.1]; if the anonymous span's parent time container is a
>> sequential time container, then the implicit duration is equivalent to zero.
>
>
> which handles the cases of the parent being a par or a seq distinctly.
>
>>
>> Best,
>>
>> -- Pierre
>>
>> [2] https://github.com/w3c/ttml1/issues/303
>>
>
Received on Saturday, 23 December 2017 22:05:20 UTC

This archive was generated by hypermail 2.3.1 : Saturday, 23 December 2017 22:05:21 UTC