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Re: Survey ready on Media Text Associations proposal

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Sat, 6 Mar 2010 12:01:37 +1100
Message-ID: <2c0e02831003051701u48fc4ec5m1abb07f302ab7c55@mail.gmail.com>
To: Markku Hakkinen <mhakkinen@acm.org>
Cc: Dick Bulterman <Dick.Bulterman@cwi.nl>, Eric Carlson <eric.carlson@apple.com>, Michael Smith <mike@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Hi Makku,

Thanks for the markup comparison. It really helped my analysis of the
differences between the proposed markup and the SMIL extract that Dick

On a side note, you might have based your comparison on an earlier
version of the TextAssociations proposal, since it now has 4 examples
and the language attribute is called @language . It's not important,
but you could update the page if you want to. Incidentally, in case
it's not clear, in the fourth example, you would need a switch element
around the alternative video source elements.


On Sat, Mar 6, 2010 at 5:40 AM, Markku Hakkinen <mhakkinen@acm.org> wrote:
> To add to Dick's SMIL example, I have taken the examples from the Text
> Associations wiki [1] and coded the SMIL equivalents [2].
> mark
> [1] http://www.w3.org/WAI/PF/HTML/wiki/Media_TextAssociations
> [2] http://www.talkinginterfaces.org/lab/video/html5smil.html
> On Fri, Mar 5, 2010 at 7:10 AM, Dick Bulterman <Dick.Bulterman@cwi.nl>
> wrote:
>> On the track proposal, just to make sure I'm not missing something:
>> Is there an implied preference order in the statements:
>>> <trackgroup media="accessibility(captions:yes") >
>>>>  <track src="en.srt" lang="en" enabled >
>>>>  <track src="fr.srt" lang="fr" >
>>>>  <track src="de.srt" lang="de" >
>>>> </trackgroup>
>> (In other words, the implied preference order is English, French, German.)
>> Compare this to the SMIL way of doing the same thing:
>>  <par>
>>    <video src="..." />
>>    <switch systemCaptions="on" allowReorder="yes">
>>      <textstream src="en.xxx" systemLanguage="en" />
>>      <textstream src="fr.xxx" systemLanguage="de" />
>>      <textstream src="de.xxx" systemLanguage="de" />
>>    </switch>
>>  </par>
>> The default behavior is that the first candidate matching a set language
>> preference is used. The 'allowReorder' attribute explicitly allows a user
>> agent the reorder the order of options if the user (via the UA) has
>> determined that he/she prefers German over French.
>> Note also that in this example, the entire <switch> is only evaluated if
>> the user (agent) has determined that captions are required. Note finally
>> that if the user has the language preference Dutch, no captions will play
>> (since he presumably can't understand them anyway). Having a final statement
>> in a <switch> without a predicate determines a result that will allows play
>> if no earlier option (reodered or not) do not provide a preference match.
>> Are the semantics of <trackgroup> similar? (If so, why invent something
>> new; if not, are at least the SMIL semantics supported?)
>> -d.
Received on Saturday, 6 March 2010 01:02:33 UTC

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