Re: TextTrack API changes

On Fri, Apr 26, 2013 at 12:03 PM, Bob Lund <> wrote:

>  On Fri, Apr 26, 2013 at 1:10 AM, Bob Lund <> wrote:
>>   From: Silvia Pfeiffer <>
>> Date: Wednesday, April 24, 2013 3:23 PM
>> To: Glenn Adams <>
>> Cc: public-html <>, "Jerry Smith, (WINDOWS)" <
>>>, Simon Pieters <>, Bob Lund <
>>>, Mark Vickers <>
>> Subject: Re: TextTrack API changes
>    I'm prepared to add the .text and getCueAsHTML() interfaces to
>> TextTrackCue if there is a definition of another XXXCue interface that has
>> these.
>>  There is a definition for in-band MPEG-2 TS text tracks here
>> that
>> is normatively referenced by the DLNA HTML5 Remote UI spec. This defines
>> use of the TextTrackCue text and getCueAsHTML attributes.
>  Thanks! Is this a spec that you are trying to standardize? Is this going
> through MPEG?
>  I can see that several time getCueAsHTML() has to be defined to return
> "null" in this document, because you don't need it. That indicates that it
> makes sense not to have it on TextTrackCue.
>  No, it is needed for the closed caption type of text track. getCueAsHTML
> is how script would get access control rendering of the Cue. The reason it
> is not used for other text track data types, for instance subtitles, is we
> wanted to minimize the text track types that the UA is required to
> recognize. However, if a UA CAN render a particular type of text track then
> getCueAsHTML would be the standard way for script to control rendering,
> just as was done for closed captions.
>  It seems to me that it would almost always be the case that a text track
> format that can be rendered by the UA could use getCueAsHTML to provide
> access to script.

What do you mean by "provide access to script"? Do you mean: handing over
the parsed data to JavaScript? Both .text and getCueAsHTML() do that.

   Even for the caption case the document states "getCueAsHTML() returns a
> DocumentFragment with an HTML representation of the TextTrackCue text
> attribute as defined in [HTML5], if the UA knows how to create such a
> representation. Otherwise, getCueAsHTML returns null." - that would only
> work for WebVTT captions IIUC.
>  No, we do that for 708 captions in our implementation.

So you convert the 708 captions into HTML for rendering? That's the
specification that I am after... do you have a link to how that is done?


Received on Friday, 26 April 2013 02:36:21 UTC