W3C home > Mailing lists > Public > public-html@w3.org > May 2013

Re: TextTrack API changes

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Mon, 6 May 2013 23:42:16 +1000
Message-ID: <CAHp8n2mzn-vzRccWEWcP5=qgOoRTGPzQ4xNGF=x61_2TuC_duA@mail.gmail.com>
To: Simon Pieters <simonp@opera.com>
Cc: Bob Lund <B.Lund@cablelabs.com>, Glenn Adams <glenn@skynav.com>, public-html <public-html@w3.org>, "Jerry Smith, (WINDOWS)" <jdsmith@microsoft.com>, "Mark Vickers @ Comcast" <mark_vickers@cable.comcast.com>
On Mon, May 6, 2013 at 11:15 PM, Simon Pieters <simonp@opera.com> wrote:

> On Mon, 06 May 2013 14:54:15 +0200, Silvia Pfeiffer <
> silviapfeiffer1@gmail.com> wrote:
>
>  I've also put together the core of the discussion at
>> http://www.w3.org/html/wg/**wiki/User:Spfeiffe/**TextTrackChange<http://www.w3.org/html/wg/wiki/User:Spfeiffe/TextTrackChange>with my
>> current thoughts on how to resolve it.
>>
>> Please let me know if I've missed an argument.
>>
>> Also, I'm looking for feedback on the suggested changes, which are in
>> summary:
>> * add a .content attribute (of type ArrayBuffer) to TextTrackCue to
>> provide
>> a generic IDL attribute for the content of a cue
>>
>
> What's the use case for .content?
>
>
>  * re-introduce the TextTrackCue constructor
>>
>
> The wiki page says
>
> [[
> previously it was possible to construct a cue of any type and append it to
> a track with interpretation of cue content done by JavaScript
> ]]
>
> This is false. It was only possible to create WebVTT cues with the
> TextTrackCue() constructor. (This is an argument against reintroducing it.)
>


You can try on Chrome. Just do cue = new TextTrackCue(0,5,"test"); It
works. Doesn't need to be anything specific.

Maybe my wording was poorly chosen: I should maybe say "construct a cue of
no type".


[[
> re-introduce constructor, but only if there is no getCueAsHTML() API,
> which would require a default conversion algorithm
> ]]
>
> This doesn't make sense to me.
>

I mean by this that if getCueAsHTML() was re-introduced for TextTrackCue,
then a constructor doesn't make sense to me because it needs a conversion
algorithm from cue content to HTML. Since TextTrackCue is created without a
cue type, no such conversion algorithm would exist.


>
> [[
>  TextTrackCue gets associated with a kind when attached to a TextTrack
> (e.g. becomes a generic caption or metadata cue)
> ]]
>
> This is no different from WebVTTCue, right?
>

Yup. Just some extra information.


[[
>  TextTrackCue by itself has no cue type - WebVTTCue has WebVTT as the cue
> type, which includes an algorithm to convert the content in .content (or
> .text) to HTML
> ]]
>
> What's the use case for constructing a cue without a cue type? What
> specifies the behavior of such a cue?
>

It has content, which can be retrieved. I'm concretely thinking about
@kind=metadata here, where we only want to retrieve the cue content, but
not render it or do anything else with it. I think this is the basic use
case and TextTrackCue by itself is sufficient for that.

Silvia.
Received on Monday, 6 May 2013 13:43:08 UTC

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