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Bug 23686 - [WebVTT] use "partial interface TextTrack" to extend TextTrack
Summary: [WebVTT] use "partial interface TextTrack" to extend TextTrack
Status: RESOLVED FIXED
Alias: None
Product: TextTracks CG
Classification: Unclassified
Component: WebVTT (show other bugs)
Version: unspecified
Hardware: PC Linux
: P2 normal
Target Milestone: ---
Assignee: Philip Jägenstedt
QA Contact: This bug has no owner yet - up for the taking
URL:
Whiteboard: v1
Keywords:
: 22961 (view as bug list)
Depends on:
Blocks:
 
Reported: 2013-10-31 08:14 UTC by Philip Jägenstedt
Modified: 2014-01-25 06:17 UTC (History)
4 users (show)

See Also:


Attachments

Description Philip Jägenstedt 2013-10-31 08:14:39 UTC
http://dev.w3.org/html5/webvtt/#extension-of-the-texttrack-interface-for-region-support

Strictly speaking, the spec is redefining the TextTrack interface, which is clearly no intended. Use "partial interface".
Comment 1 Silvia Pfeiffer 2013-10-31 12:42:14 UTC
Good catch, thanks.
Comment 2 Philip Jägenstedt 2013-11-01 22:18:53 UTC
The indentation is a bit weird as well, might want to fix that at the same time.
Comment 3 Philip Jägenstedt 2013-11-11 13:24:09 UTC
To piggy-back some more, the indentation in http://dev.w3.org/html5/webvtt/#vttcue-interface is even stranger.
Comment 4 Silvia Pfeiffer 2013-11-14 14:45:56 UTC
*** Bug 22961 has been marked as a duplicate of this bug. ***
Comment 5 Ian 'Hixie' Hickson 2014-01-18 00:11:39 UTC
Um, isn't it bad to expose these VTT features on all TextTracks? Even the non-VTT ones? It seems like the better solution would be to have a subclass of TextTrack for VTT text tracks. Am I missing something?
Comment 6 Silvia Pfeiffer 2014-01-18 00:52:02 UTC
(In reply to Ian 'Hixie' Hickson from comment #5)
> Um, isn't it bad to expose these VTT features on all TextTracks? Even the
> non-VTT ones? It seems like the better solution would be to have a subclass
> of TextTrack for VTT text tracks. Am I missing something?

Maybe. However, rendering regions are a common way of restricting the rendering of a caption track to a certain area on the video viewport. We're also about to have WebVTT always render into a region - if none is given, there is a default region that covers the whole viewport. And we want to allow users to create regions by script. So, I don't think it's worth restricting this to VTT only.
Comment 7 Philip Jägenstedt 2014-01-18 09:40:29 UTC
(In reply to Silvia Pfeiffer from comment #6)
> (In reply to Ian 'Hixie' Hickson from comment #5)
> > Um, isn't it bad to expose these VTT features on all TextTracks? Even the
> > non-VTT ones? It seems like the better solution would be to have a subclass
> > of TextTrack for VTT text tracks. Am I missing something?
> 
> Maybe. However, rendering regions are a common way of restricting the
> rendering of a caption track to a certain area on the video viewport. We're
> also about to have WebVTT always render into a region - if none is given,
> there is a default region that covers the whole viewport. And we want to
> allow users to create regions by script. So, I don't think it's worth
> restricting this to VTT only.

I don't know, I think it's unlikely that the API added for the VTT Regions concept is going to applicable to other track types as well. We've already been talking about interactions between the VTT layout algorithm and VTT Regions like having them grow to contain their content and possibly overlap avoidance.

I'd be happy with making VTT Regions tightly bound to VTT, but if we go the other route we should make sure that the regions concept is really orthogonal to VTT, and not have "VTT" in the name, a rendering-specific member like "scroll", etc.

This wasn't the topic for which I opened this bug, I'll try to remember opening another bug before closing this one.
Comment 8 Philip Jägenstedt 2014-01-24 07:12:24 UTC
Filed https://www.w3.org/Bugs/Public/show_bug.cgi?id=24380
Comment 9 Philip Jägenstedt 2014-01-25 06:17:07 UTC
IDL syntax fixed in https://github.com/w3c/webvtt/pull/12