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Bug 16864 - [WebVTT] Allow using a smaller viewport for position/size of cues
Summary: [WebVTT] Allow using a smaller viewport for position/size of cues
Status: RESOLVED FIXED
Alias: None
Product: TextTracks CG
Classification: Unclassified
Component: WebVTT (show other bugs)
Version: unspecified
Hardware: PC All
: P2 normal
Target Milestone: ---
Assignee: Ian 'Hixie' Hickson
QA Contact: This bug has no owner yet - up for the taking
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: 19536
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Reported: 2012-04-26 10:14 UTC by Simon Pieters
Modified: 2012-10-15 05:37 UTC (History)
5 users (show)

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Description Simon Pieters 2012-04-26 10:14:18 UTC
TVs with overscan would render cues outside the screen if they have their default position and the video is in fullscreen. This seems undesirable. I think it should be allowed to use a smaller viewport size for the purpose of text size and cue positioning of cues.
Comment 1 Ian 'Hixie' Hickson 2012-04-26 22:27:03 UTC
Why would we allow video outside the screen if we don't allow text outside the screen? What if the video has a <div> overlaid on it with text on it?
Comment 2 Simon Pieters 2012-04-30 09:15:54 UTC
> for the purpose of text size and cue positioning of cues.

Possibly text size still needs to be calculated from the video's full size, so that the text doesn't appear too small on a TV without overscan if we think it has overscan.

> Why would we allow video outside the screen if we don't allow text outside the screen?

Allowing video outside the screen is the point of overscan. I'm not a fan of it myself, but it's a reality. It's quite possible to watch a video where the edges are cut off without losing any vital information. However, if all the subtitles are invisible, that's quite different.

> What if the video has a <div> overlaid on it with text on it?

I don't know what to do about that.
Comment 3 Ian 'Hixie' Hickson 2012-07-24 05:56:25 UTC
I think we should just make overscan non-conforming for <video>.
Comment 4 Philip J├Ągenstedt 2012-07-24 08:56:55 UTC
Alternatively, we could just have some margins by default. Currently, the default line position is aligned perfectly with the bottom of the video, which looks rather bad, really. Having 1 or 2 line height margin by default would fix the overscan problem and make things look better (by default) on any device.
Comment 5 Ian 'Hixie' Hickson 2012-08-06 23:06:46 UTC
Fair enough. How about making just one change, namely, allowing the snap-to-lines lines be positioned inset a bit if the user agent wants to, but leaving the %-positioned text and the default font size, etc, be unchanged? Would that work?
Comment 6 Silvia Pfeiffer 2012-08-07 01:32:56 UTC
(In reply to comment #5)
> Fair enough. How about making just one change, namely, allowing the
> snap-to-lines lines be positioned inset a bit if the user agent wants to, but
> leaving the %-positioned text and the default font size, etc, be unchanged?
> Would that work?

I would think the video height that is the basis for the % calculation then has to be reduced by that inset.
Comment 7 Ian 'Hixie' Hickson 2012-10-09 21:48:24 UTC
Part 1: http://html5.org/tools/web-apps-tracker?from=7445&to=7446
Comment 8 Ian 'Hixie' Hickson 2012-10-09 22:55:59 UTC
Part 2: http://html5.org/tools/web-apps-tracker?from=7446&to=7447
Comment 9 Philip J├Ągenstedt 2012-10-12 12:32:26 UTC
I've looked through the spec changes and it looks mostly good.

It would be nice if a default (edge) margin were specified, e.g. 5vh. It would also be nice if it could be specified with CSS while still allowing a minimum to be enforced by the UA. However, I'm not sure on what pseudo-element and using which property specifying this would make sense. Something like ::cuebox { padding: 5vh; } looks OK, but it may seem strange that it's ignored for positioned cues (snap-to-lines is false).