981862 - [webvtt] Captions small in ff29

Status: RESOLVED WONTFIX

(Core :: Audio/Video, defect)

Description

[Ralph Giles (:rillian)]

Attachment: FF29 rendering

Testing today I noticed that captions display unusually small in Aurora (Firefox 29) compared to Firefox 28 or 30.

Comment 1

[Ralph Giles (:rillian)]

Attachment: FF30 rendering for comparison

Comment 2

[Rick Eyre (:reyre)]

That was probably when I changed the way cue size is calculated. Before we were using '1.5vh' which was incorrect because in the WebVTT spec the view port is redefined to be the video's area. Instead now we are correctly calculating it manually in vtt.js, instead of going through the effort of redefining the viewport for CSS computing in WebVTT.

I'm not sure what would be the best way to fix this.

Maybe uplift the relevant changes from FF30? What do you think Ralph?

Comment 3

[Ralph Giles (:rillian)]

I remember the relevant changes being fairly invasive. If there's a one-line change you can make to change the size (just the css for example?) I think that would be safer. Uplift is on Monday, so it needs to be quick either way.

Comment 4

[Rick Eyre (:reyre)]

(In reply to Ralph Giles (:rillian) from comment #3)
> I remember the relevant changes being fairly invasive. If there's a one-line
> change you can make to change the size (just the css for example?) I think
> that would be safer. Uplift is on Monday, so it needs to be quick either way.

Yeah, the changes needed for that calculation to happen are pretty invasive. Is this a fix we really want to make? We could just increase the vh setting that's set on the CSS. Probably a few decimal points in the percentage would be enough.

Comment 5

[Ralph Giles (:rillian)]

(In reply to Rick Eyre (:reyre) from comment #4)
> We could just increase the vh setting
> that's set on the CSS. Probably a few decimal points in the percentage would
> be enough.

Yeah, that. Will there by any side-effects with caption positioning?

Comment 6

[Rick Eyre (:reyre)]

(In reply to Ralph Giles (:rillian) from comment #5)

> Yeah, that. Will there by any side-effects with caption positioning?

I don't believe so. This was before we had overlap avoidance the height wasn't being taken into account for the caption positioning at that point.

Comment 7

[Rick Eyre (:reyre)]

Closing this as won't fix since we've prefed off support for WebVTT in 29. The size of the subtitles in 31 is good and that's the version in which it's enabled now.