Re: VTT/CSS (was RE: Evidence of 'Wide Review' needed for VTT)

Hey David, John,

>> when you say inline CSS, you mean both of
>> a) style-sheets in the header?
>> b) styling in the cues themselves, using CSS snippets?
>>
>> Have you looked at the old threads on this question?  I think we got
>> close to a number of possible designs, but held off until it was really
>> needed and we had real implementers on hand.

Style rules in the header are most important IMO. They allow CC
authors to style:

*) All cues in a VTT
*) Specific cues (using classes or ids)
*) Specific persons or snippets (using voices or ids)

I see inline styling as largely redundant to styling rules in the
header (most can be achieved with classes, id's and voices).

> This should be achievable through UA configuration or even through something
> like a greasemonkey script or user CSS which can override styles dynamically
> in the browser."
> (source: Media Accessibility User Requirements -
> http://www.w3.org/WAI/PF/media-a11y-reqs/#VP-2)
>
> From a practical perspective, it is significantly easier for third parties to
> write scripts and/or user style-sheets if the content is all located in
> one-place. For this reason, I would suggest that CSS be contained in a linked
> style sheet, and *NOT* written in-line in the VTT file.

This is absolutely important, but I also see this also as a separate
step. Overall there seem to be 3 tiers:

First, there's the styling rules from the environment (HTML5 browser),
which apply to all VTT files played. They're the baseline. General use
cases are to make the captions look good and read well within the
site/player design.

Second, there's the styling from the VTT author, which apply to only
that single file. Use cases include emphasis on certain types of cues
(music, voiceover, etc) and certain ranges of cues (e.g. repositioning
when the default region overlaps with in-video text). It's preferred
to have these rules live inside the VTT, as it makes for easier
authoring, file management, conversion to other formats and
implementation of parsers (outside of HTML browsers).

Third, the end user can override the styles an author has set (or,
more common, set additional rules). This is specific to the individual
user and relates to the FCC options end users can set in video
players. As David said, through CSS but more importantly system-wide
menus (iOS/Android/etc) or options in the video player
(YouTube/JWPlayer/etc).

In short, style rules in the header of a VTT file is what we (our
publishers) would like to have. Styling rules inside the cues and
links to external CSS are less relevant.

Kind regards,

Jeroen

Received on Wednesday, 21 January 2015 16:27:56 UTC