Re: Implementing time-based transitions on WebVTT with CSS

On Tue, Aug 21, 2012 at 10:57 AM, "Carlos Solís" <csolisr@riseup.net> wrote:
>
>> In general, I think we have thought that smooth *transitions* between
>> things that VTT can express, could be expressed in the (optional)
>> presentation  layer by associating CSS transitions with the appropriate
>> classes.  This is 'safe', because in the absence of the appropriate degree
>> of CSS support, one gets abrupt transitions, which is semantically the
>> same.
> It would work, at least as a fallback. It seems like we both agree that
> semantics should guide style, and not the other way around.
>>
>> Whether we should have support for arbitrary transformations, the same way
>> I rather doubt.
> As it's planned currently it doesn't work, yet. Another way to do so
> should be thought of, at least for future versions.

Do you have a suggestion? And a more concrete example with markup?
It's a bit difficult to understand what you are asking for without
more concrete details.


>> I think VTT is intended as a captioning/sub-title layer primarily;  you'll
>> need a ton of extra features if you want to use to make 'real content'
>> that has text in it (smooth blending, transformations, and so on).
> Indeed it is. As of now, it's CSS that adds that transformation layer (a
> very smart idea in my opinion). The problem would be to properly map the
> captioning layer (WebVTT) in such a way that the styling layer (CSS) is
> able to react to the time of the subtitles and do transformations
> accordingly. Either that mapping is currently incomplete, or the existing
> CSS functions needed to do time-based transitions (if any) have not been
> yet considered to interact with WebVTT.


I think synchronisation of DOM elements for CSS transitions etc is
indeed a big challenge, but not one we want to solve in WebVTT.

requestAnimationFrame is one of those initiatives that is working
towards such a goal. Is that what you're thinking about?

Cheers,
Silvia.

Received on Thursday, 23 August 2012 01:11:12 UTC