Re: Absolute region positioning (was Re: Alternative approach to scrolling, with demos)

On Tue, May 6, 2014 at 12:19 PM, Nigel Megitt <nigel.megitt@bbc.co.uk> wrote:
>
> On 05/05/2014 15:14, "Philip Jägenstedt" <philipj@opera.com> wrote:
>
>>On Mon, May 5, 2014 at 2:50 PM, Silvia Pfeiffer <silviapfeiffer1@gmail.com> wrote:
>>
>>> NB: Incidentally, following CEA708 rendering as exactly as possible is
>>> inline with what the US law prescribes, namely identical rendering
>>> between TV and Online. Though, to be honest, there is a line of "rough
>>> identity" that I am prepared to accept and I would call overlap
>>> avoidance an optimisation of sorts, which is why I'm not really
>>> accepting this as an argument.
>>
>>What will we do if the European Union introduces similar legislation
>>and broadcasters say that their existing content is EBU-TT, a TTML
>>flavor? Should the TTML model be added to WebVTT?
>
> I don't know about adding the TTML model precisely but I do think it would
> be worth considering the logical semantics encapsulated in TTML for region
> definition and overlap processing, which has an accepted mapping from
> CEA708 already, and has therefore tackled these questions. Given that
> WebVTT is on Rec track in the TTWG and one of the deliverables is a VTT
> <--> TTML mapping it would make everyones' lives easier in creating that
> deliverable if the regions models are as closely coincident as we can make
> them, accepting the differences in rendering approach and syntax between
> the two formats.
>
> I haven't seen anything in the discussion so far that looks like a CEA708
> requirement that can not already be met using TTML regions. If you want
> region overlap avoidance that would be different, but I suspect that isn't
> actually needed, and in any case would be a separate case from the z-index
> overlap order definition: I can't see how both approaches could apply to
> the same content simultaneously.

So, my question was actually rhetorical. I don't think it should be a
goal in itself to map other formats to WebVTT, or for WebVTT to be one
format to rule them all.

If other formats have features that address common use cases that
WebVTT is missing then we should consider supporting those use cases,
of course.

Philip

Received on Tuesday, 6 May 2014 13:17:47 UTC