Re: CEA-608/708 and WebVTT

On Aug 30, 2012, at 1:02 , Victor Carbune <victor.carbune@gmail.com> wrote:

> On Thu, Aug 30, 2012 at 2:39 AM, David Singer <singer@apple.com> wrote:
>> The biggest issue I see is that 708 has the concept of 'windows' -- rectangular areas into which text gets painted.  We can land text in the right place, I think, but 708 has *3* colors -- the window, the text background, and the text foreground.  I don't see a way to identify the rectangular region to paint with the window color, in WebVTT, right now.  The 'size' and 'position' on a cue effectively define the left/right extent, but we don't have a line-range, just a line number.  (I am researching when the window gets painted with that color in 708.)
> 
> I would add, to all these, the anchor point concept that describes the
> direction in which the windows expand as content is being added and
> which point within the window lies on top of the video. This is
> something impossible to achieve with the existing WebVTT spec.
> 
> There are some pages in the CEA 708-B/D document that describe in
> detail how the painting is done when using anchor points. I also
> registered a bug a while ago:
> https://www.w3.org/Bugs/Public/show_bug.cgi?id=15859

I think if we want a system that mimics 708 exactly, we should deploy 708.  Perhaps a text form of 708 would be of assistance.  I am leery of bending VTT to make it look like 708 in the absence of a demonstrated need for the function or a demand from content authors for the function.

David Singer
Multimedia and Software Standards, Apple Inc.

Received on Thursday, 30 August 2012 17:57:37 UTC