Re: Roll-up captions in WebVTT

Silvia's proposal avoids the duplicate text.

(at the beginning of this thread)

Christian

On Tue, Nov 29, 2011 at 12:05 PM, David Singer <singer@apple.com> wrote:
> At the moment, I can't think of a way of doing even jump-scroll without repeating text, unless (as is very likely) I am being dense.
>
> Maybe someone could correct me if the best practice on jump-scroll is something other than repeat?
>
>
> On Nov 29, 2011, at 17:40 , Christian Vogler wrote:
>
>> This is not quite true if the text is duplicated in the WebVTT file.
>> This would present serious accessibility issues for people who use
>> screenreaders (and that includes the deaf-blind population). It also
>> would make searching and indexing harder if text were duplicated.
>>
>> Christian
>>
>> On Tue, Nov 29, 2011 at 11:33 AM, David Singer <singer@apple.com> wrote:
>>> I think a fundamental question that needs addressing is whether we expect roll-up to be (a) 'part of' the core VTT vocabulary or (b) a presentational issue that is 'optional'?
>>>
>>> I tend to think the latter.  Yes, maybe smooth roll-up is easier on the eye than jump-scroll, but the same information is presented.
>>>
>>> If that is the case, I think using CSS transitions is a good candidate.  Alas, we don't use CSS positioning (for obvious reasons -- positioning DOES have to be part of the core of VTT).  But that doesn't hose us.
>>>
>>> Consider a stream that has Line1, Line2, …. LineN, showing in a three-line area.  A simple way to jump scroll that is simply to repeat each line, every time it 'moves' in the 3-line display.
>>>
>>> <blank>
>>> <blank>
>>> Line1
>>>
>>> then
>>>
>>> <blank>
>>> Line1
>>> Line2
>>>
>>> Line1
>>> Line2
>>> Line3
>>>
>>> Line2
>>> Line3
>>> Line4
>>>
>>> displayed simply, the lines appear to jump.
>>>
>>> If we can convince the CSS engine that Line1 in the first cue is the same as Line1 in the second, we could ask for a transition on, say, 'y'.  That's pretty easy to do with markup -- if a line of text in two consecutive cues has the same marked-id, then it's the same, and any CS transitions declared on its class apply, if you use CSS.
>>>
>>> Saying CSS transitions can be used to smooth out display transitions also allows for fade-in/fade-out (transition on color), and so on.
>>>
>>>
>>> David Singer
>>> Multimedia and Software Standards, Apple Inc.
>>>
>>>
>>
>>
>>
>> --
>> Christian Vogler, PhD
>> Director, Technology Access Program
>> Department of Communication Studies
>> SLCC 1116
>> Gallaudet University
>> http://tap.gallaudet.edu/
>> VP: 202-250-2795
>
> David Singer
> Multimedia and Software Standards, Apple Inc.
>



-- 
Christian Vogler, PhD
Director, Technology Access Program
Department of Communication Studies
SLCC 1116
Gallaudet University
http://tap.gallaudet.edu/
VP: 202-250-2795

Received on Thursday, 1 December 2011 09:21:10 UTC