Re: Roll-up captions in WebVTT

On Dec 16, 2011, at 16:43 , Glenn Maynard wrote:

> On Fri, Dec 16, 2011 at 6:07 PM, David Singer <singer@apple.com> wrote:
> I have to say I am a bit puzzled; given a display of
> 
> This is a line of text
> and this is the second
> 
> which transitions abruptly to
> 
> and this is the second
> and the third line follows here
> 
> The second line 'jump' scrolls up.  I would have thought legibility would be better if it smooth scrolled up, as it's then visually clear it's the same line, just moved.  But people seem to be saying legibility is worse.  is that an artifact of 608 etc., or a true reflection on the aesthetics of smooth scrolling?
> 
> Are you responding to "... no scrolling at all is far better than either"?  You're comparing "jump-scroll" to "smooth-scroll", but Ian was talking about no scrolling at all.  That means
> 
> This is a line of text
> and this is the second
> 
> becomes
> 
> and the third line follows here
> and this is the second

That has the sentence's phrases first A then B; then it becomes C then B, which is backward, isn't it?

But maybe there is usually a way to do short captions such that text, once on-screen, never moves.  

Nonetheless, timed-text formats should be usable when movement occurs and is needed;  credits rarely jump-scroll, in my experience.


> 
> Once a caption is on screen, it never moves; captions disappear and new captions take their place.  I agree with Ian (assuming I'm reading what he meant correctly) that this is by far the most readable way to do it, because captions don't move around while you're trying to read them.  The reduced motion also is less of a distraction from the video; things don't change and move around unnecessarily, which draws the eye to them and away from the video.  Good subtitles should pull the user away from the video as little as possible.
> 
> It's hard to do with live captions, since you can end up in situations where you don't have any good place on screen to put a caption.  It'd be interesting to try this sort of captioning with "live" captions (eg. captions without carefully-edited timing information and other tweaks), and see what actually happens, though.  Maybe I'm assuming it doesn't work well because of existing practice, when it's actually a solvable problem.
> 
> (It's also not obvious if the typical editing tweaks used for the above are possible or reliable in WebVTT, but that's a whole different conversation, which has been touched on in previous threads…)

OK, now I am beginning to understand.

I think timed-text formats are also used for other than captioning;  scrolling credits come to mind, for example.

> 
> -- 
> Glenn Maynard
> 

David Singer
Multimedia and Software Standards, Apple Inc.