Re: Roll-up captions in WebVTT

On Dec 18, 2011, at 0:07 , Silvia Pfeiffer wrote:

> 
> My argument is that there are situations where scrolling captions are
> needed and they are not necessarily rare or worse for everyone to
> watch. It's a different presentation that some prefer and others
> don't. Therefore we should have a standard means of doing them rather
> than having to do awkward text copying to simulate the effect (and
> screw up all useful automated analysis of the text).


I agree.  I think scrolling captions should be possible.  Given a long speech, it seems we have these choices:

a) each time the text changes, it's a complete replacement;
b) the text is multi-line, but once a line of text is on the screen, it stays there; the text is cyclically replaced (I think this is what Glenn suggests)
c) the text is multi-line, and jump-scrolls up as each line is added to the bottom
d) the text is multi-line, and smooth scrolls up

(a) suffers from a lack of continuity.  (b) results in order word/line weird.  (c) forces the user's visual/cognitive system to match the lines to see that they are moving, and if they are currently reading a line that moves, they have to re-find it.  (d) maintains line order, and maintains visual continuity of the cues.  In ordinary UIs we would be encouraged to do this (think of all the smooth animations and so on that happen in almost all modern UI paradigms), and so it puzzles me that (b) or (c) could be seen as better.


David Singer
Multimedia and Software Standards, Apple Inc.

Received on Monday, 19 December 2011 15:58:42 UTC