Re: Change proposals for issue-152

On Tue, 22 Mar 2011 18:33:41 +0100, Sean Hayes <>  

> Well I don't agree that the "whole point of having multiple text tracks  
> is that
> the user agent can intelligently avoid overlapping cues while ensuring
> that a single cue doesn't move around when other cues are added or
> removed at the same time" is true, in fact I'm not sure I even  
> understand what you mean by that; why is there a need to fix a caption  
> once placed?

Having one caption jump around because another becomes visible or is  
hidden would be rather annoying, don't you think? As far as I can tell,  
the example you provided would suffer from this problem.

> If you are saying that captions are going to be selected in and fixed in  
> space in temporal order; that makes no sense, as you will end up with  
> different streams interleaved. it's actually far more likely you would  
> want to assign each caption output a fixed distinct region, since the  
> 80% use case for multiple simultaneous cue tracks is mixed language  
> subtitling like Bollywood where they subtitle in both Urdu and Hindi,  
> one individual reader is only going to be looking at one of the streams  
> so they want to always flick eye-gaze directly to where those captions  
> are going to appear.
> Allowing multiple caption files to intelligently share a given space is  
> however perfectly possible (see below); I'd much rather that than a  
> bunch of hacked up special case layout rules. If you have identified a  
> layout strategy that CSS can't do, then put it in CSS where it belongs  
> so everyone can share.

I somewhat agree with this. To the fullest extent possible, we should  
reuse CSS. However, I'm not convinced that it's actually possible in this  
case, given that CSS is stateless and can have no memory of captions that  
are no longer showing.

Philip Jägenstedt
Core Developer
Opera Software

Received on Tuesday, 22 March 2011 19:30:23 UTC