[MPlayer-users] How to force SSA subtitles size to constant one ?

Παναγιώτης Κατσαλούλ Παναγιώτης Κατσαλούλ
Fri Aug 24 13:30:09 CEST 2007

On 22 Αυγ 2007, at 5:55 ΜΜ, Evgeniy Stepanov wrote:
> Right now, font sizes in libass are exactly like VSFilter's. Both  
> scaling
> dependent on video height and this patch _unapplied_ are required  
> to keep
> this compatibility. It is important, because SSA/ASS subtitles come  
> with
> predefines font sizes, and it is natural to display them as they were
> intended to be displayed.

> I could add an option to disable this compatibility hack, but is it  
> really
> that important for font sizes to be exactly as in other  
> applications ? And
> then, I won't be implementing size scaling with movie height or  
> diagonal for
> quite some time. You think the patch is useful even without this ?

OK, I understand what you mean.

The reason I am trying to find a solution is  because I am the author  
of "jubler" which is a subtitle editor and I am using mplayer to test  
subtitles in real time.
One of it's distinct features is that it has a WYSIWYG editor for  
subtitles, especially in ASS/SSA format. So, for example, the user  
selects font "Arial 24" and previews the subtitle with the given values.

If mplayer displays this subtitle, then the font size is smaller than  
expected (for the reasons described here). So, there is a mismatch I  
am trying to solve - and the reason nobody complained about it up to  
now is probably because most people write formatting by hand and not  
using a WYSIWYG environment ;)

The solutions I see are these:

1) Make mplayer use standard font metrics.

2) Execute mplayer giving a proper -ass-font-scale parameter,  
calculated from the difference font metrics

3) When jubler creates the subtitle file, instead of using the given  
font sizes, calculate new font size based on the value of OS2  
metrics. E.g. when the user requests a font size of 24, to save  
inside the file a font size of 30.

For me solution #1 is the best, since this retains compatibility with  
the whole operating system font metrics and not with an obsolete (but  
widely used) filter.
Solution #2 hides the actual problem.
Solution #3 makes a mismatch from what the user has asked and what he  
sees inside the text subtitle file.

Your suggestions are highly appreciated!

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