[MPlayer-dev-eng] [PATCH] bugfix for black bar besides gaussed vobsubs

[Reimar Döffinger]

Hi,
On Sat, Jan 08, 2005 at 02:52:05PM +0100, Csillag Kristof wrote:
> 2005-01-08, szo keltezéssel 11.35-kor Reimar Döffinger ezt írta:
> > How about memset(d2, 255, ds*dh); before scaling? Probably not much
> > slower (well, when I look at that code I think speed wasn't really much
> > considered anyway) and easier to understand.
> > Think that should work, too...
> Now that you mention it, the following solution is faster and alsa more
> simple (both to do, and to understand). (See attached patch!)
> 
> Here is how it works now:
> 
> 1. It gets the alpha values straight:
> 	- 0 means totally transparent
> 	- 1 means almost totally transparent
> 	- 255 means not transparent at all
> 	(Until so far, we set the values to the
> 	_opposite_ values before scaling.)
> 
> 2. Scales up the stuff.
> 	(The padded parts are 0 - that's totally transparent,
> 				 no more problem)
> 
> 3. Reverts the alpha values to the "normal" way:
> 	- 0 still means totally transparent
> 	- 1 is not transparent at all
> 	- 255 is almost totally transparent
> 
> 	(May I ask, why do we use this interpretation? It's a pain...)

Agree, I dislike it and it should be changed. I think it's because it
was like that in the first OSD implementation (and is used when you
define FAST_OSD). Not 100% sure though.
Wouldn't 256 - s2[i] (which is by the way equivalent -s2[i]) make more
sense than (s2[i] - 1) ^ 255 ??

Greetings,
Reimar Döffinger