Re: xine's osd

Hi,

Miguel Freitas wrote:

> On Wed, 2003-08-13 at 04:46, Reinhard Nissl wrote:
>
> > > it's hard to say from the image, but i guess you are probably
> > > experiencing some sort of "color leaking"?
> >
> > What can I do about that issue?
>
> not much, except fixing our blending code to do something better....
> (src/video_out/alphablend.c)

Well, this could be a project in future ;-)

> > > the cause is the current blending code for YV12, it doesn't account the
> > > subsampling correctly. it is possible that U and V planes are
> > > incorrectly blended on edges (the behaviour may depend on even/odd
> > > pixels).
> >
> > Please explain that a little more, if you think, that I can do anything about 
> > that issue in the supplied OSD data, because the same data looks quite ok with 
> > xshm.
>
> you are probably sending correct OSD data, it is a bug inside overlay
> blender.
>
> xshm doesn't show issues because blending is done at RGB colorspace,
> where every pixel has these 3 components. however, the YV12 format
> subsamples the U and V planes, that is, the same U value is shared by 4
> pixels.

Is there a way to choose a different format instead of YV12 or is this format 
choosen on behalf of the video stream?

> see this M$ page about the formats:
> http://msdn.microsoft.com/library/en-us/dnwmt/html/YUVFormats.asp
>
> we would need to be smarter about blending at YV12, doing some kind of
> filtering i guess.

Thank you very much for this explanation. Once I find the time I will have a 
look at the code.

Bye.
--
Dipl.-Inform. (FH) Reinhard Nissl
mailto:rnissl@xxxxxx



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