On Dienstag, 15. Juni 2004 00:15, Ville Syrj�l� wrote:
> On Tue, Jun 15, 2004 at 12:01:59AM +0200, Stefan Lucke wrote:
> > I've a question how to realize some sort of cropping
> > with SetScreenLocation ( .. ).
> > 
> > My test stream has a 4:3 frame encoded as 16:9 anamorphic mpeg2 frame.
> > To display this correct on a 4:3 or 5:4 display, a center out operation has to be
> > done.
> > 
> > Is such a operation possible with SetScreenLocation ?
> 
> I'm not exactly sure what you mean. 

Let's say the decoded picture is of size 720x576. It is anamorphic 16:9.
But I know (AFD descriptors tell that) the active area is of 4:3 format. So
only this area should be drawn on a 4:3 screen in full size. Without doing
that I would get black bars on top and bottom due to 16:9 scaling and
black bars left and right, since the active area is 4:3.

> Do you want to resize the image so 
> that parts of it go outside the visible screen?

No (virtual yes). I want to draw a part of picture so that it fills the screen.
With Xv output it is easy. There I can specify source x and y offsets and
source width and height witch should be drawn at a given destination area.
With Xv-X11 this works with matrox and radeon and I think with others too.

> In theory that should work 
> but in practise it depends on the driver. I can tell you that it works 
> with matrox and mach64 drivers. I'm not sure about the other drivers.

-- 
Stefan Lucke



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