On Wed, 16 Nov 2005, Alex Deucher wrote:
> On 11/16/05, Smoof . <[EMAIL PROTECTED]> wrote:
> > Hello,
> >
> > I am writing an application that will display up to 9 independent video
> > streams (each stream is 320 x 240). I'm new to Xv and may not be using the
> > correct terminology so please bear with me. I have tried two approaches:
> >
> > The first approach was to create one large overlay using XvShmCreateImage
> > and tile in the video frames. Once all frames are tiled in, use
> > XvShmPutImage to send them to the X server. This method works perfectly.
> > However, my ultimate goal is to send each video stream to it's own GTK
> > widget so I can have each video stream playing in a window that can be
> > moved, be surrounded by buttons, minimized, etc...
> >
> > I implemented this by creating a simple GTK app with three drawing areas
> > (ultimately I will have 9) of 320x240 and used some GDK functions to
> > determine the X window id's for the widgets. I created a separate overlay
> > (again using XvShmCreateImage) for each window. Then I call XvShmPutImage
> > once for each window. Finally I call XFlush so send the requests to the X
> > server. I tried using XSync but it seemed to interfere with the GTK event
> > loop.
> >
> > The problem with this second approach is that the overlays are flashing blue
> > (the overlay color key from what I've read). So I looking for advice on how
> > to update multiple overlays at a rate of 24fps without any flashing. Or if
> > you don't think this is possible then please let me know and I'll just have
> > to get by with my first implementation.
> >
>
> Most hardware only has one overlay so each widget will be fighting for
> it. only the one that has it at any given moment will actually
> display the video; the rest will show the colorkey.
>
> Alex
Typically, a client will grab the Xv port when using it to prevent
other clients from being able to use the same Xv port. When a new
client can't grab one Xv port, it looks for another one. That mechanism
only works when there are different clients. If you want to do all
rendering from the same client, then you need to deliberately use
different ports for each Window. Some drivers export more than one
adaptor that supports XvImages and some adaptors have more than one
port. Overlay adaptors will typically only have a single port.
Run xvinfo for a summary of adaptors and their capabilities.
Mark.
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