[Xorg] Implementing "Xv" extension on DDX which don't supportit in hardware...

[Alan Cox]

On Sul, 2004-07-11 at 20:28, Roland Mainz wrote:
> I cannot implement "Xv" in a way like Mesa implements GLX for Xvfb (e.g.
> push images via XPutImage()), right ?
> Are the "Xv" overlays _required_ to leave the underlying framebuffer
> contents intact ?

Given the 'virtual' frame buffer lacks hardware acceleration for any
Xv functionality if you use null functions apps "work" so you can
test/use them. For any real app it would perform better anyway to
use MITSHM

> > For Xnest there is certainly nothing preventing it providing you go off
> > and write enough code. Xnest is an Xwindow, that means the Xv layer of
> > the master X server is perfectly capable of handling an Xv subwindow in
> > the Xnest window - you just have to get all the overlay offsets correct
> > and propogate the functionality.
> 
> What if the underlying Xserver does not support "Xv" ?

If it doesn't support Xv (or I suppose Mesa DRI) then you would again be
better off with the client doing the work