[Xorg] Implementing "Xv" extension on DDX which don'tsupportit in hardware...

Roland Mainz roland.mainz at nrubsig.org
Sun Jul 11 13:42:10 PDT 2004

Alan Cox wrote:
> 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.

Depends... server-side image scaling is usually faster than client-side
(assuming you make the images larger :) because you transfer _less_
data. Much less...

> For any real app it would perform better anyway to
> use MITSHM

If - and only "if" - MITSHM is available and suitable for the
application. MITSHM itself is a PAIN on some OSes since the number and
size of the shared segments is _limited_. IMHO MITSHM should go away,
replaced by a shared memory X transport...



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