XVideo (Xv) feed flickers on mouse-over with certain video

Justin Anderson justin at rayonix.com
Mon Jun 9 12:30:32 PDT 2008

Dear John,

Thank you for your reply.

I'm not sure that there is anything wrong with my X environment.  The
application "tvtime", for instance, is able (with the same environment) to
display flicker-free video with menus and channel information overlaid.

I'm still hoping for a better clue.



On Wed, Jun 4, 2008 at 9:37 AM, Bridgman, John <John.Bridgman at amd.com>

> >>From: "Justin Anderson" <justin at rayonix.com>
> >>I'm trying to resolve a thorny issue.  I'm working on an application
> built with C/X/Motif in which we have a window where the feed from a
> video camera is put.  We also draw a set of "cross-hairs" (simply two
> lines) which can be moved with the mouse to target a point on the video
> feed (for user's visual reference).  We add the video with the
> "XvPutVideo" command. Everything worked OK until the 6000 series of
> nVidia graphics cards (as well as ATI cards around-about that time).
> Since then, the cross-hairs are overdrawn by the video.  If you move the
> mouse pointer over the video feed, the video flickers as you move around
> and, simultaneously, the crosshairs appear.  When you stop moving, the
> crosshairs disappear and the video stops
> flickering.  Accorging to the MythTV website, nVidia cards stopped
> having a Chroma Key feature with the 6000 series.  I'm not sure if that
> has something to do with it.
> This makes sense. ATI cards also switched from using overlay-based video
> to shader-based video (aka TexturedVideo) rendered into the frame
> buffer, starting with the X1xxx discrete and RS6xx IGP parts.
> >>I think I can resolve the problem of the cross-hairs being overdrawn
> by the video feed if I add a Pixmap ClipMask which is black (0) where
> the cross-hairs are located and white (1) everywhere else.  However, the
> video flickering is still present.
> My first thought is moving to a composited environment where (hopefully,
> maybe) the cross-hairs could be composited over top of the rendered
> video. Not sure, just a thought. The main issue is that the video image
> is now drawn directly into memory (allowing it to work with a
> compositing manager) rather than floating over the video memory and
> being composited via hardware.
> _______________________________________________
> xorg mailing list
> xorg at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/xorg

Justin Anderson
Software Engineer
Rayonix, LLC (formerly mar-usa)
justin at rayonix.com
1880 Oak Ave. Ste. 120
Evanston, IL 60201
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.x.org/archives/xorg/attachments/20080609/ca786d44/attachment.html>

More information about the xorg mailing list