On 19.06.2009 14:58, Jacques, Hugo wrote: > Hi all, > > I get a strange phenomenon using the XV texture adapter in YV12 > format on my 945G hardware and a 2.7.0 xf86-video-intel driver. > > I fill a rectangle with many 1 pixel-high horizontal lines. Odd lines > are black and even lines are white. I send this rectangle using > XVShmPutImage to a window with the same size so that no scaling > occurs. > > I would expect to see the black/white horizontal lines pattern. But I > get a uniformly grey rectangle! Same phenomenon appears on either > VGA, DVI or CVBS-TV monitors: it doesn't seem to be monitor/video > encoder issue-related. > > I also saw that on much older drivers. Maybe it has always been this > way. > > Notes: 1) When the output window is one pixel higher(upscaling) or > one pixel shorter(downscaling) than the source rectangle, I do see > the expected pattern, but with some scaling distortion (as I > expected). > > 2) Opening a bitmap or .jpeg with the same pattern with an image > viewer (GIMP), everything is fine. The phenomenon seems to be > Xv-specific. > > 3) With the XV overlay adapter, if the pattern has the same size as > the window, I do get all lines but with an unexpected scaling > distortion. If the pattern is one pixel higher than the window > (downscaling case), I do get the same phenomenon as when the texture > adapter is used with no scaling. There seems to be a skew of 1 pixel > on the overlay adapter vs. the texture one.
Not sure here, but as a wild guess (at least for textured xv) I would guess there's some half-pixel offset somewhere causing the bilinear texture filter to produce grey out of 2 black, 2 white pixels. Maybe either coords are set up slightly wrong, or chip somehow set up incorrectly (for instance d3d and ogl have a half-pixel offset difference in sampling positions - not sure though if that's actually changeable on this chip). > > Is this a known issue? Should I enter this into Bugzilla? Yes, you probably should. Roland _______________________________________________ xorg mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/xorg
