[mythtv-users] high res display oddity

[Steven Adeff]

I've got a "second" computer (fileserver, etc) with an FX5300 (PCIe
FX5200) connected to a 21" monitor. I'm thinking of using this as a
part-time frontend in my bedroom. So I've begun playing around with
it. I'm normally running 1600x1200 resolution and without XvMC. I've
always noticed in HD playback that there was a stripe of about
30lines(?) that was not quite right, it gets worse in high movement
scenes. It looks as though the lines aren't rendering with the proper
horizontal alignment, like a wave of improperly aligned pixels. I want
to run 1920x1200 to be able to use it as an HD monitor.

So lately I've been playing around with XvMC on this machine (trying
to figure out why I don't see much drop in CPU usage), and I've come
to really be bothered by these lines.

So I try running at 1280x768 and the lines go away for both 720p and
1080i content.
So I think maybe it has to do with overall screen size?

So I've charted my experiments....
I've got the vblank options enabled in nvidia-settings along with the
blit options.
I use linear deinterlace except where noted due to prebuffer pauses
that cause stuttering.
the options I played with are the Composite and Render "extensions" in
xorg and usage of XvMC.
Test 1
Composite=no, Render=no, XvMC=no
1920x1200=bad + no deint
1600x1200=bad
1680x1050=ok
1400x1050=ok
1280x1024=ok

Composite=yes, Render=yes, XvMC=no
1920x1200=bad
1600x1200=bad
1680x1050=ok
1400x1050=ok
1280x1024=ok

Composite=yes, Render=yes, XvMC=yes
1920x1200=ok!
1280x768=ok
but only for 1080i content, 720p content gives  infinite prebuffering
pauses after an osd is displayed (which may be fixed by updating to a
newer fixes svn...?).

So why is it that at 1920x1200 without XvMC I get this problem but
with XvMC I don't?

Does anyone else running a 1080p modeline see what I'm seeing?

--
Steve