When I playback my original video (1080p30 35 Mbps mp4 or 1080p50 28 Mbps Avchd) on my Ubuntu 11.10 laptop with a (NVIDIA GeForce GT555 2Gb + Optimus Technologie) video card and 1920x1080 screen, I do see a wave going from the bottom of the screen to the top. It makes it uneasy to watch the video. I do see the same effect in the Kdenlive Monitor.

Does Ubuntu have difficulties to handle full HD video?

Not in general. I have full HD footage showing on an quad-core i5 with radeon hd 56xx graphics card without problems. Some vsync issue?

@DiveO

Thanks for your reaction.
Where do I have to look for, too solve a vsync issue?

Unfortunately, I have no ideo where to look for. The only place I would try to start is with the particlar xserver documentation for your video card. I remember seing sometimes vsync-related options. But I'm not clear that they help at all, maybe they may even worsen things.

Did you check that the "wave" as you name it is not already present in the footage itself? For instance, I have to shoot my footage in 1080p as otherwise the underwater-optimized lens system causes vignetation. Besides eating up more storage capacity, the problem sometimes becomes visible above water: sitting on a zodiac in full coldwater diving gear and speeding across the water causes rolling shutter effects as every shock is immediately transferred to the camera, no chance to dampen with more than 30kg of gear (tank, jacket, weights, ...) on your back.

@DiveO
I also looked for "screen tearing" as a result of a vsync problem.
I see a band, of lets say 1 centimeter, rolling/waving from the bottom to the top over my screen. The band itself seems to give a tearing effect (hard to see because it goes quick). I will focus first on this vsync/tearing effect to find out if this is causing the problem.
The original video in the camera does not show this effect. And it is not a rolling shutter effect, I know this effect.