Issues with previewing in Timeline & Clip Monitor

Hi there Community,

the problem I have with Kdenlive is not solvable by myself, therefore I need your help.
I'm using the latest official release of the program within a generic Ubuntu Installation.

As long as I play unedited imported clips from the project tree, everything shows up fine in the monitor window.
But when I'm scrubbing through the timeline (over edited tracks) the video output messes up, an the screen slowly shrinks on the x-axis.
I attached an screenie of that.

I played with the several videodrivers in the configurations dialog, but any other driver than the default x11 lets kdenlive crash.

So far, I really hope you can help me solve this one.
Thanks in advance for any clue that might lead me in the right direction.

Update: It seems like the problem only occurs, if the source videofile is mpeg encoded. Tried with Xvid and everything works just great.

That is probably an issue with your FFmpeg version, which does not correctly seek into your mpeg files...
Which version of FFmpeg (libavformat) do you have ? Maybe you can find a more recent package.