Clunky/jittering playback in Premiere 6.5 'Monitor' window

[liorde]

Hello all,
I am using Premiere 6.5 and just yesterday, I noticed that the video playback in the 'Monitor' window is really bad, voice and video go out of sync (audio finishes before movie has finished), really clunky playback, as if watching frame->pause->frame etc...
I have no idea what caused this, or what could cause this.
It happened on various video files I have imported to Premiere, so I guess it is not the video that went wrong.
What can I do now> Where can i start digging to find out what caused this?

My system is more than enough for Premiere6.5 and I have been using it for half a year now, without any problems.

Thank-you.

[lordsmurf]

This happens with certain source files. MPEG, for example. The output is fine. The preview is the only thing borked.

[liorde]

Hi again,
The issue is that the output was also very bad. I edited a movie which is totally fine if you play it in WMP for example. When I saved it and viewed it again in WMP, it was already very bad.
I dont understand what happened to it..?!?!??