Flicker lines during playback

When i playback my mov files from my Canon 600d in Hitfilm, I get some horizontal flicker lines. Mostly when i move the camera. Quicktime player also has this problem, but no flicker in Mediaplayer classic? Downloaded newest K-lite codecpack, but no change.
Also there is no flicker when I use a HDMI cable from my camera to my TV.
I have a Asus 6850 GC, and 12 GB ram
Any ideas?