Artefacts in *.mkv playback

[theriel]

Hello,
I hope you would be able to help me with solving anissue with the quality of my video-playback.

I have configured my potplayer (+ffdshow + haali splitter) in the way suggested here - http://www.svp-team.com/forum/viewtopic.php?id=284

The problem is, while playing a video (1:1 rip of Godfather movie from blu ray using makemkv), I see artefacts - horizontal stripes, like in the attached image.

A few observations:
1) the same problem appears with a clean install of potplayer + ffdshow, as well as with kmplayer, even on default configuration.
2) this problem does not appear whatsoever when playing some other mkv movies (sometimes it appears, sometimes it does not, depending on the movie)
3) using VLC (and its internal codecs) the Godfather *.mkv video plays without any problems or artefacts.

I like potplayer and some of the ffdshow options, so I would like to continue being able to use them. The aforementioned observations seem to suggest that the source (mkv movie) is OK (VLC plays it), so I am guessing that the problem lies somewhere in potplayer or ffdshow configuration...

Please let me know if you need any further information.

I would really appreciate if you could help me solve the problem - thank you in advance for your kind help and suggestions!