Vertical jagged aliasing using DirectX/3D/GDI, not OpenGL

[Caanon]

Seem to be running into an issue with Win7 and DirectX playing video files. Using certain video output modes, I get vertical artefacts throughout the entire frame. Upon closer inspection, it looks like every 6th or 7th vertical pixel row is doubled. This happens on three different computers, regardless of file played.

DirectX, Direct3D and GDI show these vertical jagged lines


With a zoom-in here:


I know this isn't an encoding issue, as using OpenGL renders a perfect frame:


Zoom:


In addition, when VLC saves a snapshot in either mode, it always saves correctly:


Any thoughts as to why the pixel doubling might be happening under GDI/DirectX/Direct3D? Or, coincidentally, why DirecX's colors are so muddled? Didn't even notice that until now....

[VLC_help]

Does it help if you
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