Example OpenCV contour_example.au3 works with opencv_world451.dll Not sure why but had to change in example this to probably have more room to store it on 64 bits platform Local $pcontours = _cvCreateSeq(0, 64, DllStructGetSize(DllStructCreate($tagCvPoint)), $pstorage); Local $pcontours = _cvCreateSeq(0, 64*64, DllStructGetSize(DllStructCreate($tagCvPoint)), $pstorage); and this function definition changed to below returnvalue CvSeq* just to ptr or to a ptr*? i