import vapoursynth as vs
import havsfunc as haf

core = vs.get_core()

clip = core.ffms2.Source(source="foo.mkv")
clip = core.std.CropRel(clip, 10, 10, 4, 4)
clip = haf.QTGMC(clip, Preset="Slower", TFF=True)

clip.set_output()