1. A motion estimation unit for estimating a current motion vector for an area of a current video image, comprising: module determining a set of candidate motion vectors; a temporal distance detection unit which determines whether the temporal distance between a current image and a previous image has doubled due to a missing input image; module doubling at least one candidate motion vector in the set of candidate motion vectors if the temporal distance detection unit determines that the temporal distance between a current image and a previous image has doubled; module including the at least one doubled candidate motion vector in an updated set of candidate motion vectors if the temporal distance detection unit determines that the temporal distance between a current image and a previous image has been doubled; module estimating the current motion vector from the updated set of candidate motion vectors by calculating a match error only once for each candidate motion vector and comparing the calculated match errors; and module halving the candidate motion vectors and including halved candidate motion vectors in the updated set of candidate motion vectors.