1. In a video signal processing system, a method of computing a motion decision value, which comprises the following steps: inputting a video signal with an interlaced video sequence of fields; comparing mutually corresponding fields and defining a point-wise non-recursive motion decision parameter indicating motion at a given point between a previous field and a next field in the video sequence; computing a recursive motion decision parameter by combining the non-recursive motion decision parameter with a motion decision parameter of at least one associated previous field; and outputting the recursive motion decision parameter for further processing in the video signal processing system.