Abstract: A temporal error concealment is described. A video stream comprises a current frame comprising a lost image region, and a reference frame. The method comprises forming a list of motion vector candidates, the list of motion vector candidates including a set of one or more motion vectors from the current frame and a set of one or more motion vectors from the reference frame; testing each of the motion vector candidates using a matching error measure; selecting a replacement motion vector from the list based on the matching error measures; and using the selected replacement motion vector to conceal the lost image region. A mode selection method is also described. A motion vector is used to identify a motion compensated reference image region in the reference frame. A motion compensated temporal activity of an image region in the current frame is calculated based on a comparison between the image region in the current frame and the motion compensated reference image region in the reference frame.