an adaptive motion vector detector adaptively selects the pixels employed in detecting motion vectors between a first frame and a second frame of a video broadcast . the first frame includes a reference block of pixels and the second frame includes a check block of pixels . an analyzing circuit adaptively determines positions of a first subset of pixel values in the reference block based on a variable feature of the reference block . a selecting circuit samples the first subset of pixel values in the reference block and a second subset of pixel values in the check block at the positions determined by the analyzing circuit .