1. A method for determining a motion vector of a current block of a current frame for indicating a region in a reference frame comprising pixel information correlating to the current block, the current frame and reference frame being part of a sequence of frames forming a digital video, the method comprising: correlating pixel information of the current block with pixel information of the reference frame indicated by a first motion vector of a block proximate to the current block to determine a first cost function; correlating pixel information of the current block with pixel information of the reference frame indicated by a second motion vector to determine a second cost function, the second motion vector being of a block of the reference frame spatially coincident with the current block; correlating pixel information of the current block with pixel information of at least a predetermined region of the reference frame to determine at least a third motion vector and correspondingthird cost function; selecting at least one of the first, second, and third motion vectors having the lowest cost function as a candidate motion vector; correlating pixel information of the current block with pixel information of regionsoffset from regions in the reference frame indicated by the candidate motion vectors to determine refined candidate motion vectors and corresponding refined cost functions; and selecting the refined candidate motion vector having the lowest refined cost function as the motion vector of the current block.