Patent ID: 7961789

Claim:
A method for determining a search range for an adaptive motion vector in a video encoder, the video encoder receiving input image signals representing a continuity of images, and dividing images of the input image signals into a plurality of macro blocks (MBs) so as to estimate a movement of a motion vector of a macro block for encoding images, the method comprising the steps of: (a) determining the number of neighboring blocks adjacent to a current macro block; (b) determining a motion vector having the greatest movement by finding magnitudes of motion vectors of the neighboring blocks, if the number of the neighboring blocks is greater than 2; (c) defining a minimum value of a search range for an adaptive motion vector of the current macro block, the minimum value of the search range for the adaptive motion vector varying depending on a sum of the magnitudes of the motion vectors of the neighboring blocks, when the sum of the magnitudes of the motion vectors of the neighboring blocks is equal to ‘0’, setting the minimum value of the search range for the adaptive motion vector to a predetermined value, which is obtained by adding a predetermined constant to the value of the search range for the adaptive motion vector defined by a user, and then, dividing a resultant value of the search range for the adaptive motion vector by four; (d) comparing a double of a magnitude of the motion vector with the greatest movement determined at step (b) with the minimum value of the search range for the adaptive motion vector found at step (c) so as to determine a larger value as a value of the search range for the adaptive motion vector; and (e) comparing the value of the search range for the adaptive motion vector found at step (d) with a value of the search range for the adaptive motion vector defined by the user so as to determine a smaller value as a value of a search range of a final adaptive motion vector.