A first search window within a reference frame of video data is identified along with a first correlation threshold value for the first window. The first correlation threshold value is a value to which correlation factors between a pixel set being encoded and pixels sets of the first search window are compared. For example, if a correlation factor between a specific pixel set of the first search window and a pixel set being encoded meets the first threshold value, a successful match between the two pixel sets has been found, and a corresponding motion vector can be assigned to the pixel set being encoded. If none of the pixel sets within the first window meet the first threshold value, a second search window within the first frame is selected along with a second correlation threshold value. The correlation factors for pixel sets in the second window are compared to the second correlation threshold value.