1. An apparatus of estimating a motion of a three dimensional (3D) video, comprising: a color/depth motion estimating unit to estimate a motion of a depth image macroblock based on a motion vector of a color image macroblock using at least one processor and outputting a first estimation result indicative thereof; and a depth/color motion estimating unit to estimate a motion of a color image macroblock based on a motion vector of the depth image macroblock and outputting a second estimation result indicative thereof, wherein the color/depth motion estimating unit calculates the motion vector of the color image macroblock and then estimates the motion of the depth image macroblock based on the calculated motion vector of the color image macroblock, and wherein the determined motion vector of the color image macroblock is used as a motion vector for the depth image macroblock.