A method of transforming a 3D video format of a 3D video, the method including receiving a video sequence comprising 3D video that includes left-viewpoint video and right-viewpoint video; estimating at least one of disparity information between the left-viewpoint video and the right-viewpoint video and correlation information between neighboring pixel values of the left-viewpoint video and the right-viewpoint video, and determining a 3D video format of the 3D video based on a result of the estimating; transforming the left-viewpoint video and the right-viewpoint video into a format, based on the determined 3D video format; and displaying the transformed left-viewpoint video and the transformed right-viewpoint video three-dimensionally on a the display device.