2D videos and 3D videos refer to the actual dimensions in a computer's workspace. 2D is 'flat', using the X & Y (horizontal and vertical) axis', the image has only two dimensions and if turned to the side becomes a line. 3D adds the 'Z' dimension. This third dimension allows for rotation and depth.

2D to 3D video conversion (also called 2D to stereo 3D conversion and stereo conversion) is the process of transforming 2D ("flat") film to 3Dform, which in almost all cases is stereo, so it is the process of creating imagery for each eye from one 2D image.