An image processing apparatus that generates a code stream that encodes image data and includes a dividing unit that divides the image data into at least one rectangular area, a conversion unit that converts data of the rectangular area into conversion data, an ordering unit that adds the priority order to the conversion data, an encoding unit that rearranges the conversion data based on the priority order and encodes the conversion data into the code stream, and a coupling unit that adds a marker in the header part of the conversion data that identifies the priority order of the conversion data in the code stream.