A digital broadcasting transmission andor reception system having an improved reception performance and a signal-processing method thereof. A power supply housing surrounds the printed circuit board and includes a generally planar heat sink plate. The mean value computing section outputs a mean luminance level for the pixels forming an image display produced in a front passenger seat display area. In place of the outer peripheral side, one side and the other side of the bending guide portion may be open over an entire length thereof in a peripheral direction thereof. Such a modified attribute record structure obviates the need for multiple attribute negotiation cycles, and therefore saves session negotiation time. Each of the first and second openings includes a plurality of holes, and each hole of the first opening and each hole of the second opening are arranged to face each other.