A composite material comprising a core layer comprising filler and synthetic resin and containing the filler having a weight 0. Emulation of the transport stream prior to transmission determines whether a decoder underflow would occur after a splice proposed at a predetermined time. The heat conductor, which is made of metal sheet, has a ceiling piece that comes in contact with the cover and a pair of legs with the bottom surface that comes in contact with the base in both sides of the BOSA.