A method for transmitting a broadcast signal in a digital transmitter includes processing a link layer packet. In addition, the link layer packet includes a header and a payload, the header includes a base header, the base header includes packet type information for representing a first packet type, and segmentation concatenation information for representing that the payload carries a segment of a single input packet or multiple input packets, when the packet type information is used to represent a packet type extension, the header further includes an additional header for type extension, the additional header for type extension includes extended type information for representing a second packet type being different from a compressed IP (internet protocol) packet, an IPv4 packet or an MPEG (Moving Picture Experts Group)-2 transport stream, and when the payload carries the multiple input packets, the header further includes an additional header for concatenation, the additional header for concatenation includes count information for representing a number of the multiple input packets included in the link layer packet, and a value of the count information is set to a number of the multiple input packets included in the link layer packet subtracted by two; and transmitting the broadcast signal.