Apparatus for transmitting broadcast signal, apparatus for receiving broadcast signal, method for transmitting broadcast signal and method for receiving broadcast signal

A broadcast transmitter for processing input data, the broadcast transmitter comprising:

• a processor configured to process a link layer packet,
• wherein 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,
• in response to the packet type information for 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, and the extended type information is used for the second packet type different from the first packet type which is represented by the packet type information, and
• in response to the payload carrying 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
• a broadcast signal transmitter configured to transmit a broadcast signal based on the link layer packet.