Method for transmitting broadcast signal and apparatus for transmitting broadcast signal

A method for transmitting a broadcast signal in a digital transmitter includes generating a link layer packet; generating the broadcast signal based on the link layer packet; and transmitting the broadcast signal. Further, the link layer packet includes at least one header and a payload, in which the at least one header includes a packet type field, and the packet type field represents a type of input data before encapsulation into the link layer packet. In addition, in response to the packet type field represents that the input data relates to a Movie Picture Experts Group-2 (MPEG-2) Transport Stream (TS) packet, a first header included in the link layer packet includes a deleted null packet indicator for representing the number of deleted null TS packets prior to the link layer packet.