A broadcast transmitter for processing a broadcast signal is discussed. The broadcast transmitter includes a packetizer to generate transport packets based on a Layered Coding Transport (LCT) format, wherein the transport packets are used to transport at least one delivery object and signaling data; and a transmitter to transmit the broadcast signal comprising the transport packets, wherein the signaling data includes a real-time attribute which is a boolean flag that is set to true when the transport packets carry a real-time content that is comprised of the at least one delivery object, and wherein a header of at least one transport packet of the transport packets includes codepoint information for indicating a type of a payload that is carried by the at least one transport packet, transport object identifier information for identifying the at least one delivery object, and information for identifying a starting position of a fragment of the delivery object carried in the at least one transport packet.