A method for transmitting broadcast signals, the method comprising: formatting at least one input transport stream, TS, to output Physical Layer Pipe, PLP, data corresponding to each of a plurality of PLPs, wherein the input TS includes at least one null packet and input TS packets, wherein the formatting includes: removing sync bytes in first headers of the input TS packets; deleting the at least one null packet preceding a group of consecutive input TS packets in the input TS; and inserting a second header to generate a data packet included in the PLP data, wherein the data packet comprises the second header and a payload including the group of consecutive input TS packets, wherein the second header of the data packet includes information used to calculate a number of the deleted null packets; encoding the PLP data; mapping the encoded PLP data onto constellations; time interleaving the mapped PLP data; building at least one signal frame including the time interleaved PLP data; modulating data in the built at least one signal frame by an Orthogonal Frequency Division Multiplex, OFDM, scheme; and transmitting the broadcast signals having the modulated data, wherein the formatting further includes selectively compressing the input TS packets by deleting the first headers of the input TS packets so that common information of the first headers is transmitted once in the data packet. formatting at least one input transport stream, TS, to output Physical Layer Pipe, PLP, data corresponding to each of a plurality of PLPs, wherein the input TS includes at least one null packet and input TS packets, wherein the formatting includes: removing sync bytes in first headers of the input TS packets; deleting the at least one null packet preceding a group of consecutive input TS packets in the input TS; and inserting a second header to generate a data packet included in the PLP data, wherein the data packet comprises the second header and a payload including the group of consecutive input TS packets, wherein the second header of the data packet includes information used to calculate a number of the deleted null packets; removing sync bytes in first headers of the input TS packets; deleting the at least one null packet preceding a group of consecutive input TS packets in the input TS; and inserting a second header to generate a data packet included in the PLP data, wherein the data packet comprises the second header and a payload including the group of consecutive input TS packets, wherein the second header of the data packet includes information used to calculate a number of the deleted null packets; encoding the PLP data; mapping the encoded PLP data onto constellations; time interleaving the mapped PLP data; building at least one signal frame including the time interleaved PLP data; modulating data in the built at least one signal frame by an Orthogonal Frequency Division Multiplex, OFDM, scheme; and transmitting the broadcast signals having the modulated data, wherein the formatting further includes selectively compressing the input TS packets by deleting the first headers of the input TS packets so that common information of the first headers is transmitted once in the data packet.