Patent ID: 8817181

Claim:
A method of transmitting a digital broadcast signal, the method comprising: multiplexing video data, audio data, and supplementary data into MPEG2 transport stream, the supplementary data including an event information table (EIT) and a program map table (PMT), wherein the EIT or the PMT includes a caption service descriptor, wherein the caption service descriptor includes caption information indicating whether a digital television closed caption service is present in the video data or a line 21 closed caption service is present in the video data in accordance with electronic industry association (EIA) 708 and wherein the caption service descriptor further includes a caption service number field, wherein the caption service number field identifies a caption service number that corresponds to a closed caption service of the closed caption services, wherein the caption service number field is defined only when the digital television closed caption service is present, and wherein the caption information is set when the digital television closed caption service is present in accordance with EIA 708 and the caption information is clear when the line 21 closed caption service is present in accordance with EIA 708; and transmitting the digital broadcast signal.