1seg is a mobile terrestrial digital audio/video and data broadcasting service in Japan, Ajantin, Brezil, Chili, Irigwe, Paragwe, Perou, and the Philippines.

1 seg is designed as a component of ISDB-T, the terrestrial digital broadcast system used in those countries, as each channel is divided into 13 segman, with a further segment separating it from the next channel; an HDTV broadcast signal occupies 12 segman, leaving the remaining (13th) segment for mobile receivers, pakonsekan non an, “1seg” oswa “youn Seg”. See full seg.