1seg is a mobile terrestrial digital audio/video and data broadcasting service in Japan, Argentina, Brazil, Chile, Uruguay, paraguay, puv ntsoov, 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 segments, with a further segment separating it from the next channel; an HDTV broadcast signal occupies 12 segments, leaving the remaining (13tub sab) segment for mobile receivers, li no lub npe, “1seg” los sis “One Seg”. See full seg.