CTA-708 (formerly EIA-708 and CEA-708) is the standard for closed captioning for ATSC digital television (DTV) viewing in the United States and Canada.
CTA-708 caption streams can also encapsulate EIA-608 byte pairs internally, a fairly common usage.
CTA-708 caption decoders are required in the U.S. by FCC regulation in all 13-inch (33 cm) diagonal or larger digital televisions.
This structure was designed for any digital audio or metadata that is to be synchronized with a video frame.
A cdp_timecode is used when cdp data stream is discontinuous (i.e., not padded) and the cdp_service_info is used to add extra details to the PSIP broadcast metadata such as language code, easy reader, and widescreen usage.