Implementation of Closed Captioning System for Terrestrial UHD based on ATSC 3.0

In South Korea, the terrestrial UHD broadcasting based on the ATSC 3.0 standard is aired officially from the end of May 2017. To provide closed captions for the UHD programs, we developed the ATSC 3.0 closed captioning system. The closed captions in the ATSC 3.0 standard are based on IMSC1 (Internet Media Subtitles and Captions 1.0) which is mainly used in the online video streaming industry, while the captions in the previous ATSC 1.0 standard are based on CEA-708 (Consumer Electronics Association 708). The UHD programs broadcasted on the Korean UHD TV networks are the ones simulcasted on the HD TV networks, that is, the HD programs and the UHD programs are the same except the video quality. Accordingly, we reuse the captions for the HD programs produced by the live stenography for the UHD programs since the contents of the captions for the HD and UHD programs are the same. We implemented the closed captioning system, both for the MMT (MPEG Media Transport) and the ROUTE (Real-time Object Delivery over Unidirectional Transport), which are transport protocols in the ATSC 3.0 standard, and verified it by testing on commercial ATSC 3.0 UHD TV receivers. This is the world's first development of the IMSC1 closed captioning system on the terrestrial TV.

Published

2017-10

Content type

Original Research

Keywords

UHD Closed Caption, UHD Closed Captioning System, IMSC1, TTML

DOI

10.5594/M001779

ISBN

978-1-61482-959-1