Taking advantage of the technological possibilities of a digital broadcasting platform, NHK has undertaken broadcasting of captions to make TV programming more accessible to the elderly and the hearing-impaired.

A special accessory is required to view captions with analog broadcasting. But with digital broadcasting, captioning functionality is built in to the digital receiver. NHK uses automatic computerized speech recognition technology to provide real-time captioning of news, sports, music and other live programming.

And because digital broadcasting offers more audio channels than analog, separate audio channels from the main audio are used to provide explanatory materials such as plot synopses of drama programs.