boost::optional<dcp::LanguageTag> _open_subtitle_language;
/** the DCPTextTracks for each of our CCAPs */
std::vector<DCPTextTrack> _dcp_text_tracks;
boost::optional<dcp::LanguageTag> _open_subtitle_language;
/** the DCPTextTracks for each of our CCAPs */
std::vector<DCPTextTrack> _dcp_text_tracks;