film->set_burn_subtitles (true);
shared_ptr<DCPSubtitleContent> content (new DCPSubtitleContent (film, "test/data/dcp_sub.xml"));
content->set_use_subtitles (true);
film->set_burn_subtitles (true);
shared_ptr<DCPSubtitleContent> content (new DCPSubtitleContent (film, "test/data/dcp_sub.xml"));
content->set_use_subtitles (true);