shared_ptr<const FFmpegContent> fc = boost::dynamic_pointer_cast<const FFmpegContent> (i);
shared_ptr<const TextSubtitleContent> sc = boost::dynamic_pointer_cast<const TextSubtitleContent> (i);
shared_ptr<const DCPSubtitleContent> dsc = boost::dynamic_pointer_cast<const DCPSubtitleContent> (i);
if (fc) {
shared_ptr<const FFmpegContent> fc = boost::dynamic_pointer_cast<const FFmpegContent> (i);
shared_ptr<const TextSubtitleContent> sc = boost::dynamic_pointer_cast<const TextSubtitleContent> (i);
shared_ptr<const DCPSubtitleContent> dsc = boost::dynamic_pointer_cast<const DCPSubtitleContent> (i);
if (fc) {