typedef std::vector<boost::shared_ptr<Content> > ContentList;
typedef std::vector<boost::shared_ptr<VideoContent> > VideoContentList;
typedef std::vector<boost::shared_ptr<AudioContent> > AudioContentList;
typedef std::vector<boost::shared_ptr<SubtitleContent> > SubtitleContentList;
typedef std::vector<boost::shared_ptr<FFmpegContent> > FFmpegContentList;
typedef std::vector<boost::shared_ptr<Content> > ContentList;
typedef std::vector<boost::shared_ptr<VideoContent> > VideoContentList;
typedef std::vector<boost::shared_ptr<AudioContent> > AudioContentList;
typedef std::vector<boost::shared_ptr<SubtitleContent> > SubtitleContentList;
typedef std::vector<boost::shared_ptr<FFmpegContent> > FFmpegContentList;