shared_ptr<FFmpegContent> B (new FFmpegContent (film, "test/data/red_30.mp4"));
film->examine_and_add_content (B);
wait_for_jobs ();
shared_ptr<FFmpegContent> B (new FFmpegContent (film, "test/data/red_30.mp4"));
film->examine_and_add_content (B);
wait_for_jobs ();