Is there any way I can get the playing time of a movie file?

General Usage
2

AFAIK Julia does not have support for that. There has to be program that would parse the headers of the movie file to get that information. The program of choice that does that on a command in is ffmpeg or ffprobe. The following snippet would allow you to do that in Julia by invoking an external program call. You need to have ffmpeg installed on your system for this work

function getDuration(vid_filename)
       p=Pipe()
       run(pipeline(`ffprobe -i  $vid_filename`,stderr=p))
       close(p.in)
        duration=matchall(r"(\d{2}:\d{2}:\d{2}.\d{2})"
                            ,readstring(pipeline(p,`grep Duration`)))[1]
end