title: Get mp3 & mp4 time length of file in rails
body: <p>I'm using Rails 3.2+ and am wondering if there is an easy way to find out what the time length of a file is on my server.  For example if I had a video file in mp4 format, how would I find out that the length of the video is say 4 minutes 2 seconds long?  Same goes for mp3, or external sources like youtube/vimeo.  If there is a gem that does this that is fine as well, thanks.</p>