How to display the length of a video from bd with the extension getid3?

<?php
 Include ("getid3/getid3.php");

 $filename="nome_do_video.mp4";
 $getID3 = new getID3;
 $file = $getID3->analize($filename);
 echo $file['playtime_string'];

 ?>

So when I try to pull the database I can not, for example the path of the video that is saved in the bd is thus "videos/files/nomedovideo.mp4" .

How could I display the path in the $filename="nome_do_vídeo.mp4" part?

Could anyone help me?