Try to import vlc module and use if successfuly imported.

dcp.py

@@ -6,7 +6,10 @@ from os.path import isdir, basename, exists
 from shutil import copyfile
 from xml.dom.minidom import parse
 import sys
+try:
     import vlc
+except ImportError:
+    pass
 
 
 class Asset(object):
@@ -63,7 +66,7 @@ class Asset(object):
         return(self.hash == b64encode(hash.digest()).decode())
 
     def add_duration(self):
-        if hasattr(self, 'type') and self.type.find('mxf') > -1:
+        if 'vlc' in dir() and hasattr(self, 'type') and self.type.find('mxf') > -1:
             instance = vlc.Instance()
             media = instance.media_new('file://' + self.fullpath)
             media.parse()