diff --git a/render_kdenlive.py b/render_kdenlive.py
index f4aa573..147fbef 100644
--- a/render_kdenlive.py
+++ b/render_kdenlive.py
@@ -14,7 +14,7 @@ def get_propery(element, name):
 
 def melt_xml(file):
     out = None
-    real_path = os.path.realpath(path)
+    real_path = os.path.realpath(file)
     if file in _CACHE and isinstance(_CACHE[file], list):
         ts, out = _CACHE[file]
         if os.stat(real_path).st_mtime != ts: