diff --git a/ffplayout.py b/ffplayout.py
index 04801b30..c0909475 100755
--- a/ffplayout.py
+++ b/ffplayout.py
@@ -1221,7 +1221,7 @@ class GetSourceIter(object):
             else:
                 self.is_dummy = True
         else:
-            self.src_cmd = gen_dummy(self.durationk)
+            self.src_cmd = gen_dummy(self.duration)
             self.is_dummy = True
         self.set_filtergraph()