diff --git a/lddecode_core.py b/lddecode_core.py
index 04644d087..c48beb64d 100644
--- a/lddecode_core.py
+++ b/lddecode_core.py
@@ -1336,9 +1336,10 @@ def readframe(self, infile, sample, firstframe = False, CAV = False):
             combined = None
             
         self.vbi = self.mergevbi(fields)
-
-        if not f.vbi['isclv'] and f.vbi['framenr'] is not None:
-            newmtf = 1 - (f.vbi['framenr'] / 10000)
+        
+        if not self.vbi['isclv'] and self.vbi['framenr'] is not None:
+            newmtf = 1 - (self.vbi['framenr'] / 10000)
+            print(newmtf)
             if newmtf < 0:
                 newmtf = 0