diff --git a/removeads.py b/removeads.py
index 492859b..28c0260 100755
--- a/removeads.py
+++ b/removeads.py
@@ -846,9 +846,13 @@ def main():
         logger.info("Found %d frames between beginning of current part and first I-frame" % nbHeadFrames)
         logger.info("Found %d frames between last I-frame and end of current part" % nbTailFrames)
         
-        headIFrameTS = timedelta(seconds=float(headIFrame['pts_time']))
-        tailIFrameTS = timedelta(seconds=float(tailIFrame['pts_time']))
-        
+        headIFrameTS = getTSFrame(headIFrame)
+        if headIFrameTS == None:
+            exit(-1)
+        tailIFrameTS = getTSFrame(tailIFrame)
+        if tailIFrameTS == None:
+            exit(-1)
+
         checks.append(pos+headIFrameTS-ts1)
         
         subparts = []