diff --git a/master_openworm.py b/master_openworm.py
index 2e50597..a8344c0 100644
--- a/master_openworm.py
+++ b/master_openworm.py
@@ -309,7 +309,7 @@ def execute_with_realtime_output(command, directory, env=None):
     black_dur = float(out[black_dur_pos + len("black_duration:") :])
 
 if black_start == 0.0 and black_dur:
-    black_dur = int(math.ceil(black_dur))
+    black_dur = math.ceil(black_dur)
     command = "ffmpeg -ss 00:00:0%s -i %s/%s -c copy -avoid_negative_ts 1 %s/cut_%s" % (
         black_dur,
         new_sim_out,