diff --git a/examples/symba_energy_momentum/collision_movie.py b/examples/symba_energy_momentum/collision_movie.py
index 85a020183..de39bc326 100755
--- a/examples/symba_energy_momentum/collision_movie.py
+++ b/examples/symba_energy_momentum/collision_movie.py
@@ -85,7 +85,7 @@ def __init__(self, ds, param):
         self.ani = animation.FuncAnimation(self.fig, self.update, interval=1, frames=nframes,
                                           init_func=self.setup_plot, blit=False)
         self.ani.save(animfile, fps=60, dpi=300,
-                      extra_args=['-vcodec', 'mpeg4'])
+                      extra_args=['-vcodec', 'libx264'])
 
     def plot_pl_circles(self, pl, radmarker):
         patches = []