matplotlib animation issue

gistfile1.py

import matplotlib.pyplot as plt
import matplotlib.animation as animation
import matplotlib as mpl

ani_fig = plt.figure(None)
ani_ax = ani_fig.gca()

ani_ax.set_xlim(0,1)
ani_ax.set_ylim(0,1)
ani_ax.set_aspect('equal')

color = None

n = 10
def update_frame(i):
    for p in ani_ax.patches:
        p.remove()
    global color
    print i
    patch = mpl.patches.Circle(xy=(.5,.5+.1*float(i)/n), radius = .1, facecolor=color)
    ani_ax.add_patch(patch)
    ani_ax.set_title('frame: %d'%(i))

color = 'b'
ani = animation.FuncAnimation(fig=ani_fig,func=update_frame,frames=n)
ani.save('blue.mp4', fps=5, codec='mpeg4', clear_temp=False)

color = 'r'
ani = animation.FuncAnimation(fig=ani_fig,func=update_frame,frames=n/2)
ani.save('red.mp4', fps=5, codec='mpeg4', clear_temp=False)