Frame missing in .mp4 but not in .gif

[hecadr]

I tried to save the animation from the minimal example as a .mp4 file.

import matplotlib.pyplot as plt
from celluloid import Camera
fig = plt.figure()
camera = Camera(fig)
for i in range(10):
    plt.plot([i] * 10)
    camera.snap()
animation = camera.animate()
animation.save("test.mp4", writer='ffmpeg')

The resulting test.mp4 is missing the second to last frame (i=8).
Why does this happen and how can I avoid this issue?

If I replace the last line in the code by ani.save("test.gif", writer='imagemagick'), test.gif contains all frames.

[AhmadrezaAhmadi]

The same problem here, has anybody got a solution for that?
Actually I solved it just do not use writer='imagemagick' and it works!