尽管我已经安装了ffmpeg
,matplotlib报告MovieWriter ffmpeg is unavailable
和创建的MP4文件是空的。
import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
# First set up the figure, the axis, and the plot element we want to animate
fig = plt.figure()
ax = plt.axes(xlim=(0, 2), ylim=(-2, 2))
line, = ax.plot([], [], lw=2)
# initialization function: plot the background of each frame
def init():
line.set_data([], [])
return line,
# animation function. This is called sequentially
def animate(i):
x = np.linspace(0, 2, 1000)
y = np.sin(2 * np.pi * (x - 0.01 * i))
line.set_data(x, y)
return line,
# call the animator. blit=True means only re-draw the parts that have changed.
anim = animation.FuncAnimation(fig, animate, init_func=init,
frames=200, interval=20, blit=True)
# save the animation as an mp4. This requires ffmpeg or mencoder to be
# installed. The extra_args ensure that the x264 codec is used, so that
# the video can be embedded in html5. You may need to adjust this for
# your system: for more information, see
# http://matplotlib.sourceforge.net/api/animation_api.html
anim.save('basic_animation.mp4', fps=30, extra_args=['-vcodec', 'libx264'])
plt.show()
我甚至添加了plt.switch_backend('TkAgg')
在另一篇文章中提出的那句话,什么都没有改变。这是我的matplotlib:
Name: matplotlib
Version: 2.1.0
Summary: Python plotting package
Home-page: http://matplotlib.org
我的ffmpeg:
Name: ffmpeg
Version: 1.4
Summary: ffmpeg python package url [https://github.com/jiashaokun/ffmpeg]
Home-page: https://github.com/jiashaokun/ffmpeg
和我的Python版本:
Python 3.6.5
我得到的错误是:
/usr/local/lib/python3.6/site-packages/matplotlib/animation.py:1218: UserWarning: MovieWriter ffmpeg unavailable
warnings.warn("MovieWriter %s unavailable" % writer)
这个错误已经在stackoverflow上报告了很多次,每次解决方案要么是安装ffmpeg
(我的已经安装了),要么是添加关于后端的额外行,这对我来说没有任何改变。
奇怪的是,plt.show()
命令可以工作,我也预览了一个动画,但保存它的唯一文件格式是(非动画的) PNG。
https://stackoverflow.com/questions/56210075
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