如何将 matplotlib.pause animation 保存到视频中？

Question

I have an animation created with plt.pause as below...

import matplotlib.pyplot as plt

for i in range(10):
    plt.scatter(0, i)
    plt.pause(0.01)

plt.show()

How can I save this as a video file, eg a .mp4 file?

Answer 1

First, I have to redefine the plotting as a function with the plotted point given by a frame i . plt.pause() can be replaced by matplotlib.animate . Finally, I used a package suggested here to get the conversion to .mp4 format. You will need to install MoviePy :

pip install MoviePy

and then I just animate the function with matplotlib.animate into a .gif format before sending it to MoviePy . You'll need to figure out what directory you want this all to happen in. I'm just using the current working directory.

Here is the code:

import matplotlib.pyplot as plt
import matplotlib.animation as ani
import os
import moviepy.editor as mp


frames=20
fig = plt.figure()
ax = plt.gca()
def scatter_ani(i=int):
    plt.scatter(0, i)

name = r"\test.gif"
path = str(os.getcwd())

anim = ani.FuncAnimation(fig, scatter_ani, frames = frames, interval=50)
anim.save(path+name)

clip = mp.VideoFileClip(path+name)
clip.write_videofile(path+r"\test.mp4")

The gif is then

To tweak the length of the animation, check out the docs for matplotlib.animate . For example, if you want to clear all of the previous data-points and show only the dot moving up, then you need to clear the axes in the function, and bound the y-axis so you see the motion ie

def scatter_ani(i=int):
    ax.clear()
    ax.set_ylim(0, frames+1)
    plt.scatter(0, i)

to get: