Closed
Description
Bug report
Bug summary
Something goes wrong when I try to use the FFMpeg writer to write an animation. It used to work for me a couple of weeks ago and the error does not help to much either.
Code for reproduction
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as anim
writer = anim.FFMpegWriter(fps=30, codec='libx264')
fig = plt.figure()
l, = plt.plot([], [], 'k-o')
plt.xlim(-5, 5)
plt.ylim(-5, 5)
x0, y0 = 0, 0
with writer.saving(fig, "writer_test.mp4", 100):
for i in range(100):
x0 += 0.1 * np.random.randn()
y0 += 0.1 * np.random.randn()
l.set_data(x0, y0)
writer.grab_frame()Actual outcome
Traceback (most recent call last):
File "<ipython-input-19-d9a5977378d9>", line 1, in <module>
runfile('/home/bram/Documenten/TUDelft/Thesis/Phyton/test.py', wdir='/home/bram/Documenten/TUDelft/Thesis/Phyton')
File "/home/bram/.anaconda3/lib/python3.6/site-packages/spyder_kernels/customize/spydercustomize.py", line 668, in runfile
execfile(filename, namespace)
File "/home/bram/.anaconda3/lib/python3.6/site-packages/spyder_kernels/customize/spydercustomize.py", line 108, in execfile
exec(compile(f.read(), filename, 'exec'), namespace)
File "/home/bram/Documenten/TUDelft/Thesis/Phyton/test.py", line 31, in <module>
writer.grab_frame()
File "/home/bram/.anaconda3/lib/python3.6/contextlib.py", line 99, in __exit__
self.gen.throw(type, value, traceback)
File "/home/bram/.anaconda3/lib/python3.6/site-packages/matplotlib/animation.py", line 232, in saving
self.finish()
File "/home/bram/.anaconda3/lib/python3.6/site-packages/matplotlib/animation.py", line 358, in finish
self.cleanup()
File "/home/bram/.anaconda3/lib/python3.6/site-packages/matplotlib/animation.py", line 395, in cleanup
out, err = self._proc.communicate()
File "/home/bram/.anaconda3/lib/python3.6/subprocess.py", line 843, in communicate
stdout, stderr = self._communicate(input, endtime, timeout)
File "/home/bram/.anaconda3/lib/python3.6/subprocess.py", line 1505, in _communicate
selector.register(self.stdout, selectors.EVENT_READ)
File "/home/bram/.anaconda3/lib/python3.6/selectors.py", line 351, in register
key = super().register(fileobj, events, data)
File "/home/bram/.anaconda3/lib/python3.6/selectors.py", line 237, in register
key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data)
File "/home/bram/.anaconda3/lib/python3.6/selectors.py", line 224, in _fileobj_lookup
return _fileobj_to_fd(fileobj)
File "/home/bram/.anaconda3/lib/python3.6/selectors.py", line 39, in _fileobj_to_fd
"{!r}".format(fileobj)) from None
ValueError: Invalid file object: <_io.BufferedReader name=55>
Expected outcome
I expect to obtain an .mp4 file which shows all the plots at 30fps. It does not do anything except giving the ValueError: Invalid file object: <_io.BufferedReader name=55> error. I might have used an older matlabcode previously but am not sure, I therefore tried an older version with conda but it did not help, it resulted in the same error.
Matplotlib version
- Operating system: Ubuntu 18.04
- Matplotlib version: 3.0.0 (from anaconda)
- Matplotlib backend: Qt5Agg
- Python version: 3.6.6
- Other libraries: ffmpeg 3.4.1 and 4.0.2, x264
I use conda to manage my environment using the default channel, for ffmpeg I tried both the standard and conda-forge channel.