无法在 matplotlib 中保存动画：Windows 权限被拒绝

Question

我花了一天的时间来解决这个问题，检查类似的线程，但没有成功。 Stretch 的 Cannot save matplotlib Animation with ffmpeg帮助解决了以前的错误（我的 ffmpeg 路径错误），但修复后我一直遇到访问被拒绝的情况。

我的 ffmpeg 二进制文件已打开C:\ffmpeg\bin

一个不错的选择是能够导出 gif 文件，但我不断收到 imagemagick 的 ascii 错误。我认为这两个问题是相关的，所以我想先整理一下ffmpeg。

我认为这个问题可能与我正在使用 Canopy （在 Windows 8 64 位中）有关，它几乎霸占了我的路径变量并破坏了一些东西（例如，自从我安装了 Canopy 以来，我无法打开 IDLE ，还没有尝试解决这个问题）。当我一路修复问题时，我发现了至少 3 个不同的路径变量，所有这些变量都已更新：Windows 高级设置路径（手动设置）、Windows 控制台路径（通过控制台使用 setx 设置）和 sys.path（设置或检查）在运行时），添加";C:\ffmpeg\bin"，其中 ffmpeg 实际上是。不管我是否解决了问题，我都想了解这些环境变量中的哪些与什么相关，我觉得这很令人困惑。

代码如下：

# -*- coding: utf-8 -*-
import sys
import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
plt.rcParams['animation.ffmpeg_path'] = r'C:\ffmpeg\bin'
if r'C:\ffmpeg\bin' not in sys.path: sys.path.append(r'C:\ffmpeg\bin')

fig = plt.figure()
ax = plt.axes(xlim=(0, 2), ylim=(-2, 2))
line, = ax.plot([], [], lw=2)

def init():
    line.set_data([], [])
    return line,

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,

anim = animation.FuncAnimation(fig, animate, init_func=init, frames=200, interval=20, blit=True)
plt.show()

# This case generates Windows err: Access Denied
FFwriter = animation.FFMpegWriter()
# anim.save(r'C:\basic_animation.mp4', writer = FFwriter, fps=30)

# This case generates UnicodeDecodeError:'ascii' codec can't decode byte 0xa0 in position 3
# anim.save(r'C:\animation.gif', writer='imagemagick', fps=30)

的回溯anim.save(r'C:\basic_animation.mp4', writer = FFwriter, fps=30)：

%run "C:\Users\Yahveh\Documents\Vlad\Investigacion\animation saving.py"
---------------------------------------------------------------------------
WindowsError                              Traceback (most recent call last)
C:\Users\Yahveh\Documents\Vlad\Investigacion\animation saving.py in <module>()
     27 # This case generates Windows err: Access Denied
     28 FFwriter = animation.FFMpegWriter()
---> 29 anim.save(r'C:\basic_animation.mp4', writer = FFwriter, fps=30)
     30 
     31 # This case generates UnicodeDecodeError:'ascii' codec can't decode byte 0xa0 in position 3

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
    759         # since GUI widgets are gone. Either need to remove extra code to
    760         # allow for this non-existant use case or find a way to make it work.
--> 761         with writer.saving(self._fig, filename, dpi):
    762             for data in zip(*[a.new_saved_frame_seq()
    763                               for a in all_anim]):

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.5.2.2785.win-x86_64\lib\contextlib.pyc in __enter__(self)
     15     def __enter__(self):
     16         try:
---> 17             return self.gen.next()
     18         except StopIteration:
     19             raise RuntimeError("generator didn't yield")

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in saving(self, *args)
    184         '''
    185         # This particular sequence is what contextlib.contextmanager wants
--> 186         self.setup(*args)
    187         yield
    188         self.finish()

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in setup(self, fig, outfile, dpi, *args)
    174         # Run here so that grab_frame() can write the data to a pipe. This
    175         # eliminates the need for temp files.
--> 176         self._run()
    177 
    178     @contextlib.contextmanager

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in _run(self)
    202                                       stdout=output, stderr=output,
    203                                       stdin=subprocess.PIPE,
--> 204                                       creationflags=subprocess_creation_flags)
    205 
    206     def finish(self):

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.5.2.2785.win-x86_64\lib\subprocess.pyc in __init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags)
    707                                 p2cread, p2cwrite,
    708                                 c2pread, c2pwrite,
--> 709                                 errread, errwrite)
    710         except Exception:
    711             # Preserve original exception in case os.close raises.

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.5.2.2785.win-x86_64\lib\subprocess.pyc in _execute_child(self, args, executable, preexec_fn, close_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, to_close, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite)
    955                                          env,
    956                                          cwd,
--> 957                                          startupinfo)
    958             except pywintypes.error, e:
    959                 # Translate pywintypes.error to WindowsError, which is

WindowsError: [Error 5] Acceso denegado 

的回溯anim.save(r'C:\animation.gif', writer='imagemagick', fps=30)：

In [8]: %run "C:\Users\Yahveh\Documents\Vlad\Investigacion\animation saving.py"
---------------------------------------------------------------------------
UnicodeDecodeError                        Traceback (most recent call last)
C:\Users\Yahveh\Documents\Vlad\Investigacion\animation saving.py in <module>()
     30 
     31 # This case generates UnicodeDecodeError:'ascii' codec can't decode byte 0xa0 in position 3
---> 32 anim.save(r'C:\animation.gif', writer='imagemagick', fps=30)

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
    765                     # TODO: Need to see if turning off blit is really necessary
    766                     anim._draw_next_frame(d, blit=False)
--> 767                 writer.grab_frame(**savefig_kwargs)
    768 
    769         # Reconnect signal for first draw if necessary

C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in grab_frame(self, **savefig_kwargs)
    225             verbose.report('MovieWriter -- Error '
    226                            'running proc:\n%s\n%s' % (out,
--> 227                                                       err), level='helpful')
    228             raise
    229 

UnicodeDecodeError: 'ascii' codec can't decode byte 0xa0 in position 3: ordinal not in range(128) 

盯着他们看了一会儿。

谢谢你的时间！

更新：我按照这篇文章中的步骤授予对 C:\ffmpeg 和目标文件夹的访问权限，但没有运气:(

Answer 1

也许并不奇怪。我的 ffmpeg 路径C:\ffmpeg\bin是错误的；因为它应该是 exe 文件的直接路径，而不仅仅是父文件夹，正如我从 Stretch 的帖子中误解的那样，正如 Daniel 指出的那样。请注意，我之前已经尝试过此操作，但只是更改了当时的错误消息。冷静，休息一下，仔细阅读，而不是仅仅寻找适合你的代码。这只是一个错误。这就是答案。