问题

我正在使用matplotlib制作一个随时间演变的系统动画。我想将动画保存为一个文件。我的默认选择是保存为`.mp4`文件，这意味着我应该像这样使用`ffmpeg`写入器：

```python
anim.save(filename="system_evolution.mp4", writer="ffmpeg", fps=30)

问题是，我正在与我的同学分享我的代码，他们的系统上可能没有安装ffmpeg。在这种情况下，我想回退到使用pillow保存动画为.gif文件（大多数人使用Anaconda安装Python，所以他们可能也安装了Pillow）。我怎么能检查哪些写入器可用于保存动画呢？

我想要类似这样的东西：

if ffmpeg可用():
    print("保存 system_evolution.mp4")
    anim.save(filename="system_evolution.mp4", writer="ffmpeg", fps=30)
elif pillow可用():
    print("保存 system_evolution.gif")
    anim.save(filename="system_evolution.gif", writer="pillow", fps=30)
else:
    print("请安装ffmpeg以保存mp4文件，或安装pillow以保存gif文件。")

我无法弄清楚如何实际检查ffmpeg或pillow是否可用，这意味着当我尝试保存.mp4时程序会崩溃，因为没有安装ffmpeg。如何进行这种检查？

<details>
<summary>英文:</summary>

I am using matplotlib to make an animation of the evolution of a system over time. I want to be able to save the animation as a file. My default choice is to save as an `.mp4` file, which means I should use the `ffmpeg` writer like this:

```python
anim.save(filename=&quot;system_evolution.mp4&quot;, writer=&quot;ffmpeg&quot;, fps=30)

The problem is that I am sharing my code with my classmates who don't necessarily have ffmpeg installed on their systems. In this case, I would like to fall back to saving a .gif of the animation using pillow (most of them install Python using Anaconda so they probably have Pillow installed as well). How can I check which writers are available to use for saving the animation?

I would like to have something like this:

if ffmpeg_available():
    print("Saving system_evolution.mp4")
    anim.save(filename="system_evolution.mp4", writer="ffmpeg", fps=30)
elif pillow_available():
    print("Saving system_evolution.gif")
    anim.save(filename="system_evolution.gif", writer="pillow", fps=30)
else:
    print("Please install either ffmpeg to save a mp4 or pillow to save a gif.")

I couldn't figure out how to actually check if ffmpeg or pillow are available, which means the program crashes when I try to save an .mp4 and ffmpeg isn't installed. How can this be checked?

答案1

得分: 0

根据这个链接，这个模块中的writers对象有一个名为is_available()的方法，可以用来检查特定的写入器是否可用。

你可以像这样做：

import matplotlib.animation as animation

def ffmpeg_available():
    return animation.writers.is_available('ffmpeg')

def pillow_available():
    return animation.writers.is_available('pillow')

if ffmpeg_available():
    print("Saving system_evolution.mp4")
    anim.save(filename="system_evolution.mp4", writer="ffmpeg", fps=30)
elif pillow_available():
    print("Saving system_evolution.gif")
    anim.save(filename="system_evolution.gif", writer="pillow", fps=30)
else:
    print("Please install either ffmpeg to save a mp4 or pillow to save a gif.")

import matplotlib.animation as animation

def ffmpeg_available():
    return animation.writers.is_available('ffmpeg')

def pillow_available():
    return animation.writers.is_available('pillow')

if ffmpeg_available():
    print("Saving system_evolution.mp4")
    anim.save(filename="system_evolution.mp4", writer="ffmpeg", fps=30)
elif pillow_available():
    print("Saving system_evolution.gif")
    anim.save(filename="system_evolution.gif", writer="pillow", fps=30)
else:
    print("Please install either ffmpeg to save a mp4 or pillow to save a gif.")