Animation stopped working

[Ross C]

I am getting “RuntimeError: Requested MovieWriter (ffmpeg) not available” on sp-m1-4-discrete-fourier-transform first animation under 4.2

It was working last week. Has had this same error since this morning or earlier.

[Catherine Lai]

First thing to try would just be to Restart and Clear Output (from the Kernel drop-down menu). This resets various environment variables which might solve the problem.

If that doesn’t work, you might need to set the location that matplotlib looks for ffmpeg:

import matplotlib as mpl 
mpl.rcParams['animation.ffmpeg_path'] = LOCATION_OF_FFMPEG
print(mpl.rcParams['animation.ffmpeg_path']) ## to see what it's set to

If you’re running a unix terminal, you can check the location of an application in the filesystem using:

which ffmpeg

You can do this within a python note (at least if you’re using Mac or Linux) in a code cell and adding a “bang” at the front:

!which ffmpeg

If this returns nothing, then probably you need to set your PATH (where the computer looks for applications/commands) to include wherever ffmpeg is installed. You can see that with the command:

echo $PATH

Note that activating a conda enviroment will change your PATH settings, so you might need to check that you’ve activated the right environment, especially if you used conda to install ffmpeg. You can easily get into a mismatched state if you have several versions of python or conda environments on your machine!

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