Bash process substitution in Python with Popen

Question

I'm attempting to create a looped video file by calling ffmpeg from the python subprocess library. Here's the part that's giving me problems:

import subprocess as sp
sp.Popen(['ffmpeg', '-f', 'concat', '-i', "<(for f in ~/Desktop/*.mp4; do echo \"file \'$f\'\"; done)", "-c", "copy", "~/Desktop/sample3.mp4"])

With the above code I'm getting the following error:

<(for f in /home/delta/Desktop/*.mp4; do echo "file '$f'"; done): No such file or directory

I did find a similarly phrased question here . But I'm not sure how the solution might apply to solving my issue.

Answer 1

Following the advice in the comments and looking elsewhere I ended up changing the code to this:

sp.Popen("ffmpeg -f concat -i <(for f in ~/Desktop/*.mp4; do echo \"file \'$f\'\"; done) -c copy ~/Desktop/sample3.mp4",
         shell=True, executable="/bin/bash")

--which works fine. – moorej