Running cmd in python

Question

Atm I have this as my code, the first line seems to work well but the 2nd gives errrors.

os.chdir('C://Users/Alex/Dropbox/code stuff/test')
subprocess.call('ffmpeg -i test%d0.png output.avi')

Also when I try to run it as this, it gives a 1s cmd flicker and then nothing happens

os.system('ffmpeg -i test%d0.png output.avi')

Answer 1

For the later generations looking for the answer, this worked. (You have to separate the command by the spaces.)

import os
import subprocess
os.chdir('C://Users/Alex/')
subprocess.call(['ffmpeg', '-i', 'picture%d0.png', 'output.avi'])
subprocess.call(['ffmpeg', '-i', 'output.avi', '-t', '5', 'out.gif'])

Answer 2

I also use subprocess but in another way.

As @Roland Smith claimed, the preferred method is (which isn't really comfortable):

subprocess.call(['ffmpeg', '-i', 'test%d0.png', 'output.avi'])

The second method can be more comfortable to use but can have some problems:

subprocess.call('ffmpeg -i test%d0.png output.avi', shell=True)

Besides the fact that is suggested avoiding setting the shell parameter to "True", I had problems when the output folder contains round brackets, that is: "temp(5)/output.avi".

A more robust way is the following:

import subprocess
import shlex

cmd = shlex.split('ffmpeg -i test%d0.png output.avi')
subprocess.call(cmd)

To know more about shlex. In particular, for shlex.split:

Split the string s using shell-like syntax.