Running cmd in python

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'])

It is better to call subprocess.call in another way.

The preferred way is:

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

Alternatively:

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

You can find the reasons for this in the manual. I quote:

args is required for all calls and should be a string, or a sequence of program arguments. Providing a sequence of arguments is generally preferred, as it allows the module to take care of any required escaping and quoting of arguments (e.g. to permit spaces in file names). If passing a single string, either shell must be True (see below) or else the string must simply name the program to be executed without specifying any arguments.

I know this question is old, but now there is an excellent wrapper for ffmpeg in Python : ffmpeg-python. You will find it at https://github.com/kkroening/ffmpeg-python

With it, the command could be achieved this way:

import ffmpeg
ffmpeg
    .input('test*.png', pattern_type='glob')
    .output('output.avi')
    .run()