title: The system cannot find the file specified with ffmpeg
body: <p>In the process of using the ffmpeg module to edit video files i used the subprocess module </p>
  
  <p>The code is as follows:</p>
  
  <pre><code>#trim bit
  
  import subprocess
  import os
  seconds = "4"
  mypath=os.path.abspath('trial.mp4')
  subprocess.call(['ffmpeg', '-i',mypath, '-ss', seconds, 'trimmed.mp4'])
  </code></pre>
  
  <p>Error message:</p>
  
  <pre><code>Traceback (most recent call last):
    File "C:\moviepy-master\resizer.py", line 29, in &lt;module&gt;
      subprocess.call(['ffmpeg', '-i',mypath, '-ss', seconds, 'trimmed.mp4'])
    File "C:\Python27\lib\subprocess.py", line 168, in call
      return Popen(*popenargs, **kwargs).wait()
    File "C:\Python27\lib\subprocess.py", line 390, in __init__
      errread, errwrite)
    File "C:\Python27\lib\subprocess.py", line 640, in _execute_child
      startupinfo)
  WindowsError: [Error 2] The system cannot find the file specified
  </code></pre>
  
  <p>After looking up similar problems i understood that the module is unable to pick the video file because it needs its path, so i took the absolute path. But in spite of that the error still shows up.
  The module where this code was saved and the video file trial.mp4 are in the same folder.</p>