title: OSError: no such file or directory on using subprocess.Popen
body: <p>I am trying to get the duration of a video clip. But it is unable to get the file.
  Here is my code:</p>
  
  <pre><code>import subprocess
  import os
  def getLength(input_video):
      result = subprocess.Popen('ffprobe -i input_video -show_entries format=duration -v quiet -of csv="p=0"', stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
      output = result.communicate()
      return output[0]
  BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
  x = (os.path.join(BASE_DIR,'uploads/video.mkv'))
  getLength(x)
  </code></pre>
  
  <p>This is the error I am getting:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/home/aman/Desktop/stream/src/stream/uploads/sadf.py", line 9, in &lt;module&gt;
      getLength(x)
    File "/home/aman/Desktop/stream/src/stream/uploads/sadf.py", line 4, in getLength
      result = subprocess.Popen('ffprobe -i input_video -show_entries format=duration -v quiet -of csv="p=0"', stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
    File "/usr/lib/python2.7/subprocess.py", line 711, in __init__
      errread, errwrite)
    File "/usr/lib/python2.7/subprocess.py", line 1343, in _execute_child
      raise child_exception
  OSError: [Errno 2] No such file or directory
  [Finished in 0.1s with exit code 1]
  [shell_cmd: "python" -u "/home/aman/Desktop/stream/src/stream/uploads/sadf.py"]
  [dir: /home/aman/Desktop/stream/src/stream/uploads]
  [path: /home/aman/bin:/home/aman/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin]
  </code></pre>