title: UnicodeEncodeError for UTF-8 file names returned from a tk dialog
body: <p>Hi I'm trying to extract audio from a video file using <code>ffmpeg</code> with the following function (in <code>Python 2</code>):</p>
  
  <pre><code>def extractAudio(path):
      command = ''.join(('ffmpeg -i "',path,'" -ab 160k -ac 2 -ar 44100 -vn audio.wav'))
      print(command)
      subprocess.call(command,shell=True)
  </code></pre>
  
  <p>the above print statement successfully prints the following:</p>
  
  <pre><code>ffmpeg -i "C:/Users/pruthvi/Desktop/vidrec/temp\TAEYEON 태연_ I (feat. Verbal Jint)_Music Video.mp4" -ab 160k -ac 2 -ar 44100 -vn audio.wav
  </code></pre>
  
  <p>but in the next statement, it fails and throws the following error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "C:/Users/pruthvi/Desktop/vidrec/vidrec.py", line 53, in &lt;module&gt;
      main()
    File "C:/Users/pruthvi/Desktop/vidrec/vidrec.py", line 46, in main
      extractAudio(os.path.join(di,each))
    File "C:/Users/pruthvi/Desktop/vidrec/vidrec.py", line 28, in extractAudio
      subprocess.call(command,shell=True)
    File "C:\Python27\lib\subprocess.py", line 522, in call
      return Popen(*popenargs, **kwargs).wait()
    File "C:\Python27\lib\subprocess.py", line 710, in __init__
      errread, errwrite)
    File "C:\Python27\lib\subprocess.py", line 928, in _execute_child
      args = '{} /c "{}"'.format (comspec, args)
  UnicodeEncodeError: 'ascii' codec can't encode characters in position 56-57: ordinal not in range(128)
  </code></pre>
  
  <p>I've tried all the possible solutions from previous questions like encoding with correct type , setting up <code>PYTHONIOENCODING</code> etc., but none seems to work . If I convert it to <code>ascii</code>, it'll no longer function because it removes non-ascii character and ends up as <code>file not found</code> and the audio will not be extracted from the target file. Any help is appreciated, thanks :)</p>
  
  <p>To experiment, you can use the following code:</p>
  
  <pre><code># -*- coding: utf-8 -*-
  import subprocess
  
  def extractAudio():
      path = u'C:/Users/pruthvi/Desktop/vidrec/temp\TAEYEON 태연_ I (feat. Verbal Jint)_Music Video.mp4'
      command = ''.join(('ffmpeg -i "',path,'" -ab 160k -ac 2 -ar 44100 -vn audio.wav'))
      print(command)
      subprocess.call(command,shell=True)
  extractAudio()
  </code></pre>