, to read 
         tests/numbers.3ivx.avi, the user must have installed an MPEG4
         codec such as 3ivx (www.3ivx.com), DivX (www.divx.com), or XviD 
         (www.xvid.org).
       - The URL parameter should be a filename.
         - As a convenience, all forward slashes ('/') are automatically  
           converted to backslashes ('\')

     'ffmpegPopen2': safe method on Linux
       - Only supported on GNU/Linux (might work on BSD systems too like Mac 
         OS X, but this is unteste