correct to_stderr

diff --git a/youtube_dl/FileDownloader.py b/youtube_dl/FileDownloader.py
index f1931b04dfbdca5834976f07ff5a4a3e680519bd..2b76a3b09b16b9bf5bcd4c37e22fb32ccc1aae71 100644 (file)
--- a/youtube_dl/FileDownloader.py
+++ b/youtube_dl/FileDownloader.py
@@ -185,7 +185,10 @@ class FileDownloader(object):
        def to_stderr(self, message):
                """Print message to stderr."""
                assert type(message) == type(u'')
-               sys.stderr.write((message + u'\n').encode(preferredencoding()))
+               output = message + u'\n'
+               if 'b' in getattr(self._screen_file, 'mode', '') or sys.version_info[0] < 3: # Python 2 lies about the mode of sys.stdout/sys.stderr
+                       output = output.encode(preferredencoding())
+               sys.stderr.write(output)
 
        def to_cons_title(self, message):
                """Set console/terminal window title to message."""