diff --git a/youtube_dl/compat.py b/youtube_dl/compat.py
index f4a85443ed..cd46693b34 100644
--- a/youtube_dl/compat.py
+++ b/youtube_dl/compat.py
@@ -1,8 +1,10 @@
 from __future__ import unicode_literals
 
+import ctypes
 import getpass
 import optparse
 import os
+import platform
 import re
 import subprocess
 import sys
@@ -326,6 +328,22 @@ def workaround_optparse_bug9161():
         optparse.OptionGroup.add_option = _compat_add_option
 
 
+if platform.python_implementation() == 'PyPy':
+    # PyPy expects byte strings as Windows function names
+    # https://github.com/rg3/youtube-dl/pull/4392
+    def compat_WINFUNCTYPE(*args, **kwargs):
+        real = ctypes.WINFUNCTYPE(*args, **kwargs)
+
+        def resf(tpl, *args, **kwargs):
+            funcname, dll = tpl
+            return real((str(funcname), dll), *args, **kwargs)
+
+        return resf
+else:
+    def compat_WINFUNCTYPE(*args, **kwargs):
+        return ctypes.WINFUNCTYPE(*args, **kwargs)
+
+
 __all__ = [
     'compat_HTTPError',
     'compat_chr',
@@ -349,6 +367,7 @@ __all__ = [
     'compat_urllib_request',
     'compat_urlparse',
     'compat_urlretrieve',
+    'compat_WINFUNCTYPE',
     'compat_xml_parse_error',
     'shlex_quote',
     'subprocess_check_output',
diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 4b0567c938..bbe554a657 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -41,6 +41,7 @@ from .compat import (
     compat_urllib_parse_urlparse,
     compat_urllib_request,
     compat_urlparse,
+    compat_WINFUNCTYPE,
     shlex_quote,
 )
 
@@ -817,21 +818,21 @@ def _windows_write_string(s, out):
     if fileno not in WIN_OUTPUT_IDS:
         return False
 
-    GetStdHandle = ctypes.WINFUNCTYPE(
+    GetStdHandle = compat_WINFUNCTYPE(
         ctypes.wintypes.HANDLE, ctypes.wintypes.DWORD)(
         ("GetStdHandle", ctypes.windll.kernel32))
     h = GetStdHandle(WIN_OUTPUT_IDS[fileno])
 
-    WriteConsoleW = ctypes.WINFUNCTYPE(
+    WriteConsoleW = compat_WINFUNCTYPE(
         ctypes.wintypes.BOOL, ctypes.wintypes.HANDLE, ctypes.wintypes.LPWSTR,
         ctypes.wintypes.DWORD, ctypes.POINTER(ctypes.wintypes.DWORD),
         ctypes.wintypes.LPVOID)(("WriteConsoleW", ctypes.windll.kernel32))
     written = ctypes.wintypes.DWORD(0)
 
-    GetFileType = ctypes.WINFUNCTYPE(ctypes.wintypes.DWORD, ctypes.wintypes.DWORD)(("GetFileType", ctypes.windll.kernel32))
+    GetFileType = compat_WINFUNCTYPE(ctypes.wintypes.DWORD, ctypes.wintypes.DWORD)(("GetFileType", ctypes.windll.kernel32))
     FILE_TYPE_CHAR = 0x0002
     FILE_TYPE_REMOTE = 0x8000
-    GetConsoleMode = ctypes.WINFUNCTYPE(
+    GetConsoleMode = compat_WINFUNCTYPE(
         ctypes.wintypes.BOOL, ctypes.wintypes.HANDLE,
         ctypes.POINTER(ctypes.wintypes.DWORD))(
         ("GetConsoleMode", ctypes.windll.kernel32))