diff --git a/youtube_dl/compat.py b/youtube_dl/compat.py
index 646c9d79cc..27ece2d294 100644
--- a/youtube_dl/compat.py
+++ b/youtube_dl/compat.py
@@ -2897,9 +2897,24 @@ except TypeError:
         if isinstance(spec, compat_str):
             spec = spec.encode('ascii')
         return struct.unpack(spec, *args)
+
+    class compat_Struct(struct.Struct):
+        def __init__(self, fmt):
+            if isinstance(fmt, compat_str):
+                fmt = fmt.encode('ascii')
+            super(compat_Struct, self).__init__(fmt)
 else:
     compat_struct_pack = struct.pack
     compat_struct_unpack = struct.unpack
+    if platform.python_implementation() == 'IronPython' and sys.version_info < (2, 7, 8):
+        class compat_Struct(struct.Struct):
+            def unpack(self, string):
+                if not isinstance(string, buffer):
+                    string = buffer(string)
+                return super(compat_Struct, self).unpack(string)
+    else:
+        compat_Struct = struct.Struct
+
 
 try:
     from future_builtins import zip as compat_zip
@@ -2941,6 +2956,7 @@ __all__ = [
     'compat_HTMLParseError',
     'compat_HTMLParser',
     'compat_HTTPError',
+    'compat_Struct',
     'compat_b64decode',
     'compat_basestring',
     'compat_chr',
diff --git a/youtube_dl/downloader/ism.py b/youtube_dl/downloader/ism.py
index 138564267a..063fcf4446 100644
--- a/youtube_dl/downloader/ism.py
+++ b/youtube_dl/downloader/ism.py
@@ -1,25 +1,27 @@
 from __future__ import unicode_literals
 
 import time
-import struct
 import binascii
 import io
 
 from .fragment import FragmentFD
-from ..compat import compat_urllib_error
+from ..compat import (
+    compat_Struct,
+    compat_urllib_error,
+)
 
 
-u8 = struct.Struct(b'>B')
-u88 = struct.Struct(b'>Bx')
-u16 = struct.Struct(b'>H')
-u1616 = struct.Struct(b'>Hxx')
-u32 = struct.Struct(b'>I')
-u64 = struct.Struct(b'>Q')
+u8 = compat_Struct('>B')
+u88 = compat_Struct('>Bx')
+u16 = compat_Struct('>H')
+u1616 = compat_Struct('>Hxx')
+u32 = compat_Struct('>I')
+u64 = compat_Struct('>Q')
 
-s88 = struct.Struct(b'>bx')
-s16 = struct.Struct(b'>h')
-s1616 = struct.Struct(b'>hxx')
-s32 = struct.Struct(b'>i')
+s88 = compat_Struct('>bx')
+s16 = compat_Struct('>h')
+s1616 = compat_Struct('>hxx')
+s32 = compat_Struct('>i')
 
 unity_matrix = (s32.pack(0x10000) + s32.pack(0) * 3) * 2 + s32.pack(0x40000000)
 
diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 2fe9cf585d..ef44b99a55 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -866,8 +866,8 @@ def _create_http_connection(ydl_handler, http_class, is_https, *args, **kwargs):
     # expected HTTP responses to meet HTTP/1.0 or later (see also
     # https://github.com/rg3/youtube-dl/issues/6727)
     if sys.version_info < (3, 0):
-        kwargs[b'strict'] = True
-    hc = http_class(*args, **kwargs)
+        kwargs['strict'] = True
+    hc = http_class(*args, **compat_kwargs(kwargs))
     source_address = ydl_handler._params.get('source_address')
     if source_address is not None:
         sa = (source_address, 0)