diff --git a/psychopy/app/_psychopyApp.py b/psychopy/app/_psychopyApp.py
index e66f102cf4..a8b15e02bb 100755
--- a/psychopy/app/_psychopyApp.py
+++ b/psychopy/app/_psychopyApp.py
@@ -316,16 +316,20 @@ def onInit(self, showSplash=True, testMode=False):
                                           args=(True,))
         versionsThread.start()
 
-        # if we have imageio then try to download ffmpeg
         try:
             import imageio
             haveImageio = True
-        except:
+        except ImportError:
             haveImageio = False
+
         if haveImageio:
-            # download() returns immediately if we have it already
-            ffmpegDownloader = threading.Thread(target=imageio.plugins.ffmpeg.download)
-            ffmpegDownloader.start()
+            # Use pre-installed ffmpeg if available.
+            # Otherwise, download ffmpeg binary.
+            try:
+                imageio.plugins.ffmpeg.get_exe()
+            except imageio.core.NeedDownloadError:
+                ffmpegDownloader = threading.Thread(target=imageio.plugins.ffmpeg.download)
+                ffmpegDownloader.start()
 
         ok, msg = checkCompatibility(last, self.version, self.prefs, fix=True)
         # tell the user what has changed
diff --git a/psychopy/hardware/crs/bits.py b/psychopy/hardware/crs/bits.py
index b6b8d12ce9..25e66aaf87 100644
--- a/psychopy/hardware/crs/bits.py
+++ b/psychopy/hardware/crs/bits.py
@@ -581,18 +581,18 @@ def getInfo(self):
         # get product ('Bits_Sharp'?)
         self.sendMessage(b'$ProductType\r')
         time.sleep(0.1)
-        info['ProductType'] = self.read().replace('#ProductType;', '')
-        info['ProductType'] = info['ProductType'].replace(';\n\r', '')
+        info['ProductType'] = self.read().replace(b'#ProductType;', b'')
+        info['ProductType'] = info['ProductType'].replace(b';\n\r', b'')
         # get serial number
         self.sendMessage(b'$SerialNumber\r')
         time.sleep(0.1)
-        info['SerialNumber'] = self.read().replace('#SerialNumber;', '')
-        info['SerialNumber'] = info['SerialNumber'].replace('\x00\n\r', '')
+        info['SerialNumber'] = self.read().replace(b'#SerialNumber;', b'')
+        info['SerialNumber'] = info['SerialNumber'].replace(b'\x00\n\r', b'')
         # get firmware date
         self.sendMessage(b'$FirmwareDate\r')
         time.sleep(0.1)
-        info['FirmwareDate'] = self.read().replace('#FirmwareDate;', '')
-        info['FirmwareDate'] = info['FirmwareDate'].replace(';\n\r', '')
+        info['FirmwareDate'] = self.read().replace(b'#FirmwareDate;', b'')
+        info['FirmwareDate'] = info['FirmwareDate'].replace(b';\n\r', b'')
         return info
 
     @property
diff --git a/psychopy/parallel/__init__.py b/psychopy/parallel/__init__.py
index ba4f718a49..6220c591df 100644
--- a/psychopy/parallel/__init__.py
+++ b/psychopy/parallel/__init__.py
@@ -12,7 +12,7 @@
 shown below you can use one of the following as drop-in replacements,
 forcing the use of a specific driver:
 
-    - `psychopy.parallel.PParallelInpOut32`
+    - `psychopy.parallel.PParallelInpOut`
     - `psychopy.parallel.PParallelDLPortIO`
     - `psychopy.parallel.PParallelLinux`
 
@@ -31,22 +31,34 @@
 import sys
 from psychopy import logging
 
-# To make life easier, only try drivers which have a hope in heck of working
+# To make life easier, only try drivers which have a hope in heck of working.
+# Because hasattr() in connection to windll ends up in an OSError trying to
+# load 32bit drivers in a 64bit environment, different drivers defined in
+# the dictionary 'drivers' are tested.
+
 if sys.platform.startswith('linux'):
     from ._linux import PParallelLinux
     ParallelPort = PParallelLinux
 elif sys.platform == 'win32':
+    drivers = dict(inpout32=('_inpout', 'PParallelInpOut'),
+                   inpoutx64=('_inpout', 'PParallelInpOut'),
+                   dlportio=('_dlportio', 'PParallelDLPortIO'))
     from ctypes import windll
-    if hasattr(windll, 'inpout32'):
-        from ._inpout32 import PParallelInpOut32
-        ParallelPort = PParallelInpOut32
-    elif hasattr(windll, 'dlportio'):
-        from ._dlportio import PParallelDLPortIO
-        ParallelPort = PParallelDLPortIO
-    else:
+    from importlib import import_module
+    for key, val in drivers.items():
+        driver_name, class_name = val
+        try:
+            hasattr(windll, key)
+            ParallelPort = getattr(import_module('.'+driver_name, __name__),
+                                   class_name)
+            break
+        except (OSError, KeyError, NameError):
+            ParallelPort = None
+            continue
+    if ParallelPort is None:
         logging.warning("psychopy.parallel has been imported but no "
                         "parallel port driver found. Install either "
-                        "inpout32 or dlportio")
+                        "inpout32, inpoutx64 or dlportio")
 else:
     logging.warning("psychopy.parallel has been imported on a Mac "
                     "(which doesn't have a parallel port?)")
diff --git a/psychopy/parallel/_inpout32.py b/psychopy/parallel/_inpout.py
similarity index 90%
rename from psychopy/parallel/_inpout32.py
rename to psychopy/parallel/_inpout.py
index 269e44e85d..301e21e684 100644
--- a/psychopy/parallel/_inpout32.py
+++ b/psychopy/parallel/_inpout.py
@@ -3,7 +3,7 @@
 
 from __future__ import absolute_import, print_function
 
-# We deliberately delay importing the inpout32 module until we try
+# We deliberately delay importing the inpout32 or inpoutx64 module until we try
 # to use it - this allows us to import the class on machines
 # which don't have it and then worry about dealing with
 # using the right one later
@@ -11,9 +11,9 @@
 
 from past.builtins import basestring
 from builtins import object
-class PParallelInpOut32(object):
+class PParallelInpOut(object):
     """This class provides read/write access to the parallel port on a PC
-    using inpout32 (for instance for Windows 7 64-bit)
+    using inpout32 or inpoutx64 (for instance for Windows 7 64-bit)
     """
 
     def __init__(self, address=0x0378):
@@ -29,13 +29,18 @@ def __init__(self, address=0x0378):
 
         from numpy import uint8
         from ctypes import windll
+        import platform
 
         if isinstance(address, basestring) and address.startswith('0x'):
             # convert u"0x0378" into 0x0378
             self.base = int(address, 16)
         else:
             self.base = address
-        self.port = windll.inpout32
+
+        if platform.architecture()[0] == '32bit':
+            self.port = getattr(windll, 'inpout32')
+        elif platform.architecture()[0] == '64bit':
+            self.port = getattr(windll, 'inpoutx64')
 
         BYTEMODEMASK = uint8(1 << 5 | 1 << 6 | 1 << 7)
 
diff --git a/psychopy/visual/backends/pygletbackend.py b/psychopy/visual/backends/pygletbackend.py
index fb2eadfb5e..bcce2b2eed 100644
--- a/psychopy/visual/backends/pygletbackend.py
+++ b/psychopy/visual/backends/pygletbackend.py
@@ -202,9 +202,13 @@ def __init__(self, win, *args, **kwargs):
             self.winHandle.set_mouse_visible(False)
         self.winHandle.on_resize = _onResize  # avoid circular reference
         if not win.pos:
-            # work out where the centre should be
-            win.pos = [(thisScreen.width - win.size[0]) / 2,
-                        (thisScreen.height - win.size[1]) / 2]
+            # work out where the centre should be 
+            if win.useRetina:
+                win.pos = [(thisScreen.width - win.size[0]/2) / 2,
+                            (thisScreen.height - win.size[1]/2) / 2]
+            else:
+                win.pos = [(thisScreen.width - win.size[0]) / 2,
+                            (thisScreen.height - win.size[1]) / 2]
         if not win._isFullScr:
             # add the necessary amount for second screen
             self.winHandle.set_location(int(win.pos[0] + thisScreen.x),