diff --git a/xbin.py b/xbin.py
index 4724e6b..a061262 100644
--- a/xbin.py
+++ b/xbin.py
@@ -458,7 +458,7 @@ def WritePartInfo(file, index, name):
 
     @staticmethod
     def WritePartIndex(file, index):
-        data = struct.pack('Hh', 0x745A, index)
+        data = struct.pack('Hh', 0x745A, int(index))
         file.write(data)
 
     @staticmethod
@@ -468,12 +468,12 @@ def WriteFramerate(file, framerate):
 
     @staticmethod
     def WriteFrameCount(file, frame_count):
-        data = struct.pack('Hxxi', 0xB917, frame_count)
+        data = struct.pack('Hxxi', 0xB917, int(frame_count))
         file.write(data)
 
     @staticmethod
     def WriteFrameIndex(file, frame):
-        data = struct.pack('Hxxi', 0xC723, frame)
+        data = struct.pack('Hxxi', 0xC723, int(frame))
         file.write(data)
 
     @staticmethod