diff --git a/config.py b/config.py
index 1132a3e..7dfc702 100644
--- a/config.py
+++ b/config.py
@@ -3,6 +3,7 @@ import re
 import sys
 import configparser
 import time
+import typing
 from pathlib import Path
 
 G_conf_override = {
@@ -263,8 +264,8 @@ class Config:
     def media_type(self) -> str:
         return self.conf.get('media', 'media_type')
 
-    def sub_rule(self):
-        return self.conf.get('media', 'sub_type').split(',')
+    def sub_rule(self) -> typing.Set[str]:
+        return set(self.conf.get('media', 'sub_type').lower().split(','))
 
     def naming_rule(self) -> str:
         return self.conf.get("Name_Rule", "naming_rule")
@@ -445,9 +446,9 @@ class Config:
         sec11 = "media"
         conf.add_section(sec11)
         conf.set(sec11, "media_type",
-                 ".mp4,.avi,.rmvb,.wmv,.mov,.mkv,.flv,.ts,.webm,.MP4,.AVI,.RMVB,.WMV,.MOV,.MKV,.FLV,.TS,.WEBM,iso,ISO")
+                 ".mp4,.avi,.rmvb,.wmv,.mov,.mkv,.flv,.ts,.webm,iso")
         conf.set(sec11, "sub_type",
-                 ".smi,.srt,.idx,.sub,.sup,.psb,.ssa,.ass,.txt,.usf,.xss,.ssf,.rt,.lrc,.sbv,.vtt,.ttml")
+                 ".smi,.srt,.idx,.sub,.sup,.psb,.ssa,.ass,.usf,.xss,.ssf,.rt,.lrc,.sbv,.vtt,.ttml")
 
         sec12 = "watermark"
         conf.add_section(sec12)
diff --git a/core.py b/core.py
index ddf30e7..41d40e4 100644
--- a/core.py
+++ b/core.py
@@ -521,7 +521,7 @@ def paste_file_to_folder(filepath, path, multi_part, number, part, leak_word, c_
             except:
                 os.symlink(str(filepath_obj.resolve()), targetpath)
 
-        sub_res = [subext.lower() for subext in config.getInstance().sub_rule()]
+        sub_res = config.getInstance().sub_rule()
         for subfile in filepath_obj.parent.glob('**/*'):
             if subfile.is_file() and subfile.suffix.lower() in sub_res:
                 if multi_part and part.lower() not in subfile.name.lower():
@@ -572,7 +572,7 @@ def paste_file_to_folder_mode2(filepath, path, multi_part, number, part, leak_wo
             except:
                 os.symlink(str(filepath_obj.resolve()), targetpath)
 
-        sub_res = [subext.lower() for subext in config.getInstance().sub_rule()]
+        sub_res = config.getInstance().sub_rule()
         for subfile in filepath_obj.parent.glob('**/*'):
             if subfile.is_file() and subfile.suffix.lower() in sub_res:
                 if multi_part and part.lower() not in subfile.name.lower():