diff --git a/converter/avcodecs.py b/converter/avcodecs.py
index 66e015e8..02eca3c3 100644
--- a/converter/avcodecs.py
+++ b/converter/avcodecs.py
@@ -170,7 +170,7 @@ def parse_options(self, opt, stream=0):
             s = str(0)
 
         if 'encoding' in safe:
-            if not safe['encoding'] or safe['encoding'] == "":
+            if not safe['encoding'] or safe['encoding'] == "" or safe['encoding'] == "None":
                 del safe['encoding']
 
         safe = self._codec_specific_parse_options(safe)