diff --git a/src/ffx/track_codec.py b/src/ffx/track_codec.py
index 54648fc..f1b3bb7 100644
--- a/src/ffx/track_codec.py
+++ b/src/ffx/track_codec.py
@@ -34,7 +34,7 @@ class TrackCodec(Enum):
 
     def format(self):
         """Returns the codec as single letter"""
-        return str(self.value['format'])
+        return self.value['format']
 
     def extension(self):
         """Returns the corresponding extension"""