diff --git a/mediafile.py b/mediafile.py
index eb74e33..c708aa0 100644
--- a/mediafile.py
+++ b/mediafile.py
@@ -1883,7 +1883,7 @@ def as_dict(self):
     )
     popm = MediaField(
         MP3StorageStyle('POPM'),
-        MP4StorageStyle('POPM'),
+        MP4StorageStyle('POPM', as_type=int),
         StorageStyle('POPM'),
         ASFStorageStyle('Popm'),
         out_type=int