diff --git a/include/media/IMediaSource.h b/include/media/IMediaSource.h
index 709f425..4056d54 100644
--- a/include/media/IMediaSource.h
+++ b/include/media/IMediaSource.h
@@ -89,7 +89,7 @@
         SeekMode mSeekMode;
         int64_t mLatenessUs;
         bool mNonBlocking;
-    };
+    } __attribute__((packed)); // sent through Binder
 
     // Returns a new buffer of data. Call blocks until a
     // buffer is available, an error is encountered or the end of the stream