diff --git a/rtmp/rtmp_c/librtmp/amf.h b/rtmp/rtmp_c/librtmp/amf.h
index 5de414ba..b061edb9 100644
--- a/rtmp/rtmp_c/librtmp/amf.h
+++ b/rtmp/rtmp_c/librtmp/amf.h
@@ -70,16 +70,17 @@ extern "C"
     struct AMFObjectProperty *o_props;
   } AMFObject;
 
+  typedef struct P_vu {
+    double p_number;
+    AVal p_aval;
+    AMFObject p_object;
+  } P_vu;
+
   typedef struct AMFObjectProperty
   {
     AVal p_name;
     AMFDataType p_type;
-    union
-    {
-      double p_number;
-      AVal p_aval;
-      AMFObject p_object;
-    } p_vu;
+    P_vu p_vu;
     int16_t p_UTCoffset;
   } AMFObjectProperty;