diff --git a/spa/include/spa/utils/defs.h b/spa/include/spa/utils/defs.h
index a6c39f2c9..7bf19a6e7 100644
--- a/spa/include/spa/utils/defs.h
+++ b/spa/include/spa/utils/defs.h
@@ -106,7 +106,7 @@ struct spa_fraction {
 	_v > _high ? _high : ( _v < _low ? _low : _v);	\
 })
 
-#define SPA_MEMBER(b,o,t) ((t*)((uint8_t*)(b) + (o)))
+#define SPA_MEMBER(b,o,t) ((t*)((uint8_t*)(b) + (int)(o)))
 
 #define SPA_CONTAINER_OF(p,t,m) (t*)((uint8_t*)p - offsetof (t,m))