diff --git a/src/rational.h b/src/rational.h
index 045b390ca3b43e23c5080537899418518e025509..57d9bf45672df25537843a9d6f8621b301c9d7ec 100644
--- a/src/rational.h
+++ b/src/rational.h
@@ -49,7 +49,7 @@ public:
 
     // Define conversions to and from AVRational (equivalent)
     rational(AVRational r) : num_(r.num), den_(r.den) {};
-    operator AVRational() const { return AVRational{num_, den_}; }
+    operator AVRational() const { return AVRational{(int)num_, (int)den_}; }
 
     // Normal copy constructors and assignment operators