diff --git a/libmpcodecs/vf_lavc.c b/libmpcodecs/vf_lavc.c
index f8fb20c30e..cc1420405c 100644
--- a/libmpcodecs/vf_lavc.c
+++ b/libmpcodecs/vf_lavc.c
@@ -34,6 +34,10 @@
 #define coded_frame coded_picture
 #endif
 
+#if LIBAVCODEC_BUILD < 4684
+#define FF_QP2LAMBDA 1
+#endif
+
 extern int avcodec_inited;
 
 struct vf_priv_s {