diff --git a/libavfilter/vf_cuda_grid.c b/libavfilter/vf_cuda_grid.c
index 9537b54..bfc4a53 100644
--- a/libavfilter/vf_cuda_grid.c
+++ b/libavfilter/vf_cuda_grid.c
@@ -19,6 +19,7 @@
 
 #include "config_components.h"
 
+#include "libavutil/avstring.h"
 #include "libavutil/common.h"
 #include "libavutil/cuda_check.h"
 #include "libavutil/hwcontext.h"