diff --git a/libavfilter/vf_libplacebo.c b/libavfilter/vf_libplacebo.c
index a7b8a38f7b..4ee8c36d7d 100644
--- a/libavfilter/vf_libplacebo.c
+++ b/libavfilter/vf_libplacebo.c
@@ -19,6 +19,7 @@
 #include <math.h>
 
 #include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
 #include "libavutil/eval.h"
 #include "libavutil/fifo.h"
 #include "libavutil/file.h"