diff --git a/libavfilter/vf_overlay.c b/libavfilter/vf_overlay.c
index 502fde00b8..7457820526 100644
--- a/libavfilter/vf_overlay.c
+++ b/libavfilter/vf_overlay.c
@@ -245,8 +245,8 @@ static int query_formats(AVFilterContext *ctx)
         AV_PIX_FMT_NONE
     };
 
-    AVFilterFormats *main_formats;
-    AVFilterFormats *overlay_formats;
+    AVFilterFormats *main_formats = NULL;
+    AVFilterFormats *overlay_formats = NULL;
     int ret;
 
     switch (s->format) {