diff --git a/libavfilter/vf_unsharp.c b/libavfilter/vf_unsharp.c
index bd78ade39c..e6257e2cab 100644
--- a/libavfilter/vf_unsharp.c
+++ b/libavfilter/vf_unsharp.c
@@ -73,7 +73,7 @@ static void apply_unsharp(      uint8_t *dst, int dst_stride,
 
     int32_t res;
     int x, y, z;
-    const uint8_t *src2;
+    const uint8_t *src2 = NULL;  //silence a warning
 
     if (!fp->amount) {
         if (dst_stride == src_stride)