diff --git a/libavfilter/vf_deshake.c b/libavfilter/vf_deshake.c
index 55ce5e18a1..c8480e74dd 100644
--- a/libavfilter/vf_deshake.c
+++ b/libavfilter/vf_deshake.c
@@ -196,7 +196,7 @@ static int block_contrast(uint8_t *src, int x, int y, int stride, int blocksize)
     for (i = 0; i <= blocksize * 2; i++) {
         // We use a width of 16 here to match the sad function
         for (j = 0; j <= 15; j++) {
-            pos = (y - i) * stride + (x - j);
+            pos = (y + i) * stride + (x + j);
             if (src[pos] < lowest)
                 lowest = src[pos];
             else if (src[pos] > highest) {