diff --git a/src/gallium/auxiliary/vl/vl_idct.c b/src/gallium/auxiliary/vl/vl_idct.c
index 0a81134a789..087ac6e71bb 100644
--- a/src/gallium/auxiliary/vl/vl_idct.c
+++ b/src/gallium/auxiliary/vl/vl_idct.c
@@ -496,7 +496,7 @@ vl_idct_upload_matrix(struct pipe_context *pipe)
    struct pipe_box rect =
    {
       0, 0, 0,
-      BLOCK_WIDTH,
+      BLOCK_WIDTH / 4,
       BLOCK_HEIGHT,
       1
    };