diff --git a/v4l2/rgb2fimg.c b/v4l2/rgb2fimg.c
index 9e839d7..f39dccb 100644
--- a/v4l2/rgb2fimg.c
+++ b/v4l2/rgb2fimg.c
@@ -28,8 +28,8 @@ if ( d->width != w*2 || d->height != h*2 ) {
 	return -2;
 	}
 
-ox = ! (modz & 2);
-oy = ! (modz & 1);
+ox = ! ! (modz & 2);
+oy = ! ! (modz & 1);
 
 if (verbosity>2)	fprintf(stderr, "%s   %5d  %d %d\n", __func__,
 					modz, ox, oy);