diff --git a/dlls/quartz/videorenderer.c b/dlls/quartz/videorenderer.c
index 02fcc7a..eaaada6 100644
--- a/dlls/quartz/videorenderer.c
+++ b/dlls/quartz/videorenderer.c
@@ -318,7 +318,7 @@
         This->WindowPos.left = 0;
         This->WindowPos.top = 0;
         This->WindowPos.right = width;
-        This->WindowPos.bottom = height;
+        This->WindowPos.bottom = abs(height);
         GetClientRect(This->hWnd, &This->DestRect);
         This->init  = TRUE;
     }