--- a/src/video_display.cpp
+++ b/src/video_display.cpp
@@ -309,6 +309,7 @@
 }
 
 void VideoDisplay::UpdateSize() {
+	if (zoomValue<=0) zoomValue = 1;
 	if (!con->videoController->IsLoaded() || !IsShownOnScreen()) return;
 
 	videoSize.Set(con->videoController->GetWidth(), con->videoController->GetHeight());