ZBarReaderView具有自定义大小的故事板，在启动后移动，将被调用

i've got a ZBarReaderView created from storyboard with 216x20 px which is shown as roughly 230x50 px because ZBarReaderView doesn't take it's size too serious... It all works very well, however it behaves really strange when I call start on that readerView. It starts the cam but then in maybe half a second the readerView zooms a bit and the camera picture inside the readerView moves down and then up again. It's not terrible but it look kinda bad. Anyone got any ideas what might be causing this and how to solve it? Maybe the sdk has some sort of hidden callback for the readiness of the scanner, i could hide it until the scanner says it's ready and then show the scanner like .5 seconds later...i've got a ZBarReaderView created from storyboa