GPUImageMovie Filtered Video Crash when device lock

I have applying filters to existing video using GPUImageMovie, Everything is working fine, Bus issues is that when application running and at that time user press Lock button device locked and application crash, So pleas suggest me How can I Get that Device lock event, I was already implement enterBackground Notification to stop process, But its work only with Home button Not with Device lock.

Thanks in advance.

via Chebli Mohamed