title: AVAssetWriter fails once App goes in background
body: <p>I am working on iOS app in which i am creating video from images. I am using <code>AVAssetWriter</code> to achieve this. Everything works fine. But When app goes in background and switched back, the video writing fails. <code>AVAssetWriter</code>'s <code>finishWritingWithCompletionHandler</code> is not getting called when i switch back to app. </p>
  
  <p>May be duplicate of <a href="https://stackoverflow.com/questions/7638078/avassetwriter-fails-when-application-enters-background-during-rendering">AVAssetWriter fails when Application enters Background during Rendering</a> , but i am not getting any help from there.</p>
  
  <p>Any idea for this?</p>
  
  <p>Thanks</p>