title: Playing mp3 from librarydirectory with AVAudioPlayer in background
body: <p>I'm playing mp3 files with the standard AVAudioPlayer.<br>
  Since iOS 8.1 playing background audio when the device is locked is no longer working:<br>
  10-20 seconds after the device is locked the playback stops.<br>
  Leaving the app via the home button is no problem.<br>
  Running on iOS 8.0 is no problem.<br>
  Playing bundled audio is no problem.     </p>
  
  <p>The problem only occurs when all three conditions are met:
  Play file from user directory when device is locked on iOS 8.1.</p>
  
  <p>The problem seems to be that the file input stream stops providing data and thus the buffer runs empty: I debugged the playback using STK StreamingKit Player and observed that the streams hasBytesAvailable method returned NO shortly before the playback stopped.</p>
  
  <p>Are there any new rules for file access?
  I can't find any information in the release notes...
  Anybody an idea?</p>