title: iOS Swift : Error Domain=NSOSStatusErrorDomain Code=-12792?
body: <p>I'm trying to get video thumbnails with the following code:</p>
  
  <pre><code>let asset = AVAsset(URL: url)
      let imageGenerator = AVAssetImageGenerator(asset: asset)
      imageGenerator.appliesPreferredTrackTransform = true
  
      do {
          let cgImage = try imgGenerator.copyCGImageAtTime(CMTimeMake(1, 30), actualTime: nil)
          let uiImage = UIImage(CGImage: cgImage)
          imageview.image = uiImage
      }
      catch let error as NSError
      {
          print("Image generation failed with error \(error)")
      }
  </code></pre>
  
  <p>Sometimes it works and sometime it doesn't showing the following error:</p>
  
  <blockquote>
    <p>Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could
    not be completed" UserInfo={NSLocalizedDescription=The operation could
    not be completed, NSUnderlyingError=0x14eab520 {Error
    Domain=NSOSStatusErrorDomain Code=-12792 "(null)"},
    NSLocalizedFailureReason=An unknown error occurred (-12792)}</p>
  </blockquote>
  
  <p>I have tried to figure out what is <code>Domain=NSOSStatusErrorDomain Code=-12792</code> but I don't understand how I can get more details about this error code. How can I convert this error code into a string to get relevant information about what this error means?</p>