您最终将缺少exporter块，无法
AVAssetExportSession对创建的对象执行导出操作：
exporter.exportAsynchronouslyWithCompletionHandler({ //display video after export is complete, for example... let outputURL:NSURL = exporter.outputURL; let asset:AVURLAsset = AVURLAsset(URL: outputURL, options: nil) let newPlayerItem:AVPlayerItem = AVPlayerItem(asset: asset) self.mPlayer = AVPlayer.playerWithPlayerItem(newPlayerItem) as AVPlayer})
