 
     func timeRangeDidChanged(timeRange: CMTimeRange) {
         let start = timeRange.start
-        if player != nil {
-            player!.seekToTime(start, toleranceBefore: CMTimeMake(1, 30), toleranceAfter: CMTimeMake(1, 30))
+        if player != nil && self.seekFinish {
+            self.seekFinish = false
+            player!.seekToTime(start, toleranceBefore: CMTimeMake(1, 30), toleranceAfter: CMTimeMake(1, 30), completionHandler: { (finished) -> Void in
+                self.seekFinish = true
+            })
         }
     }
     

    @IBOutlet weak var videoRangeSlider : LYVideoRangeSlider!
    @IBOutlet weak var previewView : UIView!
    
    var playerLayer : AVPlayerLayer?
    var player : AVPlayer?
    var playerItem : AVPlayerItem?

        let endTime = CMTimeRangeGetEnd(timeRange)
        if playerItem != nil {
            playerItem!.forwardPlaybackEndTime = endTime
            player!.seekToTime(startTime, toleranceBefore: CMTimeMake(1, 30), toleranceAfter: CMTimeMake(1, 30), completionHandler: { (finished) -> Void in
                self.seekFinish = true
            })
        }
    }
    
