I found the solution by compiling different precedent responses from stackoverflow. Here is the working code (swift 2.2). This code loops seamlessly the video playback with a SKSVideoNode object on the scene (with an AVPlayer initializer):
override func didMoveToView(view: SKView) {
let urlStr = NSBundle.mainBundle().pathForResource("Video_Socle", ofType: "mov")
let url = NSURL(fileURLWithPath: urlStr!)
player = AVPlayer(URL: url)
NSNotificationCenter.defaultCenter().addObserverForName(AVPlayerItemDidPlayTo EndTimeNotification
, object: player!.currentItem, queue: nil)
{ notification in
let t1 = CMTimeMake(5, 100);
self.player!.seekToTime(t1)
self.player!.play()
}
videoNode = SKVideoNode(AVPlayer: player!)
videoNode!.position = CGPointMake(frame.size.width/2, frame.size.height/2)
videoNode!.size = CGSize(width: 2048, height: 1536)
videoNode!.zPosition = 0
background.addChild(videoNode!)
videoNode!.play()