backgroundvideo.swift

var filePath = NSBundle.mainBundle().pathForResource("railway", ofType: "gif")
var gif = NSData(contentsOfFile: filePath)

var webViewBG = UIWebView(frame: self.view.frame)
webViewBG.loadData(gif, MIMEType: "image/gif", textEncodingName: nil, baseURL: nil)
webViewBG.userInteractionEnabled = false;
self.view.addSubview(webViewBG)

var filter = UIView()
filter.frame = self.view.frame
filter.backgroundColor = UIColor.blackColor()
filter.alpha = 0.5
self.view.addSubview(filter)