根据URL获取视频第一帧图片 - Swift

import UIKit
import AVFoundation

class ViewController: UIViewController {

override func viewDidLoad() {
super.viewDidLoad()
let thumb = UIImageView.init(frame: CGRect.init(x: 50, y: 200, width: 300, height: 200))
self.view.addSubview(thumb)
let asset = AVURLAsset.init(url: URL.init(string: "http://gslb.miaopai.com/stream/1UKfVpOmazRYEb4fVejwhgpX~3uIxmHBV~8VCQ__.mp4")!, options: nil)
let gen = AVAssetImageGenerator.init(asset: asset)
gen.appliesPreferredTrackTransform = true
let time = CMTimeMakeWithSeconds(0.0, 1)
var actualTime : CMTime = CMTimeMakeWithSeconds(0, 0)
do {
let image = try gen.copyCGImage(at: time, actualTime: &actualTime)
thumb.image = UIImage.init(cgImage: image)
} catch  {
print("错误")
}

}

override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}

}