ViewController.swift
import UIKit
import AVFoundation

class LoginMovieViewController: UIViewController {
    
    var player = AVPlayer()
    

    override func viewDidLoad() {
        super.viewDidLoad()
        //ファイルパス
        let path = Bundle.main.path(forResource: "ファイル名", ofType: "拡張子")
        player = AVPlayer(url: URL(fileURLWithPath: path!))
        
        //AVPlayer用のレイヤーを生成
        let playerLayer = AVPlayerLayer(player: player)
        playerLayer.frame = CGRect(x: 0, y: 0, width: view.frame.size.width, height: view.frame.size.height)
        
        playerLayer.videoGravity = .resizeAspectFill
        playerLayer.repeatCount = 0 //無限ループ(終わったらまた再生のイベント後述)
        playerLayer.zPosition = -1
        view.layer.insertSublayer(playerLayer, at: 0)
        
        //終わったらまた再生
        NotificationCenter.default.addObserver(
            forName: .AVPlayerItemDidPlayToEndTime, //終わったr前に戻す
            object: player.currentItem,
            queue: .main) { (_) in
                
                self.player.seek(to: .zero)//開始時間に戻す
                self.player.play()

        }

        self.player.play()

    }