AVAudioPlayer の再生。

このAVAudioPlayerは、簡単にPlayersのインターバルが取得できる特徴がある。

class ViewController: UIViewController {
var player = AVAudioPlayer()
var url = NSUNL()
var slider = UISlider()
var Tim = Timer() 
  override func viewDidLoad(){
    url = URL(string: “https://url/audio_file.m4a”)! as NSURL
    player = try! AVAudioPlayer(contentsOf: url as URL)
    PlayMusic()
    slider.frame = CGRect(x: 10, y: self.view.frame.size.height-44, width: self.view.frame.size.width-20, 44)
    self.view.addSubview(slider)
    let btn1 = UIButton()
    btn1.frame = CGRect(x: 0, y: 300, width: 320, height: 40)
    btn1.addTarget(self, action: #selector(playing(playing:)), for: .touchUpInside)
    self.view.addSubview(btn1)
  }
  func PlayMusic(){
    let t = player.duration
    let t2 = player.currentTime
    slider.maximumValue = Float(t)
    slider.minimumValue = 0.0
    slider.value = Float(t2) 
    Tim = Timer.scheduledTimer(interval: 0.1, target: self, selector: #selector(tim(tim:)), userInfo: nil, repeats: true)
  }
  @objc func playing(playing: UIButton){
    plsyer.play()
    PlayMusic()
  }
  @objc tim(tim: Timer){
    let t = player.duration
    let t2 = player.currentTime
    slider.maximumValue = Float(t)
    slider.minimumValue = 0.0
    slider.value = Float(t2) 
  }
}

URLは独自のものを使ってください。
AVAudioPlayerはiOSのデバイス内の音声出力は確認できていますが、外部URLはどうか？
ボタンタップからの再生で、スライダーだけの　UIの実装です。