我正在尝试将WebRTC视频集成到我的iOS应用程序中。我从https://webrtc.github.io/webrtc-org/native-code/ios/下载了源代码并成功构建了它。然而，GLView在这个代码库中不受支持，所以我不得不使用MetalKit并将RTCMTLVideoView添加到我的类中。我还添加了RTCVideoRenderer和RTCVideoViewDelegate，并设置self.metalVideoView.delegate = self。
当调用处理传入视频的方法时，我可以看到从通知中接收到的对象是RTC_OBJC_TYPE（RTCMediaStreamTrack）：video janusv0 enabled Live，VideoTracks计数为：1.然而，我无法在屏幕上看到任何视频。我只看到一个空白的屏幕。在WebRTC的上一个版本中，我使用了GLView和相同的实现，它工作得很好。
您能在下面查看我的实现，并让我知道我是否遗漏了什么吗？

@objc func handleFloorPlanVideoReceived(_ notification: Notification?) {
    if let remoteVideoTrack = notification?.object as? RTCVideoTrack {

        print("Recieved Remote Video: \(remoteVideoTrack)")

        DispatchQueue.main.async {
            // Initialize the metalVideoView
            self.metalVideoView = RTCMTLVideoView(frame: CGRect.zero)
            self.metalVideoView.delegate = self

            // Add the metalVideoView to the view hierarchy
            self.view.addSubview(self.metalVideoView)
            self.metalVideoView.backgroundColor = .edgeGray
            self.metalVideoView.videoContentMode = .scaleAspectFit

            // Set up auto layout constraints
            self.metalVideoView.translatesAutoresizingMaskIntoConstraints = false
            NSLayoutConstraint.activate([
                self.metalVideoView.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor),
                self.metalVideoView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
                self.metalVideoView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
                self.metalVideoView.heightAnchor.constraint(equalTo: self.view.heightAnchor, multiplier: 1.0/3.0)
            ])

            remoteVideoTrack.add(self.metalVideoView)

            // Create and add the UIActivityIndicatorView
            let activityIndicator = UIActivityIndicatorView(style: .large)
            activityIndicator.color = .white
            self.metalVideoView.addSubview(activityIndicator)
            self.activityIndicator = activityIndicator

            // Set up constraints for the activity indicator
            activityIndicator.translatesAutoresizingMaskIntoConstraints = false
            NSLayoutConstraint.activate([
                activityIndicator.centerXAnchor.constraint(equalTo: self.metalVideoView.centerXAnchor),
                activityIndicator.centerYAnchor.constraint(equalTo: self.metalVideoView.centerYAnchor)
            ])

            activityIndicator.startAnimating()

            // Create and add the close button
            let closeButton = UIButton(type: .system)
            if let closeImage = UIImage(systemName: "xmark") {
                closeButton.setImage(closeImage, for: .normal)
            }

            self.metalVideoView.addSubview(closeButton)

            // Set up constraints for the close button
            closeButton.translatesAutoresizingMaskIntoConstraints = false
            NSLayoutConstraint.activate([
                closeButton.topAnchor.constraint(equalTo: self.metalVideoView.topAnchor, constant: 8),
                closeButton.trailingAnchor.constraint(equalTo: self.metalVideoView.trailingAnchor, constant: -8)
            ])

            // Add target for close button tap event
            closeButton.addTarget(self, action: #selector(self.closeButtonTapped), for: .touchUpInside)

            self.metalVideoView.setNeedsLayout()
        }
    }
}