ios - 拍摄 AVCaptureVideoPreviewLayer View 的快照

Question

我正在使用 WebRTC 在两个用户之间建立视频聊天。我想拍一张显示其中一个人的 localView View 。

这是我的类，它使用 configureLocalPreview 方法将视频流与 UIView 连接起来:

@IBOutlet var remoteView: RTCEAGLVideoView!
@IBOutlet var localView: UIView!

var captureSession: AVCaptureSession?
var videoSource: RTCAVFoundationVideoSource?
var videoTrack: RTCVideoTrack?

func configureLocalPreview() {
    self.videoTrack = self.signaling.localMediaStream.self.videoTracks.first as! RTCVideoTrack?
    self.videoSource = (self.videoTrack?.source as? RTCAVFoundationVideoSource)
    self.captureSession = self.videoSource?.self.captureSession

    self.previewLayer = AVCaptureVideoPreviewLayer.init(session: self.captureSession)
    self.previewLayer.frame = self.localView.bounds
    self.localView.layer.addSublayer(self.previewLayer)
    self.localView.isUserInteractionEnabled = true
    //self.localView.layer.position = CGPointMake(100, 100);
}

在我想访问快照的地方，我调用:

self.localView.pb_takeSnapshot()

pb_takeSnapshot 来 self 在另一篇文章中找到的 UIView 扩展。它是这样定义的:

extension UIView {
    func pb_takeSnapshot() -> UIImage {
    UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.main.scale)

    drawHierarchy(in: self.bounds, afterScreenUpdates: true)

    let image = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    return image
    }
}

当我在 Xcode 调试器中查看图像时，它看起来完全是绿色的，而我可以在 iphone 屏幕上(在该 View 内)看到的那个人却不在那里:

此人不可见的原因是什么？是否无法以某种方式制作流的快照？感谢您的关注!

Answer 1

您应该使用 RTCEAGLVideoView 而不是 UIView 创建 localView。我对我的 localView 使用相同的方法，并且能够使用您帖子中提到的相同代码片段拍摄快照。

下面是启动相机并显示本地预览的示例代码:

class ViewController: UIViewController,RTCEAGLVideoViewDelegate {

var captureSession: AVCaptureSession?
var previewLayer :AVCaptureVideoPreviewLayer?
var peerConnectionFactory: RTCPeerConnectionFactory!
var videoSource:RTCAVFoundationVideoSource!
var localTrack :RTCVideoTrack!

@IBOutlet var myView: UIView!
override func viewDidLoad() {
    super.viewDidLoad()
    /*myView = UIView(frame: CGRect(x: 0,
                                 y: 0,
                                 width: UIScreen.main.bounds.size.width,
                                 height: UIScreen.main.bounds.size.height))*/
    startCamera()
    // Do any additional setup after loading the view, typically from a nib.
}

fileprivate func startCamera() {

    peerConnectionFactory = RTCPeerConnectionFactory()
    RTCInitializeSSL();
    RTCSetupInternalTracer();
    RTCSetMinDebugLogLevel(RTCLoggingSeverity.info)

    videoSource = peerConnectionFactory.avFoundationVideoSource(with: nil);


    localTrack  = peerConnectionFactory.videoTrack(with: videoSource, trackId: "ARDAMSv0")



    let localScaleX = CGFloat(1.0)
    let localView : RTCEAGLVideoView = RTCEAGLVideoView(frame: self.view.bounds)
    self.view.insertSubview(localView, at: 1)
    localView.frame = self.view.bounds;
    localView.transform = CGAffineTransform(scaleX: localScaleX, y: 1)

    localTrack.add(localView)
}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

override func viewDidAppear(_ animated: Bool) {
    //previewLayer?.frame.size = myView.frame.size
}

func videoView(_ videoView: RTCEAGLVideoView, didChangeVideoSize size: CGSize) {
    print("Inside didChangeVideoSize")
}

}