Picture in Picture with WebRTC, nothing displayed

Hello 👋

I try to implement picture in picture on iOS with webRTC but I have some issue. I started by following this Apple article : https://developer.apple.com/documentation/avkit/adopting_picture_in_picture_for_video_calls

At least when my app is in background, the picture in picture view appear, but nothing is display within it :

So by searching on internet I found this post in Stackoverflow (https://stackoverflow.com/questions/71419635/how-to-add-picture-in-picture-pip-for-webrtc-video-calls-in-ios-swift), who says :

It's interesting but unfortunately, I don't know what I have to do...

Here is my PictureInPictureManager :

final class VideoBufferView: UIView {
	override class var layerClass: AnyClass {
		AVSampleBufferDisplayLayer.self
	}
	
	var sampleBufferDisplayLayer: AVSampleBufferDisplayLayer {
		layer as! AVSampleBufferDisplayLayer
	}
}

final class PictureInPictureManager: NSObject {
	static let shared: PictureInPictureManager = .init()
	private override init() { }
	
	private var pipController: AVPictureInPictureController?
	private var bufferView: VideoBufferView = .init()
	
	func configure(for videoView: UIView) {
		if AVPictureInPictureController.isPictureInPictureSupported() {
			let bufferView: VideoBufferView = .init()
			
			let pipVideoCallViewController: AVPictureInPictureVideoCallViewController = .init()
			pipVideoCallViewController.preferredContentSize = CGSize(width: 108, height: 192)
			pipVideoCallViewController.view.addSubview(bufferView)
			
			let pipContentSource: AVPictureInPictureController.ContentSource = .init(
				activeVideoCallSourceView: videoView,
				contentViewController: pipVideoCallViewController
			)

			pipController = .init(contentSource: pipContentSource)
			pipController?.canStartPictureInPictureAutomaticallyFromInline = true
			pipController?.delegate = self
		} else {
			print("❌ PIP not supported...")
		}
	}
}

With this code, the picture in picture view appear empty.

I read multiple article who talk about using the buffer but I'm not sure how to do it with webRTC...

I tried by adding this function to my PictureInPictureManager :

func updateBuffer(with pixelBuffer: CVPixelBuffer) {
	if let sampleBuffer = createSampleBufferFrom(pixelBuffer: pixelBuffer) {
		bufferView.sampleBufferDisplayLayer.enqueue(sampleBuffer)
	} else {
		print("❌ Sample buffer error...")
	}
}

private func createSampleBufferFrom(pixelBuffer: CVPixelBuffer) -> CMSampleBuffer? {
	var presentationTime = CMSampleTimingInfo()
	
	// Create a format description for the pixel buffer
	var formatDescription: CMVideoFormatDescription?
	let formatDescriptionError = CMVideoFormatDescriptionCreateForImageBuffer(
		allocator: kCFAllocatorDefault,
		imageBuffer: pixelBuffer,
		formatDescriptionOut: &formatDescription
	)
	
	guard formatDescriptionError == noErr else {
		print("❌ Error creating format description: \(formatDescriptionError)")
		return nil
	}
	
	// Create a sample buffer
	var sampleBuffer: CMSampleBuffer?
	let sampleBufferError = CMSampleBufferCreateReadyWithImageBuffer(
		allocator: kCFAllocatorDefault,
		imageBuffer: pixelBuffer,
		formatDescription: formatDescription!,
		sampleTiming: &presentationTime,
		sampleBufferOut: &sampleBuffer
	)
	
	guard sampleBufferError == noErr else {
		print("❌ Error creating sample buffer: \(sampleBufferError)")
		return nil
	}
	
	return sampleBuffer
}

but by doing that, I get this error message :

Any help is welcome ! 🙏 Thanks,

Alexandre