how to get video stream only through 'ReplayKit' iOS Swift

Question

I am using ReplayKit for getting a video stream. callback is continuously calling but rpSampleType returns something else. I want the video buffer only.

Here is my code

RPScreenRecorder.shared().startCapture(handler: { (cmSampleBuffer, rpSampleType, error) in
    if CMSampleBufferDataIsReady(cmSampleBuffer){

        switch rpSampleType {

        case RPSampleBufferType.video:
            // create the CVPixelBuffer
            let pixelBuffer = CMSampleBufferGetImageBuffer(cmSampleBuffer)!
            let rtcpixelBuffer = RTCCVPixelBuffer(pixelBuffer: pixelBuffer)
        default:
            print("sample has no matching type")
        }
    }
}) { (error) in
    print(error?.localizedDescription)
}