2 usb cameras use in the same page

BeyzaK.

I try to use 2 usb cameras in my qml page. One camera opens normally other one stays green screen.

I am having these errors in Qt Creator.
Couldn't release V4L2 buffer 22 Invalid argument 0
error calling VIDIOC_DQBUF 22 Invalid argument

I though maybe I am trying to start both cameras in the same time so I put timer to start second camera but didn't work.

MediaDevices {
        id: mediaDevices
}

CaptureSession {
        id: first_captureSession
        camera: Camera {
            cameraDevice: mediaDevices.videoInputs[0]
            id: camera1
            onErrorOccurred: function(error, errorString) {
                if (Camera.NoError !== error) {
                    console.log("[qmlvideo] CameraItem.onError error " + error + " errorString " + errorString)
                }
            }
        }
}

CaptureSession {
        id: second_captureSession
        camera: Camera {
            cameraDevice:mediaDevices.videoInputs[1]
            id: camera2
            onErrorOccurred: function(error, errorString) {
                if (Camera.NoError !== error) {
                    console.log("[qmlvideo] CameraItem.onError error " + error + " errorString " + errorString)
                }
            }
        }
}

//setVideoSources() is called by a button for now. 
//Normally cameras has to start when the page created.
function setVideoSources(){
        camera1.start()
        first_captureSession.videoOutput = main_source
        denemeTimer.start()
}

Timer {
        id:denemeTimer
        interval: 500; running: false; repeat: false
        onTriggered: {
            camera2.start()
            second_captureSession.videoOutput = minor_source
        }
}