Qt摄像头捕获图片问题：CameraBin error: "Internal data flow error."

if(camera == NULL){

        camera=new QCamera(this);

        connect(camera, SIGNAL(statusChanged(QCamera::Status)), this, SLOT(slotStateChanged(QCamera::Status)));

        connect(camera, SIGNAL(error(QCamera::Error)), this, SLOT(slotCameraError(QCamera::Error)));

    }

    if(viewfinder == NULL){

        viewfinder=new QCameraViewfinder(this);

        ui->widget->layout()->addWidget(viewfinder);

        camera->setViewfinder(viewfinder);

    }

    if(imageCapture == NULL){

        imageCapture = new QCameraImageCapture(camera);

        connect(imageCapture, SIGNAL(imageCaptured(int,QImage)), this, SLOT(displayImage(int,QImage)));

        connect(imageCapture, SIGNAL(error(int,QCameraImageCapture::Error,QString)), this, SLOT(slotError(int,QCameraImageCapture::Error,QString)));

    }

    imageCapture->setCaptureDestination(QCameraImageCapture::CaptureToBuffer);

    imageCapture->setBufferFormat(QVideoFrame::PixelFormat::Format_Jpeg);