为什么WIN7下DirectShow摄像头打不开

为什么WIN7下DirectShow摄像头打不开，注释如下代码就可以打开了，但是注释这段代码应该有问题哦
// Fix upsidedown video   // If we are using a still pin, ask for a picture
                if (videoControl != null)
                {
                    VideoControlFlags pCapsFlags;                    IPin pPin = DsFindPin.ByCategory(capFilter, PinCategory.Capture, 0);
                    hr = videoControl.GetCaps(pPin, out pCapsFlags);
                    DsError.ThrowExceptionForHR(hr);                    if ((pCapsFlags & VideoControlFlags.FlipVertical) > 0)
                    {
                        hr = videoControl.GetMode(pPin, out pCapsFlags);
                        DsError.ThrowExceptionForHR(hr);
                        hr = videoControl.SetMode(pPin, 0);// Tell the camera to send an image
                    }
                }