The IDirectDrawVideoPort::GetFieldPolarity method retrieves the status of the video field.
HRESULT GetVideoField(
LPBOOL lpbVideoField
);
If the method succeeds, the return value is DD_OK.
If the method fails, the return value may be one of the following error values:
| DDERR_INVALIDOBJECT |
| DDERR_INVALIDPARAMS |
| DDERR_UNSUPPORTED |
| DDERR_VIDEONOTACTIVE |