directshow 显示有黑边的有关问题

bool CDXGraph::SetWindow(HWND inWindow)
{
    mVideoWindow->put_Owner((OAHWND)inWindow);
    mVideoWindow->put_Visible(OATRUE);
    mVideoWindow->put_AutoShow(OATRUE);
    mVideoWindow->put_MessageDrain((OAHWND) inWindow);
    mVideoWindow->put_WindowStyle(WS_CHILD | WS_CLIPSIBLINGS | WS_CLIPCHILDREN);
    return S_OK;
}
bool CDXGraph::SetDisplayWindow(HWND inWindow)
{    
    if (mVideoWindow)
    {
        
        RECT windowRect;
        GetClientRect(inWindow, &windowRect);

        HRESULT hr = NULL;
        
        LONG lVideoWidth, lVideoHeight, lNewWidth, lNewHeight, lWidth, lHeight;
        //Read the default video size
        hr = mBasicVideo->GetVideoSize(&lVideoWidth, &lVideoHeight);
        if (FAILED(hr))
        {
            mBasicVideo->Release();
            mVideoWindow->Release();
            return FALSE;
        }
        // Ignore the video's original size and stretch to fit bounding rectangle
        hr = mVideoWindow->SetWindowPosition(0,0,windowRect.right, windowRect.bottom );
        if (FAILED(hr))
        {
            return S_FALSE;
        }

        return S_OK;
    }
    return S_FALSE;
}