Draw video frames as bitmaps to MFC Window

I'm trying to write a preview application using the BlackMagic SDK, but am getting choppy playback. I'm using MFC framework, and subclassing CWnd for my video preview window.

When each frame of video arrives, I do a color conversion to RGB and then call a function to display the RGB bitmap.

void VideoPreview::Display(int width, int height, byte* buffer)
{
    __int64 begin = GetTickCount();
    HRESULT     hr;
    CRect       rcRect, statusBarRect;

    GetClientRect (rcRect);

    BITMAPINFO bmInfo;
    ZeroMemory(&bmInfo, sizeof(BITMAPINFO));
    bmInfo.bmiHeader.biSize       = sizeof(BITMAPINFOHEADER);
    bmInfo.bmiHeader.biBitCount   = 32;
    bmInfo.bmiHeader.biPlanes     = 1;
    bmInfo.bmiHeader.biWidth      = width;
    bmInfo.bmiHeader.biHeight     = -height;

    dc->SetStretchBltMode(COLORONCOLOR);

    int iResult = StretchDIBits(*dc,
        rcRect.left, rcRect.top, rcRect.right, rcRect.bottom,
        0, 0, width, height,
        buffer, &bmInfo, 0, SRCCOPY);
    DWORD dwError;
    if (iResult == 0 || iResult == GDI_ERROR)
    {
        dwError = GetLastError();
    }
    else
        fpsCount++;
    procTimeCount += GetTickCount() - begin;
}

What can be done to create smoother video?

Update:

I ended up going with Direct2D instead of GDI and have gotten much better performance. The below code is what I'm using now for rendering:

    // initialization
HRESULT hr = D2D1CreateFactory(
    D2D1_FACTORY_TYPE_SINGLE_THREADED,
    &pD2DFactory
    );
    // Obtain the size of the drawing area.
RECT rc;
GetClientRect(&rc);

// Create a Direct2D render target              
hr = pD2DFactory->CreateHwndRenderTarget(
    D2D1::RenderTargetProperties(),
    D2D1::HwndRenderTargetProperties(
    this->GetSafeHwnd(),
    D2D1::SizeU(
        1280, 720
        /*rc.right - rc.left,
        rc.bottom - rc.top*/)
        ),
    &pRT);

D2D1_BITMAP_