Windows Mobile 6.5
A version of this page is also available for

This method determines whether DirectShow might change display mode when going to full-screen mode.

HRESULT UseWhenFullScreen(
  long UseWhenFullScreen


Set to OATRUE to cause the renderer to use DirectX in full-screen mode; otherwise, set to OAFALSE.

Returns an HRESULT value.

When asked to go to full-screen mode, DirectShow has a number of choices:

  • Determine if filters in the graph can support full-screen playback directly. If one can, it will be asked to do so.
  • Automatically add a special full-screen renderer to the filter graph that uses DirectDraw mode-changing services to play back the video.
    By changing display modes, the video effectively fills more (but not necessarily all) of the display. For example, if the current mode is 1024 x 768 pixels, a video might look relatively small, but when displayed in a 320 x 240 display mode it might look very presentable.
  • For any renderer supporting the IVideoWindow interface, have its window stretched full-screen.
    This typically offers lower performance than the second option (swapping in a full-screen DirectDraw-enabled renderer).
    If the UseWhenFullScreen parameter is set to On (OATRUE), the window is always stretched full-screen for full-screen playback.
    If the UseWhenFullScreen parameter is set to Off (the default), the filter graph manager can swap in the DirectDraw-enabled full-screen renderer.

Windows Embedded CEWindows CE 2.12 and later
Windows MobilePocket PC for Windows Mobile Version 5.0 and later, Smartphone for Windows Mobile Version 5.0 and later
NoteMicrosoft DirectShow applications and DirectShow filters have different include file and Library requirements
For more information, see Setting Up the Build Environment, Version 2.12 requires DXPAK 1.0 or later

Community Additions