IDirectDrawVideo::UseWhenFullScreen method (amvideo.h)
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The UseWhenFullScreen method determines whether DirectShow should change display mode when going to full-screen mode.
Syntax
HRESULT UseWhenFullScreen(
long UseWhenFullScreen
);
Parameters
UseWhenFullScreen
Value specifying whether to change the display mode. Set to OATRUE to cause the renderer to use DirectShow in full-screen mode; otherwise, set to OAFALSE.
Return value
Returns an HRESULT value.
Remarks
When asked to go to full-screen mode, DirectShow has a number of choices. The first choice is to determine if any filters in the graph can support full-screen playback directly; if one can, it will be asked to do so.
The second choice is to 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. So, 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.
The third and final choice is to simply take any renderer supporting the IVideoWindow interface and have its window stretched full-screen. This will typically offer 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 will always be stretched full-screen for full-screen playback; if set to Off (the default), the filter graph manager is free to swap in the DirectDraw-enabled full-screen renderer.
Requirements
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | amvideo.h (include Dshow.h) |
| Library | Strmiids.lib |