Reply 20 of 23, by Falcosoft
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BEEN_Nath_58 wrote on 2022-12-28, 13:33:...
[*]This also adds a question for the desktop movie app, if it really needs overlay, is it definitely because of the support for DDSCAPS_OVERLAY or something else?[/list]
Desktop movie has an indirect dependency on real HW overlays. Namely it relies on "Overlay Mixer" Directshow renderer to achieve seamless desktop background movie playing with minimal system resource usage.
If no HW overlay is found then Desktop movie cannot create a fully working Directshow graph since Overlay Mixer refuses connections to its pins.
https://learn.microsoft.com/en-us/windows/win … ay-mixer-filter
The Overlay Mixer uses DirectDraw for rendering. It requires an overlay surface on the graphics card...
To test whether the graphics driver supports hardware overlay, call IDirectDraw7::GetCaps. If the dwMaxVisibleOverlays field in the DDCAPS structure is greater than zero, the driver supports hardware overlay.