The WM_CAP_DRIVER_GET_CAPS message returns the capabilities of the capture driver and underlying hardware in the CAPDRIVERCAPS structure. Each time an application connects a new capture driver to the capture window, it should update the CAPDRIVERCAPS structure. The following example uses the capDriverGetCaps macro to obtain the capture driver capabilities.
CAPDRIVERCAPS CapDrvCaps;
SendMessage (hWndC, WM_CAP_DRIVER_GET_CAPS,
sizeof (CAPDRIVERCAPS), (LONG) (LPVOID) &CapDrvCaps);
// Or, use the macro to retrieve the driver capabilities.
// capDriverGetCaps(hWndC, &CapDrvCaps, sizeof (CAPDRIVERCAPS));