Playing videos still prevents the system from entering sleep mode or activating the screensaver

[Taiizor]

Hello,

I am using CefSharp in my WPF project to play a looping video. However, as long as the window remains open, neither the screensaver activates nor does the system go to sleep.

Below is a code snippet I tried as a solution, but it didn't resolve the issue:

[DllImport("user32.dll", SetLastError = true)]
private static extern void SetThreadExecutionState(uint esFlags);

private const uint ES_CONTINUOUS = 0x80000000;
private const uint ES_SYSTEM_REQUIRED = 0x00000001;
private const uint ES_DISPLAY_REQUIRED = 0x00000002;

private void AllowScreenSaver()
{
    SetThreadExecutionState(ES_CONTINUOUS);
}

private void PreventScreenSaver()
{
    SetThreadExecutionState(ES_CONTINUOUS | ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED);
}

Additionally, I tried using launcher arguments like --disable-background-timer-throttling --disable-renderer-backgrounding --disable-backgrounding-occluded-windows, but these didn’t work either.

Interestingly, the issue is resolved in MpvPlayer by setting the stop-screensaver option to no. When reviewing its code, I noticed that it uses ES_CONTINUOUS.

https://github.com/mpv-player/mpv/blob/a283f66ede58e0182ac8cd4c930238144427fa74/video/out/w32_common.c#L2326

case VOCTRL_KILL_SCREENSAVER:
	w32->disable_screensaver = true;
	SetThreadExecutionState(ES_CONTINUOUS | ES_SYSTEM_REQUIRED | ES_DISPLAY_REQUIRED);
	return VO_TRUE;
case VOCTRL_RESTORE_SCREENSAVER:
	w32->disable_screensaver = false;
	SetThreadExecutionState(ES_CONTINUOUS);
	return VO_TRUE;

[amaitland]

I've never tried this, so don't have an answer for you. Only suggestion I've got is to try calling SetThreadExecutionState on the CEF UI Thread, which by default isn't the WPF main thread.

Cef.UIThreadTaskFactory.StartNew(delegate
{
	//DO SOMETHING
});

If that doesn't work then you'll probably need to ask on https://www.magpcss.org/ceforum/viewforum.php?f=6

Also uou can search the Chromium source online at https://source.chromium.org/chromium

[Taiizor]

I've never tried this, so don't have an answer for you. Only suggestion I've got is to try calling SetThreadExecutionState on the CEF UI Thread, which by default isn't the WPF main thread.

Cef.UIThreadTaskFactory.StartNew(delegate
{
	//DO SOMETHING
});

If that doesn't work then you'll probably need to ask on https://www.magpcss.org/ceforum/viewforum.php?f=6

Also uou can search the Chromium source online at https://source.chromium.org/chromium

I tried this, but it didn't work. Most likely, video playback itself is automatically preventing sleep/screensaver in the background.

I’ll ask in the forum shortly; hopefully, there’s a solution.