[Implemented] Disable screensaver when lister plays video

[Usher]

It's an obvious feature missing in a new media player: When playing video, screensaver should be disabled. Disabling of other power saving options (standby, hibernate on AC power etc.) is also welcome.

[ghisler(Author)]

Sounds like a good idea, I will try adding it.

[Usher]

27.04.21 Added: Prevent screen saver and sleep mode while playing video. Re-enable while paused or stopped (32/64)

It doesn't work in TC 10b8 in Windows XP 32-bit.

[ghisler(Author)]

I'm using SetThreadExecutionState, which works well on Windows 10. Searching for
SetThreadExecutionState Windows XP
seems to indicate that the function is faulty on Windows XP and Vista.

I don't know what I should use instead - people seem to suggest all kinds of hacks like sending yourself fake keypresses or so...

[Usher]

2ghisler(Author)
What about direct editing registry?
It's "ScreenSaveActive" value in HKEY_CURRENT_USER\Control Panel\Desktop

EDIT:
You can store existing value, set "ScreenSaveActive" to 0 on video player start and restore saved value on player pause/stop/exit.

[Horst.Epp]

2ghisler(Author)
What about direct editing registry?
It's "ScreenSaveActive" value in HKEY_CURRENT_USER\Control Panel\Desktop

A no go for a portable installation.
And we are talking about a dead OS

[Usher]

2Horst.Epp
It's NOT April 1st today.
Suggest a better solution or stop kidding, please.

[Dalai]

2Usher
Changing such value in registry won't be applied without logging out and in again. Besides, it won't change anything in regards to the monitor going to sleep/standby.

Regards
Dalai

[Usher]

2Dalai
So how other players work? How changes from Control Panel applet are applied?

[Dalai]

Blocking the Windows Screen Saver in Delphi including the links to StackOverflow in that article.

Regards
Dalai

[ghisler(Author)]

Thanks, these seem to be for newer systems only. But the linked StackOverflow article metions that we have to intercept WM_POWERBROADCAST to prevent the screen saver from running on XP, so I will try to add that.

Edit:
Unfortunately the WM_POWERBROADCAST method does not prevent the screen saver from starting, it only seems to prevent the sleep/hibernation of the system. Reacting to WM_SYSCOMMAND, SC_SCREENSAVE and returning -1 seems to work.

[Usher]

2ghisler(Author)
It still doesn't work as expected in Windows XP. Running video in full screen kills screensaver blocking feature. Follow these steps:
1. Set screensaver delay to 1 minute.
2. Play video in Lister and wait 1 minute to ensure that screen saver won't be activated.
3. Double click the video to run it in full screen and wait another minute. Screen saver will start now.
4. Press Esc to stop screensaver, than press Esc again to go back to playing in Lister window. Wait one more minute and you will see screensaver active again.
You have to restart Lister to reactivate screensaver blocking.

[petermad]

1. Set screensaver delay to 1 minute.
2. Play video in Lister and wait 1 minute to ensure that screen saver won't be activated.
3. Double click the video to run it in full screen and wait another minute. Screen saver will start now.
4. Press Esc to stop screensaver, than press Esc again to go back to playing in Lister window. Wait one more minute and you will see screensaver active again.
You have to restart Lister to reactivate screensaver blocking.

I can confirm this under Windows 7 x64

[ghisler(Author)]

I haven't tried in full screen so far, because I don't see a reason why it should be different. I will check it.

But does it work for you in normal (not full screen) mode? I tried it on Windows XP and 7, and the screen saver didn't activate until 1 minute after the video stopped.

[Usher]

2ghisler(Author)
Screensaver blocking works OK as described in steps 1 and 2 - with normal and maximized Lister window.
Full screen is a special case (for example, no pop-up messages allowed) and should always be tested separately.