MacBook Air suddenly going to sleeping while AirPlaying to Apple TV

[Morac]

I have been using my M1 MBA to airplay a local mp4 in QuickTime to my Apple TV 4K the past couple of days while the MBA is on battery power. The MBA wasn’t going to sleep. The screen never even turned off. I even had it paused for about an hour and the Mac screen never dimmed and the ATV screensaver never kicked on.

I quit the AirPlay by using the menu button on the ATV remote. Since doing so the MBA now turns the screen off and goes to sleep during AirPlay which caused AirPlay to stop (unless the video is paused for some reason, in which case the screen turns off but the Airplay video stays paused). I tried rebooting and it made no difference it still sleeps.

If I watch the video on my Mac, the screen doesn’t turn off and it won’t sleep.

Why is the MBA suddenly turning the screen off during AirPlay? Does it do this when the battery gets lower? It’s only at 54% currently. It wasn’t sleeping at 60%.

 

[Morac]

Well I ended up with the opposite problem where the screen never turned off. At first I thought it had to do with Airplay since I plugged my MBA in and AirPlayed till the end of a video and exited from the Apple TV. When I came back and hour later, the screen was still on so I quit QuickTime and unplugged the MBA and let it sit there. The screen would dim, but not turn off on battery.

I checked the Activity Monitor energy tab and saw Blink was preventing sleeping. I never ran Blink. It’s an iOS app I had installed and somehow it ran itself on a notification. I opened and quit that and the screen turned off as expected. I’m guessing that may be what was keeping the screen active during AirPlay. I guess it’s a good workaround.