Skip down to "Update": this is a BUG.
Next guess: is this set to 15 minutes?
- AppleTV Settings.
- General.
- Sleep After.
If so, change it to something else and try music play again. Just for an extreme test, you might try "NEVER" and then play music for 20-30 minutes and see what happens.
I just checked my own AppleTV settings and that
IS set to 15 minutes for me but I don't recall the auto-shutdown you are describing when playing music from the Computer app. However, it's been a while, as I generally just airplay from Mac to the Receiver to which the AppleTV is connected... so I'm playing music "your way" for the next 20-25 minutes to see if mine will do what yours is doing: Computers app, music playlist with screensaver (and thus TV) on. I'll update this post if mine also sleeps after 15 minutes.
A key difference is I'm using the latest generation AppleTV (Ethernet connected vs. wifi) while you are using a fairly old version of the hardware and wifi. So even if mine doesn't replicate the issue, this isn't a perfect test- mostly just a test of tvOS 16.6 having a potential bug... which could conceptually exist for your AppleTV generation and not the newer generations.
Another guess: Could AppleTV be crashing instead of sleeping? Do you have plenty of free space in that "only" 32GB space or is it near full (of apps)? Perhaps you should get some music playing and then sit down in front of your TV at about 13 minutes and watch what happens. When it quits, does white "on" light go black "off" or is there some blinking signifying a crash and reboot?
Another guess: you reference "whole A/V system" so does the (presumed) Receiver have a sleep option in its menus? You might want to look through that to see if you can find any such setting. An easy test to fully rule in/out a receiver would be to temporarily bypass it: hook AppleTV directly to TV and use the TV speakers for the next 20+ minute music playback test. If that works fine, that would strongly point at something in the Receiver needing tweaked. I'm doubting this one as 15 minutes would be far too short for any default settings on a Receiver. But still, every link in the chain are suspect until ruled out.
Another guess: Anyone else in the house perhaps NOT like your kind of music and using the remote app on their iDevices to turn off your "bad" choice of music?
UPDATE: after exactly 15 minutes my "latest & greatest" AppleTV (with plenty of free storage) shut down (shutting down receiver and TV with it). So you appear to have identified a legit bug that
should be reported to Apple.
I'm now trying my own suggestion to see if the Apple "sleep after" setting is driving this. Will update again if changing that dodged the 15-minute shutdown. I've watched LOTS of stuff in other apps on AppleTV as late as this morning without it doing this, so this may be a bug solely associated with the Computers App, music playback. TBD.
UPDATE #2: after changing Apple "sleep after" to (I chose) 5 hours, music playback did not sleep it all after 15 minutes. So it appears at some point, some update to Computers app prioritized "sleep after" over music (only) playback to cause this. While video playback de-prioritizes "Sleep after" to NOT do this, music playback appears to not be set the same way.
The user "fix" is to change the default 15 minutes in "Sleep after" to something longer, up to "never." However, one of the major reasons for "Sleep after" is to help avoid burn in on some kinds of TVs, particularly popular OLED sets. So think carefully about how much time you want to "fix" this problem vs. just automatically going with "never" and potentially causing a "I fell asleep and now there's burn in on my TV screen" scenario. Be sure the screen savers will kick on if you choose a longer time. A key to avoid burn in is to not have the pixels showing the same bright color for extended time, which is easy to do with text or bright color app blocks typical of the UI on screen instead of a screensaver or blank (black) screen.
