Server starts doing work without explicit action from user

[gmile]

I just witnessed my homelab server's cooler start making an audible noise, went to check the logs and discovered this was related to audiobookshelf starting some transcoding work out of the blue.

Here are the logs - you can clearly see some interaction with audiobookshelf I had during the morning, before a very random work started around 16:32.

Details

Jul 20 09:52:22 nixos audiobookshelf[914]: [2025-07-20 09:52:22.171] INFO: [SocketAuthority] Socket Connected to /socket.io WSQ1E20qOWpyp1DdAAAB
Jul 20 09:53:00 nixos audiobookshelf[914]: [2025-07-20 09:53:00.825] INFO: [SocketAuthority] Socket WSQ1E20qOWpyp1DdAAAB disconnected from client "root" after 38654ms (Reason: client namespace disconnect)
Jul 20 09:53:11 nixos audiobookshelf[914]: [2025-07-20 09:53:11.858] INFO: Received ping
Jul 20 09:53:12 nixos audiobookshelf[914]: [2025-07-20 09:53:12.041] INFO: [SocketAuthority] Socket Connected to /socket.io 859JX0Z40iprkEYKAAAD
Jul 20 09:53:19 nixos audiobookshelf[914]: [2025-07-20 09:53:19.339] INFO: [PlaybackSessionManager] startSession: Closing open session "The Selfish Gene" for user "root" (Device: Pixel 8 Pro SDK 36 / v0.9.81-beta)
Jul 20 09:53:25 nixos audiobookshelf[914]: [2025-07-20 09:53:25.738] INFO: [PlaybackSessionManager] startSession: Closing open session "The Real Anthony Fauci: Bill Gates, Big Pharma, and the Global War on Democracy and Public Health" for user "root" (Device: Pixel 8 Pro SDK 36 / v0.9.81-beta)
Jul 20 09:59:25 nixos audiobookshelf[914]: [2025-07-20 09:59:25.322] INFO: [SocketAuthority] Socket 859JX0Z40iprkEYKAAAD disconnected from client "root" after 373282ms (Reason: ping timeout)
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.353] INFO: [PlaybackSessionManager] startSession: Closing open session "An Elegant Puzzle" for user "root" (Device: Pixel 8 Pro SDK 36 / v0.9.81-beta)
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.360] INFO: [STREAM] START STREAM - Num Segments: 3963
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.367] INFO: [INFO] FFMPEG transcoding started with command: ffmpeg -seek_timestamp 1 -f concat -safe 0 -i /var/lib/audiobookshelf/metadata/streams/7788263f-10dd-4507-8be8-536fa5ea9eed/files.txt -y -loglevel error -map 0:a -c:a copy -f hls -copyts -avoid_negative_ts make_non_negative -max_delay 5000000 -max_muxing_queue_size 2048 -hls_time 6 -hls_segment_type mpegts -start_number 0 -hls_playlist_type vod -hls_list_size 0 -hls_allow_cache 0 -hls_segment_filename /var/lib/audiobookshelf/metadata/streams/7788263f-10dd-4507-8be8-536fa5ea9eed/output-%d.ts /var/lib/audiobookshelf/metadata/streams/7788263f-10dd-4507-8be8-536fa5ea9eed/final-output.m3u8
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.367] INFO:
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.765] INFO: [adts @ 0x916d580] Scalable configurations are not allowed in ADTS
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.766] INFO: [out#0/hls @ 0x91537c0] Could not write header (incorrect codec parameters ?): Invalid data found when processing input
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.815] INFO:
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.816] ERROR: Ffmpeg Err "ffmpeg exited with code 183: "
Jul 20 16:32:58 nixos audiobookshelf[914]: [2025-07-20 16:32:58.816] INFO: [Stream] Re-attempting stream with AAC encode
Jul 20 16:33:08 nixos audiobookshelf[914]: [2025-07-20 16:33:08.837] ERROR: [STREAM] Transcode never closed...
Jul 20 16:33:08 nixos audiobookshelf[914]: [2025-07-20 16:33:08.838] INFO: Stream Reset New Start Time 0:28
Jul 20 16:33:08 nixos audiobookshelf[914]: [2025-07-20 16:33:08.838] INFO: [STREAM] START STREAM - Num Segments: 3963
Jul 20 16:33:08 nixos audiobookshelf[914]: [2025-07-20 16:33:08.843] INFO: [INFO] FFMPEG transcoding started with command: ffmpeg -seek_timestamp 1 -f concat -safe 0 -i /var/lib/audiobookshelf/metadata/streams/7788263f-10dd-4507-8be8-536fa5ea9eed/files.txt -y -loglevel error -map 0:a -c:a aac -f hls -copyts -avoid_negative_ts make_non_negative -max_delay 5000000 -max_muxing_queue_size 2048 -hls_time 6 -hls_segment_type mpegts -start_number 0 -hls_playlist_type vod -hls_list_size 0 -hls_allow_cache 0 -hls_segment_filename /var/lib/audiobookshelf/metadata/streams/7788263f-10dd-4507-8be8-536fa5ea9eed/output-%d.ts /var/lib/audiobookshelf/metadata/streams/7788263f-10dd-4507-8be8-536fa5ea9eed/final-output.m3u8
Jul 20 16:33:08 nixos audiobookshelf[914]: [2025-07-20 16:33:08.843] INFO:
Jul 20 16:33:11 nixos audiobookshelf[914]: [2025-07-20 16:33:11.845] INFO: [STREAM] Clearing isResetting
Jul 20 16:33:13 nixos audiobookshelf[914]: [2025-07-20 16:33:13.848] INFO: [STREAM] 7788263f-10dd-4507-8be8-536fa5ea9eed notifying client that stream is ready
Jul 20 16:33:13 nixos audiobookshelf[914]: [2025-07-20 16:33:13.849] INFO: [STREAM-CHECK] Check Files 40 of 3963 1.01% Furthest Segment: 39
Jul 20 16:33:15 nixos audiobookshelf[914]: [2025-07-20 16:33:15.848] INFO: [STREAM-CHECK] Check Files 56 of 3963 1.41% Furthest Segment: 55
Jul 20 16:33:17 nixos audiobookshelf[914]: [2025-07-20 16:33:17.848] INFO: [STREAM-CHECK] Check Files 73 of 3963 1.84% Furthest Segment: 72
Jul 20 16:33:19 nixos audiobookshelf[914]: [2025-07-20 16:33:19.849] INFO: [STREAM-CHECK] Check Files 89 of 3963 2.25% Furthest Segment: 88
Jul 20 16:33:21 nixos audiobookshelf[914]: [2025-07-20 16:33:21.850] INFO: [STREAM-CHECK] Check Files 106 of 3963 2.67% Furthest Segment: 105
Jul 20 16:33:23 nixos audiobookshelf[914]: [2025-07-20 16:33:23.851] INFO: [STREAM-CHECK] Check Files 124 of 3963 3.13% Furthest Segment: 123
Jul 20 16:33:25 nixos audiobookshelf[914]: [2025-07-20 16:33:25.852] INFO: [STREAM-CHECK] Check Files 140 of 3963 3.53% Furthest Segment: 139

Did my Android app in the background requested something from the server to cause this? 🤔 If so, how can I make Android app stop doing what it was doing? In my case I didn't have that many files to process, so I just waited to this "Check files..." to finish some 10 minutes later.

[advplyr]

I'm not sure but sometimes Android will play paused media when connecting a device like headphones. Was the app open in the background with the audio player open?

[gmile]

The Android was running idle in the background (at least that's how I understand apps are typically after you switch from them to another app on Android...).

Whether the player was still on inside the app - sadly, can't quite remember