When setting volume on one player in multi-mpd setup, others apply the change for the next song

[ghmrj]

Bug report

Describe the bug

I'm running multiple mpd instances in a Ubuntu Jammy (22.04) docker container environment (mpd 0.23.5) under a single user ID:

• Two proxy instances for two separate music databases
• Four satellite instances (3 on first, 1 on second database proxy) Each satellite instance has one own pulseaudio null sink and one own HTTP vorbis steam audio output.

When setting volume on one satellite instance (ex. mpc -p 6601 volume 20) while another instance is playing a playlist, the other instances applies the changed volume when switching to the next track (either when reaching end of a song in the queue, or with mpc -p 6604 next).

Expected Behavior

Volume settings are not interfering: Each player instance keeps own volume setting.

Actual Behavior

When setting volume on one satellite instance (ex. mpc -p 6601 volume 20), other instances apply the changed volume when switching to the next track (either when reaching end of a song in the queue, or with mpc -p 6604 next).

The issue has been reproduced in an isolated environment with the local mpc command line client only, no external client (smartphone etc.) could interfere. Test with mpd 23.14 on Ubuntu Noble (24.04) shows the same behaviour.

Version

Music Player Daemon 0.23.5 (0.23.5)
Copyright 2003-2007 Warren Dukes <[email protected]>
Copyright 2008-2021 Max Kellermann <[email protected]>
This is free software; see the source for copying conditions.  There is NO
warranty; not even MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Database plugins:
 simple proxy upnp

Storage plugins:
 local smbclient udisks nfs curl

Neighbor plugins:
 smbclient upnp udisks

Decoders plugins:
 [mad] mp3 mp2
 [mpg123] mp3
 [vorbis] ogg oga
 [oggflac] ogg oga
 [flac] flac
 [opus] opus ogg oga
 [sndfile] wav aiff aif au snd paf iff svx sf voc w64 pvf xi htk caf sd2
 [audiofile] wav au aiff aif
 [dsdiff] dff
 [dsf] dsf
 [hybrid_dsd] m4a
 [faad] aac
 [mpcdec] mpc
 [wavpack] wv
 [openmpt] mptm mod s3m xm it 669 amf ams c67 dbm digi dmf dsm dtm far imf ice j2b m15 mdl med mms mt2 mtm nst okt plm psm pt36 ptm sfx sfx2 st26 stk stm stp ult wow gdm mo3 oxm umx xpk ppm mmcmp
 [modplug] 669 amf ams dbm dfm dsm far it med mdl mod mtm mt2 okt s3m stm ult umx xm
 [mikmod] amf dsm far gdm imf it med mod mtm s3m stm stx ult uni xm
 [sidplay] sid mus str prg P00
 [wildmidi] mid
 [fluidsynth] mid
 [adplug] amd d00 hsc laa rad raw sa2
 [ffmpeg] 16sv 3g2 3gp 4xm 8svx aa3 aac ac3 adx afc aif aifc aiff al alaw amr anim apc ape asf atrac au aud avi avm2 avs bap bfi c93 cak cin cmv cpk daud dct divx dts dv dvd dxa eac3 film flac flc fli fll flx flv g726 gsm gxf iss m1v m2v m2t m2ts m4a m4b m4v mad mj2 mjpeg mjpg mka mkv mlp mm mmf mov mp+ mp1 mp2 mp3 mp4 mpc mpeg mpg mpga mpp mpu mve mvi mxf nc nsv nut nuv oga ogm ogv ogx oma ogg omg opus psp pva qcp qt r3d ra ram rl2 rm rmvb roq rpl rvc shn smk snd sol son spx str swf tak tgi tgq tgv thp ts tsp tta xa xvid uv uv2 vb vid vob voc vp6 vmd wav webm wma wmv wsaud wsvga wv wve rtp:// rtsp:// rtsps://
 [gme] ay gbs gym hes kss nsf nsfe rsn sap spc vgm vgz
 [pcm]

Filters:
 libsamplerate soxr

Tag plugins:
 id3tag

Output plugins:
 shout null fifo sndio pipe alsa ao oss openal pipewire pulse jack httpd snapcast recorder

Encoder plugins:
 null vorbis opus lame wave flac

Archive plugins:
 [bz2] bz2
 [zzip] zip
 [iso] iso

Input plugins:
 file io_uring archive alsa curl ffmpeg smbclient nfs mms cdio_paranoia

Playlist plugins:
 extm3u m3u pls xspf asx rss soundcloud flac cue embcue

Protocols:
 file:// alsa:// cdda:// ftp:// ftps:// gopher:// hls+http:// hls+https:// http:// https:// mms:// mmsh:// mmst:// mmsu:// nfs:// rtmp:// rtmps:// rtmpt:// rtmpts:// rtp:// rtsp:// rtsps:// scp:// sftp:// smb:// srtp://

Other features:
 avahi dbus udisks epoll icu inotify ipv6 systemd tcp un

Configuration

Four satellites with below configuration (increase suffix 1 up to 4):

pid_file "/multiroom/mpd-runtime/mra_player_1/mra_player_1.pid"
music_directory "/music/musicserver"
playlist_directory "/data/players/mra_player_1/playlists"
state_file "/data/players/mra_player_1/state/state_mra_player_1.sql"
sticker_file "/data/players/mra_player_1/sticker/sticker_mra_player_1.sql"
database {
    plugin "proxy"
    host "127.0.0.1"
    port "7601"
}
audio_output {
    type "pulse"
    name "Musik für alle"
    sink "mra_player_1"
    always_on "no"
}
audio_output {
    type "httpd"
    name "HTTP vorbis Musik für alle"
    encoder "vorbis"
    port "8801"
    format "44100:16:2"
    max_clients "5"
    enabled "no"
}
bind_to_address "0.0.0.0:6601"

decoder {
    plugin "hybrid_dsd"
    enabled "no"
}
decoder {
    plugin "wildmidi"
    enabled "no"
}

Two proxy instances on port 7601 for two separate music databases:

music_directory    "/music/musicserver"
db_file            "/multiroom/mpd-runtime/musicserver/tag_cache"
pid_file           "/multiroom/mpd-runtime/musicserver/musicserver.pid"

state_file         "/data/players/musicserver/state/state_musicserver.sql"
sticker_file       "/data/players/musicserver/sticker/sticker_musicserver.sql"
user               "multiroom"
bind_to_address    "127.0.0.1"
port               "7601"

decoder {
    plugin "hybrid_dsd"
    enabled "no"
}
decoder {
    plugin "wildmidi"
    enabled "no"
}

audio_output {
    type "null"
    name "musicserver"
}

Log

There are no related logs in mpd instances that apply volume unintentionally. If special logs required, kindly advise on how to get them.