How to transform a Raspberry Pi into a Jukebox using Navidrome in a Docker container?

[marius-hi]

I'm running deluan/navidrome:latest in a docker container under a Raspberry Pi host. I enabled jukebox by following the explanation from the page https://www.navidrome.org/docs/usage/jukebox , however it still plays on the client device instead of playing on Rapsberry PI.

In the log I can see:

time="2023-11-30T22:56:32Z" level=info msg="Starting playback server"
time="2023-11-30T22:56:32Z" level=info msg="2 audio devices found"
time="2023-11-30T22:56:32Z" level=info msg="Using audio device: alsa/default:CARD=PianoDACPlus"

Mpv is installed in the docker container and returns correctly the list of audio devices. mpv --audio-device=help:

List of detected audio devices:
  'auto' (Autoselect device)
  'alsa' (Default (alsa))
  'alsa/default:CARD=ALSA' (bcm2835 ALSA, bcm2835 ALSA/Default Audio Device)
  'alsa/sysdefault:CARD=ALSA' (bcm2835 ALSA, bcm2835 ALSA/Default Audio Device)
  'alsa/default:CARD=PianoDACPlus' (PianoDACPlus, PianoDACPlus multicodec-0/Default Audio Device)
  'alsa/sysdefault:CARD=PianoDACPlus' (PianoDACPlus, PianoDACPlus multicodec-0/Default Audio Device)
  'jack' (Default (jack))
  'sndio' (Default (sndio))

The following are also present in the docker-componse configuration:

group_add:
  - "29" # audio group ID (gid)
devices:
  - "/dev/snd:/dev/snd"

What could be the cause? How can I further debug it?