How to get audio in the container...

[emc02]

I am running the container on a libreelec installation (inside libreelec) on an RPI4 with following cmd:

docker run \
-p 8888:8888 \
-v ~/ledfx-config:/app/ledfx-config \
-v ~/audio:/app/audio \
-e HOST=192.168.1.222 \
-e FORMAT='-r 48000 -f S16_LE -c 2' \
--restart always \
--name ledfx -h ledfx shirom/ledfx

The ledfx device is showing up on the snapserver webinterface on the libreelec-Addon, but no sound is received.

The other problem is, that even a successful configuration would prevent using HDMI-Audio and Snapserver at the same time.

Maybe it's just simple and I don't get it:
I need a audio-pipe that transfers the audio from libreelec (all sounds) to the container on the same machine.
What options are needed to run the container and receive audio while playing audio with the "ALSA: vc4-hdmi-0" device?

Thanks anyway for your work!