Jellyfin MPV-Shim Linux does not send multichanel audio in passthrough over HDMI

[chp-1960]

Hi everyone,

I'm trying to configure Jellyfin MPV-Shim for Linux (flatpack) to work with multichannel audio files over HDMI in "Passthrough" mode for AC3, DTS and EAC3.
No success until now.

Nota :

1. VLC and "regular" MPV (not the one in flatpack) work fine for these same audio files in HDMI in Linux.
2. Jellyfin MPV-Shim and Jellyfin Media Player work fine in Windows.
3. My Onkyo Amp/Receiver is well configured.

I tried to modify the file mpv.conf located in : home/youruser/.var/app/com.github.iwalton3.jellyfin-mpv-shim/config/jellyfin-mpv-shim/ to use the exact same parameters as the regular mpv but without success. At best I can have stereo (prologic) sound.
If I set the same sound card as the regular mpv, mpv don't open at all.

I think there is problem with the sound device in flatpack.
Here is my regular mpv.com file in /etc/mpv and home/youruser/.var/app/com.github.iwalton3.jellyfin-mpv-shim/config/jellyfin-mpv-shim/ :

mpv.conf :
audio-device='alsa/hdmi:CARD=Generic,DEV=0'
audio-channels=5.1,stereo # audio configuration with fall back option
af=surround:chl_out=5.1 # audio filter for mixing to surround (5.1)
audio-spdif=ac3,dts,eac3 # audio passthrough on HDMI or SPDIF

Sidenote : Jellyfin Media Player (Linux flatpack) suffer from the same symptoms.

Any help is appreciated.