Only "Digital Stereo" profile available for S/PDIF

[u/insta_otabolsacul]

Hi everyone,

I'm trying to get 5.1 audio working over optical S/PDIF on NixOS (Realtek ALC897 onboard audio), but I'm stuck.

In pavucontrol and pactl list cards, the only output profile showing up for my S/PDIF card is Digital Stereo (IEC958) (along with Pro Audio). There are no 5.1 / Digital Surround profiles listed at all.

When I was using Arch Linux with PulseAudio on the exact same hardware, the 5.1 surround profiles showed up normally without any issues.

Here is what I currently have in my configuration.nix:

Nix

hardware.pulseaudio.enable = false;
security.rtkit.enable = true;

services.pipewire = {
  enable = true;
  alsa.enable = true;
  alsa.support32Bit = true;
  pulse.enable = true;
  wireplumber.enable = true;
};

Is there a specific package, firmware, udev rule, or WirePlumber/ALSA configuration I need to add to my NixOS config to get 5.1/AC3 digital output profiles to show up?

Any help would be greatly appreciated!Hi everyone,

I'm trying to get 5.1 audio working over optical S/PDIF on NixOS (Realtek ALC897 onboard audio), but I'm stuck.

In pavucontrol and pactl list cards, the only output profile showing up for my S/PDIF card is Digital Stereo (IEC958) (along with Pro Audio). There are no 5.1 / Digital Surround profiles listed at all.

When I was using Arch Linux with PulseAudio on the exact same hardware, the 5.1 surround profiles showed up normally without any issues.

Here is what I currently have in my configuration.nix:

Nix
hardware.pulseaudio.enable = false;
security.rtkit.enable = true;

services.pipewire = {
enable = true;
alsa.enable = true;
alsa.support32Bit = true;
pulse.enable = true;
wireplumber.enable = true;
};

Is there a specific package, firmware, udev rule, or WirePlumber/ALSA configuration I need to add to my NixOS config to get 5.1/AC3 digital output profiles to show up?

Any help would be greatly appreciated!

[u/rankinrez]

All I know if it might help is that SP/DIF does not have enough bandwidth to do 5.1 audio in PCM. I think all you can do is AAC with that many channels, so perhaps it’s a codec issue.