[pulseaudio-discuss] Splitting a 7.1 device into virtual 5.1 + 2.0 devices?

[紅 蒼穹]

Hello,

I'm using an ALC899 codec with 6x3.5mm jacks and so far, I've been using sink-remap [1], which worked fine, 5.1 sound being remixed to 2.0 as expected.

However, there are two problems with this:
- even though I select the Stereo sink as output in pavucontrol, the sound is also playing via my Surround sink
- the two sinks have their volumes linked.

Apparently, I could set my card to 5.1 and the grey socket would be automatically treated as a 2.0 device, however the behavior is completely the same as my earlier setup, including the caveats described above

I would like to split them in separate devices as follows:

- two sinks visible, Stereo (for the 2.0 amplifier) and Surround (for my 5.1 headset with a built-in amplifier), physical 7.1 device hidden in pavucontol/KDE's plasma-pa widget
- for the Stereo sink, I want the LFE to be mixed into the stereo channels when downmixing, but left untouched for stereo content (just like it did with PA6.0). Same for rear and center channels.
- for the Surround sink, I want the LFE to use the subwoofer, as standard PA7.0 behavior.
- selecting one of the sinks should only play sound on that sink, not both of them

Is it possible to do that with pulseaudio? Or should I be doing this in alsa? Somewhere else?

I got a hint from Raymond Yau in my bug report for another issue [2] to disable the side (grey) socket to be able to do that but I'm not sure how to go about it/where to start.


Regards,
Soukyuu.

[1] https://wiki.archlinux.org/index.php/PulseAudio/Examples&Splitting_7.1_into_5.1.2B2.0
[2] https://bugs.freedesktop.org/show_bug.cgi?id=94716