Virtual duplex devices are not detected

[RoarkGit]

I use Audio/Duplex devices for routing a bunch of inputs (e.g. microphone -> REAPER -> Duplex In; Duplex Out -> Discord), described here. These are not currently detected by this plugin.

I suspect the change would just be adding another condition to this bit of code: || strcmp(media_class, "Audio/Duplex") == 0

[dimtpap]

Should Duplex devices be shown both in the Input and Output capture sources?

[RoarkGit]

I think output is all that's needed. Consider these two duplex devices I have:

"Voice" Microphone Input -> REAPER In -> Reaper Out -> Voice In, then Voice Out actually produces the sound

"Discord" Discord Application Out -> Discord In, then Discord Out actually produces the sound

In all cases it's still the "output" end that is producing the sound to be captured. It wouldn't make sense to have OBS be feeding sound to the "input" side of things.

[RoarkGit]

Hmm, this doesn't seem to work as expected. I did this change locally as well last night to see, but wasn't sure if I did something wrong. When adding the device, OBS reports no output sound. If I add the same source as output via PulseAudio (pipewire-pulseaudio) it does seem to work, though.

[dimtpap]

What's the configuration for your virtual devices?

[RoarkGit]

I'm trying with two different devices and neither seems to work:

pipewire.conf

# This is a loopback device, I have "Desktop" set as my default audio output.
# It plays back through my physical audio interface.
context.modules = [
    {   name = libpipewire-module-loopback
        args = {
            node.description "Desktop Loopback"
            audio.position = "[ FL FR ]"
            capture.props = {
                media.class = "Audio/Sink"
                node.name = "stream.desktop.in"
                node.description "Desktop"
            }
            playback.props = {
                node.name = "stream.desktop.out"
                node.target = "alsa_output.usb-Schiit_Audio_Schiit_Unison_Universal_Dac-00.analog-stereo"
            }
        }
    }
}

# This is the Voice duplex device.
context.objects = [
    {   factory = adapter
        args = {
            factory.name      = support.null-audio-sink
            node.name         = "stream.voice"
            node.description  = "Voice"
            media.class       = "Audio/Duplex"
            audio.position    = "MONO"
        }
    }
]

The first device is set up like this (shown via qpwgraph with one application feeding output into it):

The second device is set up like this (shown via qpwgraph):

[dimtpap]

Try adding audio.channels = (number of audio channels) in playback.props

[RoarkGit]

No luck, and I do actually notice some strange behavior where the device keeps changing itself back to "Default."

This happens whenever I set the device to something else (in my case, "Desktop").

I can set it to different physical interfaces and it works fine, but any of the virtuals just get dropped and set to whatever the last physical interface was.

It's worth pointing out that no log messages get emitted when any of this happens. If I change between physical devices then I see output, but setting it to virtual devices doesn't do anything.

[dimtpap]

I got it to work after adding audio.channels = "1" in the args of the Voice duplex device and audio.channels = "2" in capture.props of the Desktop lookpback

[RoarkGit]

Interesting! That does appear to have done the trick. I've had this config going forever so haven't messed with it in awhile, I'll go read up on stuff again and see if there is something new / something I've missed that would have made this more obvious! Thanks for the help / quick fix.