Understanding audio routing and volume control on SFOS

Applications
#1

Can someone point me into the right direction where to look for documentation on audio rouring and especially volume control on SFOS?

For what I understand after going through the files in /etc/pulse/ if my app wants to play audio to “sink.primary_output” I need to add a file like /etc/pulse/xpolicy.conf.d/s1p.conf

[stream]
name     = "s1p"
group    = call

This seems to work so far and the app is then able to access “sink.primary_output”
The only problem now is that the volume control on SFOS seems not to be aware of this fact and the volume rocker has no effect at all - which makes sense as it’s still trying to set “Ringtone” volume instead.

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SFOS shortcomings & workarounds for Xperia 10 II
#2

Not sure if this is useful, I stumbled on this some time back - pulseaudio-modules-droid
It has this mention “Communication profile used for VoIP-like applications…”

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#3

Thank you, I will take a look at that.

#4

Unfortunately this seems not to make any difference.

#5

While I haven’t been able to make the volume rocker do anything useful I have been able to at least read (and successfully set) the VoIP volume over dbus:

Getting the PA socket:

dbus-send --print-reply --type=method_call --dest=org.PulseAudio1 /org/pulseaudio/server_lookup1 org.freedesktop.DBus.Properties.Get string:org.PulseAudio.ServerLookup1 string:Address
   variant       string "unix:path=/run/user/100000/pulse/dbus-socket"

With the address it’s possible to get the object path:

dbus-send --print-reply --type=method_call --address='unix:path=/run/user/100000/pulse/dbus-socket' --dest=org.PulseAudio1 /org/pulseaudio/stream_restore1 org.PulseAudio.Ext.StreamRestore1.GetEntryByName string:"sink-input-by-media-role:voip"

   object path "/org/pulseaudio/stream_restore1/entry12"

Having the object path it’s then possible to get the volume:

dbus-send --print-reply --type=method_call --address='unix:path=/run/user/100000/pulse/dbus-socket' --dest=org.PulseAudio1 /org/pulseaudio/stream_restore1/entry12 org.freedesktop.DBus.Properties.Get string:org.PulseAudio.Ext.StreamRestore1.RestoreEntry string:Volume

   variant       array [
         struct {
            uint32 0
            uint32 65535
         }
      ]

First uint32 seems to specify the channel:
0 = Mono
1 = Front left
2 = Front right

Second uint32 seems to specify the volume:
0-65535 = Volume

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