Audio Combiner

audio-combine.desktop

[Desktop Entry]
Type=Application
Name=Refresh Combined Audio
Comment=Rebuild Combined Output + Combined Input from current devices
Exec=/bin/bash -lc '~/.local/bin/audio-combine.sh'
Icon=audio-card
Terminal=false
Categories=AudioVideo;

audio-combine.service

[Unit]
Description=Auto-detect and build Combined Output/Input
After=pipewire-pulse.service bluetooth.target
Wants=bluetooth.target

[Service]
Type=oneshot
ExecStart=%h/.local/bin/audio-combine.sh
RemainAfterExit=yes
Restart=on-failure
RestartSec=10

[Install]
WantedBy=default.target

Script

#!/usr/bin/env bash
set -euo pipefail

ac.log() {
  echo "[audio] $*" >&2
}

ac.unloadPrevious() {
  # Aggressively remove any modules we own; loop until none remain
  local did_any=""
  while :; do
    did_any=""
    while IFS=$'\t' read -r id mod args; do
      case "$mod" in
        module-combine-sink)
          # Our sink by internal name or by description label
          if [[ "$args" == *"sink_name=combined_output"* || "$args" == *"device.description=Combined Output"* || "$args" == *"device.description=Combined Output (Speakers)"* ]]; then
            pactl unload-module "$id" && did_any="yes"
          fi
          ;;
        module-null-sink)
          # Our input bus null-sink
          if [[ "$args" == *"sink_name=combined_input"* || "$args" == *"device.description=Combined Input"* || "$args" == *"device.description=Combined Input (Bus)"* ]]; then
            pactl unload-module "$id" && did_any="yes"
          fi
          ;;
        module-loopback)
          # Any loopback feeding our input bus
          if [[ "$args" == *"sink=combined_input"* ]]; then
            pactl unload-module "$id" && did_any="yes"
          fi
          ;;
        module-virtual-source|module-remap-source)
          # Our virtual mic
          if [[ "$args" == *"source_name=combined_input_mic"* || "$args" == *"device.description=Combined Input (Virtual Mic)"* ]]; then
            pactl unload-module "$id" && did_any="yes"
          fi
          ;;
      esac
    done < <(pactl list modules short || true)
    [[ -z "$did_any" ]] && break
  done
}

ac.getSinkNames() {
  pactl list short sinks | awk '{print $2}'
}

ac.getSourceNames() {
  pactl list short sources | awk '{print $2}'
}

ac.createCombinedOutput() {
  local sinks=("$@")
  if [[ ${#sinks[@]} -lt 2 ]]; then
    ac.log "Need at least two sinks to combine, found: ${sinks[*]}"
    return 1
  fi
  ac.log "Creating Combined Output from: ${sinks[*]}"
  pactl load-module module-combine-sink sink_name=combined_output sink_properties=device.description="Combined Output" slaves="$(IFS=,; echo "${sinks[*]}")" >/dev/null
}

ac.createCombinedInput() {
  local sources=("$@")
  if [[ ${#sources[@]} -lt 2 ]]; then
    ac.log "Need at least two sources to combine, found: ${sources[*]}"
    return 1
  fi
  ac.log "Creating/refreshing Combined Input bus (sources detected: ${#sources[@]})"
  pactl load-module module-null-sink sink_name=combined_input sink_properties=device.description="Combined Input" >/dev/null
  for src in "${sources[@]}"; do
    pactl load-module module-loopback source="$src" sink=combined_input latency_msec=10 >/dev/null
  done
  pactl load-module module-remap-source master=combined_input.monitor source_name=combined_input_mic source_properties=device.description="Combined Input (Virtual Mic)" >/dev/null
}

main() {
  ac.unloadPrevious

  mapfile -t sinks < <(ac.getSinkNames | grep -v combined_ || true)
  mapfile -t sources < <(ac.getSourceNames | grep -v combined_ || true)

  if [[ ${#sinks[@]} -ge 2 ]]; then
    ac.createCombinedOutput "${sinks[@]}"
  else
    ac.log "Skipping combined output creation (not enough sinks)"
  fi

  if [[ ${#sources[@]} -ge 2 ]]; then
    ac.createCombinedInput "${sources[@]}"
  else
    ac.log "Skipping combined input creation (not enough sources)"
  fi
}

main "$@"