Audio coming from PC and not ALVR - Fixed

## Description

On KDE Plasma with PipeWire, ALVR headset audio was sometimes playing through my PC speakers instead of the headset.

At first, only my normal `Ryzen Analog Stereo` output appeared selected. When I changed the Ryzen audio device port from **Speakers** to **Headphones**, KDE immediately switched the selected output to **ALVR Audio**. After that, headset audio worked.

Changing the port back and forth between **Speakers** and **Headphones** also caused KDE/WirePlumber to automatically switch between the Ryzen device and `ALVR Audio`.

So this may not be an ALVR streaming/audio encoder bug. It looks like a KDE Plasma / WirePlumber routing behavior where changing the hardware output port causes PipeWire to re-evaluate the default sink, and only then does `ALVR Audio` become selected.

### Screenshots

## Workaround

If ALVR audio is coming from the PC speakers instead of the headset:

1. Open KDE Plasma audio settings.
2. Find the main analog audio device, in my case `Ryzen Analog Stereo`.
3. Change its port from **Speakers** to **Headphones**, or toggle between the two.
4. KDE may then switch the active output to `ALVR Audio`.
5. Confirm that `ALVR Audio` is selected as the playback/output device.

The equivalent terminal check is:

```bash
pactl list short sinks
pactl info | grep 'Default Sink'
```

If `ALVR Audio` exists but is not selected, this can force it as the default sink:

```bash
ALVR_SINK="$(pactl list short sinks | awk -F '\t' 'tolower($2) ~ /alvr audio/ {print $2; exit}')"

if [[ -n "$ALVR_SINK" ]]; then
pactl set-default-sink "$ALVR_SINK"
echo "Set default sink to: $ALVR_SINK"
else
echo "ALVR Audio sink not found."
fi
```

## Environment

**Desktop environment:**
KDE Plasma

**Audio stack:**

* PipeWire 1.6.7
* WirePlumber 0.5.15
* PulseAudio compatibility through `pipewire-pulse`
* ALSA for hardware audio devices

**ALVR Version:**
v20.14.1

**Install Type:**
Installed through ALVR Launcher. Not Flatpak, not AUR.

**SteamVR Version:**
SteamVR previous branch / 2.12.14, if this is still your current version.

**OS:**
Arch Linux, current as of 2026-07-01

## Notes

The confusing part is that `ALVR Audio` may exist, but KDE can still keep the PC speaker device selected. In my case, toggling the analog device port caused KDE/WirePlumber to reselect `ALVR Audio`, which fixed headset audio.

The report names no ALVR file, test, or entry point and attributes the behavior to KDE Plasma/WirePlumber routing. Start by reviewing the audio sink setup and reproducing the issue with the supplied pactl commands; the report currently documents a workaround rather than a defined code change or completion condition.

由索引模型根据 Issue 内容生成。