fix: avoid crash on mute with vlc pipewire audio output

gridplayer/vlc_player/instance.py

@@ -110,6 +110,7 @@ def init_options(self):
             "--no-keyboard-events",
             "--no-mouse-events",
             *self.vlc_options,
+            *_audio_output_options(),
             # before the options typed by hand, which are last so that
             # they still win over anything a page here has set
             *_subtitle_style_options(),
@@ -244,6 +245,15 @@ def _subtitle_style_options() -> list[str]:
     return subtitle_style_options(style)
 
 
+def _audio_output_options() -> list[str]:
+    """Audio output to ask VLC for, ahead of any typed by hand."""
+
+    if env.IS_LINUX:
+        return ["--aout=pulse,any"]
+
+    return []
+
+
 def _iter_settings_options() -> Iterator[str]:
     options = shlex.split(Settings().sync_get("misc/vlc_options"))
 

tests/test_vlc_audio_output.py

@@ -0,0 +1,75 @@
+"""Which audio output VLC is asked for on Linux.
+
+VLC's PipeWire output (vlc-plugin-pipewire 3, as shipped by Fedora) never
+sets its stream pointer when it opens, only when the first audio is played.
+A mute or a volume change before then follows whatever the allocator left
+there and the VLC process dies. Every player is muted the moment it is made,
+and a video without sound never starts the output at all, so there is no
+safe moment to wait for. PulseAudio is asked for first instead, which on a
+PipeWire desktop is served by pipewire-pulse.
+"""
+
+import logging
+
+import pytest
+from PyQt5.QtCore import QSettings
+
+from gridplayer.params import env
+from gridplayer.settings import Settings
+from gridplayer.vlc_player.instance import InstanceVLC
+
+
+@pytest.fixture(autouse=True)
+def _isolated_settings(tmp_path):
+    settings = Settings()
+    real_settings = settings.settings
+
+    settings.settings = QSettings(str(tmp_path / "test.ini"), QSettings.IniFormat)
+
+    yield
+
+    settings.settings = real_settings
+
+
+@pytest.fixture
+def _on_linux(monkeypatch):
+    monkeypatch.setattr(env, "IS_LINUX", True)
+    monkeypatch.setattr(env, "IS_WINDOWS", False)
+    monkeypatch.setattr(env, "IS_APPIMAGE", False)
+
+
+@pytest.fixture
+def _on_macos(monkeypatch):
+    monkeypatch.setattr(env, "IS_LINUX", False)
+    monkeypatch.setattr(env, "IS_WINDOWS", False)
+    monkeypatch.setattr(env, "IS_APPIMAGE", False)
+
+
+def _init_options():
+    instance = InstanceVLC(0, [])
+    instance._logger = logging.getLogger("test")
+
+    return instance.init_options
+
+
+def _aout_options(options):
+    return [opt for opt in options if opt.startswith("--aout")]
+
+
+@pytest.mark.usefixtures("_on_linux")
+class TestOnLinux:
+    def test_pulse_is_asked_for_first(self):
+        assert _aout_options(_init_options()) == ["--aout=pulse,any"]
+
+    def test_what_was_typed_by_hand_still_wins(self):
+        """Last on the command line is what VLC goes by."""
+
+        Settings().set("misc/vlc_options", "--aout=alsa")
+
+        assert _aout_options(_init_options()) == ["--aout=pulse,any", "--aout=alsa"]
+
+
+@pytest.mark.usefixtures("_on_macos")
+class TestElsewhere:
+    def test_the_platform_default_is_left_alone(self):
+        assert _aout_options(_init_options()) == []