TASK 24 post-pause polish batch (creator's 8 review issues, 2026-08-15): (1) desktop/game audio volume slider + (2) mute were no-ops — the AudioMixer's gain Func seams defaulted to unity because the VM never passed them; new AudioGainProvider (Services/Audio/) wires MicMuted/MicVolume/GameMuted/GameAudioVolume into the mixer at construction, read live each mix tick, so sliders and mutes are stream-honest; the game bar also scales TRAX locally via new MusicPlayer.LocalGain (UpdateTraxLocalGain on every game volume/mute change + on load) so the creator HEARS the controls work on the music in the headphones. (3) TRAX played once then stopped — OnPlaybackStopped only looped on Position>=Length (unreliable for MediaFoundationReader); now any clean stop rewinds + replays, errors/explicit stops surface via PlaybackEnded; unused using dropped. (4+6) TRAX moved right of Socials in the footer's left cluster (centered under scenes/sources); the mic cluster is now MIC + meter + mute + volume. (5) mic source persists — LayoutStore gains a Settings key/value table (SaveMicSourceName/LoadMicSourceName); the VM saves on pick and restores before the mixer's first Start, so a restart reconnects the same vetted device (green) or reports it missing (yellow). (7) Backdrop's missing trashcan shifted the edit/eye icons right — new HiddenBoolToVisibilityConverter keeps the trash column reserved (Hidden, not Collapsed) so every source row's icons stay in fixed columns. (8) a 1px hairline with top/bottom padding separates scenes from sources in the left panel. Docs in the same commit: ai.md (gains honest + drive TRAX locally, TRAX loops, mic persistence, footer layout), TASKS.md TASK 24, HANDOFF.md shipped state, ViewModels/index.md. ONE integration test: AudioPipelineTests.Mix_HonorsProviderGains_AndGameMute_KillsTheLoopback (real mixer + provider gains through the pipe harness: scaled loopback audible, silence after mute). Build 0 warnings, 197 tests passing

ViewModels/MainViewModel.cs

@@ -58,6 +58,7 @@ public class MainViewModel : ViewModelBase
     private readonly MusicPlayer _musicPlayer = new();
     private Music? _music;
     private bool _musicPlaying;
+    private AudioGainProvider? _gainProvider;
     private StreamStatus _streamStatus = StreamStatus.Offline;
     private StreamHealth _currentHealth = new();
     private string _streamTitle = string.Empty;
@@ -450,6 +451,7 @@ public class MainViewModel : ViewModelBase
         if (dialog.ShowDialog() == true && dialog.PickedDevice != null)
         {
             MicSourceName = dialog.PickedDevice.DisplayName;
+            _layoutStore.SaveMicSourceName(MicSourceName); // persist across restarts
             _audioMixer.RestartMic(); // swap the live device immediately
         }
     }
@@ -560,6 +562,7 @@ public class MainViewModel : ViewModelBase
         try
         {
             _musicPlayer.Load(_music.TrackPath);
+            UpdateTraxLocalGain();
             _music.IsEnabled = true;
             if (play)
                 _musicPlayer.Play();
@@ -591,6 +594,15 @@ public class MainViewModel : ViewModelBase
         OnPropertyChanged(nameof(TraxToolTip));
     }
 
+    /// <summary>Mirrors the desktop/game audio bar's volume and mute onto the
+    /// music so the creator hears the controls work in the headphones (the
+    /// track rides the loopback channel, so it must duck the same way locally).
+    /// Called whenever the game volume/mute change and on TRAX load.</summary>
+    private void UpdateTraxLocalGain()
+    {
+        _musicPlayer.LocalGain = GameMuted ? 0f : (float)GameAudioVolume;
+    }
+
     /// <summary>Live desktop/game input level (0..1), fed by the mixer's loopback
     /// capture. Read by the game meter, scaled by GameAudioVolume.</summary>
     public double GameAudioLevel
@@ -680,6 +692,7 @@ public class MainViewModel : ViewModelBase
                     _gameVolumeBeforeMute = null;
                 OnPropertyChanged(nameof(GameMeterFillWidth));
                 OnPropertyChanged(nameof(GameMeterBrush));
+                UpdateTraxLocalGain();
             }
         }
     }
@@ -1148,6 +1161,11 @@ public class MainViewModel : ViewModelBase
         _layoutStore = new LayoutStore(LayoutPathOverride ?? DefaultLayoutPath);
         _activeLayoutPath = _layoutStore.ActivePath;
 
+        // Restore the last picked mic so the mixer's first capture attaches to
+        // the same, already-vetted device (green dot) or reports it missing
+        // (yellow) instead of silently falling back to the default.
+        MicSourceName = _layoutStore.LoadMicSourceName();
+
         _cameraEnumerator = new MediaCaptureCameraEnumerator();
         _cameraManager = new CameraManager(
             _cameraEnumerator,
@@ -1158,10 +1176,21 @@ public class MainViewModel : ViewModelBase
 
         _microphoneEnumerator = new WinRtMicrophoneEnumerator();
 
+        // The mixer consumes these Func seams live each mix tick, so the volume
+        // sliders and mute buttons are stream-honest (they also update the
+        // meters' display). Before this wiring the gains defaulted to unity and
+        // the controls were decorative.
+        _gainProvider = new AudioGainProvider(
+            () => MicMuted,
+            () => MicVolume,
+            () => GameMuted,
+            () => GameAudioVolume);
         _audioMixer = new AudioMixer(
             new WasapiMicAudioSource(() => MicSourceName),
             new WasapiLoopbackAudioSource(),
-            message => AppLog.Write(message));
+            message => AppLog.Write(message),
+            micGain: _gainProvider.MicGain,
+            loopbackGain: _gainProvider.LoopbackGain);
         _audioMixer.MicLevelChanged += OnMicLevelChanged;
         _audioMixer.LoopbackLevelChanged += OnLoopbackLevelChanged;
         _audioMixer.MicConnected += OnMicConnected;