TASK 9 audio milestone: real stream audio + voice filters + auto-duck + free TRAX music — the mixer now feeds the encoder real audio (ffmpeg reads a Windows named pipe, -f f32le -ar 48000 -ac 2 -i \.\pipe\ytllive_audio, replacing anullsrc silence; explicit -map 0:v -map 1:a via EncoderOptions.AudioPipeName), with honest gains reaching the stream (MicVolume scales mic, GameAudioVolume + mute scale loopback, Func<double> seams on AudioMixer), an always-on pure-C# voice chain on the mic BEFORE the meter and mix (LowShelfFilter 120Hz +4dB → HighShelfFilter 8kHz +3dB → NoiseGate 0.005/hysteresis 0.5 → Compressor 0.5 4:1, all TDF2), AutoDucker (mic RMS>0.02 → loopback ×0.25, attack 0.05/release 0.005), and TRAX free background music (MusicPlayer = MediaFoundationReader → VolumeWaveProvider16 at fixed 0.20 → WaveOutEvent via the new sibling NAudio.WinMM 2.2.1 package; plays to the default device so the existing loopback carries it, ducked with game; footer TRAX button with red/yellow/green status dot, left-click toggles/picks, right-click opens the OpenFileDialog picker, tooltip shows the track name; persisted via schema v9 single-row Music). Build-time deviations from the plan (recorded in ai.md + TASKS.md): WasapiCapture in NAudio 2.2.1 exposes no overridable GetDefaultMixFormat so sources run device mix format and the mixer's TinyResampler normalizes any rate to 48kHz (resampler IS the design); FfmpegEncoder.cs untouched — MainViewModel.StopStream calls _audioMixer.StopLive() (pipe EOF) before the frame pump stops; sound-bar relabelled 'Desktop Audio', IsGameAudioBarVisible = game sound OR music playing. Tests: new AudioPipelineTests (DSP/ring-buffer/ducker/resampler units + the ONE integration test Mix_WithFiltersDuckAndGain_Lands_On_AudioPipe reading real pipe bytes; ring-buffer overwrite bug found + fixed), FfmpegEncoderTests/LayoutStorePersistenceTests updated — 196 tests passing, 0 warnings

Services/LayoutStore.cs

@@ -18,6 +18,10 @@ public class LayoutStore : IDisposable
     /// <summary>The app-wide social bar config loaded with the last Load() (null = never defined).</summary>
     public SocialsConfig? Socials { get; private set; }
 
+    /// <summary>The app-wide background music (TASK 9 TRAX) loaded with the last
+    /// Load() (null = no track chosen).</summary>
+    public Music? Music { get; private set; }
+
     public LayoutStore(string path)
     {
         ActivePath = path;
@@ -124,6 +128,13 @@ public class LayoutStore : IDisposable
                 SortOrder INTEGER NOT NULL DEFAULT 0
             );
             """,
+            """
+            CREATE TABLE IF NOT EXISTS Music (
+                Id TEXT PRIMARY KEY,
+                TrackPath TEXT NOT NULL,
+                IsEnabled INTEGER NOT NULL DEFAULT 0
+            );
+            """,
         };
         foreach (var sql in statements)
         {
@@ -141,7 +152,7 @@ public class LayoutStore : IDisposable
             MigrateToV3();
         using (var cmd = _connection.CreateCommand())
         {
-            cmd.CommandText = "PRAGMA user_version = 8;";
+            cmd.CommandText = "PRAGMA user_version = 9;";
             cmd.ExecuteNonQuery();
         }
     }
@@ -406,6 +417,7 @@ public class LayoutStore : IDisposable
     {
         Webcam = null;
         Socials = null;
+        Music = null;
         var scenes = new List<Scene>();
         var sourcesByScene = new Dictionary<string, List<Source>>();
         var configsByScene = new Dictionary<string, List<WebcamSceneConfig>>();
@@ -473,6 +485,20 @@ public class LayoutStore : IDisposable
             }
         }
 
+        using (var cmd = _connection.CreateCommand())
+        {
+            cmd.CommandText = "SELECT TrackPath, IsEnabled FROM Music LIMIT 1;";
+            using var reader = cmd.ExecuteReader();
+            if (reader.Read())
+            {
+                Music = new Music
+                {
+                    TrackPath = reader.GetString(0),
+                    IsEnabled = reader.GetInt32(1) != 0,
+                };
+            }
+        }
+
         using (var cmd = _connection.CreateCommand())
         {
             cmd.CommandText = """
@@ -559,7 +585,7 @@ public class LayoutStore : IDisposable
         return scenes;
     }
 
-    public void Save(IEnumerable<Scene> scenes, Webcam? webcam, SocialsConfig? socials)
+    public void Save(IEnumerable<Scene> scenes, Webcam? webcam, SocialsConfig? socials, Music? music = null)
     {
         using var tx = _connection.BeginTransaction();
         using (var cmd = _connection.CreateCommand())
@@ -593,6 +619,12 @@ public class LayoutStore : IDisposable
             cmd.ExecuteNonQuery();
         }
         using (var cmd = _connection.CreateCommand())
+        {
+            cmd.CommandText = "DELETE FROM Music;";
+            cmd.Transaction = tx;
+            cmd.ExecuteNonQuery();
+        }
+        using (var cmd = _connection.CreateCommand())
         {
             cmd.CommandText = "DELETE FROM Scene;";
             cmd.Transaction = tx;
@@ -796,6 +828,17 @@ public class LayoutStore : IDisposable
             }
         }
 
+        if (music != null && !string.IsNullOrWhiteSpace(music.TrackPath))
+        {
+            using var cmd = _connection.CreateCommand();
+            cmd.CommandText = "INSERT INTO Music (Id, TrackPath, IsEnabled) VALUES ($id, $path, $enabled);";
+            cmd.Transaction = tx;
+            cmd.Parameters.AddWithValue("$id", Guid.NewGuid().ToString());
+            cmd.Parameters.AddWithValue("$path", music.TrackPath);
+            cmd.Parameters.AddWithValue("$enabled", music.IsEnabled ? 1 : 0);
+            cmd.ExecuteNonQuery();
+        }
+
         using (var cmd = _connection.CreateCommand())
         {
             cmd.CommandText = "DELETE FROM Asset WHERE Id NOT IN (SELECT AssetId FROM Source WHERE AssetId IS NOT NULL);";