TASK 51 slice 3: per-scene webcam BackgroundEffect + BackgroundStrength on WebcamSceneConfig, persisted via additive guarded columns; radio-pill bools RemoveBackground/BlurBackground (Unit: bg-effect config)

Models/WebcamSceneConfig.cs

@@ -15,4 +15,42 @@ public class WebcamSceneConfig : SceneElement
     public override bool IsDraggable => true;
     public override ElementKind Kind => ElementKind.Dynamic;
     public override ImageSource? DisplaySource => VideoImageSource;
+
+    private BackgroundEffect _backgroundEffect = BackgroundEffect.None;
+    /// <summary>TASK 51: this scene's background effect for the webcam (persisted).</summary>
+    public BackgroundEffect BackgroundEffect
+    {
+        get => _backgroundEffect;
+        set
+        {
+            if (!Set(ref _backgroundEffect, value)) return;
+            Raise(nameof(RemoveBackground));
+            Raise(nameof(BlurBackground));
+        }
+    }
+
+    private double _backgroundStrength = 0.5;
+    /// <summary>TASK 51: 0..1 — Blur amount, or Remove's edge softness (persisted).</summary>
+    public double BackgroundStrength
+    {
+        get => _backgroundStrength;
+        set => Set(ref _backgroundStrength, Math.Clamp(value, 0, 1));
+    }
+
+    /// <summary>Pill-switch surface: Remove and Blur behave like radio buttons — turning one
+    /// on turns the other off; turning the active one off means <see cref="BackgroundEffect.None"/>.</summary>
+    public bool RemoveBackground
+    {
+        get => BackgroundEffect == BackgroundEffect.Remove;
+        set => BackgroundEffect = value ? BackgroundEffect.Remove
+            : BackgroundEffect == BackgroundEffect.Remove ? BackgroundEffect.None : BackgroundEffect;
+    }
+
+    /// <inheritdoc cref="RemoveBackground"/>
+    public bool BlurBackground
+    {
+        get => BackgroundEffect == BackgroundEffect.Blur;
+        set => BackgroundEffect = value ? BackgroundEffect.Blur
+            : BackgroundEffect == BackgroundEffect.Blur ? BackgroundEffect.None : BackgroundEffect;
+    }
 }

Models/index.md

@@ -11,8 +11,8 @@ Plain data types. No logic beyond what a property can carry. See
 | `SceneElement.cs` | Base for anything placeable in a scene: shared layout/clip/mirror/border surface, `virtual IsWebcam`/`virtual IsImageSource`/`virtual IsZoomLayer` (TASK 52); `ToggleClipShape` + persisted `RectWidth`/`RectHeight` (pre-Round rect so round→rect restores after reload) |
 | `ZoomSceneElement.cs` | **Transient zoom box (TASK 52, creator-corrected 2026-10-08):** carries the box rect AND the anchored `CaptureX`/`CaptureY` (the fixed box/2 capture window set on `ActivateZoom`; moving the box never touches it). `IsZoomActive` flips `Kind` Static→Dynamic (leaves the baked base while active); never persisted (LayoutStore save skips non-Source/non-WebcamSceneConfig rows), never shown in the layers list or the element template (`IsZoomLayer` gates both). The compositor SKIPS the active element in every layer loop and draws its 2x content LAST (layer n+1) via `ZoomMagnifier`. |
 | `Webcam.cs` | Singleton webcam identity: `Id`, `DeviceId`, `Name` (one row app-wide) |
-| `BackgroundEffect.cs` | **TASK 51:** per-webcam background effect enum `None` / `Remove` / `Blur` (not yet on `WebcamSceneConfig` — config + persistence is slice 3) |
-| `WebcamSceneConfig.cs` | Per-scene webcam placement (subclass of `SceneElement`): geometry + `IsVisible` + border (`BorderColor`/`BorderOpacity`/`BorderWidth`/`BorderAnimation`) + `VideoImageSource`; `WebcamId` links to `Webcam` |
+| `BackgroundEffect.cs` | **TASK 51:** per-webcam background effect enum `None` / `Remove` / `Blur`, carried by `WebcamSceneConfig` |
+| `WebcamSceneConfig.cs` | Per-scene webcam placement (subclass of `SceneElement`): geometry + `IsVisible` + border (`BorderColor`/`BorderOpacity`/`BorderWidth`/`BorderAnimation`) + `VideoImageSource`; `WebcamId` links to `Webcam`; **TASK 51:** `BackgroundEffect` + `BackgroundStrength` (0..1, default 0.5) + the radio-pill surface `RemoveBackground`/`BlurBackground` (one on turns the other off; both off = None) |
 | `QualityOption.cs` | Resolution tier record `(Display, Fps, Bitrate, Width, Height)`; `Label` formats as `1080p60 (8Mbps)` — drives the bottom-bar dropdown and the output-rect math |
 | `StreamConfig.cs` | `StreamConfig` (note: `TargetBitrate`/`Resolution` defaults are stale — not yet wired to the dropdown), `StreamHealth` (bitrate/FPS/dropped/duration), `StreamStatus` enum |
 | `MicStatus.cs` | Footer mic indicator: `NotConnected` / `Connected` / `Problem` — the state behind the MIC button's status dot (red = no device/capture off, green = capturing, yellow = a requested mic failed: in use/unplugged) |

Services/LayoutStore.Load.cs

@@ -165,7 +165,7 @@ public partial class LayoutStore : IDisposable
             cmd.CommandText = """
                 SELECT SceneId, WebcamId, IsVisible, X, Y, Width, Height, Opacity,
                        ClipShape, IsMirrored, BorderColor, BorderOpacity, BorderWidth, BorderAnimation,
-                       RectWidth, RectHeight, SortOrder
+                       RectWidth, RectHeight, SortOrder, BackgroundEffect, BackgroundStrength
                 FROM WebcamSceneConfig ORDER BY SortOrder
                 """;
             using var reader = cmd.ExecuteReader();
@@ -190,6 +190,8 @@ public partial class LayoutStore : IDisposable
                     BorderAnimation = Enum.TryParse<BorderAnimation>(reader.GetString(13), out var anim) ? anim : BorderAnimation.None,
                     RectWidth = reader.IsDBNull(14) ? null : reader.GetDouble(14),
                     RectHeight = reader.IsDBNull(15) ? null : reader.GetDouble(15),
+                    BackgroundEffect = Enum.TryParse<BackgroundEffect>(reader.GetString(17), out var effect) ? effect : BackgroundEffect.None,
+                    BackgroundStrength = reader.GetDouble(18),
                 };
                 if (!configsByScene.TryGetValue(sceneId, out var list))
                     configsByScene[sceneId] = list = new List<(WebcamSceneConfig, int)>();

Services/LayoutStore.Migrations.cs

@@ -75,6 +75,8 @@ public partial class LayoutStore : IDisposable
                 BorderOpacity REAL NOT NULL DEFAULT 1,
                 BorderWidth INTEGER NOT NULL DEFAULT 0,
                 BorderAnimation TEXT NOT NULL DEFAULT 'None',
+                BackgroundEffect TEXT NOT NULL DEFAULT 'None',
+                BackgroundStrength REAL NOT NULL DEFAULT 0.5,
                 SortOrder INTEGER NOT NULL DEFAULT 0,
                 PRIMARY KEY (SceneId, WebcamId)
             );
@@ -360,6 +362,21 @@ public partial class LayoutStore : IDisposable
             cmd.CommandText = "ALTER TABLE WebcamSceneConfig ADD COLUMN RectHeight REAL;";
             cmd.ExecuteNonQuery();
         }
+
+        // TASK 51: per-webcam background effect + strength (additive, no version bump).
+        if (!columns.Contains("BackgroundEffect"))
+        {
+            using var cmd = _connection.CreateCommand();
+            cmd.CommandText = "ALTER TABLE WebcamSceneConfig ADD COLUMN BackgroundEffect TEXT NOT NULL DEFAULT 'None';";
+            cmd.ExecuteNonQuery();
+        }
+
+        if (!columns.Contains("BackgroundStrength"))
+        {
+            using var cmd = _connection.CreateCommand();
+            cmd.CommandText = "ALTER TABLE WebcamSceneConfig ADD COLUMN BackgroundStrength REAL NOT NULL DEFAULT 0.5;";
+            cmd.ExecuteNonQuery();
+        }
     }
 
     // v2 → v3: the webcam leaves the Source table. Any webcam Source rows become

Services/LayoutStore.Save.cs

@@ -209,10 +209,10 @@ public partial class LayoutStore : IDisposable
                     INSERT INTO WebcamSceneConfig
                         (SceneId, WebcamId, IsVisible, X, Y, Width, Height, Opacity,
                          ClipShape, IsMirrored, BorderColor, BorderOpacity, BorderWidth, BorderAnimation,
-                         RectWidth, RectHeight, SortOrder)
+                         RectWidth, RectHeight, SortOrder, BackgroundEffect, BackgroundStrength)
                     VALUES ($sceneId, $webcamId, $isVisible, $x, $y, $w, $h, $opacity,
                             $clip, $mirrored, $borderColor, $borderOpacity, $borderWidth, $borderAnimation,
-                            $rectWidth, $rectHeight, $sort)
+                            $rectWidth, $rectHeight, $sort, $bgEffect, $bgStrength)
                     """;
                 cmd.Transaction = tx;
                 var sceneIdP = cmd.Parameters.Add("$sceneId", SqliteType.Text);
@@ -232,6 +232,8 @@ public partial class LayoutStore : IDisposable
                 var rectWidthP = cmd.Parameters.Add("$rectWidth", SqliteType.Real);
                 var rectHeightP = cmd.Parameters.Add("$rectHeight", SqliteType.Real);
                 var sortP = cmd.Parameters.Add("$sort", SqliteType.Integer);
+                var bgEffectP = cmd.Parameters.Add("$bgEffect", SqliteType.Text);
+                var bgStrengthP = cmd.Parameters.Add("$bgStrength", SqliteType.Real);
 
                 foreach (var scene in scenes)
                 {
@@ -239,6 +241,8 @@ public partial class LayoutStore : IDisposable
                     foreach (var element in scene.Elements)
                     {
                         if (element is not WebcamSceneConfig config) { z++; continue; }
+                        bgEffectP.Value = config.BackgroundEffect.ToString();
+                        bgStrengthP.Value = config.BackgroundStrength;
                         sceneIdP.Value = scene.Id;
                         webcamIdP.Value = config.WebcamId;
                         visibleP.Value = config.IsVisible ? 1 : 0;

Services/index.md

@@ -14,7 +14,7 @@ External-facing logic: YouTube API, persistence. See
 | `AlertRenderer.cs` | **The alert rasterizer (TASK 43, 2026-09-24):** renders one event's celebration animation into a BGRA `VideoFrame` — SIX DISTINCT animations (SuperChat slide-up/shine/count-up, SuperSticker scale-pop, NewMember drop-in/flash-band, MemberGift slide-left/chip-fan, GiftReceived confetti scale-in, MemberMilestone rise/growth-bar), enter/hold/exit phases, brand line on every card. **Still the fallback** when no alert clip is playable (TASK 47) |
 | `AlertOverlayLayer.cs` | **The native alert-box component (TASK 43; video branch TASK 47):** event queue (cap 10) + 33ms dispatch ticker + `RenderFrame` cache-first live path + `UpdatePreview`; **`Advance(double)` is the deterministic test clock** (tests never start the timer); `ChatEventKind.None` rows (sub mentions) never enqueue; idle = transparent (null frame). Since TASK 47 a clip branch owns `IAlertClipDecoder` per play — ctor seams `(clipDecoderFactory, clipPathResolver, audioSink)`, fade in/out over `FadeDurationSeconds = 0.30` (straight-alpha copies + volume×fade audio), EOF freeze-frame → drain, and `AlertTickerFrame` composes the scrolling message strip |
 | `AlertClipDecoder.cs` | **Per-play alert video decoder (TASK 47):** `IAlertClipDecoder` (Start/Stop/Dispose + `FrameAvailable`/`AudioReady`/`Completed`) + ffmpeg child emitting `rawvideo bgra` (`-vf scale=W:H`, read via `RawVideoFrameReader`) and `f32le -ar 48000 -ac 2` on a **carry-buffer** audio loop (float boundary straddles never drop samples), both real-time paced; bgra is opaque (layer owns alpha). One-shot lifetime — created per alert, disposed at drain; tests inject a fake |
-| `LayoutStore.cs` | SQLite persistence (`Microsoft.Data.Sqlite`) at `%APPDATA%\ytLlive\ytLlive.db`; assets stored as BLOBs keyed by SHA-256 content hash; save/open layout files; schema `user_version` 10 (`Source.ClipShape`/`IsMirrored` via `ALTER TABLE` for pre-v2 DBs; v3 = singleton `Webcam` + per-scene `WebcamSceneConfig`, migrated idempotently **without backfill** — the stale `Source.DeviceId` column remains but is no longer read/written; v4 = `WebcamSceneConfig.RectWidth`/`RectHeight`, the pre-Round rect for the round-to-rect restore; v5 = `Source.IsBackdrop` + `Source.CaptureKey`, the live-capture backdrop; v6 = `Scene.HasBackdrop` — Live-only policy, one-time backfill turns Starting/BRB/Chat/Ending off + drops their backdrop sources; v9→v10 (TASK 39) = `YppSnapshot` history table; all later columns stay additive guarded ALTERs — TASK 47 adds the five alert `Source` columns (`AlertVideoAssetId`/`AlertVideoPath`/`AlertUseDefaultVideo`/`AlertShowTicker`/`AlertVideoVolume`) without a version bump; `MainViewModel.NormalizeBackgrounds` re-normalizes on every load — TASK 25: one locked "Background" per canonical screen (static art everywhere, DisplayCapture on Live), duplicates dropped, index 0, orphaned `BackgroundUseDefault_*`/`BackgroundPath_*` Settings keys purged at save). Settings key/value table holds app state: `MicSourceName`, `ReusableStream` (TASK 9 — the cached reusable stream's id/address/name so the pump has its RTMP URL at startup), `AlertDefaultVideoAssetId` (TASK 47 — the stamped built-in alert clip's asset row; save's prune exempts it via UNION) |
+| `LayoutStore.cs` | SQLite persistence (`Microsoft.Data.Sqlite`) at `%APPDATA%\ytLlive\ytLlive.db`; assets stored as BLOBs keyed by SHA-256 content hash; save/open layout files; schema `user_version` 10 (`Source.ClipShape`/`IsMirrored` via `ALTER TABLE` for pre-v2 DBs; v3 = singleton `Webcam` + per-scene `WebcamSceneConfig`, migrated idempotently **without backfill** — the stale `Source.DeviceId` column remains but is no longer read/written; v4 = `WebcamSceneConfig.RectWidth`/`RectHeight`, the pre-Round rect for the round-to-rect restore; v5 = `Source.IsBackdrop` + `Source.CaptureKey`, the live-capture backdrop; v6 = `Scene.HasBackdrop` — Live-only policy, one-time backfill turns Starting/BRB/Chat/Ending off + drops their backdrop sources; v9→v10 (TASK 39) = `YppSnapshot` history table; all later columns stay additive guarded ALTERs — TASK 51 adds `WebcamSceneConfig.BackgroundEffect`/`BackgroundStrength`; TASK 47 adds the five alert `Source` columns (`AlertVideoAssetId`/`AlertVideoPath`/`AlertUseDefaultVideo`/`AlertShowTicker`/`AlertVideoVolume`) without a version bump; `MainViewModel.NormalizeBackgrounds` re-normalizes on every load — TASK 25: one locked "Background" per canonical screen (static art everywhere, DisplayCapture on Live), duplicates dropped, index 0, orphaned `BackgroundUseDefault_*`/`BackgroundPath_*` Settings keys purged at save). Settings key/value table holds app state: `MicSourceName`, `ReusableStream` (TASK 9 — the cached reusable stream's id/address/name so the pump has its RTMP URL at startup), `AlertDefaultVideoAssetId` (TASK 47 — the stamped built-in alert clip's asset row; save's prune exempts it via UNION) |
 | `VideoFrame.cs` | Normalized CPU frame seam (`Width`/`Height`/tightly-packed BGRA `byte[]`) — the only pixel type the rest of the app knows about; future capture sources (screen, background-removed webcam) feed the same seam |
 | `BackgroundEffects/IPersonSegmenter.cs` | **TASK 51 seam:** `Segment(VideoFrame) → SegmentationMask?` (`SegmentationMask(Width, Height, float[] Values)`, 0 = background, 1 = person); null = no mask → caller passes through. Tests inject fakes |
 | `BackgroundEffects/OnnxPersonSegmenter.cs` | **TASK 51 default segmenter:** MediaPipe Selfie Segmenter (landscape, Apache-2.0) as an embedded ONNX resource, run by onnxruntime on the CPU (2 intra-op threads); frame stretched to 256×144 RGB/255 NHWC; lazy session; never throws (fail → log once, null forever) |

TASKS/task-51-webcam-bg-effects.md

@@ -69,8 +69,8 @@ delivery shape changed:
 
 ## 2. ☐ Config surface + persistence
 
-- ☐ `WebcamSceneConfig` gains `BackgroundEffect` (`None | Remove | Blur`) + `Strength`.
-- ☐ Persist via the existing `WebcamSceneConfig` table path in `LayoutStore.Save.cs`/
+- ✅ `WebcamSceneConfig` gains `BackgroundEffect` (`None | Remove | Blur`) + `BackgroundStrength` (slice 3).
+- ✅ Persist via the existing `WebcamSceneConfig` table path in `LayoutStore.Save.cs`/
   `Load.cs` (new columns + migration). Follow `LayoutStore.Migrations.cs` conventions.
 - ☐ **Properties UI (creator spec 2026-10-09):** in the webcam's properties in the **Layers
   panel**, two **pill switches** — "Remove background" and "Blur background" — using the existing
@@ -92,7 +92,7 @@ delivery shape changed:
 - ✅ **Bundled-model contract:** the embedded ONNX model through the C# preprocessing reproduces
   MediaPipe's reference mask on a fixture (≥99.5% agreement). This is a fixed, deterministic
   contract check of the shipped bytes — not a camera/lighting quality test.
-- ☐ Config → persistence roundtrip (per webcam element).
+- ✅ Config → persistence roundtrip per scene + legacy-DB migration (`LayoutStorePersistenceTests`).
 - ☐ Engine failure → passthrough + single log, layer never dropped (code path exists; dedicated
   test lands with the hookup slice).
 - ☐ Real inference: **manual on the creator's box** (camera + lighting), not in CI.
@@ -103,7 +103,7 @@ delivery shape changed:
 ## 4. Sequencing
 
 - ✅ Separate work unit after the zoom build (zoom shipped 2026-10-08).
-- Slice order: 1 engine ✅ → 2 Blur ✅ → 3 config + persistence → 4 camera-path hookup (one
+- Slice order: 1 engine ✅ → 2 Blur ✅ → 3 config + persistence ✅ → 4 camera-path hookup (one
   processing point, both consumers) + perf check → 5 properties-panel UI.
 
 ## Related (not duplicated here)

ai.md

@@ -641,9 +641,10 @@ This replaces the old five-seeder cluster (`Seed{Starting,Brb,Ending,Chat}Backgr
   untouched, opacity preserved. The mask is computed once per frame (`TrySegment`) and rendered per
   effect (`Render`), so several variants share one inference. No mask / segmenter exception →
   passthrough + one log line, never a dropped layer.
-- **Not wired yet:** nothing calls the processor — no config, no UI, no `CameraManager` hookup. The
-  next slices add Blur, the per-webcam `BackgroundEffect` config + persistence, then the single
-  processing point on the camera path (both preview and compositor consume the processed frame).
+- **Config (slice 3):** per scene, on `WebcamSceneConfig` — `BackgroundEffect` + `BackgroundStrength`
+  (0..1, default 0.5), persisted as two additive guarded columns on `WebcamSceneConfig`
+  (`BackgroundEffect TEXT DEFAULT 'None'`, `BackgroundStrength REAL DEFAULT 0.5`, no version bump —
+  the TASK 47 convention). `RemoveBackground`/`BlurBackground` are the radio-pill bools the UI binds.
 - **Tests:** `BackgroundEffectEngineTests` — the Remove integration test (fake segmenter), and a
   model contract test that runs the BUNDLED model through the C# preprocessing on a fixture and
   matches the MediaPipe-produced reference mask (≥99.5% agreement; fixture = MediaPipe's public test

ytLive.Tests/LayoutStorePersistenceTests.cs

@@ -128,6 +128,57 @@ public class LayoutStorePersistenceTests
         }
     }
 
+    /// <summary>TASK 51 slice 3: each scene's webcam background effect + strength survives a
+    /// save and a reopen; a pre-TASK-51 DB (no columns) migrates in place and reads None/0.5.</summary>
+    [Fact]
+    public void Webcam_Background_Effect_Round_Trips_Per_Scene_And_Legacy_Db_Migrates()
+    {
+        var path = Path.Combine(Path.GetTempPath(), $"ytLlive-layout-{Guid.NewGuid():N}.db");
+        try
+        {
+            var webcam = new Webcam { DeviceId = "real-device", Name = "Logitech" };
+            var live = new Scene { Name = "Live" };
+            live.Elements.Add(new WebcamSceneConfig { WebcamId = webcam.Id, Width = 480, Height = 270, BackgroundEffect = BackgroundEffect.Remove, BackgroundStrength = 0.2 });
+            var chat = new Scene { Name = "Chat" };
+            chat.Elements.Add(new WebcamSceneConfig { WebcamId = webcam.Id, Width = 480, Height = 270, BackgroundEffect = BackgroundEffect.Blur, BackgroundStrength = 0.8 });
+            using (var store = new LayoutStore(path))
+                store.Save(new[] { live, chat }, webcam, null);
+
+            using (var reopened = new LayoutStore(path))
+            {
+                var scenes = reopened.Load();
+                var liveCfg = scenes.Single(s => s.Name == "Live").Elements.OfType<WebcamSceneConfig>().Single();
+                var chatCfg = scenes.Single(s => s.Name == "Chat").Elements.OfType<WebcamSceneConfig>().Single();
+                Assert.Equal(BackgroundEffect.Remove, liveCfg.BackgroundEffect);
+                Assert.Equal(0.2, liveCfg.BackgroundStrength, 6);
+                Assert.Equal(BackgroundEffect.Blur, chatCfg.BackgroundEffect);
+                Assert.Equal(0.8, chatCfg.BackgroundStrength, 6);
+            }
+
+            // Simulate a DB written before TASK 51: drop the two columns, reopen.
+            SqliteConnection.ClearAllPools();
+            using (var raw = new SqliteConnection($"Data Source={path}"))
+            {
+                raw.Open();
+                using var cmd = raw.CreateCommand();
+                cmd.CommandText = "ALTER TABLE WebcamSceneConfig DROP COLUMN BackgroundEffect; ALTER TABLE WebcamSceneConfig DROP COLUMN BackgroundStrength;";
+                cmd.ExecuteNonQuery();
+            }
+            SqliteConnection.ClearAllPools();
+            using (var legacy = new LayoutStore(path))
+            {
+                var cfg = legacy.Load().SelectMany(s => s.Elements).OfType<WebcamSceneConfig>().First();
+                Assert.Equal(BackgroundEffect.None, cfg.BackgroundEffect);
+                Assert.Equal(0.5, cfg.BackgroundStrength, 6);
+            }
+        }
+        finally
+        {
+            SqliteConnection.ClearAllPools();
+            try { File.Delete(path); } catch { /* best-effort cleanup */ }
+        }
+    }
+
     // The background (schema v5): permanent bottom layer holding live desktop/game
     // capture. IsBackground + CaptureKey must survive a save + reload so a
     // re-designated target isn't lost on restart.