fix(alerts): silent decoder falls back to the six animations after a 1s no-frame grace

Routing and ruling both good: 'procs in the chat windows but nothing in the alert box' with zero exceptions — every failure stage was silent by design (Debug.WriteLine-only preview catch, bare catch{} in RunAsync firing Completed regardless). A decode run that starts but yields neither a frame nor an audio chunk left _clip != null with _latestClipFrame == null, so RenderClipFrame returned null forever: the box stayed transparent for the whole alert and the six-animation fallback (which only ran on setup-time throws) never fired. Fix: AlertOverlayLayer.Advance gives a started clip a NoFrameFallbackSeconds (1.0s) grace — produce no frame AND no audio inside it and the clip is torn down, _elapsed resets, and the SAME alert continues as the animation branch (never blank, never drained early). Diagnostics stop the lying silence: BeginClip logs box id/path/size + setup failures; AlertClipDecoder.RunAsync logs frame/chunk end-state and the exception it used to swallow. Good Dog test: SilentDecoder_FallsBackToTheAnimationAfterTheNoFrameGrace (transparent inside grace, disposed past it, animation renders, drains to idle). Reference: alert playback must degrade to its fallback on dead-air, never vanish — same contract as every player/booth failure budget (e.g. OBS source fallbacks). https://obsproject.com/forum/threads/source-visibility-fallback.187383/
2026-09-26 12:08:27 -07:00
parent 7b940b6a5a
commit 80038ff152
6 changed files with 231 additions and 60 deletions
@@ -126,6 +126,57 @@ public sealed class AlertLayerVideoTests
        Assert.True(fake.DisposeCount == 1, "the per-play decoder must be torn down at drain");
    }

+    [Fact]
+    public void SilentDecoder_FallsBackToTheAnimationAfterTheNoFrameGrace()
+    {
+        _app.Run(() =>
+        {
+            var box = new Source
+            {
+                Type = SourceType.AlertBox,
+                Name = "Stream Alerts",
+                Width = 600,
+                Height = 200,
+                AlertUseDefaultVideo = true,
+            };
+            var scenes = new List<Scene> { new Scene { Name = "Main", Elements = { box } } };
+            var fake = new FakeAlertClipDecoder();
+            var layer = new AlertOverlayLayer(
+                new AlertRenderer(),
+                clipDecoderFactory: (_, _, _) => fake,
+                clipPathResolver: _ => @"C:\fake\silent.mp4");
+
+            layer.UpdateConfiguredBoxes(scenes);
+            layer.Enqueue(new ChatMessage { Kind = ChatEventKind.NewMember, AuthorName = "Funder" });
+
+            Assert.True(layer.IsPlaying);
+            Assert.Equal(1, fake.StartCount);
+
+            // Still inside the grace window: the decoder produced nothing, the box
+            // sits transparent — exactly the dead-air state the 2026-09-26 live
+            // failure showed.
+            layer.Advance(0.5);
+            Assert.Null(layer.RenderFrame(box));
+            Assert.Equal(0, fake.DisposeCount);
+
+            // Past the 1s grace: the silent decoder is torn down and the ALERT
+            // SWITCHES to the six-animation render — never a permanently blank box.
+            layer.Advance(0.6);
+            Assert.Equal(1, fake.DisposeCount);
+            Assert.True(layer.IsPlaying);
+            var animation = layer.RenderFrame(box);
+            Assert.NotNull(animation);
+            Assert.True(HasPixels(animation!), "the fallback must actually draw");
+
+            // The animation plays its full duration, then drains to idle.
+            layer.Advance(3.5);
+            Assert.True(layer.IsPlaying);
+            layer.Advance(1.0);
+            Assert.False(layer.IsPlaying);
+            Assert.Null(layer.RenderFrame(box));
+        });
+    }
+
    private static byte AlphaAt(VideoFrame frame) => frame.BgraPixels[3];

    private static bool HasPixels(VideoFrame frame) => frame.BgraPixels.Any(b => b != 0);