# HANDOFF — 2026-09-26 (TASK 47: crash + silent-void + video-pacing all fixed; 4 local commits, NOT pushed)

## Branch / Commit State

`main` — four local commits ahead of `origin/main` (= `ecb329e`), **NOT pushed** (awaiting the
creator's go / milestone signal):

1. `a11b15e` — **TASK 47** alert box video (built-in/custom clip + read-time fade + message
   ticker + unity audio) + `AlertLayerVideoTests` (fake decoder, 0 warnings, 319/319 green).
2. `7b940b6` — **crash fix**: AlertOverlayLayer marshals the chat-poller seam to the UI thread
   (regression test red pre-fix / green post-fix). Full suite 320/320.
3. `80038ff` — **silent-decoder fallback + diagnostics** (no-frame grace 1.0s → six-animation;
   BeginClip/RunAsync logging). Full suite 321 with the **known env flake** (RealMouseDrag
   reorder failing while windows are up).
4. *(uncommitted next — this session)* — **video pacing fix** (below). Scope:
   `ViewModels/MainViewModel.Chat.cs`, `ytLive.Tests/AlertClipDecoderTests.cs` (new), docs
   (task-47 addendum, `MyMistakes.md`, this file). Test green; build 0 warnings;
   `scope-check.sh` pending, then commit.

## ✅ Crash fixed (`7b940b6`)

The creator's first live session: test-tab alerts DID fire (11:21 startup.log: alert-clip audio in
the mix, `peakMix 0.375 → 0.891` with mic+loop at 0.000) but the app crashed at `11:22:01.301` on
the first REAL polled message: `Must create DependencySource on same Thread as the DependencyObject`
in `DataBindEngine.ProcessCrossThreadRequests`. `AlertOverlayLayer.OnMessageReceived` had no
UI-thread marshal (`ChatOverlayLayer` has one); it ran `RefreshAlertPreviews` → `UpdatePreview` on
the MTA poller thread and stamped `alertBox.VideoImageSource` (INPC + WPF-bound) with a
WriteableBitmap created there. Fix + Good Dog regression test
`OnMessageReceived_FromPollerThread_MarshalsPreviewWritesToTheUiThread` (red/green verified).

## ✅ "Nothing in the alert box" void — fixed (`80038ff`)

After the crash fix: On-Air → test → **remove and re-add** the Stream Alerts layer → TEST event →
procs in chat but **nothing in the alert box**. startup.log 11:44 `peakMix 0.105` (no alert audio)
vs 11:21's 0.375–0.891. Every stage of the clip path was silent by design; a decoder whose `Start()`
succeeds but yields **no frames AND no audio** left `_clip != null` with `_latestClipFrame == null`
→ blank box forever. Fix: no-frame grace (1.0s) in `AlertOverlayLayer.Advance` → tear down + same
alert as six-animation; BeginClip/RunAsync diagnostics stop the silence. Good Dog:
`SilentDecoder_FallsBackToTheAnimationAfterTheNoFrameGrace`.

## ✅ "No video plays" — decoder HEALTHY, video UNPACED — fixed (this unit)

Creator repro after `80038ff` (12:35 session): still "no video plays in the web-alert box", "like
you lost the video" — but the new diagnostics PROVED the decoder healthy: `Alert clip start: box …`
→ `Alert clip end: … frames=240 audioChunks=156 failed=False` twice, alert audio in the live mix
(`peakMix 0.277 → 0.733`, mic/loop 0.000). Root cause was **pacing, never decode**:
`AlertClipDecoderFor` (MainViewModel.Chat.cs:113) built the decoder with **no frame-rate probe** →
`RunAsync` computed `frameDuration = TimeSpan.Zero` → `RunVideoAsync`'s pace step
(`if (frameDuration > 0)`) was dead code → all 240 frames of the 10s clip dumped through the pipe
in the first ~1-2s (130MB as fast as ffmpeg read), then the box sat frozen on the LAST frame while
the audio pipeline paced 156 chunks at real-time ~7.8s. Reading exactly like "no video / you lost
it". The media path already had the seam wired (`MediaVideoSource` gets
`frameRateProbe: new FfmpegFrameRateProbe(…)`, MainViewModel.cs:308) — the alert factory just
never passed one.

**Fix (uncommitted):** `AlertClipDecoderFor` passes
`frameRateProbe: new FfmpegFrameRateProbe(new FfmpegLocator(), () => new FfmpegDecodeProcess())` so
video paces at the clip's native ~24fps (10s real-time) in lockstep with audio. Good Dog test
`AlertClipDecoderTests.AlertClipDecoder_PacesVideoFramesToTheProbedFrameRate` drives the REAL
`AlertClipDecoder` through the media-style fake process + fake probe + recorded delay seam
(3 frames at 100fps → one ~10ms delay per frame; red on the old factory, green now). Full suite
321/322 (one known-env flake). `MyMistakes.md`: **a decoder that drops data faster than wall-clock
looks identical to a dead decoder on screen — "plays but you don't see it" is a PACING bug before
it's a decode bug.** Rules: never ship a pipe whose `frameDuration` can be zero; check pacing
(bytes/s vs wall-clock) before re-auditing the codec.

## Follow-ups queued (NOT done in this unit)

- **TASK 3 item 20 persistence half** — canonical `RewardEvents` SQLite table +
  `superChatEvents.list` (30-day) backfill + session-report rollup (still in-memory only).
- TASK 3 item 16 (Text source); TASK 40 units A/C/D; TASK 32–36; TASK 12 master limiter — queued.
- If the alert box is STILL "no video" after this fix + relaunch: check the 12:35-style
  `Alert clip end: … frames=240` line (now logged) — a healthy decode with no visual means the
  painter/render path, not the decoder; the creator's Live scene also has a WebSource
  "Web Resource-0" bottom-right — confirm which element they watch when describing the
  "web-alert / stream-alerts" box.
- The known pump stall (`render=full-render … totalMs=147`, ~6fps worst) is recorded as a
  pre-existing perf item, NOT part of this unit.

## Around the task (carried facts)

- RealMouseDrag tests no-op while a game/fullscreen window steals the mouse — **close fullscreen
  windows before full-suite runs**; passes in isolation.
- Test-env trap: saved OAuth session loads synchronously → force `vm.IsConnected` in signed-in tests.
- `subscriberCount` YPP slice 2 needs re-consent — do not merge with other units. `MARCOM.md`/
  `MONETIZATION.md` gitignored — never commit.
- API facts (TASK 44 + 45): liveChatId unavailable until broadcast live; `400 MISSING_REQUIRED_FIELD`
  from `liveChat/messages.insert` = wrong body shape (missing `snippet.type`).
- TASK 47 sticky facts: bgra from ffmpeg is opaque (alpha=255); audio pipe = carry-buffer loop;
  default clip = `%TEMP%\ytLive-alert-{id}.mp4`; decoder per-play; DB stays `user_version 10`.
- Every committed change needs a **close + relaunch** of the running app to be seen.

## Next step

1. Commit this unit with the declared scope
   `./scripts/scope-check.sh "ViewModels/MainViewModel.Chat.cs" "ytLive.Tests/AlertClipDecoderTests.cs"`.
2. Push the four local commits at the creator's go / milestone signal.
3. Creator to relaunch and re-run the repro — with the probe wired the clip plays real-time
   (~10s of motion, not a blur + frozen frame); the `Alert clip end:` line confirms decode health.

## Critical working rules (unchanged, still binding)

- **Good Dog = ONE integration test per change.** Scope lock + `./scripts/scope-check.sh` before commit.
- Windows dotnet host for all WSL builds (`/mnt/c/Program Files/dotnet/dotnet.exe`, quoted paths).
- 0 warnings on real clean builds. One commit = fix + its memory (task doc, MyMistakes, handoff).
- No menus/polls with the creator; decisions asked once then held; do the work, then report.