LlamaCasty/HANDOFF.md

HANDOFF — 2026-10-09 (TASK 51 quality pass: jitter FIXED; blur-heavy is the next unit)

Branch

• main (no feature branch). Pushed through 5685c5d (TRAX toggle); everything after is local, not pushed (push at the creator's call).

Dirty files — split by ownership

• This work unit (COMMIT these): Services/BackgroundEffects/MaskSmoother.cs (new), the smoother wiring in Services/CameraManager.cs, ytLive.Tests/CameraManagerTests.cs (new integration test), and the same-commit memory updates (Services/index.md, ai.md, TASKS/task-51-webcam-bg-effects.md, TASKS.md row 51, and this file) — all ship in the SAME commit.
• NOT mine — do NOT commit: the in-flight "pinned chat" work unit (Models/YouTube.cs, ViewModels/MainViewModel.Chat.cs, untracked Helpers/RelayCommandGeneric.cs, and its hunks in Controls/LeftPanel.xaml — only the webcam-properties region is TASK 51; the pinned-chat hunks stayed unstaged/untouched), plus the creator's untracked Assets/llamacasty* art.
• ⚠️ Pre-commit: scripts/verify.sh runs scripts/scope-check.sh against ALL working-tree changes — the not-mine files WILL flag. Pass them to the script as declared-known (checksums unchanged since 5685c5d) or let the script's output be reconciled before committing.

What just happened — temporal jitter fix

• Creator check: bg Remove is "jittery", Blur is "heavy". User picked jitter first.
• Root cause: OnnxPersonSegmenter classifies each frame independently (256×144 mask, bilinear upsample) → zero temporal coherence → edge flutter. There is no temporal smoothing upstream.
• Fix: MaskSmoother — per-session blend of each raw mask with the previous smoothed one, 0.75×new + 0.25×previous (CurrentWeight, internal). Wired at the ONE production point (CameraManager.RunEffectWorker → session.Smoother.Smooth(TrySegment(source))); state on CameraSession, NOT the segmenter (segmenter is shared app-wide and contract-pinned to raw output). Null mask resets history; first frame/size-change passthrough; never aliases the caller's array; two ping-pong buffers, no per-frame LOH alloc. Weights: OBS obs-backgroundremoval 0.85 default test, Jitsi jitsi/jitsi-meet#17080 0.7/0.3 best (0.5/0.5 smears on motion).
• Test: CameraManagerTests.Temporal_Smoothing_Damps_Segmentation_Jitter_Across_Frames — PASSED. A SteppingMaskSegmenter returns fresh masks per call: {1,1,0,0} then {1,0.2,0,0}; 16×4 frame, Remove 0.5. Asserts x=6: frame1 = 255 (passthrough), frame2 smoothed = 58, raw-unsmoothed = 0; person core x=1 = 255, background x=14 = 0. ⚠️ Gotcha: the worker's latest-frame-drop guard treats a re-queued IDENTICAL frame reference as "no new frame" — pump frame2 as a NEW VideoFrame instance.
• Assert.Equal(255, first[...])/58/0 predictions were hand-verified; other pixels differ by float rounding (e.g. x=5 Python 34 vs C# 36) — only assert x=6/x=1/x=14.

Next step

1. Run ./scripts/verify.sh with the declared file list; reconcile the not-mine dirty files with scope-check; commit the unit (message …(Unit: bg-removal jitter fix) + OBS/Jitsi citations).
2. Next unit = Blur "heavy" — soften the radius curve in BackgroundEffectProcessor.ApplyBlur (MinBlurRadius=1 / MaxBlurRadius=12 at ¼ res ≈ 26–50 full px; strength 0.5 → 6 small px). The creator needs a retry pass on the real camera after both.

Also still open

• Vertical-format regression (STALE, not fixed): 1080p60 vertical selection no longer shrinks the capture border in the preview. Mechanism mapped (see prior summary): the crop Rectangle Controls/PreviewPane.xaml:319-322 bound to OutputRectX/Y/W/H + IsOutputCropped, driven by MainViewModel.Streaming.cs ApplyStreamQuality from SelectedQuality (binding + ctor only, new("Vertical 1080p60", 60, 8.0, 1080, 1920)), DimRects in MainViewModel.cs:91-94. Root cause unknown — paused.
• Vertical recording file closed: the recording itself is 1080×1920 60fps correctly; the "whitespace" was the app's preview UI, not the file. Audio loudness (ebur128) for the private video was never run and the thread is closed unless the user reopens it.
• Blur-heaviness = next unit (above). Yellow-border regression = stale thread.
• ⛔ Sudo password rotation pending (user; then update both password lines in CREDENTIALS.md).
• TASK 56 secret scan before gramps/LlamaCasty goes public. TASK 55 disk hygiene queued.

Tests

• Full suite 416 passed / 1 known env flake at 5685c5d; the new smoothing test passes standalone (1 test run, Duration < 1 s after warm). 0 build warnings. Known environment flakes: Mix_HonorsProviderGains… (fails while system audio plays), RealMouseDrag… (needs an idle desktop).