# HANDOFF — Session State

## Branch / Commit State

**`main`**, working through TASK 21 (media source). Local commits ahead of
`origin/main` (not yet pushed — user pushes at agreed checkpoints):
- `f89b9f9` — docs: default-device audio assumption (README + startup log)
- `e8ff4df` — TASK 22: global audio sync offset (positive delay at the mixer out)
- `670fe3a` — TASK 31 (already pushed; listed for context)

Prior milestones pushed through `origin/main`: TASK 31 (`3bf053a..670fe3a`), plus
the full refactor series (Commit F `3107f92`, Commit G `85893ea`).

## What's In Flight

**TASK 21 (media source) — Increment B (the decoder) implemented, uncommitted-or-pending-commit, awaiting next unit.**

Increment A (the `Source` model: `MediaSourceType`, `SourceType.MediaSource`,
`MediaPath`/`MediaIsLooping`/`MediaVolume`/`MediaPlaybackState` + LayoutStore
persistence) shipped earlier. This session shipped **Increment B — the decoder**:

New files:
- `Services/RawVideoFrameReader.cs` — pure: parses a rawvideo BGRA stream into
  `VideoFrame`s (exactly W×H×4 per frame; partial reads kept across `Feed`).
- `Services/IDecodeProcess.cs` + `Services/FfmpegDecodeProcess.cs` — binary-stdout
  subprocess seam (mirror of `IEncoderProcess`).
- `Services/MediaVideoSource.cs` — spawns ffmpeg `-f rawvideo -pix_fmt bgra -an`,
  drains the pipe, raises `FrameReady` per frame; `Completed` on EOF.
- `ytLive.Tests/MediaVideoSourceTests.cs` — 3 pure reader tests + 1 integration
  (fake `IDecodeProcess`+`IFfmpegLocator` through the real source loop, frames in
  order). **Verified: 4/4 pass, build 0 warnings.**

Still open (next slices): native-FPS pacing (ffprobe probe), loop control, volume,
the `ResolveOutputFrame` resolver case + wire into `SceneCompositor`, the file-picker
UI, and the remaining tests.

**Landmine:** a stale `testhost` can lock `ytLive.Tests`'s `ytLive.dll` and break
`dotnet build` of the test project — kill it first (`cmd.exe /c "taskkill /PID N /F"`)
on MSB3027. Full-suite vstest hangs headless (RealAppHost/WASAPI) — only filtered
pure tests run in WSL; user verifies the GUI suites on native Windows PowerShell
(which may also hang if WASAPI startup blocks — pre-existing, not this change).

## Next

1. Commit Increment B (decoder) as one work unit (scope-check + docs already
   staged in ai.md/TASKS.md/HANDOFF.md).
2. Next slice: native-FPS pacing + wire media into `ResolveOutputFrame` and the
   compositor, per TASK 21 steps 6–7.
3. Await user push checkpoint for the TASK 22/21 commits.

## The directive (2026-08-31, user)

Rewrite the project into functional components to aid AI retrieval —
`Services/ChatOverlayLayer.cs` / `SceneGraph.cs` style (owner-state extraction),
not line-count chasing. Audio assumption is now an explicit contract (README
"Audio Assumption"): the app uses system defaults, never fights Windows device
locking, and does not debug user audio issues — OS's problem, not ours.