# 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):
- `a1d9751` — docs: ffmpeg decode-contract verification recipe + WSL CLR boundary
- `8f49010` — TASK 21 Increment B: FFmpeg rawvideo video decoder -> VideoFrame
- `f89b9f9` — docs: default-device audio assumption (README + startup log)
- `e8ff4df` — TASK 22: global audio sync offset (positive delay at the mixer out)

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) — slice 1 step 3 shipped (the session-manager + interface); next open work is the VM wire-in (slice 1 step 4).**

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

This session:
- Refactored `Services/MediaVideoSource.cs` onto the new
  `Services/IMediaFrameSource.cs` (`Key`, `FrameAvailable`, `Completed`,
  `StartAsync`/`StopAsync`; `Start`→`StartAsync`, `FrameReady`→`FrameAvailable`)
  — behavior preserved, `MediaVideoSourceTests` updated and passing.
- Added `Services/MediaVideoSourceManager.cs` — app-wide decode-session
  ownership refcounted by `MediaPath`, `Func<string, IMediaFrameSource?>` factory
  seam, `AcquireAsync`/`ReleaseAsync`/`ReleaseAllAsync`/`GetLatestFrame`, frames
  coalesced onto the UI dispatcher onto one shared `WriteableBitmap` per file,
  `MediaFailed` + `PreviewBitmapChanged`. Structural mirror of `ScreenCaptureManager`.
- Added `ytLive.Tests/MediaVideoSourceManagerTests.cs` (5 unit + 1 integration:
  single shared bitmap, coalesce-to-latest). **Verified: all 10 media tests pass
  (5 manager + 3 reader + 1 decoder integration + 1), build 0 warnings.**

Next (slice 1 step 4 — VM wire-in): create `_mediaManager` in the ctor with
`path => new MediaVideoSource(path, <W>, <H>, new FfmpegLocator(), new FfmpegDecodeProcess())`,
subscribe `OnMediaPreviewBitmapChanged` (set `source.VideoImageSource` for every
`IsMediaSource` with that `MediaPath`), add the `Source { IsMediaSource: true, MediaPath: not null }`
case to `ResolveOutputFrame` (`MainViewModel.cs:447`), add `or SourceType.MediaSource`
to `Source.DisplaySource` (Source.cs:119-121) so media previews route `VideoImageSource`,
and dispose the manager on shutdown. Then slices 2 (native-FPS pacing) and 3 (loop).

**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 slice 1 step 3 (this unit): manager + `IMediaFrameSource` + tests. Commit
   is already covered by `TASKS.md`/`HANDOFF.md`; this HANDOFF is the shipping doc.
2. Slice 1 step 4: wire `_mediaManager` into the resolver + preview routing (see above).
3. Slice 2: native-FPS pacing (ffprobe FPS probe + per-frame pacing seam).
4. Await user push checkpoint for the pending 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.