# Recording foundation validation

The first recording milestone proves the OBS capture, encoder and segment
pipeline before the UI is built (SPEC.md, "Implementation validation before
building out the UI"). `clipbin-probe` drives the real `clipbin-obs` engine and
prints `key=value` lines; the scripts in `scripts/validate/` turn them into
pass/fail results.

| Where | Script | Status |
| --- | --- | --- |
| Linux, headless rig (Wayland portal + Xwayland) | `scripts/validate/linux-rig.sh` | All 9 scenarios pass on devbox (Intel UHD 770, VA-API) |
| Linux, real session (CachyOS, Hyprland, RX 9070 XT, 1440p60) | `scripts/validate/linux-hardware.sh` | Not run yet |
| Windows (Game Capture, NVENC/AMF/QSV) | `scripts/validate/windows.ps1` | Not run yet; script untested |

## Probe commands

```sh
cargo run -p clipbin-probe -- encoders --verify          # hardware encoders per codec, proven by encoding
cargo run -p clipbin-probe -- record --target monitor     # records; prints status, health and segments
cargo run -p clipbin-probe -- check                       # keyframes, codec, durations, cross-boundary remux
```

`record` targets `monitor`, `window` or `game` (Game Capture on Windows; the
same as `window` elsewhere). On Windows and X11, `--window` takes OBS's window
identifier; on Wayland the portal picker chooses and `--restore-token` reuses
an earlier choice. See the top of `crates/clipbin-probe/src/main.rs` for all
options. `check` needs FFmpeg's `ffprobe` and `ffmpeg` on `PATH`.

## Linux headless rig

`scripts/rig/headless.sh [--x11] <command>` runs a command inside a private
D-Bus session with PipeWire, a virtual audio sink, headless Sway on the GPU,
xdg-desktop-portal-wlr (auto-selecting the only output) and a 60 FPS test
pattern with a tone. `--x11` runs the game and command on Sway's Xwayland.

Arch packages: `sway xdg-desktop-portal xdg-desktop-portal-wlr xorg-xwayland
xorg-xwininfo pipewire pipewire-pulse wireplumber libpulse ffmpeg` plus a VA-API
driver (`intel-media-driver` or `libva-mesa-driver`).

The suite covers:

1. Encoder verification: H.264 must be usable; HEVC and AV1 are reported.
2. Wayland monitor capture in H.264 and HEVC: segments start on keyframes,
   last 2 s, remux to MP4 across boundaries, decode cleanly, carry the tone.
3. X11 window capture (Xcomposite).
4. Failures that must end in `status=failed`: PipeWire stream lost, captured
   X11 window closed, segment directory unwritable, free space below the margin.
5. A portal that grants no usable source never reports `Recording`.

## Linux hardware sign-off

Run `scripts/validate/linux-hardware.sh` from the Hyprland session. It verifies
encoders at 1440p60, records the monitor with each usable codec (the first run
shows the portal picker; later runs pass the restore token and ask whether the
picker stayed away), records a window, and asks you to close a window
mid-recording. Send back `report.txt` from the output directory.

## Windows

Run `scripts/validate/windows.ps1 -GameWindow "<title>:<class>:<exe>"` with a
game running. It assembles the official OBS 32.0.4 runtime, checks the Game
Capture hook signatures, builds the probe, verifies NVENC/AMF/QSV encoders and
records Monitor, Game and Window Capture.

Windows status:

- `clipbin-core`, `clipbin-obs` and `clipbin-probe` pass `cargo clippy` for
  `x86_64-pc-windows-msvc` (cross-checked from Linux). Nothing has been linked
  or run on Windows.
- The GPUI desktop crate has not been checked for Windows; its `ring`
  dependency needs the MSVC C toolchain.
- The assembled runtime keeps the six Game Capture hook binaries byte-identical
  to the release, with their Authenticode signatures present; signature
  validity has not been checked on Windows.
- Unvalidated: encoder ids and settings for NVENC, AMF and QSV; Game Capture
  hooking and its loss detection (the engine expects the source size to drop
  to 0); WASAPI audio; `obs-ffmpeg-mux.exe` beside the executable; linking
  `dstr_vprintf` through the libobs crate's `obs.lib`.

## Findings for the next milestones

- **Plugin loading.** libobs always adds default plugin paths: the build-time
  install prefix on Linux and `../../obs-plugins/64bit` relative to the
  working directory on Windows. Searching would load other OBS installations'
  plugins or load ours twice, so the engine opens exactly the bundled
  allowlist (`runtime::PLUGINS`) by path.
- **Segment timestamps.** The FFmpeg muxer restarts each segment's video and
  audio timestamps at zero independently. Concatenating segments naively leaves
  22–43 ms video gaps at boundaries. Video is constant frame rate and AAC
  packets are continuous, so a segment's exact session offset is the count of
  earlier frames and audio packets; the A/V offset stays within one AAC packet
  (≤21 ms) and does not drift. The timeline and export work must place
  segments this way.
- **Availability.** With 1 s keyframes and 2 s segments, splits happen on
  schedule every 2.0 s, so the newest complete footage is about 2 s behind
  plus finalisation: inside the spec's 2–5 s window.
- **Honest status needs more than OBS's counters.** OBS kept counting bytes
  into a dead muxer process, and once reported a clean stop after the disk
  filled. Status therefore requires footage to grow on disk, and recording
  stops while 1 GB remains so the last segment can be finalised.
- **PipeWire source loss.** OBS's PipeWire capture keeps its size and renders
  its last frame after the stream stops, and only logs the stream state. The
  engine reads that log line (stable for the pinned OBS version). A more robust
  follow-up is watching the PipeWire node state directly.
- **Audio capture failures are not detected yet.** When the PulseAudio server
  was unreachable, recording continued with a silent track.
- **Linux runtime dependencies.** The Linux OBS build links the system's
  FFmpeg, PipeWire and other libraries, so it is tied to the distribution it
  was built on. Packaging (for example Flatpak, or bundling FFmpeg) is an open
  decision; OBS 32.0 needs mbedtls 3 (`mbedtls3` on Arch).
- **OBS objects.** Scenes and sources are created private (OBS 31+ otherwise
  registers scenes with the main canvas, which keeps them alive), unknown
  source types fail instead of becoming placeholders, and shutdown drains
  libobs's destroy queue first.
- **Plugin configuration.** libobs is started without a module config path;
  set one under the app's config directory before plugins that save settings
  are added.