# scene-actor-extraction

A face-recognition pipeline that finds when each actor appears on screen in a
film or TV episode — built on [KPN++](https://gitea.tourolle.paris/dtourolle/KPN)
(a C++20 Kahn Process Network library) for the detect → track → match → scene
pipeline, with a Jellyfin-integrated gallery and an X-Ray-validated optimizer.

This is a perfect X-Ray second, on a film the optimizer never saw:

![A perfect X-Ray second: three faces named at 100%, two more correctly carried off-screen](assets/images/lovelace_perfect_second.jpg)

Every visible face named at 100% — Chris Noth, Hank Azaria, Bobby Cannavale —
the background extra honestly left unnamed, and the two credited cast without
a visible face correctly carried as present off-screen by the tracker's
presence windows. That's the pipeline exactly reproducing Amazon X-Ray's
record for this second.

It doesn't always go like that: the hardest held-out film scores 46% F1, and
the report is honest about *why* — one tunable trade (extinction bridging at
hard cuts), one structural ceiling (X-Ray credits people whose faces never
appear), and a few cases where the pipeline is right and X-Ray is wrong. The
evidence for all of it is in the pages below.

## Start here — four questions this bake-off answers

<div class="grid cards" markdown>

-   :material-trophy:{ .lg .middle } **[Which model is best?](best-model.md)**

    ---

    Calibration curves first (discriminative power, independent of any
    threshold), then F1 on the actual benchmark. LVFace-B Glint360K wins
    both.

-   :material-filter:{ .lg .middle } **[Whole vs. cast-restricted gallery](gallery-scope.md)**

    ---

    Restricting the matcher to a film's credited cast is a clean win on
    every axis (+3.3pp F1, less than a third the misIDs) — but isn't a
    shipped runtime feature yet.

-   :material-account-convert:{ .lg .middle } **[Does pose expansion help?](pose-expansion.md)**

    ---

    A convincing training-set effect that didn't reproduce on 5 held-out
    films once two methodology bugs were caught and fixed. An honest null
    result, not a forced narrative.

-   :material-magnify-expand:{ .lg .middle } **[Deep dive: LVFace-B Glint360K](lvface-deep-dive.md)**

    ---

    The held-out generalization gap, how the error budget decomposes
    (extinction bridging at hard cuts, X-Ray's scene-membership vs.
    on-screen-face ceiling), and the frames where the pipeline is right
    and the ground truth is wrong.

</div>

## The full technical log

- **[Model bake-off + threshold re-tune](model-bakeoff.md)** —
  the complete experiment log behind the four pages above: the ROCm teardown
  deadlock root cause and fix, DE concurrency tuning, the full 16-combo
  results table, and every caveat. This is where the shipped
  [`src/config.hpp`](https://REPOLINK/src/config.hpp) defaults come from.
- **[Optimizer experiments (prior round)](optimizer-experiments.md)** — the
  earlier scene-union-metric tuning pass, superseded by the per-second metric
  used in the bake-off but kept for the ground-truth/architecture background.
- **[Service conversion (proposal)](service-conversion.md)** — design sketch
  for a native idle-GPU worker gated on screen lock, not yet built.

## Reproducing the benchmarks

Gallery `.h5` files, embedding dumps, the X-Ray corpus, montage frame images,
and DE trajectories are not committed to this repository — they're pushed to
the Gitea package registry and pulled on demand:

```bash
scripts/artifacts/pull_artifacts.sh galleries
scripts/artifacts/pull_artifacts.sh experiment-data
scripts/artifacts/pull_artifacts.sh montage-frames <film-slug>
```

See [`scripts/artifacts/push_artifacts.sh`](https://REPOLINK/scripts/artifacts/push_artifacts.sh)
for the upload side (requires a `GITEA_TOKEN` with package write scope).