Commit Graph
5 Commits
Author SHA1 Message Date
dtourolle 24d35cbde3 fix(AR-013): reap tracks on the evidence watermark, not the tracker's clock
The registry closed a track when the *tracker's* timestamp passed
`track_extinction_sec`. But votes arrive from the matcher, which is a separate
KPN node behind a channel, and much the slower of the pair. Backpressure —
working exactly as AR-004 intends — turns that channel's depth into lag, so
the tracker's clock can be far ahead of the last frame anybody has voted on.
Tracks were therefore closed before their evidence arrived: the votes landed
on ids that no longer existed, were counted as dropped, and the track was
emitted unowned or not at all.

The symptom is the part worth remembering: **a deeper channel produced fewer
identifications, from identical input.** On the SuperHero fixture, 5 actors /
16 windows at depth 32 against 3 actors / 5 windows at depth 10322; through
the replay harness, capacity 32 gave 5 actors and 10322 gave 0. A throughput
knob was silently changing the answer, which makes every sweep tuned against
it suspect.

The fix is not to bound the channel against `track_extinction_sec` — that
makes an algorithm constant police a throughput knob and leaves the result a
function of scheduling. It is to reap on an evidence watermark: the matcher
advances it as it folds each frame in, and a track is only finished once
everything up to its extinction point has actually been voted on. Same device
`SceneBoundaries::scored_through()` uses for the AR-010 join — a consumer past
that point is asking about frames nobody has looked at yet, and the honest
answer is to wait rather than guess.

Association keeps the tracker's clock, and separating the two is the other
half. They answer different questions: "may this detection link to that
track?" is asked now, about a box seen `track_extinction_sec` ago; "is that
track finished?" cannot be answered until every vote is in. Deferring
association to the evidence clock — which deferring the erase alone did — left
retired tracks associable for as long as the matcher lagged, so a new face
re-associated onto a long-dead track and two people merged into one window.

The watermark is monotonic and only ever *delays* a reap, so no window is
extended by it: AR-013's "a window ends at the last sighting, never after" is
a property of `emit_locked`, which takes `last_seen` and never `now`.

`dropped_votes` is exposed and reported — by main at shutdown and through the
replay bindings — because this failed silently for as long as it did precisely
because nothing counted it. It warns rather than aborts: a dropped frame means
the output describes footage nobody analysed and is always wrong, while a
dropped vote degrades a claim without falsifying it, and there is no
measurement yet of how often it happens on real content.

replay.py's channel capacity stops being the whole film. It was sized that way
to dodge a PyNode overflow drop that AR-004 has since replaced with parking,
and removing backpressure that way is what made the defect above so extreme.

Tag separators in kpn_bindings.cpp corrected to pipes between requirement
types, which the traceability gate was reporting as diagnostics; the matrix is
regenerated and reports 0 orphan tags.

149/149.

TRACES: AR-004, AR-012, AR-013, AR-025 | VR-011 | SR-002 | PR-002
2026-08-08 12:08:15 +02:00
dtourolle 7c7d4934ae refactor(presence): execute the extinction_sec/anneal_sec withdrawal
docs/SPEC.md specified this removal, listed its parts, and ended "grep
for both names and expect no survivors". There were about forty.
docs/requirements.md meanwhile recorded both constants as Withdrawn and
"deleted rather than retained at zero", on the grounds that a field
naming a mechanism the pipeline no longer has is actively misleading.
Neither statement was true of the code: Config still carried
extinction_sec 57.4 and anneal_sec 35.5, --extinction and --anneal still
parsed, and SceneTrackerFunc still ran its keep-alive in both shipped
pipelines, announcing its timeout at every startup.

SceneTrackerFunc is replaced by FrameAnnotationFunc, which is stateless:
same ports, same output type, no keep-alive. Presence belongs to
TrackRegistry (AR-012), where a window is the extent of a track an actor
owned and ends at the last sighting (AR-013). The keep-alive answered
that question a second time and answered it worse, by re-opening exactly
the trailing cool-down AR-013 refuses.

Visible change: --verbosity standard's frames[].identified listed every
actor inside the keep-alive, including ones absent from the frame. It
now lists what was matched in that frame. Minimal and xray output is
untouched -- both were already built from registry claims and never
consulted this node. No schema bump: the published extraction block
reports track_extinction_sec, a different knob that bounds
re-association and never extends a claim.

TrackRegistry::Config::extinction_sec is renamed track_extinction_sec to
match the Config field feeding it, so the grep SPEC.md asks for now
returns nothing rather than one confusing false positive.

Two targets turned out to have been silently dead, both since the
AR-007/AR-008 tracker redesign, and both for the same reason -- they
construct FaceTrackerFunc from a Config alone, a signature that stopped
existing when association moved into probability space:

- scene_preview is fixed here. It now mirrors main.cpp's construction
  order exactly (matcher, then registry, then tracker) and wires the
  registry's claims into the sink, which it was not doing. DP-001 says
  modes are front-ends that must not fork pipeline logic; this one had
  forked it and then rotted.
- sae_kpn is not fixed. Restructuring the seam so the tracker can reach
  a calibration that only exists once the matcher is built is VR-011's
  rewrite, not a patch, and presence claims do not cross the seam at all
  today. It is now behind SAE_BUILD_KPN_BINDINGS=OFF with the reason
  recorded, so `cmake --build` succeeds and the breakage is attributed
  rather than rediscovered.

That second one is worth stating plainly: VR-002 ("replay drives the
real KPN nodes, not a reimplementation") is marked Done, and the module
that makes replay possible has not compiled for some time. The .so in a
stale build/ predates the change.

Python side: the two names are gone from optimize.py, replay.py and
run_holdout_all_models.py as Config keys. anneal_sec survives as
REPLAY_LOCAL_KEYS -- it still configures replay.py's own windowing,
which is a Python reimplementation that no longer matches the sink and
is documented as such. That divergence is VR-011's.

TRACES: AR-012, AR-013 | DP-001 | SR-002
2026-08-05 16:21:15 +02:00
dtourolleandClaude Opus 5 b4318f8d9e fix: belief accumulates across frames (lazy-OR), not once
A track recognised on 318 of 385 frames was owned on none, so the truth file
named nobody while the matcher was accepting almost continuously.

The correlation discount was an annihilator rather than an attenuator. Weight
was 1 - P(same view), so once a track had one stored view every later frame of
that same face scored ~0.01 and the belief stopped moving. One observation just
over the accept threshold is logit(0.78) ~ 1.27, under the ownership bar — hence
recognised always, owned never.

Two changes, in the order they were found.

Correlated evidence is now attenuated by effective sample size,
n_eff = n / (1 + (n-1)·rho), each frame contributing the marginal gain. That has
the right shape at both ends: uncorrelated evidence accumulates linearly, and a
held pose converges on 1/rho rather than growing without bound. A constant floor
was tried first and rejected — it grows linearly forever, so a long shot could
out-argue genuinely varied evidence purely by lasting longer.

Combination is now weighted lazy-OR: P = 1 - (1-P_old)·(1-p)^w, stored as
log(1-P) so the update is additive and precision stays where it matters as P
approaches 1. Each frame is new evidence that this track is that actor, and the
belief is the probability that at least one sighting was right. It converges
faster than summing log-odds at the same effective count — 2.98 vs 2.53 after
two observations at p=0.78 — which is what a real clip needs.

Note that summing log-odds was already a correct sequential Bayesian update:
the matcher fits with prior 0.5, so logit(p) IS the per-frame log-likelihood
ratio and the running sum carries the prior forward. It was not wrong, it was
slow. What blocked ownership was the discount, not the combination rule.

Also fixes a real correctness bug: the observation count lived on the
discounter, which is shared by every track, so tracks pooled into one effective
sample and each was discounted by how many others happened to be on screen. It
is now a per-track parameter.

The registry's frame scope holds its lock for its lifetime and the mutex is not
recursive, so calling observe() inside a scope self-deadlocks. The pipeline
never does — separate nodes — but the test did, and hung rather than failing.
Documented at the call site.

Verified end to end: the same clip that produced zero actors now identifies
Bing Crosby and Dorothy Lamour with belief 0.97.

Suite: 96 cases, 6142 assertions.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

TRACES: AR-025 | SR-002
2026-07-31 16:51:08 +02:00
dtourolleandClaude Opus 5 843852e19c feat: registry owns correlation discounting (AR-024, AR-025)
Moves two responsibilities inside the registry that callers should never have
been trusted with.

AR-025 — per-frame evidence is discounted for correlation by the registry
itself, via EvidenceDiscounter. Log-odds accumulation is only valid for
independent observations, and consecutive frames of one track are anything but:
near-identical pose, lighting and expression. Accumulated naively, thirty frames
of the same face at the same angle drive the posterior to certainty on what is
effectively one measurement.

Each observation is weighted by how much it adds — a view already contributed
counts for ~nothing, a genuinely new pose counts in full. This reuses the
novelty judgement gallery expansion already makes rather than inventing a second
one. The discounter is a separate class the registry holds, so it stays testable
and swappable, but it is a constructor argument rather than an option: there is
no correct way to accumulate without it.

AR-024 — observe() takes a calibrated probability and converts to log-odds
internally. A caller can no longer hand it a raw cosine, which would have been
silently wrong rather than obviously so. Retiring the remaining raw-cosine
constants in the tracker is still open.

DeadTrack now reports effective_obs alongside observations: the raw count and
the evidence that actually counted. A large gap between them is a track the
camera stared at, and worth seeing.

Three tests, one of which is the point: two tracks given the same number of
observations at the same posterior, one repeating a single view and one seeing
eight distinct ones, must not end up equally confident. Without discounting they
would be identical.

Fixed a test that asserted a belief swap on tied evidence. A tie leaves
ownership where it is — a challenger must out-accumulate the incumbent, since
one contrary observation is noise. The original test passed only because it fed
raw log-odds directly.

Suite: 78 cases, 3245 assertions. Coverage 20/63 to 22/63.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

TRACES: AR-024, AR-025 | SR-002
2026-07-31 09:15:44 +02:00
dtourolleandClaude Opus 5 f0c7126f80 feat: TrackRegistry — presence follows track extent
The spine of the redesign. Presence is now the extent of a track an actor owns,
[first_seen, last_seen], rather than the subset of frames in which recognition
happened to succeed. An actor recognised only at the end of a long track is
present for all of it, which is what the scene-scoped ground truth actually
records.

AR-013 — `last_seen` as an optional carries the entire liveness state: unset
means on screen, set means went off at that timestamp and still revivable,
reaped means emitted and erased. No missing-frame counter, no expired flag. It
subsumes the tracker's existing two-pool split, so there is no separate revival
path — matching a dormant track is ordinary inter-frame association.

The asymmetry is the point: interior gaps are claimed, the trailing cool-down is
not. A face lost and re-associated within the timeout never closed its track, so
the gap is presence — someone briefly occluded has not left the scene. But a
track that dies ends at its last sighting, never at the death time. That is
precisely the over-claim the retired extinction_sec keep-alive produced, where
presence ran on into the closing credits.

AR-014 — a belief swap A→B closes the track and opens a successor at the swap
frame. Not a correction: two non-twins both clearing the threshold on one face
is not realistic, whereas a track_id carried across a viewpoint change onto a
different person is. Treating it as a swap-and-continue would emit one window
blending two people; treating it as a boundary yields two that are each right.

AR-015 — two live tracks owned by one actor means at least one is wrong, since a
person cannot be in two places at once. A reverse index catches it on the update
that causes it rather than by scanning. This makes identity a third cut
detector, independent of the histogram and TransNetV2 and firing where those
failed.

AR-016 — flush() closes tracks still live at EOF. Without it a film ending
mid-shot silently drops its closing cast, which presents as a recognition miss
rather than a bookkeeping bug.

Reaping hands the dead track to the aggregator and erases it, so the registry
holds only live tracks and its size is bounded by concurrent on-screen faces
rather than growing with the film.

Locking: a frame's association pass is atomic as a unit via FrameScope, since
per-call locking would let another thread observe a half-updated frame.
owner() reads tally and verdict under one lock — separately, a track could be
both unowned and owned within a single promotion decision. A vote for an
already-reaped track is dropped and counted, because a nonzero count means the
timeout is shorter than the matcher's lag.

11 unit tests, driven directly against the registry with no network and no
fixture — the awkward cases are constructed rather than hunted for. Suite: 75
cases, 3236 assertions. Coverage 14/63 to 20/63.

Not yet wired into FaceTrackerFunc; that is AR-007/AR-008.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

TRACES: AR-012, AR-013, AR-014, AR-015, AR-016, AR-017 | SR-002
2026-07-31 09:08:39 +02:00