From 1da6ae37d0091cd0c3ff9176e58a082eada39293 Mon Sep 17 00:00:00 2001
From: Kalle <38327916+Sendouc@users.noreply.github.com>
Date: Thu, 6 Aug 2026 15:27:38 +0300
Subject: [PATCH] Optimize

---
 app/features/scanner/README.md                |  42 +-
 app/features/scanner/capture/vod-frames.ts    | 104 ++---
 app/features/scanner/components/VodPage.tsx   | 386 ++++++++++++------
 app/features/scanner/components/styles.css    |  27 ++
 .../scanner/core/detectors/death/index.ts     |  11 +-
 .../scanner/core/detectors/map-start/index.ts |   7 +-
 .../scanner/core/detectors/minimap/index.ts   |   7 +-
 .../scanner/core/detectors/scheduler.ts       | 311 ++++++++++++++
 .../core/detectors/scoreboard-own/index.ts    |   7 +-
 .../core/detectors/scoreboard-replay/index.ts |   9 +-
 .../core/detectors/scoreboard/index.ts        |   8 +-
 .../scanner/core/detectors/suppressor.ts      |  83 ----
 .../scanner/core/detectors/telemetry.ts       |  85 ++++
 .../scanner/core/detectors/throttle.ts        |  24 --
 app/features/scanner/core/detectors/types.ts  |  40 +-
 app/features/scanner/tests/scheduler.test.ts  | 218 ++++++++++
 app/features/scanner/tests/suppressor.test.ts |  64 ---
 app/features/scanner/tests/throttle.test.ts   |  47 ---
 .../scanner/worker/analyzer.worker.ts         | 264 ++++++++++--
 app/features/scanner/worker/client.ts         |  98 ++++-
 app/features/scanner/worker/pool.ts           |  80 ----
 app/features/scanner/worker/protocol.ts       |  53 ++-
 package.json                                  |   1 +
 scripts/scanner/replay-frames.ts              |  82 ++++
 24 files changed, 1507 insertions(+), 551 deletions(-)
 create mode 100644 app/features/scanner/core/detectors/scheduler.ts
 delete mode 100644 app/features/scanner/core/detectors/suppressor.ts
 create mode 100644 app/features/scanner/core/detectors/telemetry.ts
 delete mode 100644 app/features/scanner/core/detectors/throttle.ts
 create mode 100644 app/features/scanner/tests/scheduler.test.ts
 delete mode 100644 app/features/scanner/tests/suppressor.test.ts
 delete mode 100644 app/features/scanner/tests/throttle.test.ts
 delete mode 100644 app/features/scanner/worker/pool.ts
 create mode 100644 scripts/scanner/replay-frames.ts

diff --git a/app/features/scanner/README.md b/app/features/scanner/README.md
index e7036c9ff..967542b6f 100644
--- a/app/features/scanner/README.md
+++ b/app/features/scanner/README.md
@@ -15,6 +15,7 @@ from the emberz repo; see `MIGRATION.md` there.
 pnpm test:scanner                       # golden-file suite over tests/fixtures/ (Vitest, Node)
 pnpm scanner:report                     # accuracy table + name character error rate across fixtures
 pnpm scanner:fixtures [name-substring]  # run detectors over matching fixtures, verbose
+pnpm scanner:replay <dir> <startT> <fps> # replay ffmpeg-extracted frames through the scheduler+detectors
 pnpm scanner:bootstrap-atlas            # harvest labeled fixture crops into the glyph atlases
 pnpm scanner:build-glyph-atlas          # add the font-rendered charset (fonts required, see below)
 pnpm scanner:build-localized-entries    # regen localized closed sets from ../splat3
@@ -38,8 +39,8 @@ sequenceDiagram
   participant UI as Live/VoD tab
   participant ING as /ingest (scanner-ingest)
   participant DB as IngestedMatch / IngestedScoreboard
-  Cap->>W: frame + t
-  W->>W: detectors gate() → parse()
+  Cap->>W: frame + t (live/screenshot/seek) — VoD: worker decodes its own slice
+  W->>W: scheduler dueDetectors() → gate() → parse()
   W-->>TL: DetectedEvents
   TL-->>UI: deduped timeline (IndexedDB on Live)
   UI->>MB: buildScannerMatches(events)
@@ -91,13 +92,36 @@ sequenceDiagram
   accuracy-critical matching internals in `core/glyphs.ts` and
   `core/detectors/scoreboard/weapons.ts` — read those before touching
   recognition code.
-- A detector can declare `checkIntervalS` (objective: 1s) to cap how often
-  it is checked at all — the analyzer worker skips gate+parse in between
-  (`core/detectors/throttle.ts`) and exempts it from steady-frame
-  suppression — and `attachFrame: false` to keep continuously-firing events
-  from storing a frame PNG each. In the UI a match's objective reads render
-  as one step-line timeline (`components/ObjectiveTimeline.tsx`) instead of
-  per-event cards.
+- Scheduling (`core/detectors/scheduler.ts`): per scan session the
+  DetectorScheduler decides which detectors look at a frame. While a gate
+  keeps failing its detector is checked every `searchIntervalS` (default
+  0.25s — produced/casted VoDs cut screens to ~1s with transition flicker
+  inside, so search cadence must not assume raw-gameplay screen lifetimes;
+  gates are ~ms-cheap, so this costs little); once the gate passes it
+  drops to the dense refine cadence for best-read refinement. Suppression ends a refinement streak
+  once it stagnates by parse count AND elapsed time (~3s — the time floor
+  keeps a dense cadence from suppressing during a screen's entry animation
+  before it is readable) or immediately at `sufficientConfidence`; death
+  adds `rearmCooldownS` (safe because it fits inside the Death timeline
+  merge window). `checkIntervalS` (objective: 1s)
+  still hard-caps both phases and exempts from suppression; a detector can
+  also declare `attachFrame: false` to keep continuously-firing events from
+  storing a frame PNG each. In the UI a match's objective reads render as
+  one step-line timeline (`components/ObjectiveTimeline.tsx`) instead of
+  per-event cards. Frames no detector is due for skip canvas readback
+  entirely, and everything is counted in `core/detectors/telemetry.ts`
+  (surfaced in the VoD tab's telemetry panel).
+- VoD scans (`components/VodPage.tsx`): on the WebCodecs path the file's
+  duration is split into one contiguous slice per worker and each worker
+  demuxes + decodes its slice itself (mediabunny in the worker — no frames
+  cross the main thread). When the scheduler reports calm (no gate pass for
+  a quiet period, no open match — a confident map-start pins the scan
+  active until a scoreboard or timeout), the worker stops sequential decode
+  and skims keyframe-to-keyframe (single-frame decodes, hop capped at 2.5s
+  so short screens can't hide), snapping back to dense decode on any gate
+  pass. Chunks start dense, so slice boundaries are covered. The seek
+  fallback drives one worker and widens its stride over calm footage the
+  same way.
 - Recognition is language-agnostic: OCR output snaps against every game
   language at once (`core/localized-entries.ts`, generated) and events carry
   sendou ids. English display names come from `components/labels.ts`.
diff --git a/app/features/scanner/capture/vod-frames.ts b/app/features/scanner/capture/vod-frames.ts
index c8e7c5051..564b1883f 100644
--- a/app/features/scanner/capture/vod-frames.ts
+++ b/app/features/scanner/capture/vod-frames.ts
@@ -1,45 +1,27 @@
 /**
- * VoD frame extraction: step through a video file yielding (frame, t) as
- * fast as decoding allows — no real-time playback. The primary path demuxes
- * the file and decodes **every frame** sequentially with WebCodecs (via
- * mediabunny), yielding the VideoFrames themselves (transferable to the
- * analyzer workers with no main-thread conversion); when the container/codec
- * can't be read that way, it falls back to seek-stepping a <video> element
- * at a small fixed step, which handles anything the browser can play at the
- * cost of per-seek latency and frame-exact coverage.
+ * VoD scan entry points. The primary path probes whether WebCodecs (via
+ * mediabunny) can decode the file — if so, the analyzer workers each demux
+ * and decode their own time slice of it (worker/analyzer.worker.ts) and no
+ * frames cross the main thread at all. When the container/codec can't be
+ * read that way, the fallback seek-steps a <video> element, which handles
+ * anything the browser can play at the cost of per-seek latency; its stride
+ * is supplied per step so the caller can widen it over calm footage.
  */
-import { ALL_FORMATS, BlobSource, Input, VideoSampleSink } from "mediabunny";
-
-/**
- * Seek fallback step: a <video> element can't enumerate frames, so seek in
- * increments small enough that anything but blink-and-miss overlays is caught.
- */
-const SEEK_STEP_SECONDS = 0.25;
+import { ALL_FORMATS, BlobSource, Input } from "mediabunny";
 
 interface VodFrame {
 	/** the consumer owns the frame and must close() it */
-	frame: ImageBitmap | VideoFrame;
+	frame: ImageBitmap;
 	/** seconds into the video */
 	t: number;
 }
 
-export interface VodScan {
-	method: "webcodecs" | "seek";
-	duration: number;
-	frames: AsyncGenerator<VodFrame>;
-	dispose(): void;
-}
-
 /**
- * Open a scan over `file`, yielding every decoded frame (or, on the seek
- * fallback, one frame every SEEK_STEP_SECONDS). `video` must already have
- * the file loaded (metadata not required yet); it is only driven by the
- * seek fallback.
+ * Whether mediabunny + WebCodecs can decode `file`, and its duration if so.
  */
-export async function openVodScan(
+export async function probeWebCodecs(
 	file: File,
-	video: HTMLVideoElement,
-): Promise<VodScan> {
+): Promise<{ duration: number } | null> {
 	const input = new Input({
 		formats: ALL_FORMATS,
 		source: new BlobSource(file),
@@ -47,52 +29,40 @@ export async function openVodScan(
 	try {
 		const track = await input.getPrimaryVideoTrack();
 		if (track && (await track.canDecode())) {
-			const duration = await input.computeDuration([track]);
-			return {
-				method: "webcodecs",
-				duration,
-				frames: webCodecsFrames(input, new VideoSampleSink(track)),
-				dispose: () => input.dispose(),
-			};
+			return { duration: await input.computeDuration([track]) };
 		}
-		input.dispose();
+		return null;
 	} catch {
-		input.dispose();
-	}
-
-	await loadMetadata(video);
-	if (!Number.isFinite(video.duration)) {
-		throw new Error("video has no known duration — cannot scan by seeking");
-	}
-	return {
-		method: "seek",
-		duration: video.duration,
-		frames: seekFrames(video),
-		dispose: () => {},
-	};
-}
-
-async function* webCodecsFrames(
-	input: Input,
-	sink: VideoSampleSink,
-): AsyncGenerator<VodFrame> {
-	try {
-		for await (const sample of sink.samples()) {
-			if (!sample) continue;
-			const t = sample.timestamp;
-			const frame = sample.toVideoFrame();
-			sample.close();
-			yield { frame, t };
-		}
+		return null;
 	} finally {
 		input.dispose();
 	}
 }
 
-async function* seekFrames(video: HTMLVideoElement): AsyncGenerator<VodFrame> {
-	for (let t = 0; t < video.duration; t += SEEK_STEP_SECONDS) {
+/**
+ * Open a seek-stepping scan over `video` (which must already have the file
+ * loaded; metadata is awaited here). `nextStrideS` is consulted after every
+ * yielded frame, so analysis feedback can adjust the step on the fly.
+ */
+export async function openSeekScan(
+	video: HTMLVideoElement,
+	nextStrideS: () => number,
+): Promise<{ duration: number; frames: AsyncGenerator<VodFrame> }> {
+	await loadMetadata(video);
+	if (!Number.isFinite(video.duration)) {
+		throw new Error("video has no known duration — cannot scan by seeking");
+	}
+	return { duration: video.duration, frames: seekFrames(video, nextStrideS) };
+}
+
+async function* seekFrames(
+	video: HTMLVideoElement,
+	nextStrideS: () => number,
+): AsyncGenerator<VodFrame> {
+	for (let t = 0; t < video.duration; ) {
 		await seekTo(video, t);
 		yield { frame: await createImageBitmap(video), t };
+		t += Math.max(0.01, nextStrideS());
 	}
 }
 
diff --git a/app/features/scanner/components/VodPage.tsx b/app/features/scanner/components/VodPage.tsx
index ffb886cba..fd960a908 100644
--- a/app/features/scanner/components/VodPage.tsx
+++ b/app/features/scanner/components/VodPage.tsx
@@ -1,25 +1,30 @@
 /**
  * VoD tab: load a video file and scan it for scoreboard matches as fast as
- * decoding allows — no real-time playback (see src/capture/vod-frames.ts).
- * Every frame is decoded and handed to a pool of analyzer workers; decode
- * never waits on analysis (a frame arriving while all workers are busy is
- * dropped — the next is ~1/60s away), so the scan runs at decode speed and
- * analysis coverage stays as dense as the machine keeps up with — dense
- * enough that even overlays visible for a fraction of a second are seen.
- * Each match can be opened in the screenshot page with the exact frame
- * that was analyzed.
+ * decoding allows — no real-time playback. On the primary (WebCodecs) path
+ * the file's duration is split into one contiguous slice per analyzer
+ * worker and each worker demuxes, decodes, schedules and analyzes its slice
+ * by itself (worker/analyzer.worker.ts): no frames cross the main thread,
+ * scheduling state is exact per slice, and calm stretches are skimmed by
+ * keyframe hops instead of decoded frame-by-frame. The seek fallback drives
+ * a <video> element through a single worker, widening its stride over calm
+ * footage. Each match can be opened in the screenshot page with the exact
+ * frame that was analyzed.
  *
  * Completed scans are persisted to IndexedDB keyed by file name
  * (src/store/vods.ts); the default view lists them for reinspection.
  */
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import { Link } from "react-router";
-import { openVodScan } from "../capture/vod-frames";
+import { openSeekScan, probeWebCodecs } from "../capture/vod-frames";
 import { connectAbilities } from "../core/ability-harvest";
 import {
 	OBJECTIVE_EVENT_TYPE,
 	type ObjectiveData,
 } from "../core/detectors/objective/index";
+import {
+	mergeScanTelemetry,
+	type ScanTelemetry,
+} from "../core/detectors/telemetry";
 import type { DetectedEvent } from "../core/detectors/types";
 import {
 	buildScannerMatches,
@@ -36,7 +41,11 @@ import {
 	saveVod,
 	type VodSummary,
 } from "../store/vods";
-import { AnalyzerPool, defaultPoolSize } from "../worker/pool";
+import {
+	AnalyzerClient,
+	type DoneInfo,
+	defaultScanWorkerCount,
+} from "../worker/client";
 import { withoutRepeatEvents } from "./dedupe-events";
 import { EventCard, type GetFrame } from "./EventCard";
 import { EventsSummary } from "./EventsSummary";
@@ -55,16 +64,14 @@ import {
 import { sendouUpload } from "./sendou-upload";
 import { thumbnailFromBlob } from "./thumbnail";
 
+/** seek-fallback stride while the worker reports activity */
+const SEEK_ACTIVE_STRIDE_S = 0.25;
 /**
- * Hard coverage floor: at most this much video may pass between two analyzed
- * frames. Busy-dropping alone is not enough — around match results every
- * gate fires and each analyzed frame runs a full parse (+ PNG encode), so
- * the whole pool can stay busy for hundreds of ms while decode races ahead
- * whole seconds of video; short screens (the own-results screen shows ~3s)
- * then fall into the gap. When the budget is spent and no worker is free,
- * decode waits.
+ * seek-fallback stride over calm footage (nothing detected for a while, no
+ * match open) — small enough that the screens that can start activity from
+ * dead air (results ~10s, match intro ~7s) still get sampled
  */
-const MAX_ANALYSIS_GAP_SECONDS = 0.25;
+const SEEK_CALM_STRIDE_S = 2.5;
 
 type Status = "idle" | "scanning" | "done" | "error";
 
@@ -108,7 +115,12 @@ export function VodPage({
 }) {
 	const videoRef = useRef<HTMLVideoElement>(null);
 	const previewRef = useRef<HTMLCanvasElement>(null);
-	const poolRef = useRef<AnalyzerPool | null>(null);
+	const clientsRef = useRef<AnalyzerClient[]>([]);
+	// cancels the in-flight chunk scans of the previous scan, if any
+	const abortScanRef = useRef<(() => void) | null>(null);
+	// seek fallback: latest per-frame done info + the waiter for the next one
+	const doneInfoRef = useRef<DoneInfo | null>(null);
+	const frameDoneRef = useRef<(() => void) | null>(null);
 	const timelineRef = useRef(new TimelineBuilder());
 	// latest gate score from any worker; flushed to state on the UI throttle
 	const gateScoreRef = useRef<number | null>(null);
@@ -131,6 +143,7 @@ export function VodPage({
 	const [matches, setMatches] = useState<VodMatch[]>([]);
 	const [vods, setVods] = useState<VodSummary[]>([]);
 	const [error, setError] = useState<string | null>(null);
+	const [telemetry, setTelemetry] = useState<ScanTelemetry | null>(null);
 	const [over, setOver] = useState(false);
 	const [eventsOpen, setEventsOpen] = useState(false);
 	const [resultsSend, setResultsSend] = useState<ResultsSend | null>(null);
@@ -207,7 +220,9 @@ export function VodPage({
 		void refreshVods();
 		return () => {
 			abortRef.current.aborted = true;
-			poolRef.current?.dispose();
+			abortScanRef.current?.();
+			for (const client of clientsRef.current) client.dispose();
+			clientsRef.current = [];
 			if (urlRef.current) URL.revokeObjectURL(urlRef.current);
 		};
 	}, [refreshVods]);
@@ -215,10 +230,12 @@ export function VodPage({
 	const scan = useCallback(
 		async (file: File) => {
 			abortRef.current.aborted = true;
+			abortScanRef.current?.();
 			const abort = { aborted: false };
 			abortRef.current = abort;
 
 			setError(null);
+			setTelemetry(null);
 			setMatches([]);
 			setResultsSend(null);
 			setEventsOpen(false);
@@ -229,7 +246,6 @@ export function VodPage({
 			setSource("scan");
 			setStatus("scanning");
 
-			let dispose = () => {};
 			try {
 				// the element is used by the seek fallback and for post-scan review
 				const video = videoRef.current!;
@@ -237,109 +253,83 @@ export function VodPage({
 				urlRef.current = URL.createObjectURL(file);
 				video.src = urlRef.current;
 
-				poolRef.current ??= new AnalyzerPool(
-					defaultPoolSize(),
-					(result) => {
-						gateScoreRef.current = result.gate.score;
-						if (!result.gate.pass) return;
-						for (const event of result.events as DetectedEvent<FixtureData>[]) {
-							const action = timelineRef.current.push(event);
-							if (action.action !== "added" && action.action !== "replaced")
-								continue;
-							const frame = result.frame;
-							sideWorkRef.current.push(
-								(async () => {
-									const thumbnail = frame
-										? await thumbnailFromBlob(frame)
-										: undefined;
-									const replaced =
-										action.action === "replaced"
-											? matchesRef.current.find(
-													(m) => m.event === action.replaced,
-												)
-											: undefined;
-									const next = matchesRef.current.filter((m) => m !== replaced);
-									next.push({
-										event,
-										key: replaced?.key ?? nextMatchKeyRef.current++,
-										thumbnail,
-										frame,
-									});
-									next.sort((a, b) => a.event.t - b.event.t);
-									matchesRef.current = next;
-									setMatches(next);
-								})().catch(() => {}),
-							);
-						}
-					},
-					(message) => {
-						setError(message);
-						setStatus("error");
-					},
-				);
-				const pool = poolRef.current;
-				await pool.whenReady();
-				// let frames still in flight from an aborted scan finish before the
-				// timeline resets, so their results can't bleed into this scan
-				await pool.whenIdle();
+				if (clientsRef.current.length === 0) {
+					clientsRef.current = Array.from(
+						{ length: defaultScanWorkerCount() },
+						() =>
+							new AnalyzerClient(
+								(result) => {
+									gateScoreRef.current = result.gate.score;
+									if (!result.gate.pass) return;
+									for (const event of result.events as DetectedEvent<FixtureData>[]) {
+										const action = timelineRef.current.push(event);
+										if (
+											action.action !== "added" &&
+											action.action !== "replaced"
+										)
+											continue;
+										const frame = result.frame;
+										sideWorkRef.current.push(
+											(async () => {
+												const thumbnail = frame
+													? await thumbnailFromBlob(frame)
+													: undefined;
+												const replaced =
+													action.action === "replaced"
+														? matchesRef.current.find(
+																(m) => m.event === action.replaced,
+															)
+														: undefined;
+												const next = matchesRef.current.filter(
+													(m) => m !== replaced,
+												);
+												next.push({
+													event,
+													key: replaced?.key ?? nextMatchKeyRef.current++,
+													thumbnail,
+													frame,
+												});
+												next.sort((a, b) => a.event.t - b.event.t);
+												matchesRef.current = next;
+												setMatches(next);
+											})().catch(() => {}),
+										);
+									}
+								},
+								(message) => {
+									frameDoneRef.current?.();
+									frameDoneRef.current = null;
+									setError(message);
+									setStatus("error");
+								},
+								(_t, info: DoneInfo) => {
+									doneInfoRef.current = info;
+									frameDoneRef.current?.();
+									frameDoneRef.current = null;
+								},
+							),
+					);
+				}
+				const clients = clientsRef.current;
+				await Promise.all(clients.map((c) => c.whenReady()));
+				// let work still in flight from an aborted scan finish before the
+				// timeline resets, so its results can't bleed into this scan
+				await Promise.all(clients.map((c) => c.whenIdle()));
 				if (abort.aborted) return;
 				matchesRef.current = [];
 				sideWorkRef.current = [];
 				timelineRef.current = new TimelineBuilder();
 
-				const vod = await openVodScan(file, video);
-				dispose = () => vod.dispose();
-				if (abort.aborted) return;
-				setMethod(vod.method);
-
 				const started = performance.now();
-				// each frame goes to an idle worker; with none free it is dropped
-				// unless MAX_ANALYSIS_GAP_SECONDS of video has passed unanalyzed,
-				// in which case decode waits for a worker. Preview/progress
-				// re-renders are throttled off the hot loop (the preview draw must
-				// precede tryAnalyze — transferring the frame to a worker detaches it).
-				let lastUiUpdate = Number.NEGATIVE_INFINITY;
-				let lastAnalyzedT = Number.NEGATIVE_INFINITY;
-				for await (const { frame, t } of vod.frames) {
-					if (abort.aborted) {
-						frame.close();
-						break;
-					}
-					const now = performance.now();
-					if (now - lastUiUpdate >= 250) {
-						lastUiUpdate = now;
-						drawPreview(previewRef.current, frame);
-						setGateScore(gateScoreRef.current);
-						const elapsed = (now - started) / 1000;
-						setProgress({
-							t,
-							duration: vod.duration,
-							rate: elapsed > 0 ? t / elapsed : 0,
-						});
-					}
-					if (!pool.hasIdle()) {
-						if (t - lastAnalyzedT < MAX_ANALYSIS_GAP_SECONDS) {
-							frame.close();
-							continue;
-						}
-						await pool.whenAnyIdle();
-						if (abort.aborted) {
-							frame.close();
-							break;
-						}
-					}
-					pool.tryAnalyze(frame, t);
-					lastAnalyzedT = t;
-				}
-				await pool.whenIdle();
-				await Promise.all(sideWorkRef.current);
-				if (!abort.aborted) {
+				const finalize = async (duration: number) => {
+					await Promise.all(sideWorkRef.current);
+					if (abort.aborted) return;
 					matchesRef.current = withoutInvalidObjectives(matchesRef.current);
 					setMatches(matchesRef.current);
-					setProgress((p) => (p ? { ...p, t: vod.duration } : p));
+					setProgress((p) => (p ? { ...p, t: duration } : p));
 					setStatus("done");
 					await saveVod(
-						{ name: file.name, savedAt: Date.now(), duration: vod.duration },
+						{ name: file.name, savedAt: Date.now(), duration },
 						matchesRef.current.map((m) => ({
 							type: m.event.type,
 							t: m.event.t,
@@ -350,14 +340,126 @@ export function VodPage({
 						})),
 					);
 					await refreshVods();
+				};
+
+				const probe = await probeWebCodecs(file);
+				if (abort.aborted) return;
+
+				if (probe) {
+					// each worker demuxes, decodes and analyzes its own slice of
+					// the file; the main thread only aggregates progress
+					setMethod("webcodecs");
+					const { duration } = probe;
+					const chunkSpan = duration / clients.length;
+					const chunks = clients.map((client, i) => ({
+						client,
+						tStart: i * chunkSpan,
+						tEnd: i === clients.length - 1 ? duration : (i + 1) * chunkSpan,
+						t: i * chunkSpan,
+						done: false,
+						telemetry: null as ScanTelemetry | null,
+					}));
+					abortScanRef.current = () => {
+						for (const client of clients) client.abortChunk();
+					};
+					const mergedTelemetry = () =>
+						mergeScanTelemetry(
+							chunks.flatMap((c) => (c.telemetry ? [c.telemetry] : [])),
+						);
+					let lastUiUpdate = Number.NEGATIVE_INFINITY;
+					const pushUiUpdate = () => {
+						const now = performance.now();
+						if (now - lastUiUpdate < 250) return;
+						lastUiUpdate = now;
+						const covered = chunks.reduce(
+							(sum, c) => sum + (Math.min(c.t, c.tEnd) - c.tStart),
+							0,
+						);
+						const elapsed = (now - started) / 1000;
+						setGateScore(gateScoreRef.current);
+						setProgress({
+							t: covered,
+							duration,
+							rate: elapsed > 0 ? covered / elapsed : 0,
+						});
+						setTelemetry(mergedTelemetry());
+					};
+					await Promise.all(
+						chunks.map((chunk, chunkIndex) =>
+							chunk.client
+								.scanChunk(
+									{ file, chunkIndex, tStart: chunk.tStart, tEnd: chunk.tEnd },
+									(progress) => {
+										chunk.t = progress.t;
+										chunk.telemetry = progress.telemetry;
+										if (progress.preview) {
+											// show one chunk at a time: the earliest still running
+											if (chunks.find((c) => !c.done) === chunk) {
+												drawPreview(previewRef.current, progress.preview);
+											}
+											progress.preview.close();
+										}
+										pushUiUpdate();
+									},
+								)
+								.then((chunkTelemetry) => {
+									chunk.done = true;
+									chunk.t = chunk.tEnd;
+									chunk.telemetry = chunkTelemetry;
+								}),
+						),
+					);
+					if (abort.aborted) return;
+					setTelemetry(mergedTelemetry());
+					await finalize(duration);
+					return;
 				}
+
+				// seek fallback: one worker, one frame in flight; the worker's calm
+				// signal widens the stride over dead air
+				setMethod("seek");
+				const strideRef = { current: SEEK_ACTIVE_STRIDE_S };
+				const vod = await openSeekScan(video, () => strideRef.current);
+				if (abort.aborted) return;
+				const client = clients[0]!;
+				let lastUiUpdate = Number.NEGATIVE_INFINITY;
+				for await (const { frame, t } of vod.frames) {
+					if (abort.aborted) {
+						frame.close();
+						break;
+					}
+					const now = performance.now();
+					if (now - lastUiUpdate >= 250) {
+						lastUiUpdate = now;
+						// the preview draw must precede analyze — transferring the
+						// frame to the worker detaches it
+						drawPreview(previewRef.current, frame);
+						setGateScore(gateScoreRef.current);
+						const elapsed = (now - started) / 1000;
+						setProgress({
+							t,
+							duration: vod.duration,
+							rate: elapsed > 0 ? t / elapsed : 0,
+						});
+						if (doneInfoRef.current)
+							setTelemetry(doneInfoRef.current.telemetry);
+					}
+					await new Promise<void>((resolve) => {
+						frameDoneRef.current = resolve;
+						if (!client.analyze(frame, t)) resolve();
+					});
+					strideRef.current = doneInfoRef.current?.calm
+						? SEEK_CALM_STRIDE_S
+						: SEEK_ACTIVE_STRIDE_S;
+				}
+				if (doneInfoRef.current) setTelemetry(doneInfoRef.current.telemetry);
+				await finalize(vod.duration);
 			} catch (e) {
 				if (!abort.aborted) {
+					abortScanRef.current?.();
 					setError(String(e));
 					setStatus("error");
 				}
-			} finally {
-				dispose();
 			}
 		},
 		[refreshVods],
@@ -365,6 +467,8 @@ export function VodPage({
 
 	const openStored = useCallback(async (name: string) => {
 		abortRef.current.aborted = true;
+		abortScanRef.current?.();
+		setTelemetry(null);
 		try {
 			const events = await loadVodEvents(name);
 			// VoDs saved before objective reads were mode-gated may carry them
@@ -408,6 +512,8 @@ export function VodPage({
 
 	const backToList = useCallback(() => {
 		abortRef.current.aborted = true;
+		abortScanRef.current?.();
+		setTelemetry(null);
 		matchesRef.current = [];
 		setMatches([]);
 		setResultsSend(null);
@@ -534,6 +640,9 @@ export function VodPage({
 				)}
 			</div>
 			{error && <p className="error">{error}</p>}
+			{showVodView && telemetry ? (
+				<TelemetryPanel telemetry={telemetry} />
+			) : null}
 			{!showVodView && (
 				<div className="vod-list">
 					{vods.length === 0 && (
@@ -689,6 +798,51 @@ function frameLoader(m: VodMatch): GetFrame | undefined {
 			: undefined;
 }
 
+function TelemetryPanel({ telemetry }: { telemetry: ScanTelemetry }) {
+	const detectors = Object.entries(telemetry.detectors).sort(([a], [b]) =>
+		a.localeCompare(b),
+	);
+	const coveredS = telemetry.activeVideoS + telemetry.skimVideoS;
+	return (
+		<details className="telemetry">
+			<summary>
+				telemetry · analyzed {telemetry.analyzedFrames}/
+				{telemetry.decodedFrames} decoded frames
+				{coveredS > 0 &&
+					` · skimmed ${formatTime(telemetry.skimVideoS)} of ${formatTime(coveredS)}`}
+				{telemetry.wallMs > 0 &&
+					` · ${formatTime(telemetry.wallMs / 1000)} cpu`}
+			</summary>
+			<table>
+				<thead>
+					<tr>
+						<th>detector</th>
+						<th>checks</th>
+						<th>gate pass</th>
+						<th>gate ms</th>
+						<th>parses</th>
+						<th>parse ms</th>
+						<th>suppressed</th>
+					</tr>
+				</thead>
+				<tbody>
+					{detectors.map(([id, d]) => (
+						<tr key={id}>
+							<td>{id}</td>
+							<td>{d.checks}</td>
+							<td>{d.gatePasses}</td>
+							<td>{Math.round(d.gateMs)}</td>
+							<td>{d.parses}</td>
+							<td>{Math.round(d.parseMs)}</td>
+							<td>{d.suppressedParses}</td>
+						</tr>
+					))}
+				</tbody>
+			</table>
+		</details>
+	);
+}
+
 function drawPreview(
 	canvas: HTMLCanvasElement | null,
 	frame: ImageBitmap | VideoFrame,
diff --git a/app/features/scanner/components/styles.css b/app/features/scanner/components/styles.css
index 5aa12c845..b5e43d460 100644
--- a/app/features/scanner/components/styles.css
+++ b/app/features/scanner/components/styles.css
@@ -1066,6 +1066,33 @@ html.light {
 	padding: 10px 12px;
 }
 
+.scanner-app .telemetry {
+	margin: 8px 0;
+	font-size: var(--font-2xs);
+	color: var(--color-text-high);
+}
+
+.scanner-app .telemetry summary {
+	cursor: pointer;
+}
+
+.scanner-app .telemetry table {
+	margin-top: 6px;
+	border-collapse: collapse;
+}
+
+.scanner-app .telemetry table th,
+.scanner-app .telemetry table td {
+	padding: 2px 10px 2px 0;
+	text-align: right;
+	font-variant-numeric: tabular-nums;
+}
+
+.scanner-app .telemetry table th:first-child,
+.scanner-app .telemetry table td:first-child {
+	text-align: left;
+}
+
 @media (prefers-reduced-motion: reduce) {
 	.scanner-app .match-card,
 	.scanner-app .match-card.sending::after,
diff --git a/app/features/scanner/core/detectors/death/index.ts b/app/features/scanner/core/detectors/death/index.ts
index 5eae40a56..11b7cced7 100644
--- a/app/features/scanner/core/detectors/death/index.ts
+++ b/app/features/scanner/core/detectors/death/index.ts
@@ -820,5 +820,14 @@ export function createDeathDetector(
 		];
 	}
 
-	return { id: "death", gate, parse };
+	// the death cam's animated background flickers the gate; after a
+	// sufficient read the 4s rearm hold stays inside the timeline's 8s
+	// Death merge window, so every parse it skips would merge anyway
+	return {
+		id: "death",
+		sufficientConfidence: 0.98,
+		rearmCooldownS: 4,
+		gate,
+		parse,
+	};
 }
diff --git a/app/features/scanner/core/detectors/map-start/index.ts b/app/features/scanner/core/detectors/map-start/index.ts
index d0d036935..8e5d8b54f 100644
--- a/app/features/scanner/core/detectors/map-start/index.ts
+++ b/app/features/scanner/core/detectors/map-start/index.ts
@@ -365,5 +365,10 @@ export function createMapStartDetector(
 		];
 	}
 
-	return { id: "map-start", gate, parse };
+	return {
+		id: "map-start",
+		sufficientConfidence: 0.98,
+		gate,
+		parse,
+	};
 }
diff --git a/app/features/scanner/core/detectors/minimap/index.ts b/app/features/scanner/core/detectors/minimap/index.ts
index ca97a0c85..845753bb8 100644
--- a/app/features/scanner/core/detectors/minimap/index.ts
+++ b/app/features/scanner/core/detectors/minimap/index.ts
@@ -639,5 +639,10 @@ export function createMinimapDetector(
 		];
 	}
 
-	return { id: "minimap", gate, parse };
+	return {
+		id: "minimap",
+		sufficientConfidence: 0.98,
+		gate,
+		parse,
+	};
 }
diff --git a/app/features/scanner/core/detectors/scheduler.ts b/app/features/scanner/core/detectors/scheduler.ts
new file mode 100644
index 000000000..729ac9535
--- /dev/null
+++ b/app/features/scanner/core/detectors/scheduler.ts
@@ -0,0 +1,311 @@
+/**
+ * DetectorScheduler: one temporally-ordered scan session's answer to "which
+ * detectors should look at the frame at time t, and which of those should
+ * pay for a parse?". It folds together three ideas:
+ *
+ * - Cadence. While a detector's gate keeps failing it is checked every
+ *   `searchIntervalS` (default 0.25s — produced VoDs cut screens to as
+ *   little as ~1s with transition flicker inside that, so the search
+ *   cadence must not assume raw-gameplay screen lifetimes; gates are
+ *   ~1.6ms, so searching at the analysis floor costs nothing). Once the
+ *   gate passes it drops to the dense `refineIntervalS` so the best-read
+ *   refinement loop still sees every frame it wants. `checkIntervalS`
+ *   (objective counter) remains a hard cap on both phases and exempts the
+ *   detector from suppression, as before. `nextDueT()` lets the caller
+ *   skip a frame's canvas readback + normalize entirely when no detector
+ *   is due.
+ *
+ * - Suppression. A static screen that keeps a gate firing stops paying for
+ *   parses once a streak stagnates: at least `maxStagnantParses`
+ *   consecutive parses AND `stagnantAfterS` seconds without the best
+ *   confidence improving. The time floor matters — a gate often fires
+ *   during a screen's entry animation while parses still read nothing, and
+ *   at a dense sampling cadence a pure parse count would suppress before
+ *   the screen ever becomes readable (with the gate held high, it would
+ *   then never re-arm). A parse reaching the detector's
+ *   `sufficientConfidence` suppresses immediately: the timeline keeps the
+ *   best read per merge window, so once a read is that good further parses
+ *   cannot change the outcome. A
+ *   detector with `rearmCooldownS` (death: the overlay's animated
+ *   background makes its gate flicker) additionally skips parses for that
+ *   long after a sufficient read, across gate drops; safe only where the
+ *   timeline merges purely on time and the cooldown fits inside the merge
+ *   window.
+ *
+ * - Activity. The scheduler tracks when any gate last passed and whether a
+ *   match is open (a confident map-start without a closing scoreboard), so
+ *   the VoD chunk scanner can tell dead air ("calm") from footage that
+ *   deserves dense decoding.
+ *
+ * All state is keyed to the scan's own clock; a `t` jumping backwards means
+ * a new capture session or rescan and resets everything.
+ */
+
+import type { DetectedEvent } from "./types";
+
+export interface SchedulingInfo {
+	id: string;
+	checkIntervalS?: number;
+	searchIntervalS?: number;
+	sufficientConfidence?: number;
+	rearmCooldownS?: number;
+}
+
+export interface SchedulerOptions {
+	/**
+	 * false = one-shot harness mode: every detector is due on every frame and
+	 * parses are never suppressed
+	 */
+	suppressSteadyFrames: boolean;
+	/** check cadence while a detector's gate is passing */
+	refineIntervalS: number;
+	/** check cadence while a detector's gate is failing (per-detector
+	 * searchIntervalS overrides) */
+	searchIntervalS: number;
+	/** consecutive non-improving parses tolerated before suppression */
+	maxStagnantParses: number;
+	/** seconds without improvement tolerated before suppression */
+	stagnantAfterS: number;
+	/** minimum confidence gain that counts as an improvement */
+	minImprovement: number;
+	/** seconds without any gate pass before the scan counts as calm */
+	quietAfterS: number;
+	/** a match opened this long ago without closing is assumed abandoned */
+	matchOpenMaxS: number;
+	/** event types that open a match (map-start) */
+	matchOpeningTypes: readonly string[];
+	/** event types that close a match (the scoreboard family) */
+	matchClosingTypes: readonly string[];
+}
+
+const DEFAULT_SCHEDULER_OPTIONS: SchedulerOptions = {
+	suppressSteadyFrames: true,
+	refineIntervalS: 0.15,
+	searchIntervalS: 0.25,
+	maxStagnantParses: 6,
+	// give a screen ~3s to animate in and produce its best read, whatever
+	// the sampling cadence
+	stagnantAfterS: 3,
+	minImprovement: 0.001,
+	quietAfterS: 15,
+	matchOpenMaxS: 8 * 60,
+	matchOpeningTypes: [],
+	matchClosingTypes: [],
+};
+
+/** events below this are too dubious to drive match-open/close state */
+const MATCH_STATE_MIN_CONFIDENCE = 0.6;
+
+/** tolerated backwards jitter in t before the session counts as restarted */
+const RESET_TOLERANCE_S = 5;
+
+const INTERVAL_EPSILON_S = 1e-6;
+
+interface StreakState {
+	best: number;
+	stagnant: number;
+	lastImprovementT: number;
+	suppressed: boolean;
+}
+
+interface DetectorState {
+	info: SchedulingInfo;
+	lastCheckT: number | undefined;
+	gatePassing: boolean;
+	streak: StreakState | null;
+	/** parses skipped until this t after a sufficient read (rearmCooldownS) */
+	parseHoldUntilT: number;
+}
+
+export class DetectorScheduler {
+	#options: SchedulerOptions;
+	#states = new Map<string, DetectorState>();
+	#maxT = Number.NEGATIVE_INFINITY;
+	#lastActivityT = Number.NEGATIVE_INFINITY;
+	#matchOpenUntilT = Number.NEGATIVE_INFINITY;
+
+	constructor(
+		detectors: readonly SchedulingInfo[],
+		options: Partial<SchedulerOptions> = {},
+	) {
+		this.#options = { ...DEFAULT_SCHEDULER_OPTIONS, ...options };
+		for (const info of detectors) {
+			this.#states.set(info.id, freshState(info));
+		}
+	}
+
+	/** Drop all session state; `t` seeds the activity clock (chunk start). */
+	reset(t = Number.NEGATIVE_INFINITY): void {
+		for (const [id, state] of this.#states) {
+			this.#states.set(id, freshState(state.info));
+		}
+		this.#maxT = t;
+		this.#lastActivityT = t;
+		this.#matchOpenUntilT = Number.NEGATIVE_INFINITY;
+	}
+
+	/**
+	 * Earliest t at which any detector wants a check — frames before it can
+	 * skip analysis (and its canvas readback) entirely.
+	 */
+	nextDueT(): number {
+		let next = Number.POSITIVE_INFINITY;
+		for (const state of this.#states.values()) {
+			if (state.lastCheckT === undefined) return Number.NEGATIVE_INFINITY;
+			next = Math.min(next, state.lastCheckT + this.#interval(state));
+		}
+		return next;
+	}
+
+	/** Detector ids that should gate the frame at `t`. */
+	dueDetectors(t: number): string[] {
+		if (t + RESET_TOLERANCE_S < this.#maxT) this.reset(t);
+		// the first frame seeds the activity clock so a fresh session is never
+		// instantly calm — it has to earn its quiet period first
+		if (this.#lastActivityT === Number.NEGATIVE_INFINITY) {
+			this.#lastActivityT = t;
+		}
+		this.#maxT = Math.max(this.#maxT, t);
+		const due: string[] = [];
+		for (const [id, state] of this.#states) {
+			if (state.lastCheckT === undefined) {
+				due.push(id);
+				continue;
+			}
+			if (t - state.lastCheckT >= this.#interval(state) - INTERVAL_EPSILON_S) {
+				due.push(id);
+			}
+		}
+		return due;
+	}
+
+	/** Report a gate outcome for a detector this scheduler marked due. */
+	recordGate(id: string, t: number, pass: boolean): void {
+		const state = this.#states.get(id);
+		if (!state) return;
+		state.lastCheckT = t;
+		state.gatePassing = pass;
+		if (pass) {
+			this.#lastActivityT = Math.max(this.#lastActivityT, t);
+		} else {
+			state.streak = null;
+		}
+	}
+
+	/** Whether the (passed) gate should be followed by a parse at `t`. */
+	shouldParse(id: string, t: number): boolean {
+		if (!this.#options.suppressSteadyFrames) return true;
+		const state = this.#states.get(id);
+		if (!state) return true;
+		if (state.info.checkIntervalS !== undefined) return true;
+		if (t < state.parseHoldUntilT) return false;
+		return !state.streak?.suppressed;
+	}
+
+	/** Report the outcome of a parse this scheduler approved. */
+	recordParse(
+		id: string,
+		t: number,
+		events: readonly Pick<DetectedEvent, "type" | "confidence">[],
+	): void {
+		this.#recordMatchState(t, events);
+		const state = this.#states.get(id);
+		if (!state || state.info.checkIntervalS !== undefined) return;
+		// no events counts as confidence 0: a false-firing gate on a static
+		// screen stagnates and gets suppressed just like a parsed one
+		const confidence = events.reduce(
+			(max, e) => Math.max(max, e.confidence),
+			0,
+		);
+		const { sufficientConfidence, rearmCooldownS } = state.info;
+		if (
+			sufficientConfidence !== undefined &&
+			confidence >= sufficientConfidence
+		) {
+			state.streak = {
+				best: confidence,
+				stagnant: 0,
+				lastImprovementT: t,
+				suppressed: true,
+			};
+			if (rearmCooldownS !== undefined) {
+				state.parseHoldUntilT = t + rearmCooldownS;
+			}
+			return;
+		}
+		if (!state.streak) {
+			state.streak = {
+				best: confidence,
+				stagnant: 0,
+				lastImprovementT: t,
+				suppressed: false,
+			};
+			return;
+		}
+		const streak = state.streak;
+		if (confidence > streak.best + this.#options.minImprovement) {
+			streak.best = confidence;
+			streak.stagnant = 0;
+			streak.lastImprovementT = t;
+			return;
+		}
+		streak.stagnant += 1;
+		if (
+			streak.stagnant >= this.#options.maxStagnantParses &&
+			t - streak.lastImprovementT >= this.#options.stagnantAfterS
+		) {
+			streak.suppressed = true;
+		}
+	}
+
+	/**
+	 * True when the footage at `t` is dead air as far as detection goes: no
+	 * gate has passed for quietAfterS and no match is open — the VoD scanner
+	 * may skim by keyframes instead of decoding densely.
+	 */
+	calm(t: number): boolean {
+		if (!this.#options.suppressSteadyFrames) return false;
+		return (
+			t - this.#lastActivityT >= this.#options.quietAfterS &&
+			t >= this.#matchOpenUntilT
+		);
+	}
+
+	#interval(state: DetectorState): number {
+		if (!this.#options.suppressSteadyFrames) return 0;
+		const { info } = state;
+		if (info.checkIntervalS !== undefined) return info.checkIntervalS;
+		const search = info.searchIntervalS ?? this.#options.searchIntervalS;
+		// while suppressed only the gate keeps running (to spot the screen
+		// changing), which the sparser search cadence covers
+		if (state.streak?.suppressed) return search;
+		return state.gatePassing ? this.#options.refineIntervalS : search;
+	}
+
+	#recordMatchState(
+		t: number,
+		events: readonly Pick<DetectedEvent, "type" | "confidence">[],
+	): void {
+		for (const event of events) {
+			if (event.confidence < MATCH_STATE_MIN_CONFIDENCE) continue;
+			if (this.#options.matchOpeningTypes.includes(event.type)) {
+				this.#matchOpenUntilT = Math.max(
+					this.#matchOpenUntilT,
+					t + this.#options.matchOpenMaxS,
+				);
+			} else if (this.#options.matchClosingTypes.includes(event.type)) {
+				this.#matchOpenUntilT = Math.min(this.#matchOpenUntilT, t);
+			}
+		}
+	}
+}
+
+function freshState(info: SchedulingInfo): DetectorState {
+	return {
+		info,
+		lastCheckT: undefined,
+		gatePassing: false,
+		streak: null,
+		parseHoldUntilT: Number.NEGATIVE_INFINITY,
+	};
+}
diff --git a/app/features/scanner/core/detectors/scoreboard-own/index.ts b/app/features/scanner/core/detectors/scoreboard-own/index.ts
index 98831b386..4369227cf 100644
--- a/app/features/scanner/core/detectors/scoreboard-own/index.ts
+++ b/app/features/scanner/core/detectors/scoreboard-own/index.ts
@@ -256,5 +256,10 @@ export function createScoreboardOwnDetector(
 		];
 	}
 
-	return { id: "scoreboard-own", gate, parse };
+	return {
+		id: "scoreboard-own",
+		sufficientConfidence: 0.98,
+		gate,
+		parse,
+	};
 }
diff --git a/app/features/scanner/core/detectors/scoreboard-replay/index.ts b/app/features/scanner/core/detectors/scoreboard-replay/index.ts
index 840073750..d7b65d530 100644
--- a/app/features/scanner/core/detectors/scoreboard-replay/index.ts
+++ b/app/features/scanner/core/detectors/scoreboard-replay/index.ts
@@ -426,5 +426,12 @@ export function createScoreboardReplayDetector(
 		];
 	}
 
-	return { id: "scoreboard-replay", gate, parse };
+	// no rearm cooldown — distinct replays browsed in quick succession are
+	// told apart by content
+	return {
+		id: "scoreboard-replay",
+		sufficientConfidence: 0.98,
+		gate,
+		parse,
+	};
 }
diff --git a/app/features/scanner/core/detectors/scoreboard/index.ts b/app/features/scanner/core/detectors/scoreboard/index.ts
index 831dd3a63..7c1911c63 100644
--- a/app/features/scanner/core/detectors/scoreboard/index.ts
+++ b/app/features/scanner/core/detectors/scoreboard/index.ts
@@ -321,5 +321,11 @@ export function createScoreboardDetector(
 		];
 	}
 
-	return { id: "scoreboard", gate, parse };
+	// a 0.98 mean field score is a clean full read
+	return {
+		id: "scoreboard",
+		sufficientConfidence: 0.98,
+		gate,
+		parse,
+	};
 }
diff --git a/app/features/scanner/core/detectors/suppressor.ts b/app/features/scanner/core/detectors/suppressor.ts
deleted file mode 100644
index 2f653d6fb..000000000
--- a/app/features/scanner/core/detectors/suppressor.ts
+++ /dev/null
@@ -1,83 +0,0 @@
-/**
- * ParseSuppressor: bails out of re-parsing a static screen.
- *
- * A screen that keeps a detector's gate firing (the results scoreboard can
- * sit for tens of seconds, a paused VoD indefinitely) makes the pipeline
- * re-run the expensive parse() on every sampled frame even though nothing
- * changes. Per detector this tracks the best event confidence seen during a
- * continuous gate-pass streak; once `maxStagnantParses` consecutive parses
- * fail to improve on it, parse() is skipped (the cheap gate keeps running)
- * until the gate drops — i.e. the screen actually changed.
- */
-
-export interface SuppressorOptions {
-	/** consecutive non-improving parses tolerated before suppression kicks in */
-	maxStagnantParses: number;
-	/** minimum confidence gain that counts as an improvement */
-	minImprovement: number;
-}
-
-const DEFAULT_SUPPRESSOR_OPTIONS: SuppressorOptions = {
-	// at the 2fps sample rate: give a stable screen ~3s to produce its best
-	// read, then stop paying for parses until the screen changes
-	maxStagnantParses: 6,
-	minImprovement: 0.001,
-};
-
-interface StreakState {
-	best: number;
-	stagnant: number;
-	suppressed: boolean;
-}
-
-export class ParseSuppressor {
-	#options: SuppressorOptions;
-	#streaks = new Map<string, StreakState>();
-
-	constructor(options: Partial<SuppressorOptions> = {}) {
-		this.#options = { ...DEFAULT_SUPPRESSOR_OPTIONS, ...options };
-	}
-
-	/**
-	 * Call once per detector per frame with the gate outcome; returns whether
-	 * parse() should run. A failed gate ends the streak, so the next gate pass
-	 * starts a fresh, unsuppressed streak.
-	 */
-	shouldParse(detectorId: string, gatePass: boolean): boolean {
-		if (!gatePass) {
-			this.#streaks.delete(detectorId);
-			return false;
-		}
-		return !this.#streaks.get(detectorId)?.suppressed;
-	}
-
-	/** Report the outcome of a parse this suppressor approved. */
-	recordParse(
-		detectorId: string,
-		events: readonly { confidence: number }[],
-	): void {
-		// no events counts as confidence 0: a false-firing gate on a static
-		// screen stagnates and gets suppressed just like a parsed one
-		const confidence = events.reduce(
-			(max, e) => Math.max(max, e.confidence),
-			0,
-		);
-		const streak = this.#streaks.get(detectorId);
-		if (!streak) {
-			this.#streaks.set(detectorId, {
-				best: confidence,
-				stagnant: 0,
-				suppressed: false,
-			});
-			return;
-		}
-		if (confidence > streak.best + this.#options.minImprovement) {
-			streak.best = confidence;
-			streak.stagnant = 0;
-			return;
-		}
-		streak.stagnant += 1;
-		if (streak.stagnant >= this.#options.maxStagnantParses)
-			streak.suppressed = true;
-	}
-}
diff --git a/app/features/scanner/core/detectors/telemetry.ts b/app/features/scanner/core/detectors/telemetry.ts
new file mode 100644
index 000000000..ae951ea4d
--- /dev/null
+++ b/app/features/scanner/core/detectors/telemetry.ts
@@ -0,0 +1,85 @@
+/**
+ * Scan telemetry: counters the analyzer accumulates so scan performance is
+ * measurable instead of guessed at — how many frames were decoded vs.
+ * actually analyzed, where detector time goes (gate vs. parse), how much
+ * work scheduling saved, and how much of a VoD was covered in skim mode.
+ * Plain JSON so it travels over the worker boundary as-is.
+ */
+
+export interface DetectorTelemetry {
+	/** frames on which the detector's gate ran */
+	checks: number;
+	gatePasses: number;
+	gateMs: number;
+	parses: number;
+	parseMs: number;
+	/** gate passed but parse() was skipped (suppression / cooldown) */
+	suppressedParses: number;
+}
+
+export interface ScanTelemetry {
+	decodedFrames: number;
+	/** frames that went through canvas readback + normalize + detectors */
+	analyzedFrames: number;
+	/** video seconds covered by dense sequential decode (chunk scan) */
+	activeVideoS: number;
+	/** video seconds covered by keyframe-hop skimming (chunk scan) */
+	skimVideoS: number;
+	wallMs: number;
+	detectors: Record<string, DetectorTelemetry>;
+}
+
+/** Fresh all-zero telemetry for one scan/session. */
+export function createScanTelemetry(): ScanTelemetry {
+	return {
+		decodedFrames: 0,
+		analyzedFrames: 0,
+		activeVideoS: 0,
+		skimVideoS: 0,
+		wallMs: 0,
+		detectors: {},
+	};
+}
+
+/** Get-or-create the per-detector counters bucket. */
+export function detectorTelemetry(
+	telemetry: ScanTelemetry,
+	id: string,
+): DetectorTelemetry {
+	const existing = telemetry.detectors[id];
+	if (existing) return existing;
+	const created: DetectorTelemetry = {
+		checks: 0,
+		gatePasses: 0,
+		gateMs: 0,
+		parses: 0,
+		parseMs: 0,
+		suppressedParses: 0,
+	};
+	telemetry.detectors[id] = created;
+	return created;
+}
+
+/** Sum telemetry across parallel chunk scans into one report. */
+export function mergeScanTelemetry(
+	parts: readonly ScanTelemetry[],
+): ScanTelemetry {
+	const out = createScanTelemetry();
+	for (const part of parts) {
+		out.decodedFrames += part.decodedFrames;
+		out.analyzedFrames += part.analyzedFrames;
+		out.activeVideoS += part.activeVideoS;
+		out.skimVideoS += part.skimVideoS;
+		out.wallMs = Math.max(out.wallMs, part.wallMs);
+		for (const [id, d] of Object.entries(part.detectors)) {
+			const bucket = detectorTelemetry(out, id);
+			bucket.checks += d.checks;
+			bucket.gatePasses += d.gatePasses;
+			bucket.gateMs += d.gateMs;
+			bucket.parses += d.parses;
+			bucket.parseMs += d.parseMs;
+			bucket.suppressedParses += d.suppressedParses;
+		}
+	}
+	return out;
+}
diff --git a/app/features/scanner/core/detectors/throttle.ts b/app/features/scanner/core/detectors/throttle.ts
deleted file mode 100644
index 2a2c6cb89..000000000
--- a/app/features/scanner/core/detectors/throttle.ts
+++ /dev/null
@@ -1,24 +0,0 @@
-/**
- * CheckThrottle: caps how often a detector is checked at all (gate included),
- * for detectors that declare a checkIntervalS — screens like the objective
- * counter change at most once a second, so sampling them at the full frame
- * rate buys nothing.
- */
-
-export class CheckThrottle {
-	#lastCheckT = new Map<string, number>();
-
-	/**
-	 * Whether detector `id` should run its check on the frame at `t` seconds.
-	 * Approving a check starts the detector's next interval; a `t` earlier
-	 * than the last approved check (a fresh capture session, a VoD rescan)
-	 * resets the window instead of blocking until the old timeline catches up.
-	 */
-	shouldCheck(id: string, t: number, intervalS: number | undefined): boolean {
-		if (intervalS === undefined) return true;
-		const last = this.#lastCheckT.get(id);
-		if (last !== undefined && t >= last && t - last < intervalS) return false;
-		this.#lastCheckT.set(id, t);
-		return true;
-	}
-}
diff --git a/app/features/scanner/core/detectors/types.ts b/app/features/scanner/core/detectors/types.ts
index f1d964b02..e72d4c964 100644
--- a/app/features/scanner/core/detectors/types.ts
+++ b/app/features/scanner/core/detectors/types.ts
@@ -33,15 +33,41 @@ export interface GateResult {
 export interface Detector<TData = unknown> {
 	id: string;
 	/**
-	 * Minimum seconds between checks: frames inside the interval skip gate
-	 * and parse entirely (core/detectors/throttle.ts, applied by the
-	 * analyzer worker — per worker, so a VoD pool checks up to poolSize×
-	 * this often). Declaring an interval also exempts the detector from
-	 * steady-frame suppression: it marks a screen that stays up for minutes
-	 * with *changing* content, which the stagnating-confidence heuristic
-	 * would wrongly silence.
+	 * Minimum seconds between checks in *both* scheduling phases: frames
+	 * inside the interval skip gate and parse entirely
+	 * (core/detectors/scheduler.ts, applied by the analyzer worker).
+	 * Declaring an interval also exempts the detector from steady-frame
+	 * suppression: it marks a screen that stays up for minutes with
+	 * *changing* content, which the stagnating-confidence heuristic would
+	 * wrongly silence.
 	 */
 	checkIntervalS?: number;
+	/**
+	 * Check cadence while the gate keeps failing (the search phase); unset =
+	 * the scheduler's default (0.25s). Do not reason from raw-gameplay
+	 * screen lifetimes here: produced/casted VoDs cut screens (results,
+	 * intros) to as little as ~1s, with transition flicker eating frames
+	 * inside that window — the search cadence must sample such a window
+	 * several times. Gates cost ~1.6ms, so searching at the analysis floor
+	 * is effectively free; only override upward with strong evidence.
+	 */
+	searchIntervalS?: number;
+	/**
+	 * A parse reaching this confidence ends the streak's refinement
+	 * immediately: the timeline keeps the best read per merge window, so a
+	 * read this good cannot be improved upon in any way that matters.
+	 * Conservative by construction — if real reads never reach it, behavior
+	 * falls back to stagnation-based suppression.
+	 */
+	sufficientConfidence?: number;
+	/**
+	 * After a sufficient read, skip parses for this long even across gate
+	 * drops — for overlays whose animated background flickers the gate
+	 * (death). Only safe when the event type's timeline merge is purely
+	 * time-based and the cooldown fits inside the merge window, so every
+	 * parse the cooldown skips would have merged into the same event anyway.
+	 */
+	rearmCooldownS?: number;
 	/**
 	 * false = worker results for this detector's events ship without the
 	 * analyzed-frame PNG — for detectors whose events fire continuously,
diff --git a/app/features/scanner/tests/scheduler.test.ts b/app/features/scanner/tests/scheduler.test.ts
new file mode 100644
index 000000000..6e95d51e2
--- /dev/null
+++ b/app/features/scanner/tests/scheduler.test.ts
@@ -0,0 +1,218 @@
+/**
+ * Unit tests for DetectorScheduler: search/refine check cadence,
+ * steady-frame suppression (stagnation and sufficient-confidence early
+ * stop), the rearm cooldown, checkIntervalS compatibility, and the calm
+ * signal that drives VoD skim mode.
+ */
+
+import assert from "node:assert/strict";
+import {
+	DetectorScheduler,
+	type SchedulingInfo,
+} from "../core/detectors/scheduler";
+import test from "./node-test-compat";
+
+const OPTS = {
+	refineIntervalS: 0.1,
+	searchIntervalS: 0.1,
+	maxStagnantParses: 3,
+	stagnantAfterS: 0.25,
+	minImprovement: 0.001,
+	quietAfterS: 10,
+	matchOpenMaxS: 60,
+	matchOpeningTypes: ["MapStart"],
+	matchClosingTypes: ["Scoreboard"],
+};
+
+function make(detector: Partial<SchedulingInfo>, options = {}) {
+	return new DetectorScheduler([{ id: "d", ...detector }], {
+		...OPTS,
+		...options,
+	});
+}
+
+function feed(
+	s: DetectorScheduler,
+	t: number,
+	options: { pass: boolean; confidence?: number; type?: string },
+): "skipped" | "gated" | "parsed" {
+	if (!s.dueDetectors(t).includes("d")) return "skipped";
+	s.recordGate("d", t, options.pass);
+	if (!options.pass || !s.shouldParse("d", t)) return "gated";
+	s.recordParse(
+		"d",
+		t,
+		options.confidence === undefined
+			? []
+			: [{ type: options.type ?? "Event", confidence: options.confidence }],
+	);
+	return "parsed";
+}
+
+test("a failing gate is only re-checked at the search cadence", () => {
+	const s = make({ searchIntervalS: 1 });
+	assert.equal(feed(s, 0, { pass: false }), "gated");
+	assert.equal(feed(s, 0.5, { pass: false }), "skipped");
+	assert.equal(feed(s, 0.99, { pass: false }), "skipped");
+	assert.equal(feed(s, 1, { pass: false }), "gated");
+});
+
+test("a passing gate drops to the dense refine cadence", () => {
+	const s = make({ searchIntervalS: 1 });
+	assert.equal(feed(s, 0, { pass: true, confidence: 0.7 }), "parsed");
+	assert.equal(feed(s, 0.05, { pass: true, confidence: 0.7 }), "skipped");
+	assert.equal(feed(s, 0.1, { pass: true, confidence: 0.7 }), "parsed");
+	assert.equal(feed(s, 0.2, { pass: true, confidence: 0.7 }), "parsed");
+});
+
+test("suppresses after stagnant parses on a static screen", () => {
+	const s = make({});
+	assert.equal(feed(s, 0.0, { pass: true, confidence: 0.9 }), "parsed");
+	assert.equal(feed(s, 0.1, { pass: true, confidence: 0.9 }), "parsed");
+	assert.equal(feed(s, 0.2, { pass: true, confidence: 0.9 }), "parsed");
+	assert.equal(feed(s, 0.3, { pass: true, confidence: 0.9 }), "parsed");
+	assert.equal(feed(s, 0.4, { pass: true, confidence: 0.9 }), "gated");
+	assert.equal(feed(s, 0.5, { pass: true, confidence: 0.9 }), "gated");
+});
+
+test("an improving read resets the stagnation counter", () => {
+	const s = make({});
+	feed(s, 0.0, { pass: true, confidence: 0.7 });
+	feed(s, 0.1, { pass: true, confidence: 0.7 });
+	feed(s, 0.2, { pass: true, confidence: 0.7 });
+	assert.equal(feed(s, 0.3, { pass: true, confidence: 0.85 }), "parsed");
+	assert.equal(feed(s, 0.4, { pass: true, confidence: 0.85 }), "parsed");
+	assert.equal(feed(s, 0.5, { pass: true, confidence: 0.85 }), "parsed");
+	assert.equal(feed(s, 0.6, { pass: true, confidence: 0.85 }), "parsed");
+	assert.equal(feed(s, 0.7, { pass: true, confidence: 0.85 }), "gated");
+});
+
+test("a gate drop ends the streak and re-enables parsing", () => {
+	const s = make({});
+	for (let i = 0; i < 5; i++) feed(s, i * 0.1, { pass: true, confidence: 0.9 });
+	assert.equal(feed(s, 0.5, { pass: true, confidence: 0.9 }), "gated");
+	assert.equal(feed(s, 0.6, { pass: false }), "gated");
+	assert.equal(feed(s, 0.7, { pass: true, confidence: 0.9 }), "parsed");
+});
+
+test("gate firing without events stagnates too", () => {
+	const s = make({});
+	for (let i = 0; i < 4; i++) {
+		assert.equal(feed(s, i * 0.1, { pass: true }), "parsed");
+	}
+	assert.equal(feed(s, 0.4, { pass: true }), "gated");
+});
+
+test("dense no-read parses during an entry animation respect the time floor", () => {
+	const s = make({}, { stagnantAfterS: 3 });
+	// the gate fires from t=0 while the screen is still animating in and
+	// parses read nothing — a parse count alone must not suppress here
+	for (let i = 0; i < 8; i++) {
+		assert.equal(feed(s, i * 0.15, { pass: true }), "parsed");
+	}
+	// the screen becomes readable and the read still lands
+	assert.equal(feed(s, 1.35, { pass: true, confidence: 0.88 }), "parsed");
+	// once truly static past the time floor, suppression still kicks in
+	for (let i = 0; i < 25; i++) {
+		feed(s, 1.5 + i * 0.15, { pass: true, confidence: 0.88 });
+	}
+	assert.equal(feed(s, 5.4, { pass: true, confidence: 0.88 }), "gated");
+});
+
+test("a sufficient read suppresses immediately", () => {
+	const s = make({ sufficientConfidence: 0.95 });
+	assert.equal(feed(s, 0.0, { pass: true, confidence: 0.96 }), "parsed");
+	assert.equal(feed(s, 0.1, { pass: true, confidence: 0.99 }), "gated");
+	// gate drop = screen changed = fresh streak parses again
+	feed(s, 0.2, { pass: false });
+	assert.equal(feed(s, 0.3, { pass: true, confidence: 0.7 }), "parsed");
+});
+
+test("rearm cooldown skips parses across gate flicker", () => {
+	const s = make({ sufficientConfidence: 0.95, rearmCooldownS: 4 });
+	assert.equal(feed(s, 1.0, { pass: true, confidence: 0.96 }), "parsed");
+	feed(s, 1.5, { pass: false });
+	assert.equal(feed(s, 2.0, { pass: true, confidence: 0.9 }), "gated");
+	assert.equal(feed(s, 4.9, { pass: true, confidence: 0.9 }), "gated");
+	assert.equal(feed(s, 5.1, { pass: true, confidence: 0.9 }), "parsed");
+});
+
+test("checkIntervalS caps both phases and exempts from suppression", () => {
+	const s = make({ checkIntervalS: 1 });
+	assert.equal(feed(s, 0.0, { pass: true, confidence: 0.9 }), "parsed");
+	assert.equal(feed(s, 0.5, { pass: true, confidence: 0.9 }), "skipped");
+	for (let t = 1; t < 10; t++) {
+		assert.equal(feed(s, t, { pass: true, confidence: 0.9 }), "parsed");
+	}
+});
+
+test("suppressSteadyFrames=false checks and parses every frame", () => {
+	const s = make(
+		{ searchIntervalS: 1, sufficientConfidence: 0.5 },
+		{ suppressSteadyFrames: false },
+	);
+	for (let i = 0; i < 10; i++) {
+		assert.equal(feed(s, 0, { pass: true, confidence: 0.9 }), "parsed");
+	}
+	assert.equal(s.calm(1000), false);
+});
+
+test("calm needs a quiet period and no open match", () => {
+	const s = make({});
+	assert.equal(feed(s, 0, { pass: false }), "gated");
+	assert.equal(s.calm(5), false);
+	assert.equal(s.calm(10), true);
+	// a gate pass resets the quiet clock
+	feed(s, 10, { pass: true, confidence: 0.9 });
+	assert.equal(s.calm(15), false);
+	assert.equal(s.calm(20), true);
+	// a confident map-start keeps the scan active for matchOpenMaxS
+	feed(s, 21, { pass: true, confidence: 0.9, type: "MapStart" });
+	assert.equal(s.calm(50), false);
+	assert.equal(s.calm(21 + 60), true);
+});
+
+test("a scoreboard closes the match early", () => {
+	const s = make({});
+	feed(s, 0, { pass: true, confidence: 0.9, type: "MapStart" });
+	assert.equal(s.calm(30), false);
+	feed(s, 31, { pass: true, confidence: 0.9, type: "Scoreboard" });
+	// quiet period still applies after the closing read
+	assert.equal(s.calm(35), false);
+	assert.equal(s.calm(41), true);
+});
+
+test("a t jumping backwards resets the session", () => {
+	const s = make({ searchIntervalS: 1 });
+	feed(s, 100, { pass: false });
+	assert.equal(feed(s, 100.5, { pass: false }), "skipped");
+	// a rescan starts earlier than anything seen — fresh state, due again
+	assert.equal(feed(s, 0, { pass: false }), "gated");
+});
+
+test("detectors are tracked independently", () => {
+	const s = new DetectorScheduler(
+		[{ id: "a" }, { id: "b", searchIntervalS: 1 }],
+		OPTS,
+	);
+	assert.deepEqual(s.dueDetectors(0), ["a", "b"]);
+	s.recordGate("a", 0, true);
+	s.recordGate("b", 0, false);
+	assert.deepEqual(s.dueDetectors(0.5), ["a"]);
+	assert.deepEqual(s.dueDetectors(1), ["a", "b"]);
+});
+
+test("nextDueT lets frames skip analysis entirely", () => {
+	const s = new DetectorScheduler(
+		[
+			{ id: "a", searchIntervalS: 0.5 },
+			{ id: "b", searchIntervalS: 1 },
+		],
+		OPTS,
+	);
+	assert.equal(s.nextDueT(), Number.NEGATIVE_INFINITY);
+	s.dueDetectors(0);
+	s.recordGate("a", 0, false);
+	s.recordGate("b", 0, false);
+	assert.equal(s.nextDueT(), 0.5);
+});
diff --git a/app/features/scanner/tests/suppressor.test.ts b/app/features/scanner/tests/suppressor.test.ts
deleted file mode 100644
index 5d2a31833..000000000
--- a/app/features/scanner/tests/suppressor.test.ts
+++ /dev/null
@@ -1,64 +0,0 @@
-/**
- * Unit tests for ParseSuppressor: a static screen (gate keeps passing,
- * confidence stops improving) gets its parse() suppressed after the
- * stagnation budget, and any gate drop resets the streak.
- */
-
-import assert from "node:assert/strict";
-import { ParseSuppressor } from "../core/detectors/suppressor";
-import test from "./node-test-compat";
-
-const OPTS = { maxStagnantParses: 3, minImprovement: 0.001 };
-
-function feed(
-	s: ParseSuppressor,
-	id: string,
-	confidence: number | null,
-): boolean {
-	const allowed = s.shouldParse(id, true);
-	if (allowed) s.recordParse(id, confidence === null ? [] : [{ confidence }]);
-	return allowed;
-}
-
-test("suppresses after stagnant parses on a static screen", () => {
-	const s = new ParseSuppressor(OPTS);
-	assert.equal(feed(s, "scoreboard", 0.9), true); // sets the baseline
-	assert.equal(feed(s, "scoreboard", 0.9), true); // stagnant 1
-	assert.equal(feed(s, "scoreboard", 0.9), true); // stagnant 2
-	assert.equal(feed(s, "scoreboard", 0.9), true); // stagnant 3 -> suppressed
-	assert.equal(s.shouldParse("scoreboard", true), false);
-	assert.equal(s.shouldParse("scoreboard", true), false);
-});
-
-test("an improving read resets the stagnation counter", () => {
-	const s = new ParseSuppressor(OPTS);
-	feed(s, "scoreboard", 0.7);
-	feed(s, "scoreboard", 0.7);
-	feed(s, "scoreboard", 0.7);
-	assert.equal(feed(s, "scoreboard", 0.85), true); // improvement, counter resets
-	assert.equal(feed(s, "scoreboard", 0.85), true);
-	assert.equal(feed(s, "scoreboard", 0.85), true);
-	assert.equal(feed(s, "scoreboard", 0.85), true); // stagnant 3 -> suppressed
-	assert.equal(s.shouldParse("scoreboard", true), false);
-});
-
-test("a gate drop ends the streak and re-enables parsing", () => {
-	const s = new ParseSuppressor(OPTS);
-	for (let i = 0; i < 5; i++) feed(s, "scoreboard", 0.9);
-	assert.equal(s.shouldParse("scoreboard", true), false);
-	assert.equal(s.shouldParse("scoreboard", false), false); // screen changed
-	assert.equal(feed(s, "scoreboard", 0.9), true); // fresh streak parses again
-});
-
-test("gate firing without events stagnates too", () => {
-	const s = new ParseSuppressor(OPTS);
-	for (let i = 0; i < 4; i++) assert.equal(feed(s, "death", null), true);
-	assert.equal(s.shouldParse("death", true), false);
-});
-
-test("detectors are tracked independently", () => {
-	const s = new ParseSuppressor(OPTS);
-	for (let i = 0; i < 5; i++) feed(s, "scoreboard", 0.9);
-	assert.equal(s.shouldParse("scoreboard", true), false);
-	assert.equal(s.shouldParse("death", true), true);
-});
diff --git a/app/features/scanner/tests/throttle.test.ts b/app/features/scanner/tests/throttle.test.ts
deleted file mode 100644
index ffab9e9ea..000000000
--- a/app/features/scanner/tests/throttle.test.ts
+++ /dev/null
@@ -1,47 +0,0 @@
-/**
- * Unit tests for CheckThrottle: a detector with a check interval is checked
- * at most once per interval, timeline regressions reset the window, and
- * detectors without an interval are never throttled.
- */
-
-import assert from "node:assert/strict";
-import { CheckThrottle } from "../core/detectors/throttle";
-import test from "./node-test-compat";
-
-test("no interval means every frame is checked", () => {
-	const throttle = new CheckThrottle();
-	assert.equal(throttle.shouldCheck("scoreboard", 0, undefined), true);
-	assert.equal(throttle.shouldCheck("scoreboard", 0.1, undefined), true);
-	assert.equal(throttle.shouldCheck("scoreboard", 0.2, undefined), true);
-});
-
-test("frames inside the interval are skipped", () => {
-	const throttle = new CheckThrottle();
-	assert.equal(throttle.shouldCheck("objective", 10, 1), true);
-	assert.equal(throttle.shouldCheck("objective", 10.5, 1), false);
-	assert.equal(throttle.shouldCheck("objective", 10.99, 1), false);
-	assert.equal(throttle.shouldCheck("objective", 11, 1), true);
-	assert.equal(throttle.shouldCheck("objective", 11.5, 1), false);
-});
-
-test("a skipped frame does not push the next check later", () => {
-	const throttle = new CheckThrottle();
-	assert.equal(throttle.shouldCheck("objective", 0, 1), true);
-	assert.equal(throttle.shouldCheck("objective", 0.9, 1), false);
-	assert.equal(throttle.shouldCheck("objective", 1.1, 1), true);
-});
-
-test("a timeline regression resets the window", () => {
-	const throttle = new CheckThrottle();
-	assert.equal(throttle.shouldCheck("objective", 100, 1), true);
-	// new capture session / VoD rescan starts its clock over
-	assert.equal(throttle.shouldCheck("objective", 0.2, 1), true);
-	assert.equal(throttle.shouldCheck("objective", 0.6, 1), false);
-});
-
-test("detectors are tracked independently", () => {
-	const throttle = new CheckThrottle();
-	assert.equal(throttle.shouldCheck("objective", 0, 1), true);
-	assert.equal(throttle.shouldCheck("objective", 0.5, 1), false);
-	assert.equal(throttle.shouldCheck("other", 0.5, 1), true);
-});
diff --git a/app/features/scanner/worker/analyzer.worker.ts b/app/features/scanner/worker/analyzer.worker.ts
index 0f93a33f8..1c6ee2aa3 100644
--- a/app/features/scanner/worker/analyzer.worker.ts
+++ b/app/features/scanner/worker/analyzer.worker.ts
@@ -1,22 +1,68 @@
 /**
- * AnalyzerWorker: owns OpenCV.js (WASM) and the detector registry.
- * The main thread posts ImageBitmaps; results come back as plain JSON.
+ * AnalyzerWorker: owns OpenCV.js (WASM), the detector registry and a
+ * DetectorScheduler. Two ways in:
+ *
+ * - "frame": the main thread posts one ImageBitmap/VideoFrame at a time
+ *   (live capture, screenshot harness, the VoD seek fallback). Results come
+ *   back per detector, then a "done" carrying the scheduler's calm signal
+ *   and telemetry.
+ * - "scanChunk": a VoD time slice is demuxed and decoded entirely in the
+ *   worker with mediabunny. The worker owns a contiguous slice, so
+ *   scheduling is exact, frames that no detector is due for skip canvas
+ *   readback entirely, and calm stretches are skimmed by keyframe hops
+ *   instead of decoding every frame — the big VoD speedup, since sequential
+ *   decode is what bounds scan wall-clock time.
  */
+import {
+	ALL_FORMATS,
+	BlobSource,
+	EncodedPacketSink,
+	Input,
+	type VideoSample,
+	VideoSampleSink,
+} from "mediabunny";
 import { loadOpenCV } from "../core/cv";
-import { createAllDetectors } from "../core/detectors/registry";
-import { ParseSuppressor } from "../core/detectors/suppressor";
-import { CheckThrottle } from "../core/detectors/throttle";
+import { MAP_START_EVENT_TYPE } from "../core/detectors/map-start/index";
+import {
+	createAllDetectors,
+	SCOREBOARD_EVENT_TYPES,
+} from "../core/detectors/registry";
+import { DetectorScheduler } from "../core/detectors/scheduler";
+import {
+	createScanTelemetry,
+	detectorTelemetry,
+} from "../core/detectors/telemetry";
 import type { Detector } from "../core/detectors/types";
 import { normalizeFrame, toMat } from "../core/image";
-import type { AnalyzeRequest, InitRequest, WorkerResponse } from "./protocol";
+import type {
+	AnalyzeRequest,
+	InitRequest,
+	ScanChunkRequest,
+	WorkerRequest,
+	WorkerResponse,
+} from "./protocol";
 import { fetchScoreboardResources } from "./resources";
 
-let detectors: Detector<unknown>[] = [];
-let suppressor: ParseSuppressor | null = null;
-let throttle = new CheckThrottle();
+/**
+ * Widest skim hop: calm footage is sampled at the keyframe cadence, capped
+ * here so long-GOP recordings still cannot slip a results screen (~10s) or
+ * a match intro (~7s) between two samples.
+ */
+const MAX_SKIM_STRIDE_S = 2.5;
+const PROGRESS_POST_INTERVAL_MS = 400;
+const PREVIEW_POST_INTERVAL_MS = 600;
+const PREVIEW_WIDTH = 480;
+const PREVIEW_HEIGHT = 270;
 
-function post(message: WorkerResponse): void {
-	self.postMessage(message);
+let detectors: Detector<unknown>[] = [];
+let scheduler: DetectorScheduler | null = null;
+let telemetry = createScanTelemetry();
+let chunkAborted = false;
+/** last per-frame t, to reset telemetry when a new session rewinds the clock */
+let lastFrameT = Number.NEGATIVE_INFINITY;
+
+function post(message: WorkerResponse, transfer: Transferable[] = []): void {
+	self.postMessage(message, { transfer });
 }
 
 async function init({
@@ -27,20 +73,36 @@ async function init({
 		await loadOpenCV();
 		const resources = await fetchScoreboardResources(assetsBaseUrl);
 		detectors = createAllDetectors(resources);
-		suppressor = suppressSteadyFrames ? new ParseSuppressor() : null;
-		throttle = new CheckThrottle();
+		scheduler = new DetectorScheduler(detectors, {
+			suppressSteadyFrames,
+			matchOpeningTypes: [MAP_START_EVENT_TYPE],
+			matchClosingTypes: SCOREBOARD_EVENT_TYPES,
+		});
+		telemetry = createScanTelemetry();
 		post({ kind: "ready" });
 	} catch (error) {
 		post({ kind: "error", message: `init failed: ${String(error)}` });
 	}
 }
 
-async function analyze({ bitmap, t }: AnalyzeRequest): Promise<void> {
+/**
+ * Run the due detectors over one frame; closes `bitmap`. When the scheduler
+ * has no detector due, the canvas readback and normalize are skipped too.
+ */
+async function analyzeFrame(
+	bitmap: ImageBitmap | VideoFrame,
+	t: number,
+): Promise<void> {
+	const due = scheduler!.dueDetectors(t);
+	if (due.length === 0) {
+		bitmap.close();
+		return;
+	}
 	const width = "displayWidth" in bitmap ? bitmap.displayWidth : bitmap.width;
 	const height =
 		"displayHeight" in bitmap ? bitmap.displayHeight : bitmap.height;
 	const canvas = new OffscreenCanvas(width, height);
-	const ctx = canvas.getContext("2d")!;
+	const ctx = canvas.getContext("2d", { willReadFrequently: true })!;
 	ctx.drawImage(bitmap, 0, 0);
 	bitmap.close();
 	const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
@@ -56,6 +118,7 @@ async function analyze({ bitmap, t }: AnalyzeRequest): Promise<void> {
 	} finally {
 		src.delete();
 	}
+	telemetry.analyzedFrames++;
 
 	// On detection, ship back the exact analyzed pixels (lossless, at capture
 	// resolution) so the UI never has to re-grab a later frame — encoded at
@@ -66,18 +129,24 @@ async function analyze({ bitmap, t }: AnalyzeRequest): Promise<void> {
 
 	try {
 		for (const detector of detectors) {
-			if (!throttle.shouldCheck(detector.id, t, detector.checkIntervalS))
-				continue;
+			if (!due.includes(detector.id)) continue;
+			const counters = detectorTelemetry(telemetry, detector.id);
+			counters.checks++;
+			const gateStart = performance.now();
 			const gate = detector.gate(frame);
-			// interval-limited detectors watch changing content and opt out of
-			// steady-frame suppression (see Detector.checkIntervalS)
-			const suppressible =
-				detector.checkIntervalS === undefined ? suppressor : null;
-			const runParse = suppressible
-				? suppressible.shouldParse(detector.id, gate.pass)
-				: gate.pass;
-			const events = runParse ? detector.parse(frame, t, gate) : [];
-			if (runParse) suppressible?.recordParse(detector.id, events);
+			counters.gateMs += performance.now() - gateStart;
+			scheduler!.recordGate(detector.id, t, gate.pass);
+			if (gate.pass) counters.gatePasses++;
+			const runParse = gate.pass && scheduler!.shouldParse(detector.id, t);
+			if (gate.pass && !runParse) counters.suppressedParses++;
+			let events: ReturnType<typeof detector.parse> = [];
+			if (runParse) {
+				const parseStart = performance.now();
+				events = detector.parse(frame, t, gate);
+				counters.parses++;
+				counters.parseMs += performance.now() - parseStart;
+				scheduler!.recordParse(detector.id, t, events);
+			}
 			const blob =
 				events.length > 0 && detector.attachFrame !== false
 					? await frameBlob()
@@ -91,16 +160,147 @@ async function analyze({ bitmap, t }: AnalyzeRequest): Promise<void> {
 				frame: blob,
 			});
 		}
-	} catch (error) {
-		post({ kind: "error", message: `analyze failed: ${String(error)}` });
 	} finally {
 		frame.delete();
-		post({ kind: "done", t });
+	}
+}
+
+async function analyze({ bitmap, t }: AnalyzeRequest): Promise<void> {
+	if (t + 5 < lastFrameT) telemetry = createScanTelemetry();
+	lastFrameT = t;
+	try {
+		await analyzeFrame(bitmap, t);
+	} catch (error) {
+		post({ kind: "error", message: `analyze failed: ${String(error)}` });
+	}
+	post({ kind: "done", t, calm: scheduler!.calm(t), telemetry });
+}
+
+async function scanChunk({
+	file,
+	chunkIndex,
+	tStart,
+	tEnd,
+}: ScanChunkRequest): Promise<void> {
+	chunkAborted = false;
+	scheduler!.reset(tStart);
+	telemetry = createScanTelemetry();
+	const wallStart = performance.now();
+	let lastProgressAt = 0;
+	let lastPreviewAt = 0;
+	let cursor = tStart;
+	let mode: "active" | "skim" = "active";
+
+	const input = new Input({
+		formats: ALL_FORMATS,
+		source: new BlobSource(file),
+	});
+	try {
+		const track = await input.getPrimaryVideoTrack();
+		if (!track || !(await track.canDecode())) {
+			throw new Error("worker cannot decode this file");
+		}
+		const samples = new VideoSampleSink(track);
+		const packets = new EncodedPacketSink(track);
+
+		const handleSample = async (sample: VideoSample): Promise<void> => {
+			telemetry.decodedFrames++;
+			const t = sample.timestamp;
+			const span = Math.max(0, t - cursor);
+			if (mode === "active") telemetry.activeVideoS += span;
+			else telemetry.skimVideoS += span;
+			cursor = Math.max(cursor, t);
+			const frame = sample.toVideoFrame();
+			sample.close();
+			const now = performance.now();
+			let preview: ImageBitmap | undefined;
+			if (now - lastPreviewAt >= PREVIEW_POST_INTERVAL_MS) {
+				lastPreviewAt = now;
+				preview = await createImageBitmap(frame, {
+					resizeWidth: PREVIEW_WIDTH,
+					resizeHeight: PREVIEW_HEIGHT,
+				});
+			}
+			if (t >= scheduler!.nextDueT()) {
+				await analyzeFrame(frame, t);
+			} else {
+				frame.close();
+			}
+			if (preview || now - lastProgressAt >= PROGRESS_POST_INTERVAL_MS) {
+				lastProgressAt = now;
+				telemetry.wallMs = performance.now() - wallStart;
+				post(
+					{
+						kind: "chunkProgress",
+						chunkIndex,
+						t: cursor,
+						mode,
+						telemetry,
+						preview,
+					},
+					preview ? [preview] : [],
+				);
+			}
+		};
+
+		scan: while (!chunkAborted && cursor < tEnd) {
+			if (mode === "active") {
+				// dense sequential decode: every frame is seen, the scheduler
+				// decides which are worth analyzing
+				for await (const sample of samples.samples(cursor)) {
+					if (!sample) continue;
+					if (chunkAborted || sample.timestamp >= tEnd) {
+						sample.close();
+						break scan;
+					}
+					await handleSample(sample);
+					if (scheduler!.calm(cursor)) {
+						mode = "skim";
+						break;
+					}
+				}
+				if (mode === "active") break; // media ended before tEnd
+			} else {
+				// skim: hop keyframe to keyframe (single-frame decodes) while
+				// calm, capped so long GOPs cannot hide a short screen
+				const key = await packets.getKeyPacket(cursor + MAX_SKIM_STRIDE_S, {
+					verifyKeyPackets: true,
+				});
+				const target =
+					key && key.timestamp > cursor
+						? key.timestamp
+						: cursor + MAX_SKIM_STRIDE_S;
+				if (target >= tEnd) {
+					cursor = tEnd;
+					break;
+				}
+				const sample = await samples.getSample(target);
+				if (!sample) {
+					cursor = target;
+					continue;
+				}
+				await handleSample(sample);
+				cursor = Math.max(cursor, target);
+				if (!scheduler!.calm(cursor)) mode = "active";
+			}
+		}
+
+		telemetry.wallMs = performance.now() - wallStart;
+		post({ kind: "chunkDone", chunkIndex, telemetry });
+	} catch (error) {
+		post({
+			kind: "error",
+			message: `chunk ${chunkIndex} scan failed: ${String(error)}`,
+		});
+	} finally {
+		input.dispose();
 	}
 }
 
 self.onmessage = (e: MessageEvent) => {
-	const msg = e.data as { kind: string } & Record<string, unknown>;
-	if (msg.kind === "init") void init(msg as unknown as InitRequest);
-	else if (msg.kind === "frame") void analyze(msg as unknown as AnalyzeRequest);
+	const msg = e.data as WorkerRequest;
+	if (msg.kind === "init") void init(msg);
+	else if (msg.kind === "frame") void analyze(msg);
+	else if (msg.kind === "scanChunk") void scanChunk(msg);
+	else if (msg.kind === "abortChunk") chunkAborted = true;
 };
diff --git a/app/features/scanner/worker/client.ts b/app/features/scanner/worker/client.ts
index 5de51d9e9..e742192e9 100644
--- a/app/features/scanner/worker/client.ts
+++ b/app/features/scanner/worker/client.ts
@@ -1,16 +1,38 @@
 /**
- * Main-thread wrapper around the AnalyzerWorker: init handshake, one
- * in-flight frame at a time (the sampler drops frames while busy). Each
- * frame yields one result per registered detector, then a single "done".
+ * Main-thread wrapper around the AnalyzerWorker: init handshake, then either
+ * one in-flight frame at a time (live capture / screenshot / seek fallback —
+ * each frame yields one result per due detector, then a "done" carrying the
+ * scheduler's calm signal and telemetry) or one in-flight chunk scan (the
+ * worker decodes and analyzes a VoD time slice by itself, streaming results
+ * and progress until "chunkDone").
  */
 import { Config } from "../../../config";
+import type { ScanTelemetry } from "../core/detectors/telemetry";
 import type { WorkerResponse } from "./protocol";
 
 export type ResultHandler = (
 	result: Extract<WorkerResponse, { kind: "result" }>,
 ) => void;
 export type ErrorHandler = (message: string) => void;
-export type DoneHandler = (t: number) => void;
+export interface DoneInfo {
+	calm: boolean;
+	telemetry: ScanTelemetry;
+}
+export type DoneHandler = (t: number, info: DoneInfo) => void;
+export type ChunkProgress = Extract<WorkerResponse, { kind: "chunkProgress" }>;
+export type ChunkProgressHandler = (progress: ChunkProgress) => void;
+
+/** each chunk-scanning worker decodes and analyzes on its own; leave a core
+ * for the main thread and one for the browser's media stack */
+export function defaultScanWorkerCount(): number {
+	return Math.min(4, Math.max(1, (navigator.hardwareConcurrency || 4) - 2));
+}
+
+interface PendingChunk {
+	resolve(telemetry: ScanTelemetry): void;
+	reject(error: Error): void;
+	onProgress?: ChunkProgressHandler;
+}
 
 export class AnalyzerClient {
 	#worker: Worker;
@@ -20,6 +42,8 @@ export class AnalyzerClient {
 	#onError: ErrorHandler;
 	#onDone: DoneHandler | undefined;
 	#readyPromise: Promise<void>;
+	#idleWaiters: (() => void)[] = [];
+	#chunk: PendingChunk | null = null;
 
 	constructor(
 		onResult: ResultHandler,
@@ -49,23 +73,27 @@ export class AnalyzerClient {
 			} else if (msg.kind === "result") {
 				this.#onResult(msg);
 			} else if (msg.kind === "done") {
-				this.#busy = false;
-				this.#onDone?.(msg.t);
+				this.#settle();
+				this.#onDone?.(msg.t, { calm: msg.calm, telemetry: msg.telemetry });
+			} else if (msg.kind === "chunkProgress") {
+				this.#chunk?.onProgress?.(msg);
+			} else if (msg.kind === "chunkDone") {
+				const chunk = this.#chunk;
+				this.#chunk = null;
+				this.#settle();
+				chunk?.resolve(msg.telemetry);
 			} else if (msg.kind === "error") {
-				this.#busy = false;
-				this.#onError(msg.message);
+				this.#fail(msg.message);
 			}
 		};
 		// A throw outside the worker's own try/catch posts neither "error" nor
 		// "done"; without these handlers `busy` would stay true forever and the
 		// sampler / VoD scan would silently freeze.
 		this.#worker.onerror = (e: ErrorEvent) => {
-			this.#busy = false;
-			this.#onError(`worker error: ${e.message || String(e)}`);
+			this.#fail(`worker error: ${e.message || String(e)}`);
 		};
 		this.#worker.onmessageerror = () => {
-			this.#busy = false;
-			this.#onError("worker message deserialization failed");
+			this.#fail("worker message deserialization failed");
 		};
 		this.#worker.postMessage({
 			kind: "init",
@@ -82,6 +110,13 @@ export class AnalyzerClient {
 		return this.#busy || !this.#ready;
 	}
 
+	/** Resolves once no frame or chunk scan is in flight. Call whenReady() first. */
+	async whenIdle(): Promise<void> {
+		while (this.#busy) {
+			await new Promise<void>((resolve) => this.#idleWaiters.push(resolve));
+		}
+	}
+
 	/** Returns false (and closes the bitmap) if the worker is still busy. */
 	analyze(bitmap: ImageBitmap | VideoFrame, t: number): boolean {
 		if (this.busy) {
@@ -93,7 +128,46 @@ export class AnalyzerClient {
 		return true;
 	}
 
+	/**
+	 * Scan [tStart, tEnd) of `file` inside the worker. Results stream to the
+	 * shared result handler; resolves with the chunk's telemetry once done
+	 * (an aborted chunk resolves too — abort is not an error).
+	 */
+	scanChunk(
+		request: { file: File; chunkIndex: number; tStart: number; tEnd: number },
+		onProgress?: ChunkProgressHandler,
+	): Promise<ScanTelemetry> {
+		if (this.busy) {
+			return Promise.reject(new Error("analyzer is busy"));
+		}
+		this.#busy = true;
+		return new Promise((resolve, reject) => {
+			this.#chunk = { resolve, reject, onProgress };
+			this.#worker.postMessage({ kind: "scanChunk", ...request });
+		});
+	}
+
+	/** Ask a running chunk scan to stop; it resolves after the current frame. */
+	abortChunk(): void {
+		if (this.#chunk) this.#worker.postMessage({ kind: "abortChunk" });
+	}
+
 	dispose(): void {
 		this.#worker.terminate();
 	}
+
+	#settle(): void {
+		this.#busy = false;
+		const waiters = this.#idleWaiters;
+		this.#idleWaiters = [];
+		for (const waiter of waiters) waiter();
+	}
+
+	#fail(message: string): void {
+		const chunk = this.#chunk;
+		this.#chunk = null;
+		this.#settle();
+		if (chunk) chunk.reject(new Error(message));
+		else this.#onError(message);
+	}
 }
diff --git a/app/features/scanner/worker/pool.ts b/app/features/scanner/worker/pool.ts
deleted file mode 100644
index b479a25fb..000000000
--- a/app/features/scanner/worker/pool.ts
+++ /dev/null
@@ -1,80 +0,0 @@
-/**
- * AnalyzerPool: several AnalyzerClients so frame analysis parallelizes
- * across cores. The VoD scan hands each decoded frame to any idle worker
- * and never waits; when all workers are busy the frame is dropped — the
- * next one is milliseconds of video away, so coverage stays as dense as
- * the machine can analyze. Results arrive out of decode order, which the
- * consumer must tolerate (TimelineBuilder does: it merges on |Δt| and
- * keeps its list sorted, independent of arrival order).
- */
-import {
-	AnalyzerClient,
-	type ErrorHandler,
-	type ResultHandler,
-} from "./client";
-
-/** leave cores for the main thread and the video decoder */
-export function defaultPoolSize(): number {
-	return Math.min(4, Math.max(1, (navigator.hardwareConcurrency || 4) - 2));
-}
-
-export class AnalyzerPool {
-	#clients: AnalyzerClient[];
-	#idleWaiters: (() => void)[] = [];
-
-	constructor(size: number, onResult: ResultHandler, onError: ErrorHandler) {
-		const wake = () => {
-			const waiters = this.#idleWaiters;
-			this.#idleWaiters = [];
-			for (const waiter of waiters) waiter();
-		};
-		this.#clients = Array.from(
-			{ length: size },
-			() =>
-				new AnalyzerClient(
-					onResult,
-					(message) => {
-						wake(); // an errored frame is also a finished frame — don't hang whenIdle
-						onError(message);
-					},
-					wake,
-				),
-		);
-	}
-
-	whenReady(): Promise<void> {
-		return Promise.all(this.#clients.map((c) => c.whenReady())).then(() => {});
-	}
-
-	hasIdle(): boolean {
-		return this.#clients.some((c) => !c.busy);
-	}
-
-	/** Resolves once at least one worker is free. Call whenReady() first. */
-	async whenAnyIdle(): Promise<void> {
-		while (!this.hasIdle()) {
-			await new Promise<void>((resolve) => this.#idleWaiters.push(resolve));
-		}
-	}
-
-	/** Hand the frame to an idle worker; false (and the frame closed) when all are busy. */
-	tryAnalyze(frame: ImageBitmap | VideoFrame, t: number): boolean {
-		const idle = this.#clients.find((c) => !c.busy);
-		if (!idle) {
-			frame.close();
-			return false;
-		}
-		return idle.analyze(frame, t);
-	}
-
-	/** Resolves once no worker has a frame in flight. Call whenReady() first. */
-	async whenIdle(): Promise<void> {
-		while (this.#clients.some((c) => c.busy)) {
-			await new Promise<void>((resolve) => this.#idleWaiters.push(resolve));
-		}
-	}
-
-	dispose(): void {
-		for (const client of this.#clients) client.dispose();
-	}
-}
diff --git a/app/features/scanner/worker/protocol.ts b/app/features/scanner/worker/protocol.ts
index eb1d81e1d..399ca25a7 100644
--- a/app/features/scanner/worker/protocol.ts
+++ b/app/features/scanner/worker/protocol.ts
@@ -1,3 +1,4 @@
+import type { ScanTelemetry } from "../core/detectors/telemetry";
 import type { DetectedEvent, GateResult } from "../core/detectors/types";
 
 export interface InitRequest {
@@ -10,8 +11,9 @@ export interface InitRequest {
 	assetsBaseUrl: string;
 	/**
 	 * skip parse() for a detector whose gate keeps firing without confidence
-	 * improving (static screen); default true — one-shot consumers like the
-	 * screenshot harness turn it off
+	 * improving (static screen), and let the scheduler thin out checks;
+	 * default true — one-shot consumers like the screenshot harness turn it
+	 * off to get every detector on every frame
 	 */
 	suppressSteadyFrames?: boolean;
 }
@@ -25,6 +27,32 @@ export interface AnalyzeRequest {
 	t: number;
 }
 
+/**
+ * Scan a time slice of a VoD entirely inside the worker: demux + decode with
+ * mediabunny, schedule detectors, post results as they fire. Decoding in the
+ * worker removes the per-frame main-thread hop and lets each worker own a
+ * contiguous slice, so scheduler state (cadence, suppression, calm) is exact
+ * instead of split across a pool.
+ */
+export interface ScanChunkRequest {
+	kind: "scanChunk";
+	file: File;
+	chunkIndex: number;
+	/** seconds; the chunk scans [tStart, tEnd) */
+	tStart: number;
+	tEnd: number;
+}
+
+export interface AbortChunkRequest {
+	kind: "abortChunk";
+}
+
+export type WorkerRequest =
+	| InitRequest
+	| AnalyzeRequest
+	| ScanChunkRequest
+	| AbortChunkRequest;
+
 export type WorkerResponse =
 	| { kind: "ready" }
 	| {
@@ -36,6 +64,23 @@ export type WorkerResponse =
 			/** lossless PNG of the exact frame that was analyzed; present when events fired */
 			frame?: Blob;
 	  }
-	/** all detectors have reported for frame t */
-	| { kind: "done"; t: number }
+	/** all due detectors have reported for frame t (per-frame path only) */
+	| {
+			kind: "done";
+			t: number;
+			/** scheduler sees dead air — the caller may widen its sampling stride */
+			calm: boolean;
+			telemetry: ScanTelemetry;
+	  }
+	| {
+			kind: "chunkProgress";
+			chunkIndex: number;
+			/** seconds of video the chunk scan has reached */
+			t: number;
+			mode: "active" | "skim";
+			telemetry: ScanTelemetry;
+			/** small bitmap of the latest decoded frame, for the preview canvas */
+			preview?: ImageBitmap;
+	  }
+	| { kind: "chunkDone"; chunkIndex: number; telemetry: ScanTelemetry }
 	| { kind: "error"; message: string };
diff --git a/package.json b/package.json
index 0d4de0f4a..9ab41b966 100644
--- a/package.json
+++ b/package.json
@@ -33,6 +33,7 @@
 		"test:scanner": "vitest run --project scanner",
 		"scanner:report": "vite-node -c scripts/scanner/vite-node.config.ts scripts/scanner/report.ts",
 		"scanner:fixtures": "vite-node -c scripts/scanner/vite-node.config.ts scripts/scanner/run-fixtures.ts",
+		"scanner:replay": "vite-node -c scripts/scanner/vite-node.config.ts scripts/scanner/replay-frames.ts",
 		"scanner:bootstrap-atlas": "vite-node -c scripts/scanner/vite-node.config.ts scripts/scanner/bootstrap-atlas-from-fixture.ts",
 		"scanner:build-glyph-atlas": "vite-node -c scripts/scanner/vite-node.config.ts scripts/scanner/build-glyph-atlas.ts",
 		"scanner:build-localized-entries": "vite-node -c scripts/scanner/vite-node.config.ts scripts/scanner/build-localized-entries.ts",
diff --git a/scripts/scanner/replay-frames.ts b/scripts/scanner/replay-frames.ts
new file mode 100644
index 000000000..f4784b951
--- /dev/null
+++ b/scripts/scanner/replay-frames.ts
@@ -0,0 +1,82 @@
+/** biome-ignore-all lint/suspicious/noConsole: CLI script output */
+/**
+ * CLI harness: replay a directory of extracted VoD frames through the full
+ * detector registry driven by a DetectorScheduler, mirroring the analyzer
+ * worker's chunk scan — to reproduce scheduling-dependent misses offline.
+ * This is the tool for "the browser scan missed an event that a fixture
+ * parses fine": extract the surrounding footage with
+ *   ffmpeg -ss <startT> -i vod.mkv -t 30 -vf fps=6 frames/f%04d.png
+ * then replay it and watch which checks the scheduler ran and what they saw.
+ *
+ * Usage: pnpm scanner:replay <framesDir> <startT> <fps>
+ * (frames are ffmpeg-numbered f0001.png..; t = startT + (n-1)/fps)
+ */
+import { readdirSync } from "node:fs";
+import { join } from "node:path";
+import { loadOpenCV } from "../../app/features/scanner/core/cv";
+import { MAP_START_EVENT_TYPE } from "../../app/features/scanner/core/detectors/map-start/index";
+import {
+	createAllDetectors,
+	SCOREBOARD_EVENT_TYPES,
+} from "../../app/features/scanner/core/detectors/registry";
+import { DetectorScheduler } from "../../app/features/scanner/core/detectors/scheduler";
+import { normalizeFrame, toMat } from "../../app/features/scanner/core/image";
+import { readImage } from "../../app/features/scanner/node/image-io";
+import { loadScoreboardResources } from "../../app/features/scanner/node/resources";
+
+const [framesDir, startTArg, fpsArg] = process.argv.slice(2);
+if (!framesDir || !startTArg || !fpsArg) {
+	console.error("usage: pnpm scanner:replay <framesDir> <startT> <fps>");
+	process.exit(1);
+}
+const startT = Number(startTArg);
+const fps = Number(fpsArg);
+
+await loadOpenCV();
+const detectors = createAllDetectors(await loadScoreboardResources());
+const scheduler = new DetectorScheduler(detectors, {
+	matchOpeningTypes: [MAP_START_EVENT_TYPE],
+	matchClosingTypes: SCOREBOARD_EVENT_TYPES,
+});
+scheduler.reset(startT);
+
+const files = readdirSync(framesDir)
+	.filter((f) => f.endsWith(".png"))
+	.sort();
+
+for (const [i, file] of files.entries()) {
+	const t = startT + i / fps;
+	const due = scheduler.dueDetectors(t);
+	if (due.length === 0) continue;
+	const image = await readImage(join(framesDir, file));
+	const src = toMat(image);
+	const frame = normalizeFrame(src);
+	src.delete();
+	for (const detector of detectors) {
+		if (!due.includes(detector.id)) continue;
+		const gate = detector.gate(frame);
+		scheduler.recordGate(detector.id, t, gate.pass);
+		if (!gate.pass) {
+			if (process.env.LOG_GATES?.includes(detector.id)) {
+				console.log(
+					`${t.toFixed(2)} ${file} ${detector.id} gate=${gate.score.toFixed(3)} FAIL`,
+				);
+			}
+			continue;
+		}
+		if (!scheduler.shouldParse(detector.id, t)) {
+			console.log(
+				`${t.toFixed(2)} ${file} ${detector.id} gate=${gate.score.toFixed(3)} PARSE-SUPPRESSED`,
+			);
+			continue;
+		}
+		const events = detector.parse(frame, t, gate);
+		scheduler.recordParse(detector.id, t, events);
+		console.log(
+			`${t.toFixed(2)} ${file} ${detector.id} gate=${gate.score.toFixed(3)} events=[${events
+				.map((e) => `${e.type}@${e.confidence.toFixed(3)}`)
+				.join(", ")}]`,
+		);
+	}
+	frame.delete();
+}