[vanceingalls]

What

An optional stage input, segmentVideoFrames. When it's present, each capture segment extracts only the source frames it shows into <workDir>/segment-frames/segment_NNNNN/, deletes them when it closes, and the stage deletes segment files after a successful join. Nothing sets it yet: the routing is the next PR, so no render changes here.

Why

Part 2 of 3. See the last PR for the whole picture.

How

• One stable hook per worker, surviving a recycle. prepare swaps in an injector over that segment's frames, and release removes the folder on success, failure and abort.
• Outside a prepared window, the hook extracts on demand. The drawElement self-verify runs at session open and at each recycle, and stores ground-truth screenshots at samples across the whole composition. A no-op hook would have bypassed its guard at frameCapture.ts and stored black video boxes. Note that captureSegmentedStage does not itself compare drawElement frames with that ground truth, which predates this stack, so what this protects today is the arming path and any later check. So the hook extracts each sampled frame, injects it and deletes it, and carries fresh() for the isolated truth page. frameCapture.ts is unchanged.
• The stall timer starts after prepare, and progress says Reading video for segment N/M, so slow seeks neither trip it nor look frozen.

Test plan

• segmentVideoFrames.test.ts, with a stubbed extractor.
• Stage tests: order of prepare and release, retry, resume, abort mid-capture and mid-extraction, recycle, stall budget, segment delete after a join.
• Resume after segments were deleted recaptures rather than failing, pinned beside validateCompletedSegments.
• Comments follow CONTRIBUTING.md.

🤖 Generated with Claude Code

[heygengenesis]

Verdict: APPROVE · 0 blocker · 1 important · 1 nit · 79072a0

The on-demand hook holds up. fresh() is the only one the engine calls (frameCapture.ts:5629, the self-verify truth page). Recycles only happen between segments, at cadence or on retry, while injector is null. Static dedup turns itself off whenever a hook is set. So each worker's self-verify truth frames come from frames it has actually extracted.

• nit: removeJoinedSegments (captureSegmentedStage.ts:382) doesn't lower the peak. The orchestrator already runs rmSync(segmentDir) on success under the same keepSegments check, right after this stage returns. The peak happens during the concat, which both deletes come after.

Scope

Read segmentVideoFrames.ts and the stage diff end to end, plus the tests. I also traced the engine's BeforeCaptureHook callers: self-verify, prepareFrameForCapture, motion-blur accumulation and deferred drawElement init. CI doesn't run on stacked PRs. The dispatched run 42039548198 on the top branch, 1768fb8, includes this diff and is green.

— Genesis (Claude)

[heygengenesis]

important: Windowed extraction has no transient retry. Flag off, every ffmpeg extraction runs inside runVideoExtractionWithRetry, and so does extractAllDeferredFrames in #7242. These per-segment and on-demand calls don't. A long render makes about one call per video per segment, plus one per self-verify sample on every session open, all while the workers' Chromes are running. One EAGAIN/EMFILE (ffmpeg_transient) or download_transient on any of them propagates: retryAfterTargetLoss rethrows anything that isn't a target loss, so the render fails at segment N. The calibration forFrames call in #7242 also runs before its try, so the same error there kills a render that calibration would otherwise only downgrade to a conservative worker budget.

Fix: wrap this call in runVideoExtractionWithRetry({ signal, maxTransientRetries, onRetry: () => { rmSync(dir, …); mkdirSync(dir, …) } }), passing maxTransientRetries in from the orchestrator as resolveVideoExtractionPolicy().maxTransientRetries. That covers prepare, on-demand and forFrames together. Add one stage test where the stubbed extractor throws a retryable VideoSourceExtractionError once.

The base branch was changed.

[github-actions]

Edit accuracy: accurate 267 (base branch 267), smooth 97 of those

The gate passes.
Smoothness is reported in the artifact, not gated. A case fails only if it fails 2 of 3 runs.

Quarantined, measured but not gated (8)

• seqplainkeys-none-center-r0-nested-z100 (fixed by studio: undo/redo on a keyframed plain element sometimes leaves the box 230-400px off (edit-accuracy seqplainkeys-none-*) #6989): fail / pass / pass, passes
• seqplainkeys-none-center-r0-root-z100 (fixed by studio: undo/redo on a keyframed plain element sometimes leaves the box 230-400px off (edit-accuracy seqplainkeys-none-*) #6989): pass, passes
• seqplainkeys-none-center-r30-root-z100 (fixed by studio: undo/redo on a keyframed plain element sometimes leaves the box 230-400px off (edit-accuracy seqplainkeys-none-*) #6989): not run
• seqplainkeys-none-pct-r0-root-z100 (fixed by studio: undo/redo on a keyframed plain element sometimes leaves the box 230-400px off (edit-accuracy seqplainkeys-none-*) #6989): pass, passes
• seqplainkeys-none-pct-r30-root-z100 (fixed by studio: undo/redo on a keyframed plain element sometimes leaves the box 230-400px off (edit-accuracy seqplainkeys-none-*) #6989): not run
• seqplainkeys-none-px-r0-nested-z100 (fixed by studio: undo/redo on a keyframed plain element sometimes leaves the box 230-400px off (edit-accuracy seqplainkeys-none-*) #6989): pass, passes
• seqplainkeys-none-px-r30-nested-z100 (fixed by studio: undo/redo on a keyframed plain element sometimes leaves the box 230-400px off (edit-accuracy seqplainkeys-none-*) #6989): not run
• seqplainkeys-none-px-r30-root-z100 (fixed by studio: undo/redo on a keyframed plain element sometimes leaves the box 230-400px off (edit-accuracy seqplainkeys-none-*) #6989): not run

Unstable (1)

• seqrotatenudge-none-pct-r0-root-z100: tracking 0.03, pressJump 0, drop 0, reload 3.03, render 0.04, renderKey -, undo false, teleport true / tracking 0.03, pressJump 0, drop 0, reload 0, render 0.08, renderKey -, undo true, teleport true / tracking 0.03, pressJump 0, drop 0, reload 0, render 0.08, renderKey -, undo true, teleport true