[Higgs32584]

Part of #1615 (the memory-sized default and the partial .mp4 stay open as follow-ups)

CPU exports kept one frame per thread in flight (batch_size() = threads, clamp 2..16), and Cx::frames rendered the whole batch at once. Only GPU renders had a cap (#879, EFFECTCRAFT_GPU_INFLIGHT). A heavy comp needs gigabytes per frame, so a 16-thread machine got OOM-killed. The headless CLI doesn't read prefs.json, so memory.* budgets gave no way to lower this.

Change (crates/export/src/pipeline.rs)

• New EFFECTCRAFT_CPU_INFLIGHT=N caps how many frames render at once. It reuses the existing capped path map_frames_while: renders go in chunks of N, encodes stay parallel, and there's no lock, so a failing frame can't deadlock or leak.
• cpu_inflight() parses the value. Unset or blank means no cap, which is today's behaviour. An invalid value logs a warning and leaves frames uncapped.
• Inflight { gpu, cpu } combines the caps. While the GPU renders, the smaller cap applies. Once the GPU stops for good (Export: render in parallel once the GPU stops for good #1511), the GPU cap lapses and the CPU cap alone applies (uncapped when there is none), so EFFECTCRAFT_CPU_INFLIGHT=4 on a GPU project falls back to 4 renders at once, not 1.
• A CPU cap also bounds the window of finished images waiting to encode: windows are cpu frames instead of one per thread, so a cap of 2 on 16 threads never holds more than 2 rendered images. Each window still encodes in parallel. A GPU cap alone keeps its window of max(cap, threads) as before.
• Unit tests cover the parsing, the combination rules, a cap of 2 on an 8-thread pool keeping at most 2 renders in flight and at most 2 images waiting to encode, and the CPU cap taking over after the GPU stops.

Not in this PR (follow-up design)

• An automatic default sized from available memory, e.g. min(threads, (available - memory.ramReservedGb) / frame_bytes). This needs a per-frame cost estimate. The issue measures 1.8 to 5.5 GB per 1080p frame, about 50 to 150 times the 33 MB output image, so output size alone is no guide. System memory reading also lives in effectcraft-engine::sysinfo, which sits above the export crate.
• A partial .mp4 after a kill. The triage comment asks for that to go in its own ticket.

Tested

• cargo test -p effectcraft-export --lib -- pipeline (16 passed)
• cargo clippy -p effectcraft-export --lib --tests -- -D warnings (clean), cargo fmt --check (clean)
• Not run: the full workspace suite, cargo xtask ci, or an export of a heavy comp to measure peak memory.

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features
  • Added an optional limit on CPU frames in flight, configurable with EFFECTCRAFT_CPU_INFLIGHT.
  • When both CPU and GPU limits are configured, the stricter limit applies while GPU processing is active. The CPU limit remains effective after GPU processing stops.
  • With a CPU limit, completed images waiting to be encoded count toward the limit. Without an active limit, frames can render and encode in parallel.
• Bug Fixes
  • Invalid CPU limit values trigger a warning and are ignored; unset or blank values leave the CPU limit disabled.

[FredApps]

• pipeline.rs:76 (inflight_cap): with both caps set, the smaller one never lapses. The GPU cap defaults to 1 (GPU_INFLIGHT_DEFAULT), so on a GPU project EFFECTCRAFT_CPU_INFLIGHT=4 means that once the GPU stops for good, the remaining frames render one at a time, not four. Is that intended? Falling back to the CPU cap when the GPU stops would match what you set. The test at pipeline.rs:700 pins the current behaviour, so please say why.
• "Fixes #1615": the maintainer comment on the issue splits the unplayable partial .mp4 into its own ticket, and the PR lists the memory-sized default as follow-up. Please change this to "Part of" so the issue stays open for the follow-ups, or confirm that the issue can close.
• The code and tests otherwise look right: unset keeps today's behaviour, invalid values warn and leave frames uncapped.
• Holding as a comment: no hosted CI ran on this head, so I have asked for a local run.

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• crates/export/src/pipeline.rs

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📝 Walkthrough

The export pipeline now supports an optional CPU frame-in-flight cap. It combines that cap with the GPU cap and applies the resulting limits to frame scheduling and encoding windows. Tests cover parsing, cap selection, bounded windows, output order, and GPU fallback.

Changes: CPU Frame In-Flight Cap

Layer / File(s)	Summary
Parse and combine frame caps crates/export/src/pipeline.rs	Adds EFFECTCRAFT_CPU_INFLIGHT parsing. While the GPU is live, the smaller configured cap applies. After the GPU stops, the CPU cap applies on its own.
Apply caps to rendering and encoding crates/export/src/pipeline.rs	Cx::frames passes both caps and GPU availability to the scheduler. CPU-capped windows limit frames being rendered and images waiting for encoding. Tests cover parsing, cap selection, window limits, output order, and GPU fallback.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix · Severity of issue fixed: Medium

Sequence Diagram(s)

sequenceDiagram
  participant CxFrames
  participant FrameScheduler
  participant Renderer
  participant Encoder
  CxFrames->>FrameScheduler: provide caps and GPU availability
  FrameScheduler->>Renderer: render frames within the active limits
  Renderer->>FrameScheduler: return rendered images
  FrameScheduler->>Encoder: encode each completed window

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Suggested reviewers: matejkozlovsky

Merge Risk: ⚪ Minimal · up to 88f94

No actionable merge-blocking risk is identified for the CPU frame cap. Normal validation remains appropriate before merging.

Security architecture risk: ⚪ Minimal · up to 88f94

The new setting limits simultaneous frame work and remains effective after a GPU failure without granting additional access. Unset or invalid settings retain the previous scheduling behavior.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The protection bounds frame work and retained input images within one scheduling invocation. It is not a process-wide admission controller or byte-memory quota. Movie export still collects converted pixel buffers for a full batch, so the setting does not bound all export memory.

Trust Boundaries and Controls

• observed — The CPU limit is independent of GPU availability, so losing the accelerator cannot remove a configured CPU limit. While both limits apply, minimum selection preserves the stricter concurrency restriction.

Resilience and Maintainability Implications

• observed — Output ownership remains with the existing export context: created filesystem outputs are recorded, and explicit export cancellation invokes their removal. The scheduling change adds no persistent reservation or recovery state; it does not add cleanup guarantees for forced process termination.

Pre-merge checks: 5

Check name	Status	Explanation
Linked Issues check		Issue #1615 identifies CPU frame limiting as a solution for OOM risk. The PR adds EFFECTCRAFT_CPU_INFLIGHT, applies it through map_frames_while, bounds the render and encode window, combines CPU a…
Out of Scope Changes check		The changes stay in crates/export/src/pipeline.rs. They add the issue-related environment variable, cap-combination logic, scheduling behavior, and supporting tests. The reviewed summary shows no un…
Docstring Coverage		Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 16 functions across 1 files.
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: adding a CPU frame-in-flight cap controlled by EFFECTCRAFT_CPU_INFLIGHT.

Full details: Linked Issues check

Explanation

Issue #1615 identifies CPU frame limiting as a solution for OOM risk. The PR adds EFFECTCRAFT_CPU_INFLIGHT, applies it through map_frames_while, bounds the render and encode window, combines CPU and GPU caps, and tests parsing and scheduling behavior. The issue's memory-based sizing, memory-pressure errors, and partial-output handling are suggestions or follow-up work, not unmet coding requirements for this cap.

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Explanation

The changes stay in crates/export/src/pipeline.rs. They add the issue-related environment variable, cap-combination logic, scheduling behavior, and supporting tests. The reviewed summary shows no unrelated product behavior or files.

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Inline comments:
Review comments at @crates/export/src/pipeline.rs:
- Line 249: Update the `map_frames_while` call in the frame pipeline so its
render window never exceeds the configured CPU in-flight cap, rather than
scaling up to the thread-pool size. Ensure retained completed frame images are
also bounded by that cap while preserving parallel encoding.

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[Higgs32584]

@FredApps thanks for the review. Both points are addressed in 88f940d.

• Cap after the GPU stops (inflight_cap): that behaviour wasn't intended. I've changed it. The caps are now an Inflight { gpu, cpu } that map_frames_while checks again for each window and chunk. While the GPU renders, the smaller cap applies. Once the GPU stops for good (Export: render in parallel once the GPU stops for good #1511), the GPU cap lapses and only the CPU cap applies. So EFFECTCRAFT_CPU_INFLIGHT=4 on a GPU project renders 4 at a time after the fallback, not 1. The test that pinned the old behaviour now checks renders(false) == Some(4) for gpu: Some(1), cpu: Some(4). A new test, the_cpu_cap_takes_over_once_the_gpu_stops, runs it on an 8-thread pool and checks that 2 to 4 frames are in flight after the stop.
• "Fixes CLI/export: CPU renders keep one frame per thread in flight with no memory cap, so heavy comps get OOM-killed #1615": changed to "Part of CLI/export: CPU renders keep one frame per thread in flight with no memory cap, so heavy comps get OOM-killed #1615", so the issue stays open for the memory-sized default and the partial .mp4 ticket.

The same commit also fixes CodeRabbit's point that a CPU cap still left up to one finished image per thread waiting to encode. A CPU cap now sets the window size too.

Local run on Windows: cargo test -p effectcraft-export --lib -- pipeline (16 passed), cargo clippy -p effectcraft-export --lib --tests -- -D warnings (clean), and cargo fmt --check (clean). I did not run the full workspace suite or cargo xtask ci, and I did not measure peak memory on a heavy comp.

[FredApps]

Re-reviewed fe88196. The CPU cap now bounds both renders and finished images waiting to encode, and it remains effective after GPU fallback. The updated tests cover these paths, and the description now correctly says Part of #1615. I found no remaining source blocker in the one-file change.

I have not independently verified execution on this head: no hosted workflow run is available, and the reported local test/clippy/fmt result is not an inspectable execution receipt. Please provide a verifiable result for the current head before I approve. I did not launch tests or jobs.

[FredApps]

Approving at fe88196. My earlier comment only held this back for a run I could verify, and I've now done that run myself.

Both points from my review are addressed in 88f940d:

• crates/export/src/pipeline.rs:68 / :88: the caps are an Inflight { gpu, cpu }, checked again for each window. Once the GPU stops, only the CPU cap applies. the_cpu_cap_takes_over_once_the_gpu_stops (:776) covers it.
• A CPU cap now also sizes the encode window, so no more than the cap's worth of finished images waits to encode. a_cpu_cap_bounds_the_images_waiting_to_encode (:747) covers it.
• The description now says "Part of #1615".

fe88196 itself is only a merge of main. git merge-tree against current main is clean, and the diff is still the single file crates/export/src/pipeline.rs.

Checked locally in a fresh worktree at fe88196: cargo fmt --all --check passes, cargo clippy -p effectcraft-export --all-targets -- -D warnings is clean, and cargo test -p effectcraft-export --lib gives 24 passed, 0 failed. No hosted CI workflow has run at this head; the only hosted result is CodeRabbit (success).