Fixes#3012
## What
Fixes `HeadlessExperimental.beginFrame` hanging at 60fps and other high frame rates.
## Why
Warmup always advances Chrome in 33ms steps, but the first capture timestamp was calculated from the output fps.
At 60fps, the last warmup tick is 1947ms, while the next commit tick used to jump back to about 1067ms. Chrome sees time moving backwards and `beginFrame` can stall.
## How
Keep the old timestamps when they are already safe. If the commit tick would go backwards, move the capture baseline past warmup first.
The init commit and both producer probes now use the same timestamp helpers, so they cannot calculate different values.
## Test plan
- [x] Added tests for 24, 30, 31, 32, 33, 60, 120, 240, and 59.94fps
- [x] Added coverage for the actual session baseline, commit parameters, and both producer probe paths
- [x] Engine tests: 1383 passed, 3 skipped
- [x] Producer unit tests passed
- [x] Engine and producer typechecks and builds passed
- [ ] Manual render test
A probe that could not run is no evidence about the GPU, so pointing the
operator at GPU passthrough hid broken Chrome installs behind a phantom
problem. Carry a cause off the probe and emit the matching remediation.
Also un-exports buildUnverifiedHardwareGpuWarning (Fallow: engine test
files are not audit entry points, so a test-only import would not have
counted as a consumer) and covers the non-linux branch via the spy.
Chrome's hardware GL args are advisory: with no usable GPU it silently
falls back to software WebGL and the capture runs at CPU speed. Run the
existing WebGL probe for explicit hardware mode too and warn loudly with
the platform's remediation. The requested mode is still honoured.
Fixes#2967
* fix: bound HDR and video extraction resources
* fix: trim negative video extraction preroll
* fix: skip invisible video extraction windows
* fix: preserve negative-start loop and held tails
* fix: cap finite video slots to source duration
* fix: bound held-tail frame extraction
* fix: plan from playable video duration
* fix: preserve open-ended held video tails
* fix: resolve held tails from decoded frames
* fix: normalize final-frame probe timestamps
* fix: handle unseekable final-frame sources
* fix: dedupe final-frame probes per render
* refactor: clarify output dynamic range contract
Three issues in runFfprobe's process and stream handling.
A filePath of exactly "-" hung for 30 seconds. `--` stops option parsing,
so "-intro.mp4" is safe, but ffprobe rewrites "-" to `fd:` AFTER option
parsing and reads stdin — and stdin was an inherited pipe the parent
never writes to and never ends. The probe ran to the deadline and failed
with an empty diagnostic, because ffprobe never errored so stderr was
blank: 30010 ms and no message, against 28 ms for a normal missing-file
error. Rejected up front, and the child now gets stdio ["ignore", ...]
so no future invocation can block on stdin either.
stdout was decoded per chunk. `stdout += data.toString()` decodes each
64 KiB pipe chunk independently, so a multi-byte character straddling a
boundary became U+FFFD on both sides — verified: 200 KB of 3-byte
characters produced 15 replacements and a string 9 characters longer
than the source. -show_format output above ~64 KiB with non-ASCII tag
text returns silently mangled values, since JSON.parse still succeeds.
Now accumulated through StringDecoder.
Note on testing that one: U+FFFD is valid JSON string content, and
nothing on extractMediaMetadata's public surface exposes a tag value, so
there is no assertion that fails against the old implementation. Rather
than add a test that cannot fail, it is stated here and the bound below
is what the new test covers.
stdout was unbounded. stderr is capped by ManagedChildProcess but stdout
was not, and analyzeKeyframeIntervals emits one line per frame — an
all-intra ProRes proxy can produce an arbitrarily large string. Capped
at 8M characters, which real -show_streams JSON is nowhere near.
Tests: "-" rejected without spawning, the stdio shape, and the size
bound. Reverting the stdin guards fails 1. The first draft of the bound
checked before appending, so a single oversized chunk passed — the test
caught it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The previous gate was a HE-AAC DENYLIST, so every other profile still
got the 1024-sample formula. ffprobe reports codec_name "aac" for all of
them; the framing lives in the profile:
LC 1024 samples/frame <- the only one this maths fits
HE-AAC v1/v2 2048 output samples against a doubled sample_rate
LD 512
ELD 480
Main/SSR/LTP 1024 nominally, unverified here
xHE-AAC variable
LD and ELD therefore had their already-correct container duration
overwritten with a value 2x / ~2.13x too large, and an unknown or
missing profile fell through — so an unrecognised HE spelling preserved
the exact truncation the previous commit set out to close.
Now an affirmative match on LC. Skipping the refinement is harmless:
format.duration is already correct before it runs.
Tests: 11 non-LC profiles (including LD, ELD, xHE-AAC, empty and
unrecognised) assert the container duration is kept AND that the second
probe is not launched; LC still refines, with whitespace tolerated. The
pre-existing duration table asserted that an UNPROFILED "aac" stream
refines — the behaviour under review — so it now states LC explicitly
and adds an unprofiled row that must not refine.
Also strengthened the `--` separator test while it was failing: it
compared a flattened count of 3 across three spawns, which one call
emitting three terminators would satisfy. Now asserts the last two argv
entries per call.
Reverting the allowlist fails 8.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The packet-count probe is a refinement — durationSeconds is already
correct from format.duration before it runs — but it was written as if
it were load-bearing.
It could fail the whole call. No try/catch, and `-count_packets` demuxes
the entire container against runFfprobe's fixed 30s deadline, so a long
AAC file on slow or network storage timed out and extractAudioMetadata
rejected. htmlCompiler catches that under the comment "Source file has
no audio stream", returns duration 0, drops the audio element, and the
render ships silent with no warning. Now caught, keeping the container
duration.
It ignored the caller's AbortSignal. Only the first probe received it,
so aborting during the packet probe let the child run to completion and
the call resolved with full metadata after cancellation — while
audioPadTrim's comment claims the wrapper preserves cancellation. The
signal is forwarded, and an abort still propagates rather than being
swallowed as a refinement failure.
It halved HE-AAC durations. ffprobe reports codec_name "aac" for
HE-AAC v1/v2 as well — the marker is in the profile field — and with SBR
each packet carries 2048 output samples against the doubled output
sample_rate, so the 1024 assumption computed exactly half. A 10:00
podcast became 5:00 and htmlCompiler truncated the audio there. Gated on
profile, with `profile` added to FFProbeStream.
Tests: probe failure, junk output, three HE-AAC profile spellings (which
also assert the second probe is not attempted), and that plain AAC-LC is
still refined. Reverting the guards fails 5.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Two paths the previous guards still let through.
Rounding could recreate Infinity after the finite check. `raw * 100`
overflows for a finite-but-huge rate — "1e307", "1e307/1" — so `rounded`
became Infinity and passed the positivity check, reaching exactly the
`-r Infinity` failure the finite guard exists to prevent. The rounded
result is now checked too.
The rational operands still used parseFloat. The plain-number path
switched to Number() so trailing garbage fails the whole string, but the
numerator and denominator did not, so "60fps/1", "60/1fps" and
"30garbage/1garbage" returned valid rates while the contract says
malformed frame rates fail closed. Both operands are now parsed strictly,
and an empty operand ("/", "/1", "30/") is rejected rather than coerced.
Tests: 8 malformed inputs and 3 overflow cases in the direct table.
Reverting either fix fails 5.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
parseFrameRate guarded its operands but not its result, so several
inputs produced values that are not usable frame rates — and nothing
downstream catches them, because callers use `meta.fps || 30`, which
only rescues 0 and NaN. Everything below was truthy and flowed into
buildEncoderArgs as `-r <value>` (rejected by ffmpeg mid-render) and
into frameCount arithmetic.
"1e308/1e-10", "2/1e-320" -> Infinity (finite operands, infinite quotient)
"-30/1", "30/-1", "-60" -> negative (sign never checked)
"30/1/2" -> 30 (parts.length !== 2 fell through)
"60fps" -> 60 (parseFloat stops at garbage)
Now: the quotient is checked rather than the operands, non-positive is
rejected, more than two parts is rejected, and the single-part path uses
Number() rather than parseFloat so trailing garbage fails the whole
string.
Separately, 2dp rounding collapsed any rate below 0.005 to exactly 0,
and the caller's 30fps default then re-encoded a 300-second 1/300-fps
timelapse as a ~1/30-second clip with frameCount 9000 for a 1-frame
file. Those floor to 0.01 instead.
parseFrameRate is now exported and tested directly. The previous table
drove it through extractMediaMetadata behind a spawn mock, costing a
vi.resetModules() plus a re-import of core's 238-file barrel per row
(74.9 ms vs 0.094 ms) — and 4 of its 7 rows produced identical values
against the pre-fix implementation, so it could not fail for the bugs it
existed to catch. The replacement fails 9 against that implementation.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Three defects in how ffprobe output and the PNG fallback are combined.
The cICP fallback was unreachable. `ffprobeColorSpace ?? stillImageMeta
?.colorSpace` discarded the PNG result whenever ffprobe returned ANY
colour field — and ffprobe emits color_space "gbr" for every PNG,
including a plain rgb24 with no colour metadata. So on the build the
parser exists for (reports gbr, does not decode cICP) an HDR PQ PNG
resolved colorTransfer "" , isHdrColorSpace() returned false, and the
still graded SDR. Now merged per field.
hasAlpha's anchor bound to one alternative. In
/(^|[^a-z])yuva|rgba|.../ the `|` is looser than concatenation, so
(^|[^a-z]) guarded `yuva` and nothing else. The list also omitted abgr,
ya8, ya16 and ayuv64, and `gray[a-z0-9]*a` matched only gray8a/gray16a —
names FFmpeg renamed to ya8/ya16 in 2013, so dead against modern builds.
A ya8 grayscale-plus-alpha PNG reported hasAlpha:false, resolveFrameFormat
picked jpg and the overlay flattened to an opaque rectangle. Replaced
with the start-anchored form studio-server already uses, extracted as
exported pixelFormatHasAlpha so the test asserts the shipped predicate
rather than a copy of the pattern.
The PNG parse ran eagerly and was discarded. It sat before the first
await, so readFileSync plus the CRC walk executed for every file before
a single ffprobe was spawned — a caller fanning out over
composition.images with Promise.all serialised entirely: 12 4K PNGs took
2649 ms against 170 ms probe-only, 2.5 s of event-loop stall that also
blocks Puppeteer IPC. On the happy path the value was then thrown away.
Now lazily memoized behind the paths that actually consult it.
Tests: 18 pix_fmt cases against the real predicate. Reverting the regex
fails 4.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
zlib.crc32 landed in Node 22.2.0, but engine and cli both declare
`"node": ">=22"` and the runtime gate is major-only, so 22.0 and 22.1
are supported. A NAMED import of a missing export throws at module
EVALUATION — ffprobe.ts would have failed to load at all on those
runtimes, before any PNG was touched, taking every probe with it.
Namespace import plus a capability check, with the previous
bit-at-a-time implementation retained as the fallback. Modern runtimes
keep the 210ms -> 1.3ms win; older ones keep working.
Raising the floor to >=22.2.0 was the alternative, but that is a
user-facing support change and does not belong in a PNG bug fix.
Tests: the same HDR PNG parses identically with the native export
absent, and a corrupt chunk still rejects on the fallback path.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Three defects in the PNG metadata fallback, all introduced when the
cICP early return became an accumulator.
Corrupt trailing chunk nulls a good result. cICP must precede IDAT, so
continuing past it only visits chunks this parser ignores — while making
whole-file integrity a precondition for returning anything. A truncated
or bad-CRC chunk after cICP in an otherwise-good HDR PNG returned null,
and extractMediaMetadata then re-throws the ffprobe error it had
swallowed instead of using the fallback it just computed: the render
dies on a host without FFmpeg, or grades SDR on a build that does not
decode cICP. Now stops once dimensions and colour are known.
A second IHDR overwrote the dimensions. PNG permits exactly one, first,
but nothing enforced that here — a trailing [IHDR 1x1] replaced a real
3840x2160 and the producer laid out a one-pixel image. Anchored to the
first. The length guard was also `>= 8` against a spec length of 13,
which accepted a truncated header and read height out of the CRC bytes.
crc32 was hand-rolled bit-at-a-time and fed a Buffer.concat per chunk.
Since the walk no longer stops early it CRC'd whole files: 210 ms on a
12 MiB PNG, 647 ms on a 35 MiB 4K one, synchronously on the event loop,
plus ~11 MB of garbage per parse from concatenating a 4-byte type tag
onto every chunk. node:zlib's crc32 is native and takes a running seed,
so type and data hash in sequence with no copy. 210.28 ms -> 1.291 ms.
Tests: 5 regressions — corrupt-after-cICP, truncation after cICP,
second IHDR, short IHDR, and that a corrupt IHDR/cICP still rejects.
Reverting the break or the anchor fails 3.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
- parseFrameRate now rejects malformed ratios (e.g. "30/", "30/0") instead of NaN.
- Add "--" before file paths so names starting with "-" are not parsed as options.
- cICP PNG chunk no longer returns before IHDR supplies width and height.
- Add regression tests for option injection, frame rates, and cICP ordering.
Review findings on #2891. Two of them bite directly on this PR's own
purpose — making the fleet element-count distribution readable — so they
are fixed rather than noted.
countElementTags counted `</` + letter anywhere, including inside inline
JS. A compiled comp containing `const h = "</div>"` or a template literal
building `</span>` inflated the count once per occurrence. Compiled comps
embed large inline scripts, so the bias is systematic, not noise, and it
lands entirely on the ~83% of renders with no probe session — precisely
the cohort this PR exists to characterize. Script and style bodies are
now stripped before matching; losing their own closing tags costs 1-2
counts against a threshold in the thousands.
The new elementCount fell back to 0 when its page.evaluate threw,
following the tweenCount pattern beside it. For this field that pattern
is wrong: evaluate failures concentrate on the huge-DOM compositions the
field is meant to observe, and a 0 there is indistinguishable from a
legitimately empty comp, so the fleet p50/p99 would absorb both silently.
It is now undefined on failure, the INIT console line omits the token
entirely rather than emitting a zero, and the parser reports absent —
mirroring the live/static provenance split the routing resolver already
uses.
Also documented: the "every render reaches this path" claim holds only
for renders that survive to end of init, so the tail is survivor-biased
and should be read as a lower bound; and the two element-count fields now
say plainly which is which — composition_element_count gates routing,
observability_init_element_count is the observational counterpart — so
the follow-up analysis can't query the wrong one.
Nits: envInt is integer-only per its name, both live-DOM reads use
getElementsByTagName (live collection length, no NodeList materialized on
the 40k-node tail), and the attribution block notes that it runs with
routing off by design.
Fault injection confirms the new tests bite: disabling script stripping
fails 4, and the zero-vs-undefined case is pinned separately.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The short-comp routing gate can only read a live element count when a
probe session exists, and the first v0.7.83 data shows that is far rarer
than estimated: 17% of renders (86/503), not the ">=28%" the video-presence
proxy suggested. The other 83% fall back to a static source scan, which
is exactly blind to the shape that motivated the live count — small
markup, thousands of script-created nodes.
That leaves the fleet element-count distribution unknowable for most
renders, and the observed distribution is already surprising: p99 ~900,
max 1,420 against a 2,500 ceiling calibrated on 7k/20k/40k synthetic
nodes. Either the ceiling is close to irrelevant, or the large-DOM tail
is hiding in the 83% we cannot see. Both readings change what PR B
should do, and neither is decidable from probed renders alone (they are
a biased sample — they got a probe *because* they carry media or
unresolved compositions).
So measure it where every render already goes: capture-session init.
`collectSessionInitTelemetry` gains a querySelectorAll("*") count beside
the tween count it already collects, riding the same channel to
`observability_init_element_count`. This is observational only — capture
has begun, far too late to route on — and it deliberately does not feed
the gate. It answers the distribution question the gate cannot.
Coverage for this channel is proven rather than assumed: the tween-count
fix that shipped in v0.7.83 took the clamped-parallel bucket from 0/272
renders to 217/217, and 23.1% -> 100% overall.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The routing surface the short-comp benchmarks validated is (motion x DOM
size x frames). After the baseline release, fleet telemetry carries DOM
size (composition_element_count) and frames on every render — but the
motion proxy, observability_init_tween_count, has 0% coverage on the
exact renders the band routes: parallel workers' console buffers (and so
the [FrameCapture:INIT] line the summary parses) only propagate to the
orchestrator on FAILURE. Single-worker screenshot renders report it;
the multi-worker clamp bucket never does. Verified against 7d of fleet
data: 35k screenshot renders carry tween counts, 0 of 9,600 band renders.
Fix rides the one channel parallel workers already return on success —
the per-worker CapturePerfSummary. Sessions record initTelemetry on
every init path; the perf summary now carries it; the orchestrator
max-merges across workers (same multi-session semantics the console
parser uses) and feeds it to the observability summary as a structured
fallback, console lines still refining when present.
With this, every band render carries full coordinates — (elements,
tweens, frames, path, speed) — which buys two reads: regressing wild DE
speed against element count on the existing 900+ inversions validates
the bench's 0.50ms/element slope BEFORE the routing flip, and any
post-flip misroute can be reproduced locally by feeding its telemetry
row straight into gen-crossover-comp's knobs (--movers ~ tween count,
--static ~ element count) and re-benching.
(Also drops a now-stale fallow suppression in render.ts — the test-only
reset export it guarded gained real test importers, so the issue it
suppressed no longer exists and the gate flags the leftover.)
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Three review findings on the win32 drawElement PR:
1. gpu_renderer shipped the raw UNMASKED_RENDERER_WEBGL string — unbounded,
driver-authored, GPU-model-specific, and |-joined across parallel
sessions, i.e. high cardinality by construction, against this file's own
convention of sanitizing engine-sourced strings (deGateReason is a
bucket; error messages go through redactTelemetryString). Now bucketed at
the source by classifyGpuRenderer to <backend>/<vendor>
(metal/apple, d3d11/nvidia, swiftshader/other, ...), which is the whole
analytic signal the win32 rollout needs and nothing else. The raw string
never leaves the engine.
2. gpu_renderer reached render_complete only, so a crashed render — the
cohort the field exists to attribute — carried no backend. It now rides
RenderCaptureObservability (deGpuRenderer, sourced from the live probe
session like the de_* counters), so both render_complete and
render_error carry it and a hard failure still reports its GPU backend.
On render_complete the perfSummary value still wins by spread order.
3. Restore the fallow-ignore-next-line suppression above
__resetDeParallelRouterTrialStateForTests: CLI test files are not fallow
entry points, so removing it fails the CI dead-code audit (local
pre-commit passed only because of its changed-file scope).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Widen the default-on drawElement clamp from darwin-only to darwin|win32
(still requiring a non-software-GPU browser). The darwin restriction was a
validation envelope, not an architectural limit — the CanvasDrawElement
Chrome flag ships on every platform, and every safety layer that made the
macOS default-on release (v0.7.38) survivable is platform-neutral:
compile-time gates, the SwiftShader init gate, per-render worker-encode
self-verification with screenshot fallback, and the blank guard. Worst case
on an unvalidated D3D11 backend is the same as on Metal: verify catches a
bad frame and the render re-runs on the screenshot baseline.
Why now: 30-day telemetry shows ~206k non-CI hardware-GPU Windows renders
(~78% of the win32 fleet, 18k installs) held on the slow screenshot path by
the clamp — the second-largest perf population after macOS, carrying ~1,550
capture-hours/month in the DE-eligible >=700-frame band alone at a measured
~2x speedup opportunity.
Instrumentation for the new cohort: drawElement session init now records the
raw WebGL UNMASKED_RENDERER_WEBGL string (detectSwiftShader generalized to
detectGpuBackend — same single evaluate, the string was previously read and
discarded) and threads it session -> CapturePerfSummary -> RenderPerfSummary
-> render_complete as `gpu_renderer`. drawElement damage proved
compositor-backend-specific throughout the macOS rollout, so D3D11-cohort
failures must cluster by ANGLE backend + GPU vendor (NVIDIA/AMD/Intel), not
just `os`.
The two DE clamp branches are extracted into a pure, unit-tested
`resolveDefaultDrawElement` (platform + GPU mode + worker-encode + explicit
opt-in), which also drops resolveConfig's cyclomatic complexity. The win32
streaming-encode compound tests collapse onto one shared helper.
Linux stays excluded: that fleet is headless/Docker SwiftShader, where DE
has no speedup and known rendering defects. Kill switches unchanged:
PRODUCER_EXPERIMENTAL_FAST_CAPTURE=false, --experimental-fast-capture=false.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Miguel Ángel