Address @vanceingalls and @miguel-heygen review findings on #852:
1. Asymmetric soft-skip — only the N=1 plan+render+assemble call was
wrapped in the host-Chrome-failure catch; an SwiftShader / cold-Chrome
flake on the N=4 call would hard-fail instead of soft-skip. Factor a
local runRender() helper and wrap both calls.
2. Vacuously-passing length assertion — 'expect(framesOne.length).toBe(
framesFour.length)' passes when both runs produce 0 frames. Pin the
absolute count (EXPECTED_FRAME_COUNT = 60) so a regression that
identically truncates both renders shows red.
3. CDN version drift — anime-boundary loaded gsap@3.14.2 from jsdelivr
while every other boundary fixture loaded 3.12.2 from cdnjs. Unify on
cdnjs@3.12.2 so the next reader doesn't have to wonder why one fixture
diverges. (gsap is an empty duration-driver in all six fixtures so
the version was never load-bearing — but the divergence reads as
intentional and isn't.)
4. VIDEO_EXT type narrowing — the lookup is Record<"mp4"|"mov"|"webm">
but outputFormat includes "png-sequence". The isPngSequence ternary
short-circuits before png-sequence can reach the indexing site, but TS
can't narrow through that. Add an explicit cast at the indexing site
(not the lookup definition — over-widening to include "png-sequence":
undefined would defeat the existence guarantee).
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Address @vanceingalls review on #851:
1. validateMetadata's codec/format check read 'rc.codec !== undefined &&
rc.format !== undefined && rc.format !== "mp4"'. The behavior was
correct (omitted format defaults to mp4 downstream so codec is legal)
but relied on the reader knowing that default. Normalize 'effectiveFormat
= rc.format ?? "mp4"' before the comparison so the intent reads
directly.
2. The mp4-h264-sdr sibling carries inline rationale for the no-audio
choice (AAC frame quantization extends container.duration past
nb_frames/fps and trips the harness PSNR sampler) and the chunk-seam
mapping (crossfade window 0.9-1.1s straddles frame 30). mp4-h265-sdr
stripped both. Carry them back so the two fixtures stay parallel.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Address @vanceingalls review on #848: the mp4-h264-sdr sibling fixture
explains the crossfade-straddles-frame-30 and continuous-rotation
chunk-seam design choices inline; mov-prores didn't. Add the parallel
comment so the next contributor reading either fixture finds the same
context. Notes specifically that ProRes is intra-only and therefore
exercises the QuickTime atom / -c copy contract rather than frame-level
state continuity.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Address @vanceingalls review on #847: the maxFrameFailures=0 byte-identity
threshold will fail when Chromium's CDP screenshot bytes or libpng's
deflate output shifts on a Docker image bump. Pin the recovery procedure
in the fixture's description so a future on-call sees 'regenerate
baselines' rather than spending time investigating a non-regression.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
James