Files
hyperframes/skills/remotion-to-hyperframes/assets/test-corpus/tier-2-multi-scene
James 9ff46d79b7 feat(skills): remotion-to-hyperframes corpus T1+T2 (3/7)
Adds the first two test fixtures the skill is graded against. Each fixture
ships:
  - remotion-src/  full Remotion project (package.json, src/, remotion.config.ts, tsconfig.json)
  - hf-src/        hand-translated HyperFrames composition (index.html)
  - expected.json  tier metadata + SSIM threshold + translation notes + measured validation
  - README.md      human walk-through of the translation choices
  - setup.sh       (T2 only) generates binary assets (PNG, WAV) via ffmpeg

T1 — title-card-fade
- 3 s @ 30 fps, 1280x720
- Single AbsoluteFill, single useCurrentFrame interpolate
  with multi-segment input [0,15,75,90] -> [0,1,1,0]
- Validated mean SSIM 0.974, threshold 0.95
  (~0.025 gap from font-fallback divergence between Remotion's bundled
   Chromium and HF's chrome-headless-shell)

T2 — title-image-outro
- 6 s @ 30 fps, 1280x720, three Sequences (TitleScene, ImageScene, OutroScene)
- Exercises spring, interpolate, Audio, Img, staticFile
- Spring -> GSAP back.out(1.4) translation
- Validated mean SSIM 0.985, threshold 0.95
  (translation came out cleaner than predicted; spring->back.out drift was
   smaller than the ~0.05 budget I'd expected)
- setup.sh generates a 200x200 blue PNG and a 6 s silent WAV via ffmpeg
  so binaries stay out of the repo

Calibration done end-to-end: rendered Remotion baseline + HF translation,
ran scripts/render_diff.sh, set thresholds ~0.02 below measured p05.

Critical Remotion config: setVideoImageFormat("png") + setColorSpace("bt709").
The default JPEG output writes yuvj420p (full-range) which costs ~0.05 SSIM
vs HF's yuv420p (limited-range). Both fixtures' remotion.config.ts encode
this so render_diff.sh measures translation fidelity, not encoder differences.

Both fixtures lint clean (0 blockers via scripts/lint_source.py).
T2 staticFile() references correctly flagged as info-level findings.

The fixtures are not yet wired into CI — that comes with PR 7's orchestrator.
For now, render and eval are documented in each README and run by hand.
2026-04-27 23:54:28 +00:00
..

Tier 2 — title-image-outro

What it tests

Three-scene composition. Each scene exercises a different Remotion idiom:

  1. Scene 1 (02 s) — TitleScene with spring({damping:12, stiffness:100, mass:1}) driving a transform: scale() on text. Tests the lossy spring → GSAP ease translation.
  2. Scene 2 (24 s) — ImageScene that fades in a staticFile-loaded image and linearly scales it from 0.8 → 1.0. Tests asset paths + linear interpolate.
  3. Scene 3 (46 s) — OutroScene with a 1-s linear fade-in. Sanity check after the harder scenes.

A silent 6-second WAV plays throughout at volume={0.5}. Tests <Audio> translation.

If a translation passes T2, the skill correctly handles <Sequence> boundaries, <Audio> / <Img> / staticFile, and the Remotion spring → GSAP ease heuristic.

Translation walk-through

Remotion HyperFrames
<Sequence from={0} durationInFrames={60}> <div data-start="0" data-duration="2" data-track-index="0">
spring({frame, fps, config: {damping:12, stiffness:100, mass:1}}) gsap.to(target, { scale: 1, duration: 0.7, ease: "back.out(1.4)" })
<Audio src={staticFile("music.wav")} volume={0.5} /> <audio src="assets/music.wav" data-start="0" data-duration="6" data-volume="0.5" data-track-index="1">
<Img src={staticFile("square.png")} /> <img src="assets/square.png"> (with setup.sh copying into both trees)
interpolate(frame, [0, 15], [0, 1]) at 30 fps gsap.to(target, { opacity: 1, duration: 0.5, ease: "none" })

The scene crossfading is a HyperFrames idiom, not a Remotion one: at scene boundaries we gsap.set(scene, { opacity: 0 }) so the previous scene disappears at the right time. Remotion does this implicitly by virtue of <Sequence>'s durationInFrames.

How to render and evaluate

# 1. Generate the binary assets (PNG + WAV) via ffmpeg
./setup.sh

# 2. Render Remotion baseline
cd remotion-src && npm install && npm run render

# 3. Render HyperFrames translation
cd ../hf-src && npx hyperframes render --output ../hf.mp4

# 4. Compare
../../../scripts/render_diff.sh ./remotion-src/out/baseline.mp4 ./hf.mp4 ./diff

Why threshold 0.95?

Same threshold as T1 (expected.json codifies it for the orchestrator). Spring → back.out(1.4) came in cleaner than predicted during calibration — the validated mean is 0.985 against the 0.95 gate. If the translation breaks anything else (spring overshoot wrong, stagger off, asset path drift), mean SSIM will fall well below 0.95 — that's the failure signal.