HyperFrames

HTML is the source of truth for video. A composition is an HTML file with data-* attributes for timing, a GSAP timeline for animation, and CSS for appearance. The HyperFrames engine captures the page frame-by-frame and encodes to MP4/WebM with FFmpeg.

Complement to manim-video: Use manim-video for mathematical/geometric explainers (equations, 3B1B-style). Use hyperframes for motion-graphics, talking-head with captions, product tours, social overlays, shader transitions, and anything driven by real video/audio media.

When to Use

• User asks for a rendered video from text, a script, or a website
• Animated title cards, lower thirds, or typographic intros
• Captioned narration video (TTS + captions synced to waveform)
• Audio-reactive visuals (beat sync, spectrum bars, pulsing glow)
• Scene-to-scene transitions (crossfade, wipe, shader warp, flash-through-white)
• Social overlays (Instagram/TikTok/YouTube style)
• Website-to-video pipeline (capture a URL, produce a promo)
• Any HTML/CSS/JS animation that must render deterministically to a video file

Do not use this skill for:

• Pure math/equation animation (→ manim-video)
• Image generation or memes (→ meme-generation, image models)
• Live video conferencing or streaming

Quick Reference

npx hyperframes init my-video               # scaffold a project
cd my-video
npx hyperframes lint                        # validate before preview/render
npx hyperframes preview                     # live-reload preview (long-lived server, port 3002)
npx hyperframes render --output final.mp4   # render to MP4
npx hyperframes doctor                      # diagnose environment issues

preview is a long-lived Next.js server that holds Chrome render workers open. Always stop it when done (see [Cleanup](#cleanup)) — a forgotten preview keeps idle chrome-headless-shell workers alive that, on GPU-less hosts (WSL, containers, CI), spin a CPU core each indefinitely via software WebGL (swiftshader).

Render flags: --quality draft|standard|high · --fps 24|30|60 · --format mp4|webm · --docker (reproducible) · --strict.

Full CLI reference: [references/cli.md](references/cli.md).

Setup (one-time)

bash "$(dirname "$(find ~/.hermes/skills -path '*/hyperframes/SKILL.md' 2>/dev/null | head -1)")/scripts/setup.sh"

The script:

1. Verifies Node.js >= 22 and FFmpeg are installed (prints fix instructions if not).
2. Installs the hyperframes CLI globally (npm install -g hyperframes@>=0.4.2).
3. Pre-caches chrome-headless-shell via Puppeteer — required for best-quality rendering via Chrome's HeadlessExperimental.beginFrame capture path.
4. Runs npx hyperframes doctor and reports the result.

See [references/troubleshooting.md](references/troubleshooting.md) if setup fails.

Procedure

1. Plan before writing HTML

Before touching code, articulate at a high level:

• What — narrative arc, key moments, emotional beats
• Structure — compositions, tracks (video/audio/overlays), durations
• Visual identity — colors, fonts, motion character (explosive / cinematic / fluid / technical)
• Hero frame — for each scene, the moment when the most elements are simultaneously visible. This is the static layout you'll build first.

Visual Identity Gate (HARD-GATE). Before writing ANY composition HTML, a visual identity must be defined. Do NOT write compositions with default or generic colors (#333, #3b82f6, Roboto are tells that this step was skipped). Check in order:

1. DESIGN.md at project root? → Use its exact colors, fonts, motion rules, and "What NOT to Do" constraints.
2. User named a style (e.g. "Swiss Pulse", "dark and techy", "luxury brand")? → Generate a minimal DESIGN.md with ## Style Prompt, ## Colors (3-5 hex with roles), ## Typography (1-2 families), ## What NOT to Do (3-5 anti-patterns).
3. None of the above? → Ask 3 questions before writing any HTML:

• Mood? (explosive / cinematic / fluid / technical / chaotic / warm)
• Light or dark canvas?
• Any brand colors, fonts, or visual references?

Then generate a DESIGN.md from the answers. Every composition must trace its palette and typography back to DESIGN.md or explicit user direction.

2. Scaffold

npx hyperframes init my-video --non-interactive

Templates: blank, warm-grain, play-mode, swiss-grid, vignelli, decision-tree, kinetic-type, product-promo, nyt-graph. Pass --example <name> to pick one, --video clip.mp4 or --audio track.mp3 to seed with media.

3. Layout before animation

Write the static HTML+CSS for the hero frame first — no GSAP yet. The .scene-content container must fill the scene (width:100%; height:100%; padding:Npx) with display:flex + gap. Use padding to push content inward — never position: absolute; top: Npx on a content container (content overflows when taller than the remaining space).

Only after the hero frame looks right, add gsap.from() entrances (animate to the CSS position) and gsap.to() exits (animate from it).

See [references/composition.md](references/composition.md) for the full data-attribute schema and composition rules.

4. Animate with GSAP

Every composition must:

• Register its timeline: window.__timelines["<composition-id>"] = tl
• Start paused: gsap.timeline({ paused: true }) — the player controls playback
• Use finite repeat values (no repeat: -1 — breaks the capture engine). Calculate: repeat: Math.ceil(duration / cycleDuration) - 1.
• Be deterministic — no Math.random(), Date.now(), or wall-clock logic. Use a seeded PRNG if you need pseudo-randomness.
• Build synchronously — no async/await, setTimeout, or Promises around timeline construction.

See [references/gsap.md](references/gsap.md) for the core GSAP API (tweens, eases, stagger, timelines).

5. Transitions between scenes

Multi-scene compositions require transitions. Rules:

1. Always use a transition between scenes — no jump cuts.
2. Always use entrance animations on every scene element (gsap.from(...)).
3. Never use exit animations except on the final scene — the transition IS the exit.
4. The final scene may fade out.

Use npx hyperframes add <transition-name> to install shader transitions (flash-through-white, liquid-wipe, etc.). Full list: npx hyperframes add --list.

6. Audio, captions, TTS, audio-reactive, highlighting

• Audio: always a separate <audio> element (video is muted playsinline).
• TTS: npx hyperframes tts "Script text" --voice af_nova --output narration.wav. List voices with --list. Voice ID first letter encodes language (a/b=English, e=Spanish, f=French, j=Japanese, z=Mandarin, etc.) — the CLI auto-infers the phonemizer locale; pass --lang only to override. Non-English phonemization requires espeak-ng installed system-wide.
• Captions: npx hyperframes transcribe narration.wav → word-level transcript. Pick style from the transcript tone (hype / corporate / tutorial / storytelling / social — see the table in references/features.md). Language rule: never use .en whisper models unless the audio is confirmed English — .en translates non-English audio instead of transcribing it. Every caption group MUST have a hard tl.set(el, { opacity: 0, visibility: "hidden" }, group.end) kill after its exit tween — otherwise groups leak visible into later ones.
• Audio-reactive visuals: pre-extract audio bands (bass / mid / treble) and sample per-frame inside the timeline with a for loop of tl.call(draw, [], f / fps) — a single long tween does NOT react to audio. Map bass → scale (pulse), treble → textShadow/boxShadow (glow), overall amplitude → opacity/y/backgroundColor. Avoid equalizer-bar clichés — let content guide the visual, audio drive its behavior.
• Marker-style highlighting: highlight, circle, burst, scribble, sketchout effects for text emphasis are deterministic CSS+GSAP — see references/features.md#marker-highlighting. Fully seekable, no animated SVG filters.
• Scene transitions: every multi-scene composition MUST use transitions (no jump cuts). Pick from CSS primitives (push slide, blur crossfade, zoom through, staggered blocks) or shader transitions (flash-through-white, liquid-wipe, cross-warp-morph, chromatic-split, etc.) via npx hyperframes add. Mood and energy tables live in references/features.md#transitions. Do not mix CSS and shader transitions in the same composition.

7. Lint, validate, inspect, preview, render

npx hyperframes lint              # catches missing data-composition-id, overlapping tracks, unregistered timelines
npx hyperframes validate          # WCAG contrast audit at 5 timestamps
npx hyperframes inspect           # visual layout audit — overflow, off-frame elements, occluded text
npx hyperframes preview           # live browser preview
npx hyperframes render --quality draft --output draft.mp4    # fast iteration
npx hyperframes render --quality high --output final.mp4     # final delivery

hyperframes validate samples background pixels behind every text element and warns on contrast ratios below 4.5:1 (or 3:1 for large text). hyperframes inspect is the layout-side companion — runs the page at multiple timestamps and flags issues that a static lint can't see (a caption that wraps past the safe area only at 4.5s, a card that overflows when its title is the longest variant, an element that ends up behind a transition shader). Run inspect especially on compositions with speech bubbles, cards, captions, or tight typography.

8. Website-to-video (if the user gives a URL)

Use the 7-step capture-to-video workflow in [references/website-to-video.md](references/website-to-video.md): capture → DESIGN.md → SCRIPT.md → storyboard → composition → render → deliver.

Cleanup

render is one-shot (workers exit when it finishes). preview is not — it runs a background Next.js server that keeps Chrome workers resident until you stop it. Never leave one running: on GPU-less hosts each idle worker's swiftshader process pegs a CPU core, and a preview left open for days stacks up multiple.

Stop a preview when the user is done reviewing (or before starting a new one):

pkill -f "hyperframes.*preview"     # the Studio server (frees port 3002)
pkill -f chrome-headless-shell      # its render workers; only safe if nothing else uses them

If unsure whether other tools use chrome-headless-shell, check first: pgrep -af chrome-headless-shell. Recover a wedged host (many idle workers spinning CPU) the same way — see [references/troubleshooting.md](references/troubleshooting.md#runaway-cpu-from-leftover-preview-workers).

Pitfalls

• Leaving preview running — it's a long-lived server holding Chrome workers; on WSL/containers/CI those idle workers spin a CPU core each (software WebGL). Stop it when done — see [Cleanup](#cleanup).

• HeadlessExperimental.beginFrame' wasn't found — Chromium 147+ removed this protocol. Ensure you're on hyperframes@>=0.4.2 (auto-detects and falls back to screenshot mode). Escape hatch: export PRODUCER_FORCE_SCREENSHOT=true. See hyperframes#294 and [references/troubleshooting.md](references/troubleshooting.md).
• System Chrome (not chrome-headless-shell) — renders hang for 120s then timeout. Run npx puppeteer browsers install chrome-headless-shell (setup.sh does this). hyperframes doctor reports which binary will be used.
• repeat: -1 anywhere — breaks the capture engine. Always compute a finite repeat count.
• gsap.set() on clip elements that enter later — the element doesn't exist at page load. Use tl.set(selector, vars, timePosition) inside the timeline instead, at or after the clip's data-start.
• <br> inside content text — forced breaks don't know the rendered font width, so natural wrap + <br> double-breaks. Use max-width to let text wrap. Exception: short display titles where each word is deliberately on its own line.
• Animating visibility or display — GSAP can't tween these. Use autoAlpha (handles both visibility and opacity).
• Calling video.play() or audio.play() — the framework owns playback. Never call these yourself.
• Building timelines async — the capture engine reads window.__timelines synchronously after page load. Never wrap timeline construction in async, setTimeout, or a Promise.
• Standalone index.html wrapped in <template> — hides all content from the browser. Only sub-compositions loaded via data-composition-src use <template>.
• Using video for audio — always muted <video> + separate <audio>.

Verification

Before and after rendering:

1. Lint + validate + inspect pass: npx hyperframes lint --strict && npx hyperframes validate && npx hyperframes inspect (lint catches structural issues, validate catches contrast, inspect catches visual layout / overflow issues — see troubleshooting.md if warnings appear).
2. Animation choreography — for new compositions or significant animation changes, run the animation map. npx hyperframes init copies the skill scripts into the project, so the path is project-local:

   node skills/hyperframes/scripts/animation-map.mjs <composition-dir> \
     --out <composition-dir>/.hyperframes/anim-map

Outputs a single animation-map.json with per-tween summaries, ASCII Gantt timeline, stagger detection, dead zones (>1s with no animation), element lifecycles, and flags (offscreen, collision, invisible, paced-fast <0.2s, paced-slow >2s). Scan summaries and flags — fix or justify each. Skip on small edits.

1. File exists + non-zero: ls -lh final.mp4.
2. Duration matches data-duration: ffprobe -v error -show_entries format=duration -of default=nw=1:nk=1 final.mp4.
3. Visual check: extract a mid-composition frame: ffmpeg -i final.mp4 -ss 00:00:05 -vframes 1 preview.png.
4. Audio present if expected: ffprobe -v error -show_streams -select_streams a -of default=nw=1:nk=1 final.mp4 | head -1.

If hyperframes render fails, run npx hyperframes doctor and attach its output when reporting.

References

• [composition.md](references/composition.md) — data attributes, timeline contract, non-negotiable rules, typography/asset rules
• [cli.md](references/cli.md) — every CLI command (init, capture, lint, validate, inspect, preview, render, transcribe, tts, doctor, browser, info, upgrade, benchmark)
• [gsap.md](references/gsap.md) — GSAP core API for HyperFrames (tweens, eases, stagger, timelines, matchMedia)
• [features.md](references/features.md) — captions, TTS, audio-reactive, marker highlighting, transitions (load on demand)
• [website-to-video.md](references/website-to-video.md) — 7-step capture-to-video workflow
• [troubleshooting.md](references/troubleshooting.md) — OpenClaw fix, env vars, common render errors