hyperframes — HTML → deterministic MP4
The render_video tool renders an HTML composition you write into a pixel-exact
MP4. A headless Chrome steps a GSAP master timeline frame by frame, captures one
image per frame, and FFmpeg encodes them — so the same HTML always produces the same
video. This is the right tool for anything programmatic and data-driven; reach for
generate_video only when you need photoreal/AI-generated footage.
Great fits: animated bar/line/donut charts, KPI dashboards, "N facts about X" explainers, quote/announcement cards, kinetic typography, countdowns, before/after reveals, branded intros/outros, vertical social clips.
The composition contract (this is what makes or breaks a render)
Write ONE self-contained HTML document. Two things are mandatory and non-obvious:
- A paused GSAP timeline registered to
window.__timelines[<composition-id>]. HyperFrames seeks this timeline to render each frame. Total video duration =tl.duration()— you do NOT set duration with an attribute. data-*attributes on the root and on every timed element.
Root composition element — required: data-composition-id (must match the
window.__timelines key), data-width, data-height, data-start; plus
data-track-index.
Timed children — data-start + data-track-index on every one; visible
elements (<img>, text/graphic <div>s) also need class="clip"; <img> also
takes data-duration. Do not put data-duration on the root/composition — its
duration comes from the timeline.
html<!doctype html> <html> <head> <meta charset="utf-8" /> <!-- Load GSAP (see "GSAP + assets" below). --> <script src="https://cdn.jsdelivr.net/npm/gsap@3/dist/gsap.min.js"></script> <style> body { margin: 0; } .stage { width: 1080px; height: 1920px; position: relative; overflow: hidden; background: #0b0b12; color: #fff; font-family: system-ui, sans-serif; } .title { position: absolute; top: 220px; left: 80px; font-size: 96px; font-weight: 800; opacity: 0; transform: translateY(24px); } </style> </head> <body> <div class="stage" data-composition-id="promo" data-width="1080" data-height="1920" data-start="0" data-track-index="0"> <div class="title clip" data-start="0" data-duration="4" data-track-index="0"> Ship faster. </div> </div> <script> // A PAUSED timeline — HyperFrames drives playback by seeking it per frame. const tl = gsap.timeline({ paused: true }); tl.to(".title", { opacity: 1, y: 0, duration: 0.7, ease: "power2.out" }, 0.4) .to(".title", { opacity: 0, duration: 0.5, ease: "power2.in" }, 3.5); // Register under the SAME id as data-composition-id. This is mandatory. window.__timelines = window.__timelines || {}; window.__timelines["promo"] = tl; </script> </body> </html>
- Vertical
1080×1920for TikTok/Reels/Shorts,1920×1080for landscape,1080×1080for square feed posts. - Frame rate is an engine default (the tool doesn't expose an fps flag) — author for smooth motion at 30fps.
GSAP + assets
The tool renders a single standalone index.html (no project scaffold), so the
composition must bring its own GSAP and assets:
- GSAP: load it via a
<script src="…gsap.min.js">(CDN as above) or paste the minified source inline. It must be defined before your timeline script runs. - Assets: embed images/fonts as
data:URIs so nothing depends on external files. - Determinism: never drive motion from
Date.now(),Math.random(),setTimeout, or a hand-rolledrequestAnimationFrameloop — put all motion on the GSAP timeline. Off-timeline animation desyncs from the frame stepper.
Workflow
- Write the composition to the contract above with real data/text (never lorem).
- Call
render_videowith{ html, output_name?, lint? }. It lints, renders in an isolated subprocess (a real render legitimately takes a minute or more), and returns a saved MP4 as aMEDIA:<path>line. - Deliver it with
send_media({ path }). - Handle failures by
errorType:composition_invalid— read the lint message, fix the HTML, retry.render_failed— read the stderr excerpt (bad timeline id, missing GSAP, etc.).render_timeout— the composition is too heavy; simplify or shorten it.render_unavailable— the engine/FFmpeg isn't installed (see below).
Design quality (make it look intentional, not templated)
- Pick a palette that fits the subject; commit to one accent and keep the rest quiet. Set a real type scale; give headings weight and letter-spacing.
- Stagger reveals (offset each element's timeline position by 0.15–0.3s) so motion reads as choreographed, not simultaneous.
- Keep text ≥64px from every edge on vertical video so platform UI never clips it.
- Ease everything (
power2.outin,power2.inout). Linear motion reads robotic. - For charts, animate the value (bar height, arc sweep, a counting number) on the timeline rather than swapping static frames.
Requirements & install
Needs Node 22+, the @hyperframes/producer engine (an optional dependency —
install it to enable video), and FFmpeg on PATH. A headless Chromium is
auto-downloaded by the engine on first render (needs network once).
bashnpm i @hyperframes/producer # the render engine (optional; enables render_video) # FFmpeg: brew install ffmpeg | winget install ffmpeg | apt install ffmpeg
Overrides: BRIGADE_HYPERFRAMES_PATH (explicit producer entry file), FFMPEG_PATH,
BRIGADE_BROWSER_EXECUTABLE / PUPPETEER_EXECUTABLE_PATH.
