Split open up and down from the centre

Use this transition between my clips: "Split open up and down from the centre" from the 24fps video editor library.
Preset JSON: https://24fps.dev/video-editor/transitions/split-open-vertical-cc2/preset.json (pass its "preset" to the engine).
Engine (MIT, no dependencies, ES module): https://24fps.dev/editor/engine.js. Download the engine next to your page (curl -O) rather than importing cross-origin, then import { mount } from "./engine.js" in a <script type="module"> served over http.
Wiring: root = a position:relative box at the video's size. media = { a, b }: two wrappers holding clip A and clip B, both filling the root. Clip A plays first; the cut happens at preset.at (1.2s) over preset.dur (0.7s), so start clip B at preset.at. Then const fx = mount(root, { kind: "transition", preset, media }) and call fx.render(seconds) every frame. It is seek-safe: drive it from the GSAP timeline in HyperFrames or call render(frame / fps) in Remotion. Before capturing frames, await (fx.ready ?? document.fonts.ready).
Field reference: https://24fps.dev/video-editor/llms.txt. Keep sizes as fractions of the frame height so it works at any resolution. Credit: 24fps.dev/video-editor