Stepped pull-back reveals handset

Use this transition between my clips: "Stepped pull-back reveals handset" from the 24fps video editor library.
Preset JSON: https://24fps.dev/video-editor/transitions/stepped-pull-back-reveal-handset-e2x/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 (1.4s) over preset.dur (0.5s), 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).
Sound design: sub-drop at 1.85s on last pull-back step, handset body fully in view (low thump around 60-120 Hz, ~0.2 s decay, no top end; starts on the last step (3.75 s in the music clip, ~4.7 s in the streetwear clip)). In HyperFrames, fetch each with media-use (e.g. npx hyperframes media-use resolve --type sfx --intent "sub-drop" --project .; media-use needs `heygen auth login`, without it use `--local-only`, check with `--doctor`); elsewhere use royalty-free SFX or ones I give you.
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