Feature grid, 1 top + 2 below

Lay out my footage like this: "Feature grid, 1 top + 2 below" from the 24fps video editor library.
Preset JSON: https://24fps.dev/video-editor/layouts/grid-2x1-feature/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 = { main, second, fg }: main = wrapper holding my video, second = wrapper holding my other clip (often the background), fg = cut-out of the person (see below); the engine positions and crops them into the layout's slots. Then const fx = mount(root, { kind: "layout", 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).
This look needs a cut-out of the person: fg is a second copy of my video with the background removed (video with alpha, e.g. WebM VP9 or HEVC with alpha; e.g. npx hyperframes remove-background clip.mp4 -o clip.fg.webm, or any person-segmentation tool such as rembg or MediaPipe), stacked above the other clips.
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