Velocity speed ramp

Playback ramps between 1x and 0.35x slow-mo each 3 s cycle (video elements only). Velocity edits on motion clips.

Apply this to my video: "Velocity speed ramp" from the 24fps video editor library.
Preset JSON: https://24fps.dev/video-editor/effects/velocity-ramp/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 }: main is a wrapper holding my video, filling the root. Then const fx = mount(root, { kind: "effect", 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
Same idea
Also called: Velocity (Speed Ramp), Velocity Echo, Montage, Hero, Bullet, Jump Cut, Velocity edit, Velocity / slow-motion templates
Technique
Velocity edit speed ramp, trending in video editor
Footage
City lights bokeh, Pexels

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