OpenFilm Lets Coding Agents Build and Edit Videos With Plain HTML

OpenFilm is a new MIT-licensed open-source project that turns a film into a folder of web pages. Coding agents write shots with familiar browser technologies, while OpenFilm supplies the timeline, local editor, verification tools, and renderer. Its GitHub repository has 1.3k stars.

Developers can ask Claude Code, Codex, Cursor, Gemini CLI, or another shell-capable agent to create a video. The agent writes the source files, and a browser-based editor called Studio lets users select any generated element and revise it directly.

A timeline built from browser primitives

Every OpenFilm project contains a film.html file. Each section defines a track, and document order controls its top-to-bottom position on the timeline. Clips can contain web pages, videos, still images, or audio files.

• Media fragments such as #t=12,18 define clip timing.
• CSS properties including left, top, width, and height control placement.
• Manual changes are stored as overrides that agents can preserve during later revisions.

Animated web-page shots expose a small JavaScript interface:

window.film = {
  frame(t) { /* draw the complete picture at t seconds */ },
  duration: 4,
  ready: loadFonts(),
  width: 480,
  height: 320,
};

Each call to frame(t) must draw the same complete image for the same timestamp, regardless of earlier calls. OpenFilm can request frames out of order, render several concurrently, and sample fractional timestamps for motion blur. Time-driven shots that follow this contract produce reproducible exports when the browser, fonts, and assets remain consistent.