HTML Video

Make a real MP4 without any video-generation model. You write a single HTML file whose animation is a pure function of time, a script photographs every frame in a headless browser, and FFmpeg stitches the frames into a video. Everything runs locally and offline.

The one rule everything depends on

The page MUST expose window.seek(t) where t is seconds, and calling it must draw the exact frame for that moment. Rendering jumps from frame to frame; nothing is ever "played". Therefore, in the frame path:

• No Date.now(), no unseeded Math.random(), no requestAnimationFrame progression, no CSS animation/transition for anything that moves.
• All motion is computed inside seek from t (transforms, opacity, text).
• No network requests. Inline all CSS and JS; images must be local files.