From the source
How Replit turns any web page into a deterministic video by virtualizing time itself, patching key browser audio APIs, and waging war against headless Chrome's quirks.
Published: Updated: The Problem: Browsers Don't Want to Be Cameras Here's a deceptively simple product requirement: take a web page with animations, and turn it into a video file.
Sounds easy, right?
Open a browser.
Record the screen.
Export MP4.
Ship it.
We tried that.
It doesn't work.
The core issue is that browsers are real-time systems.
They render frames when they can, skip frames under load, and tie animations to wall-clock time.
If your screenshot takes 200ms but your animation expects 16ms frames, you get a stuttery, unwatchable mess.
The browser kept rendering at its pace while we captured at ours , and the two never agreed.
We needed something more radical.
We needed to make the browser believe time moves only when we say it does.
Why Not Remotion?
Before we go further, a reasonable question: why build this at all?
Remotion exists and it's genuinely great.
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