Make a green screen video without a green screen

MP4 with H.264, the format every editor and phone reads, cannot hold transparency. A flat key colour does the same job in one click in any editor, and plays everywhere as it is.

Chroma green, #00B140, is the standard broadcast key colour and the default here. Use blue if the person or their clothes are green.

Short and tidy hair keys well. Loose strands and flyaway hair are simplified by the model into a smooth outline, which looks fine at normal viewing size but not in extreme close-ups.

No. The frames are redrawn and encoded in this tab, on your device.

Every frame is examined and redrawn on your device, so it can take longer than the video plays. The default finder, Better edges, runs on the graphics chip where the browser offers one. On a MacBook Pro with an M3 Max chip a 10-second 30 fps clip took about 6 seconds in Chrome and about 10 seconds in Safari, so a 10-minute clip would take about 6 to 11 minutes (we timed 10 seconds, not the longer clip). Where the browser cannot use a graphics chip (software rendering, some virtual machines and browser settings) it falls back to the processor, and the same clip took about 55 seconds, so a 10-minute clip would take about an hour. The Fast option runs on the processor and took about 5 seconds in Chrome and 8 to 9 seconds in Safari on the same clip, so it is only a little quicker than Better edges on a graphics chip and several times quicker than Better edges without one, but its edges are rougher around hair and in dim light. Phones vary and we have not benchmarked one with the graphics chip: a single run on an iPhone in Safari, before this change, took roughly 5 to 10 minutes for a 2-minute video, which is a rough guide, not a measurement. Slower devices take longer, and so do longer or 60 fps videos. The page shows the time left once it is running; keep the tab open while it works.

The open-source MediaPipe engine that finds the person tries to send its own usage log to a Google address. This site’s security policy makes the browser refuse that request, so it fails and you see an error in the console. Your video is not part of it and it never leaves your device.