Understanding a video with `agent-motion`

agent-motion is a CLI on $PATH. It answers what changed, when, and where for a video, as JSON you can act on, and it writes images when you need to see something. It never uploads anything; decoding is local FFmpeg.

It is built for fixed-viewport recordings — a screen capture, a browser session, a visual test, a rendered scene. A handheld or panning camera makes every pixel change at once, and the results become much weaker.