Camera-based movement guidance: what Jinni sees and what it does not store

Pointing a camera at yourself in your living room is a reasonable thing to hesitate over. It is also the most direct way for software to understand how you are actually moving, rather than how you reported you moved. Both of those things are true, and the interesting question is how to get the second without giving up the first.

The answer is where the processing happens. During a session, the camera feed is analysed on your device. The app looks at where your joints are, how they travel, and how that changes across repetitions, and turns that into measurements. The frames themselves are not uploaded.

So it is worth being precise about three different things. Raw video is the footage — Jinni does not store it and does not send it for human review. Derived movement data is the numbers calculated from it: which movements you did, how many repetitions, summary measures of range and control. Session history is the record of what you did over time. The second and third are kept, because without them there is no progress view and no adaptation. The first is not.

Camera permission is used only while a session or assessment that needs it is running. You can revoke it at any time in your device settings; camera-based guidance stops working and the rest of the app carries on.

Apple Health is separate and optional. It is off unless you turn it on, it reads only the signals you authorise, and it is used for readiness context — never for advertising, and never sold.

A few practical notes for setting up, because framing affects how well any of this works. Put the device somewhere stable where it cannot fall or be tripped over. Give yourself enough clear space to move in every direction the session asks for. Make sure the camera can see your whole body, not just your top half. Even, front-facing light beats a bright window behind you. And clothing that shows the outline of your limbs reads better than something very loose.

None of this makes camera guidance risk-free, and no honest privacy page would claim otherwise. What it does is make the trade explicit: the app gets the movement information it needs to be useful, and the recording of you moving in your own home never exists in the first place.

Useful guidance should not require turning a workout into a stored recording. That is a design decision, and it is one worth asking every app you use to explain.