What a camera check can prove

A camera check can prove a narrow thing. For about 15 seconds, the page looked at frames from your camera, in the browser, and either saw a person or saw enough change between frames to call it movement. That is the pass. It is a check that you were there with the phone, not a check that the session was good.

The person check has two paths, and only one of them may be available. If the pose model loads, Miss and Pay uses MediaPipe's Pose Landmarker in the browser. The model file and the code come from a public CDN. It looks for body landmarks on sampled frames. Seeing a pose is enough. Seeing only part of a pose can still pass the day, and if you bought the coach it can make tomorrow a repeat so you can get a clearer frame. The model does not count squats. It does not know the difference between a hinge and a stretch.

If the browser has the FaceDetector API, Miss and Pay also asks it whether a face is in a sampled frame. That API is in Chromium. It is not a promise about Safari or Firefox. A face counts as a person. No face, and no pose, is not an automatic fail if the frames still move enough.

Movement is the other path. The page shrinks frames and compares them. A still camera pointed at a wall fails. A slow pan across a desk, or a person shifting, can pass. The score is a simple average of how much the pixels changed. The pass line is a motion score of 20 when no person was found. Below that, the reason is plain: not enough movement, or no person in frame if a detector ran and the picture was almost still. If the clip is under 12 seconds, the reason is that it was cut short.

If the browser will not open the camera, the page shows a video file input. That is the backup. The file is played locally, sampled the same way, and then dropped. Miss and Pay does not upload it and does not store it. You can delete it from the phone after.

What the server receives is the verdict only: pass or fail, a short reason, the duration, the motion score, whether a pose was seen, the lane, and the date. A fail is not stored, so you can try again today. A second pass on the same date is rejected. A date that is not today in the contract's timezone is rejected. The server does not re watch the video. If you need a check that knows whether the pushups were real, this is the wrong tool. If you need a check that is hard to satisfy with a dark room and a still phone, this is that tool.