Cadence
Teach the camera your pedalling. Set the phone where it sees your face and shoulders, keep a cadence sensor, bike computer or metronome in sight, and mark the true RPM every time it changes.
True RPM
Good recordings: 50–110 RPM, a change of cadence every 20–30 s, dim and bright light, phone low on the bars and high, standing pedalling.
Only the tracked points (nose, eyes, ears, shoulders, hips) and your marks are saved, never the image. The recording goes to your Dirty Ride account to improve movement recognition and, later, to personalise it for you.