Tennis Strokedex

Tennis AI Coach looks at a video of your strokes and tells you what your body did during each swing. Record a session with the camera or pick a clip you already have. The app reads your body position frame by frame using Apple's Vision framework, measures your form at each frame, finds your swings from the peaks in wrist speed, and writes up what looked solid and what to work on. All of it happens on your iPhone. WHAT YOU GET Every session opens into five views. Overview gives you your median form numbers. Video plays the clip back with the skeleton drawn on top. Charts plots each metric over time. Strokes breaks the session down swing by swing with a 0 to 100 form score. Coaching turns the numbers into a short list of strengths and things to focus on. You can save an annotated MP4 with the skeleton and a metric readout burned into the video, or share a summary card of the session. Sessions stay in a library on your phone and reopen instantly. Home shows how your form score has moved across sessions, and you can put two sessions side by side to see what changed between them. WHAT IT MEASURES Knee angle on each leg, so you can see how low you are getting. Elbow angle on each arm. Torso lean, as a signed angle away from vertical. Stance width, as the distance between your ankles relative to your hips. Wrist speed for each arm, which is also how the app works out which arm you hit with. Missing measurements stay missing. If tracking was poor for a swing, that swing is left ungraded rather than given an invented score. PRIVACY There is no account, no server, and no analytics code. Your video is analyzed on the device and stays there. The app asks for the camera and microphone to record, and for add-only access to Photos if you want to save an annotated video. It cannot read or browse your photo library. WHAT IT DOES NOT DO This is a pose coach, so the edges are worth stating. It does not see the ball, the court, or your racket. It does not label a swing as a forehand or a backhand. It tracks one player, the clearest person in the frame. Swing speed is measured in pixels, so it means something within a single clip but is not comparable between clips shot from different distances. That is why speed is left out of the trend line and out of session comparisons, where only the scale-independent form angles are used. GETTING GOOD FOOTAGE Film from the side rather than from behind, keep your whole body in frame, and shoot somewhere with decent light. A few clean groundstrokes read better than a long rally at the far end of the court.