Face tracking for the Pocket 3
on a Mac
A webcam on a gimbal should follow you when you lean back, stand up or move to the other side of the desk. In webcam mode, the Pocket 3 just sits still. Here's how to get real face tracking on a Mac, where the gimbal turns to keep you in the shot instead of the picture being cropped.
Why it doesn't track by itself
The Pocket 3 has its own subject tracking, ActiveTrack, but in webcam mode you can't start it from the Mac: it's set on the camera. What the camera does accept over USB is a standard webcam command to set pan, tilt and zoom. So a Mac app can do the tracking itself: find your face in the picture, work out where the gimbal should point, and tell the camera to turn there.
That's different from the "center stage" kind of tracking many webcams use, which crops into a wide picture and loses sharpness. Here the camera actually moves, so the picture stays at full resolution.
Turn it on
- Connect the Pocket in Webcam mode and open Pocket+.
- Click the face tracking button next to the record button, or press ⌘T.
- Move around: a yellow frame follows your face and the gimbal turns with you.
To track someone else, double-click their face in the picture. Double-click another face to switch to it, or the tracked face again to stop. Face tracking is part of the free version.
How it keeps the shot steady
Tracking a face with a gimbal sounds simple, but the first version we built swung back and forth. The camera and the face detection each add a small delay, so by the time the app saw where you were, the gimbal had already moved on, and it overshot.
Now each frame is matched to where the gimbal was pointing at the moment that frame was taken. The app aims for your face's position at that moment and eases the gimbal there smoothly. A small dead zone means it ignores tiny movements, so you're not chased around for every nod.
It also keeps your framing. Instead of pushing your face to the dead center, it keeps the top of your head at the same height in the frame, so the headroom you had stays the same while you move.
When you take over
- Moving the gimbal yourself with the joystick pauses tracking. It picks up again two seconds after you let go.
- Jumping to a scene, centering the camera or flipping it to face the other way turns tracking off, because you've chosen a new shot.
- If your face leaves the picture, the gimbal stops where it is and the app shows that it's looking for a face. It doesn't wander around searching.
Face tracking and ActiveTrack
If ActiveTrack is on, you end up with two things trying to steer one gimbal. Pocket+ watches the gimbal's real position. When it turns without the app asking, Pocket+ stops its own tracking within a second or two and shows a card asking you to turn ActiveTrack off on the camera. After that, Resume tracking picks up where you left off.
Privacy
Face detection runs on your Mac with Apple's Vision framework. Nothing is uploaded, and the app doesn't store faces or recognize who someone is. It only finds where a face is in the current frame.
Tracking vs. auto framing
Face tracking follows you continuously. If you'd rather set up a good shot once and have the camera stay put, use auto framing (⌘⇧T, Pro). One click turns and zooms the camera so your face sits at a natural size with proper headroom. With several people in the shot, it frames the whole group. It takes about a second, then leaves the camera alone.
Pocket+ is a free Mac app for the DJI Osmo Pocket 2, 3, 4 and 4P: aim the gimbal, track your face, switch scenes and record to your Mac.
Download Pocket+