StrokeLens: Tennis Swing Sync

Pick two tennis clips. StrokeLens finds the moment of contact in each and plays them back stacked, in sync, at 0.3x slow motion. Three comparisons every month, free.

Two swings. One moment.

StrokeLens takes two tennis videos from your camera roll and lines them up on the one thing they have in common — the moment of contact. What comes back is a single portrait video: both strokes stacked, playing together at full speed, then again at 0.3x slow motion.

No scores. No arrows. No advice. StrokeLens does not tell you what to fix. It puts the two swings side by side at the same instant and lets your own eye do the work.

How it works

1. Pick two clips — yours and a pro's, this month's and last month's, or the same shot from two different lessons.
2. Trim each one down to a single stroke with the dial.
3. Tap once. The contact alignment is automatic.

Built for the way tennis actually gets filmed • Ordinary iPhone footage — no tripod, no markers, no sensors • Forehand, backhand (one- and two-handed) and serve, with nothing to choose — StrokeLens never asks you which shot it is • Different angles, different distances, different frame rates: nothing has to match • Portrait output, ready to post

Everything happens on your iPhone Your videos never leave the device — trimming, alignment and rendering all happen on the phone itself. There is no account and no sign-in, and StrokeLens works the same with the phone in airplane mode.