Automatic stroke clips
Finds forehands, backhands, and serves, then separates each stroke into its own clip.
BeliefCraft Products
Products
We enable AI to perceive and understand the world, making life easier. Starting with sports and tennis, we make sure every great moment is captured in full.
iPhone App
Swrrl
Your tennis strokes, already clipped and ready to study.
Swrrl automatically finds every forehand, backhand, and serve in your tennis video, then turns them into clean clips that stay centered on you. Compare, slow down, zoom in, and focus on the details that improve your game.
Available on the App StoreDownload on the App Store
No account · Fully offline · Nothing uploaded
Player tracking
Keeps you centered even when you move across the frame.
Fine-grained playback
Adjust speed, zoom, and clip length to examine the details that matter.
Private by design
Runs on your device with no account, cloud upload, or data collection.
Three simple steps
Record
Set up your phone and film a match, practice session, drill, or wall rally.
Import
Choose the video in Swrrl. Stroke detection and player tracking run automatically.
Review
Compare clips, slow them down, zoom in, and save the moments you want to keep.
Multi-Camera Court System
Swrrl Court
Turn every court into a content hub, where every great moment is captured in full.
Swrrl Court is a highlight replay system for tennis venues, automatically capturing, live-streaming, and analyzing every point so it can be seen, reviewed, and shared from every angle.
Swrrl Court is installed and running at Superisland in Shanghai; the live court views shown here were captured on site.
Automatic capture and live streaming
Synchronized cameras automatically record every point and support live streaming from the court.
Analysis and highlight replay
Review movement and rallies from more angles, then preserve and share every great moment.