Documentation

Prerequisites

• Windows 10 or 11
• A USB webcam or a phone with a camera and a browser — no phone app needed
• A microphone (built-in, USB, or phone mic) if using audio or hybrid trigger mode

Installation

1. Download the installer from the Download section or the GitHub Releases page.
2. Run ReplaySwing-Setup.exe — no admin privileges required.
3. Launch ReplaySwing from the Start Menu or desktop shortcut.

First Launch

1. Click Add camera and pick your webcam — a live preview appears immediately.
2. Click Arm (or press A). The tally strip at the top of the window turns amber: the app is watching.
3. Address the ball and hold still for a beat — the strip locks green (SET).
4. Swing. The app records automatically and loops the replay on screen.

Recordings are saved to ~/GolfSwings/, organized by session timestamp.

USB Cameras

Plug in any USB webcam and click Add camera — ReplaySwing uses the same camera engine as Chrome, so if your camera works in a browser, it works here. Hot-plug is detected automatically.

For best results, use a camera that supports 720p or higher.

Camera Controls

Each camera tile has controls for adjusting the view:

• Zoom — zoom in to crop the frame closer
• Rotate — rotate the image in 90° increments
• Mirror — flip the image horizontally (useful for face-on cameras)

Multi-Camera Recording

Add up to four cameras (USB and phones can mix). When a swing triggers, every camera saves its own clip from the same moment:

• Primary: shot_0001.mp4
• Secondary: shot_0001_cam1.mp4

The live view auto-layouts cameras: 1 → full, 2 → side-by-side, 3–4 → 2×2 grid.

The Primary Camera

One camera is the primary camera — the one whose footage is used as the main replay angle. It’s also the camera that drives the vision trigger and auto-arm pose detection. Pick it in Settings.

Any phone becomes a wireless camera in about ten seconds — no app to install.

Pairing

1. Click Add phone in ReplaySwing. A QR code appears.
2. Scan it with your phone's camera. The pairing page opens in your phone's browser.
3. Tap Start camera and allow camera access.
4. The phone's feed appears in ReplaySwing as a normal camera tile.

While Connected

• Keep the pairing page open — the app keeps your phone's screen awake for you.
• Use Flip camera on the phone to switch between front and back lenses.
• If the phone locks or drops, ReplaySwing holds its spot and reconnects when the page returns.
• Phone microphones can be used as your audio trigger source — select the phone in the Microphone setting.

Requirements

• Phone and PC on the same Wi-Fi network (not cellular data).
• Guest networks often isolate devices from each other — use your main network.

Video streams directly from your phone to your PC over your local network. It never touches the internet.

ReplaySwing supports three trigger modes, selectable in Settings:

Hybrid (Recommended)

Combines motion detection with audio confirmation for the most reliable triggering. The app watches the primary camera for the swing sequence — still address followed by fast motion — then confirms with the impact sound from your microphone. This virtually eliminates false triggers.

Audio Only

Listens for any loud sound above the configured threshold. Simple and works with any camera angle, but can trigger on non-swing sounds. Good for environments where the camera can’t see the golfer clearly.

Manual Only

No automatic triggering. Press Record now (or T) to capture whenever you want. The buffer is always running while cameras are live, so the pre-roll footage is still captured.

The Tally Strip

The tally strip across the top of the window shows the current trigger state, readable from across the bay:

1. WATCHING (amber) — armed, waiting for you to address the ball.
2. SET (green) — you’ve been still for a moment; the trigger is live.
3. CAPTURE (red) — swing detected; the clip is being saved.

Enable Auto-arm when a person steps into view in Settings for fully hands-free operation.

How It Works

ReplaySwing uses pose detection on the primary camera to detect when someone is standing in frame. When a person is detected for about 1.5 seconds, the system automatically arms. When they leave the frame for about 5 seconds, it disarms.

Manual Override

Manual arm/disarm always takes priority. If you manually disarm while auto-arm is active, the system stays disarmed until you leave the frame and return (a full reset cycle). You can always arm or disarm manually regardless of the auto-arm setting.

Works With Any Trigger Mode

Auto-arm controls when the system is armed. The trigger mode (hybrid, audio, manual) controls what causes a capture. They work together:

• Hybrid + auto-arm — walk up, system arms, swing triggers on motion + sound
• Audio + auto-arm — walk up, system arms, swing triggers on impact sound
• Manual + auto-arm — walk up, system arms, press Record to capture

Pre-Roll Buffer

ReplaySwing continuously buffers every camera in memory, so a trigger saves footage from before the moment it fired — your full backswing is always in the clip. Defaults: 2s before and 4s after the trigger, adjustable in Settings.

Instant Replay

The moment a clip saves, it takes over the main view and loops. You stay armed the whole time — step up and hit the next ball, and the new swing replaces the replay. Press Esc or click Back to live to return to the camera view.

Slow Motion

Drag the speed slider on the replay bar from 1× down to 0.1× to study the moment through impact in slow motion. It works on the instant replay and on any shot you pick from the rail.

Files

Clips are H.264 MP4s that play anywhere — Windows, phones, editing apps. Each session gets a folder in ~/GolfSwings/ with per-camera MP4s, JPG thumbnails, and a clips.json index.

Mark up any swing with lines and circles — a swing-plane line, an alignment circle on the ball or your head.

Drawing

1. Click the pencil at the top-left of the video.
2. Pick Line or Circle and a color, then drag on the video.
3. Switch to Select to move a shape, drag a line’s ends to re-angle it, or drag a circle’s edge to resize. A swatch recolors the selected shape; Delete removes it.

Where drawings live

Drawings belong to each camera and are saved between sessions. They appear on that camera’s live view, on its replays, and burned into the PiP overlay on your sim screen. Turn the pencil off and they stay on screen without getting in the way.

Put two swings side by side to see what changed — today’s move against a reference from last week.

Opening a comparison

1. Click Compare in the toolbar. A window opens with two panes.
2. Use the dropdown above each pane to pick a shot. Shots are grouped by session, so you can compare across different days.

Studying the swings

• Both clips play on one timeline — play/pause, scrub, and slow-motion speeds apply to both at once.
• Step through frame by frame with the frame buttons.
• The two swings rarely start at the same instant, so use the offset (− / +) to nudge the right swing until both line up at the same moment — the top of the backswing, or impact.

Get any clip off your PC without cables or cloud uploads. Both buttons sit on the replay bar.

Send to your phone

1. Play a shot, click Share, and a QR code appears.
2. Scan it with your phone’s camera — a page opens that plays the swing with a Save button.
3. Share more shots and they appear on the same page automatically, so you only scan once.

Your phone must be on the same Wi-Fi as your PC. The video streams directly between them and never touches the internet. On iPhone, long-press the video and choose “Save to Photos”; on Android, use the Save button.

Save to your PC

Click Save to copy the clip anywhere on your computer — to a coaching folder, a USB drive, or your desktop.

The PiP window floats on top of everything — including your fullscreen simulator — and mirrors whatever ReplaySwing is showing: live cameras between shots, the looping replay after each swing.

Using It

• Click PiP in the toolbar (or press P) to open or close it.
• Drag it anywhere on the sim screen; resize from the edges.
• Its position and size are remembered between sessions.

Because it mirrors the main app, there's nothing to configure — arm once, and every replay appears over your simulator automatically.

The Shot Rail

Every capture lands in the rail on the right with a thumbnail, shot number, and time. Click any shot to replay it on the main stage.

Pin & Delete

• Hover a shot and click ☆ to pin your best swings.
• Hover and click ✕ to delete a mishit — the video files go with it.

Sessions

Each app run records into a new session folder named by date and time. Use the dropdown at the top of the rail to browse earlier sessions — including ones recorded with older versions of ReplaySwing.

Key	Action
A	Arm / disarm the swing trigger
T	Record now (manual trigger)
P	Show / hide the PiP overlay
Delete	Remove the selected drawing (while drawing)
Esc	Exit drawing, dismiss replay, or close the compare window

Setting	Options / Range	What it does
Shots folder	Any directory	Where sessions and clips are saved (default: ~/GolfSwings/)
Trigger mode	Hybrid / Audio / Manual	How auto-recording is triggered — hybrid is recommended
Microphone	Any mic or phone	Audio source for the trigger (shown when trigger uses audio)
Trigger threshold	0.01–0.4	Audio level that fires the trigger — lower is more sensitive
Pre-roll	0.5–5s	Seconds kept from before the trigger — covers your backswing
Post-roll	1–8s	Seconds recorded after the trigger — covers the finish and ball flight
Primary camera	Any camera	Which camera is used as the main replay angle and for vision detection
Auto-arm	On / Off	Automatically arm when a person steps into the primary camera’s view

Settings save automatically to ~/GolfSwings/settings.v2.json. Window and PiP positions are remembered too. The current app version is displayed at the bottom of the settings panel.

In-App Feedback

Click the Feedback button in the app toolbar to submit a bug report or feature request directly from ReplaySwing. Your system info (OS, app version, camera count) is attached automatically. Feedback is submitted as a GitHub issue — no browser window opens, it’s all handled in the app.

Website Bug Report

Use the bug report form on the website to file issues from any device.

Troubleshooting

The trigger doesn't fire

• Check the tally strip: it must reach green (SET) before a swing counts. Hold still at address for about a second.
• If using hybrid or audio mode, check that your microphone is working — the level preview in Settings should bounce when you clap.
• Lower the trigger threshold in Settings to make it more sensitive.
• Make sure the primary camera actually sees you — check which camera is selected in Settings.

It fires when it shouldn't

• Raise the trigger threshold.
• Switch to Hybrid mode — it requires both motion and sound, which virtually eliminates false triggers.
• Point the primary camera so people walking behind you aren't in frame.

Phone won't connect

• Phone and PC must be on the same Wi-Fi. Turn off cellular data to be sure.
• Guest and hotel-style networks often block devices from seeing each other.
• Re-scan the QR code — pairing codes expire after a few minutes.

Capture problems on a specific PC

Run the built-in hardware check from Command Prompt and include its output in a bug report:

"%LOCALAPPDATA%\Programs\ReplaySwing\ReplaySwing.exe" --spike=encode

Logs live in ~/GolfSwings/logs/ if you want to attach detail.