DualSync

DualSync 🎬

DualSync is a Chrome Extension that synchronizes video playback (play, pause, seek, playback rate) across multiple browser tabs in real-time. It is purpose-built for watching reaction videos perfectly in sync with the original source content.[Currently only working for YouTube, working on adding support for more platforms]

Features

• Real-Time Sync: Play, pause, seek, or change the playback speed on the leader video, and all follower videos instantly match.
• Configurable Time Offsets: Adjust for delayed start times if the reactor pauses at the beginning of their video.
• Picture-in-Picture Overlay: Pop the original video out into a floating, resizable window that sits on top of the reaction video.
• Drift Correction: Automatic background heartbeat ensures videos never drift out of sync during long watch sessions.
• Privacy First: 100% offline. No backend server, no data collection. Sync commands are passed securely between your own local tabs.

How It Works

DualSync uses a Hub-and-Spoke architecture within Chrome Manifest V3:

1. Content Scripts hook into the HTML5 <video> elements using MutationObserver to handle dynamically loaded single-page applications like YouTube.
2. Background Service Worker acts as the central router, tracking state in chrome.storage.session and relaying commands.
3. Echo Prevention guards against infinite loops when programmatically forcing video state updates.

Installation (Developer Mode)

1. Clone this repository: git clone https://github.com/YOUR-USERNAME/DualSync.git
2. Open Chrome and navigate to chrome://extensions/
3. Enable Developer mode in the top right corner.
4. Click Load unpacked and select the DualSync directory.

License

MIT License