See protection in action
YT Dimmer is a privacy-first browser extension that softens sudden flashes and sustained bright video scenes. It is designed for more comfortable late-night viewing on YouTube, Twitch, Vimeo, and other sites that use HTML video.
YT Dimmer is a viewing-comfort tool, not a medical device or a substitute for medical guidance, platform accessibility controls, or photosensitivity-safe content.
- Temporal flash detection using changes between recent frames
- Bright-region and peak-luminance analysis, not only average brightness
- Fast dimming with gradual recovery and hysteresis
- Efficient video-frame scheduling with
requestVideoFrameCallback - Dominant-video selection for pages containing several players
- Gentle, Balanced, and Maximum protection profiles
- Per-site pause controls and a global keyboard shortcut
- Optional night-time protection boost that preserves manual settings
- Live scene-luminance status and local daily activation count
- A visual comfort calibration flow
- Import, export, and reset controls
All frame analysis happens in the current browser tab. Video frames are never recorded, stored, or transmitted.
Requirements: Node.js 20+ and pnpm.
git clone https://github.com/C-W-D-Harshit/ytdimmer.git
cd ytdimmer
pnpm install
pnpm buildThen open chrome://extensions, enable Developer mode, choose Load unpacked,
and select .output/chrome-mv3.
Firefox can be built with:
pnpm build:firefox| Command | Purpose |
|---|---|
pnpm dev |
Run WXT development mode |
pnpm compile |
Type-check the project |
pnpm test |
Run detector tests |
pnpm build |
Build the Chrome MV3 extension |
pnpm build:firefox |
Build the Firefox extension |
pnpm zip |
Create a Chrome release archive |
The default quick-toggle shortcut is Alt + Shift + D. Browser shortcut settings can override it.
entrypoints/background.ts settings initialization and keyboard command
entrypoints/content.ts video discovery, frame scheduling, and dimming
entrypoints/popup/ React popup and controls
lib/detector.ts pure temporal/spatial detector
lib/settings.ts version 2 settings model and helpers
The detector is documented in ALGORITHM.md. Privacy behavior is documented in PRIVACY.md.
Some sites serve protected cross-origin video that blocks canvas pixel reads. YT Dimmer detects this condition and leaves the player untouched instead of claiming active protection. Browser-internal pages cannot run content scripts.
See CONTRIBUTING.md. Bug reports and focused test cases are especially valuable for unusual players and scene transitions.
MIT — see LICENSE.