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Quick Skip Silence

A browser extension that automatically speeds up silent parts of videos and audio. Forked from vantezzen/skip-silence.

What it does

When a video or audio has silent pauses, Quick Skip Silence detects them and speeds up playback (default: 3x) so you don't have to wait. When speech or sound resumes, it returns to normal speed.

Normal audio:    |████████████░░░░░░░░|████████████████|
                  1x playing          silent pause      1x playing

With extension:  |████████████░░░░|████████████████|
                  1x playing       3x (skipped!)      1x playing

Features

• Tab Capture audio analysis — captures tab audio via chrome.tabCapture API (Chrome MV3 + offscreen document)
• Configurable silence threshold — set the volume level below which audio is considered silent (default: 30%)
• Dynamic threshold — automatically adjusts the silence threshold based on the audio content
• Adjustable speeds — set custom playback speed for normal parts (default: 1x) and silent parts (default: 3x)
• Mute silence — optionally mute audio during sped-up sections
• Audio sync fix — periodically resyncs audio/video to work around a Chromium bug
• Language selector — English and Japanese UI (toggle in the header)
• Command bar — quick-access overlay with keyboard shortcuts
• VU meter — visual volume indicator in the popup

Installation

Chrome (recommended)

1. Download or clone this repository
2. Build the extension:

   pnpm install
   pnpm run build:mv3

3. Open chrome://extensions
4. Enable Developer mode
5. Click Load unpacked and select the build/chrome-mv3-prod folder

Manual build

# Install dependencies
pnpm install

# Build for Chrome MV3
pnpm run build:mv3

# The output will be at build/chrome-mv3-prod/

Usage

1. Open any page with video/audio (e.g. YouTube)
2. Click the extension icon in the toolbar
3. Toggle Enable Quick Skip Silence on
4. The VU meter shows the current volume:
   • Blue = normal playback
   • Orange = sped up (silent section detected)
5. Adjust the silence threshold slider to fine-tune detection sensitivity
6. Set your preferred playback and silence speeds

Keyboard shortcuts

Shortcut	Action
Ctrl+Shift+S	Toggle enable/disable
Alt+Shift+S	Show/hide command bar

How it works

1. When enabled, the background service worker calls chrome.tabCapture.getMediaStreamId() to get a stream ID for the active tab
2. An offscreen document is created and receives the stream ID
3. The offscreen document calls getUserMedia() with the tab audio stream, creates an AudioContext + AnalyserNode
4. Every 25ms, the RMS volume is calculated from the audio waveform
5. The volume is sent back to the background via chrome.runtime.sendMessage()
6. TabCaptureController compares the volume against the threshold
7. When volume stays below threshold for N samples → speeds up (state.media_speed = 3)
8. When volume rises above threshold → slows down (state.media_speed = 1)
9. The content script detects the state change and applies element.playbackRate

Architecture

┌─────────────┐     streamId      ┌──────────────────┐
│  Background  │ ────────────────> │  Offscreen Doc   │
│  (Service    │ <──────────────── │  (AudioContext +  │
│   Worker)    │   tab-capture-    │   AnalyserNode)  │
│              │   volume          │                   │
│  TabCapture  │                   └──────────────────┘
│  Controller  │
│              │   media_speed change
│              │ ────────────────> ┌──────────────────┐
└─────────────┘                   │  Content Script   │
                                  │  (SpeedController) │
                                  │  → playbackRate    │
                                  └──────────────────┘

Settings

Setting	Default	Description
Playback Speed	1x	Speed during normal (non-silent) audio
Silence Speed	3x	Speed during silent sections
Silence Threshold	30%	Volume level below which audio is considered silent
Dynamic Threshold	off	Auto-adjusts threshold based on audio content
Sample Threshold	10	Number of consecutive silent samples before speeding up
Mute Silence	off	Mute audio during sped-up sections
Keep Audio in Sync	off	Periodically resync to fix Chromium desync bug

Known limitations

• Does not work on sites that use non-standard audio playback (e.g. Spotify Web Player)
• On Firefox, tab capture is not supported — only element-based analysis works
• Chromium has a bug where audio/video desync when repeatedly changing speed (workaround: "Keep Audio in Sync" setting)

Development

Built with Plasmo framework.

# Install
pnpm install

# Dev server (Chrome MV3)
pnpm run dev:mv3

# Build
pnpm run build:mv3

Project structure

src/
├── background/
│   ├── BackgroundManager.ts    # Tab management + TabCaptureController
│   └── index.ts                # Entry point
├── contents/
│   ├── index.tsx               # Content script entry
│   └── lib/
│       ├── SpeedController.ts  # Applies playbackRate to media elements
│       ├── AudioSync.ts        # Audio/video resync workaround
│       └── command-bar/        # Command bar overlay
├── shared/
│   ├── i18n.ts                 # Internationalization (EN/JA)
│   ├── state.ts                # Extension state definition
│   ├── analytics.ts            # Analytics (disabled)
│   ├── components/
│   │   ├── switch.tsx          # Toggle switch component
│   │   └── speedSetting.tsx    # Speed selector component
│   └── lib/
│       ├── SilenceSkipper.ts   # Element-based silence detection
│       └── DynamicThresholdCalculator.ts
├── popup/
│   ├── index.tsx               # Popup entry
│   └── components/
│       ├── header.tsx          # Header with language toggle
│       ├── SettingsForm.tsx    # Settings UI
│       └── Footer.tsx          # Fork credit
├── assets/
│   ├── offscreen.html          # Offscreen document for tab capture
│   └── offscreen.js            # Audio analysis in offscreen context
locales/
├── en/messages.json            # English strings
└── ja/messages.json            # Japanese strings

Credits

This project is forked from vantezzen/skip-silence by vantezzen.

Original work inspired by CaryKH's automatic on-the-fly video editing tool.

License

MIT License — Copyright (c) 2019 Michael Xieyang Liu