Watch YouTube with Bilibili’s Live Danmaku: A Complete Guide to the B2Y Extension

Keywords: B2Y, YouTube danmaku, sync Bilibili comments, browser extension, cross-platform

Have you ever wished you could watch a 4 K YouTube upload and read the hilarious, fast-scrolling comments that only Bilibili provides?
The B2Y browser extension makes this possible. It quietly overlays real-time Bilibili danmaku on any YouTube video, so you keep the superior video quality while never losing the chat-like energy that makes Bilibili unique.

Below you will find everything you need—without jargon—to install, use, and even help improve B2Y. Nothing here goes beyond the official README; every detail, link, and instruction is taken directly from the project’s own documentation.

1. What B2Y Actually Does

2. Pick Your Browser, Install in Minutes

B2Y is built with the WXT framework, so the same codebase runs on Chrome, Firefox, Edge, and Safari.
The authors strongly recommend the store version when possible; manual install is only a fallback.

2.1 One-Click Store Install (Recommended)

2.2 Manual Install (Fallback)

Use this only if the store is blocked or you are on Firefox/Safari.

A. Download the Correct File

1. Visit the project’s Release page.
2. Download the zip that matches your browser:

   • Chrome: B2Y-YouTube-Bilibili-Danmaku-vX.X.X-chrome.zip
   • Firefox: B2Y-YouTube-Bilibili-Danmaku-vX.X.X-firefox.zip
   • Edge: B2Y-YouTube-Bilibili-Danmaku-vX.X.X-edge.zip
   • Safari: B2Y-YouTube-Bilibili-Danmaku-vX.X.X-safari.zip

B. Load the Extension

⚠️ Notes

• Firefox and Safari require you to re-load the extension after every browser restart.
• Manual installs do not auto-update; revisit the Release page for new builds.

3. First Run: Four Simple Steps

Prerequisites

• You are logged in to your Bilibili account.
• The extension is installed.

1. Open the YouTube video
   Example: https://www.youtube.com/watch?v=xxxxxxxx

2. Let it auto-match

   • If the creator is in the public database, danmaku appears in 1–2 seconds.
   • If nothing shows, click the B2Y icon → follow the prompt to link the creator’s Bilibili space or paste the Bilibili URL.

3. Fix timing if needed
   Click the extension icon → “Time-axis calibration”

   • Drag the slider or type seconds (negative allowed).
   • Changes apply instantly.

4. Tweak the look
   Extension icon → “Display settings”

   • Font size 12–36 px
   • Opacity 0–100 %
   • Speed 0.5×–3×
   • Vertical spacing: compact / loose / custom
   • Display area: top 1⁄3, middle, bottom 1⁄3, or full screen

4. Power-User Features

4.1 Link a Creator Once, Forget It Forever

Ideal when:

• You follow a small creator whose videos are rarely auto-matched.
• A re-upload channel uses different titles.

Steps

1. Open any YouTube video from that creator.
2. Click the B2Y icon → “Search & link creator” → paste the Bilibili space URL (example: https://space.bilibili.com/123456).
3. Future uploads from that channel will fetch danmaku automatically.

4.2 Built-In Anime Episodes

Conditions

• The video is on the official “哔哩哔哩动画Anime Made By Bilibili” channel.
• The content is the main episode (not PV, recap, or clip).

When both are true, B2Y reads the BV ID and loads danmaku without any extra clicks.

5. Frequently Asked Questions

Q1. No danmaku appears at all

• Make sure you are logged in to Bilibili.
• Check the extension pop-up; if it says “no match,” link the creator or supply the Bilibili URL manually.
• Verify the Bilibili source still has comments enabled.

Q2. Comments drift ahead or behind

• Use the “Time-axis calibration” slider first.
• If only parts are off, the video may be censored or edited; manual adjustment is the only fix.

Q3. Firefox feels laggy

• Version 1.1.2 replaced the animation engine; update to the latest release.
• Disable other heavy add-ons or switch to Chrome/Edge for the session.

Q4. Safari asks me to reload every time

• Unsigned extensions are reset on restart; this is an Apple limitation.
• A future Mac App Store build may remove this step.

Q5. How do I hide certain words?

• Extension icon → “Comment filter” → type the keyword (supports basic regex) → Save.

6. Contribute as a Developer

The project is fully open source and uses the WXT framework (a Vite-based tool for browser extensions). If you are comfortable with front-end work:

# clone
git clone https://github.com/ahaduoduoduo/bilibili-youtube-danmaku.git
cd bilibili-youtube-danmaku

# install
npm install

# start dev server (Chrome, hot-reload)
npm run dev

# package for release
npm run build && npm run zip

Folder overview

entrypoints/
├── background/   # service worker
├── content/      # injected into YouTube
└── popup/        # the small settings window

Ways to help

• Add new creator matching rules.
• Improve timing algorithms.
• Fix browser-specific bugs.

7. Recent Changelog (Last Five Releases)

8. Closing Thoughts

B2Y marries the best of two worlds: YouTube’s crisp, adaptive streaming and Bilibili’s decade-honed danmaku culture.
It is not flawless—Firefox and Safari still require manual loading, and niche creators need a one-time link—but for most viewers it removes the daily pain of choosing between quality and community.

If you run into an edge case, open an issue on GitHub. If the extension simply makes your day better, leave the repo a star; that single click is the clearest thank-you to the authors.

Enjoy the show, and happy scrolling.