Lumi
Add to Chrome中
For YouTube · Bilibili

Watch videos without language barriers

Lumi is a browser extension for YouTube and Bilibili with bilingual subtitles, AI video summaries, and chapter jumps. Install it once and turn watching into learning.

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Free to install · Your watch history stays local
Core features

Three small upgrades that make videos learnable

01 · Bilingual subtitles

Understand every second with bilingual subtitles

Whether the video is on YouTube or Bilibili, and whether the captions are generated or uploaded by the creator, Lumi detects and translates them in sync.

  • ASR and manual tracksAuto-detect generated and creator-uploaded subtitles.
  • Source + translationSource and translated lines stay aligned.
  • Adjustable styleTune font size, position, and color per video.

The hardest part of learning is admitting what you don't know yet.

学习最难的部分，是承认自己还不懂。

LanguageEnglish
Font size18px
PositionBottom center
SourceASRManual
02 · AI video summary

Read the gist before you spend 20 minutes

Lumi reads the transcript and gives you a structured summary with chapters and timestamps. Click a chapter to jump directly to that moment.

  • Chaptered outlineKey points organized with timestamps.
  • Click to seekJump to any section instantly.
  • Multilingual outputGenerate summaries in Chinese, English, Japanese, Korean, and more.
AI SummaryGenerated by Lumi from the transcript

This episode explains active recall, gives three ways to turn watching into output, and ends with a 20-minute practice loop.

  • 00:00Why active recall beats rereading
  • 03:42Three ways to turn watching into output
  • 08:15A 20-minute practice loop you can use today
  • 14:08Common pitfalls when you start
03 · Focus mode

Auto-skip ads and stay in the flow

Ads break focus when you are learning. Lumi detects them and skips them so you can keep the session intact.

  • Live detectionDetects ad state from page changes.
  • Configurable retryAdjust delay and retry limits.
  • One toggleTurn it on or off from the popup.
Ad

Sponsored video · 0:08 of 0:15

Lumi auto-skip
Back to video

Continued at 03:18

Auto-skip enabled
How it works

Three steps to start learning from videos

  1. 01

    Install Lumi

    One click from the Chrome or Edge store. No signup required.

  2. 02

    Open any video

    Lumi detects subtitles on YouTube and Bilibili automatically.

  3. 03

    Watch and learn

    Read bilingual subtitles, open the AI summary, and jump by chapter.

Where Lumi works

YouTube and Bilibili are supported today

YT

YouTube

Full subtitle translation, AI summaries, chapter seeking, and automatic ad-skip.

B

Bilibili

Works with ASR and uploaded subtitles across anime, courses, and public lectures.

···

More platforms

Vimeo, Coursera, and course platforms are next.

FAQ

Things people usually ask

Is Lumi free?
All current core features, including bilingual subtitles, AI summaries, and ad-skip, are free. Advanced memory and multi-video learning features will be paid later, but the basics will stay free.
Which video platforms are supported?
YouTube and Bilibili are supported now. Vimeo, Coursera, and other course platforms are next on the roadmap.
Which AI model powers translation?
Lumi supports Anthropic, OpenAI, and Deepseek. You can choose the provider that fits you best in extension settings.
Do you upload my watch history?
No. Lumi only sends subtitle text to AI providers when you trigger a feature. Your watch history stays in local browser storage.
Can Lumi work on videos without subtitles?
If the platform exposes ASR captions, Lumi uses them. A small number of videos with no captions at all are not supported yet.

Ready to turn watching into learning?

Install in a minute and see it work on YouTube and Bilibili.

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