Real-Time Subtitles for Any Video in Your Browser
Overline adds live AI captions and translation to any video playing in Chrome — YouTube, Zoom, streaming sites, lectures, and more.
Add real-time subtitles to any video — install Overline free.
Add to Chrome — it's freeWhat Overline Does
Overline is a Chrome extension that adds a real-time caption and translation overlay to any video playing in your browser. Unlike platform-specific subtitle tools, Overline works at the browser level — it doesn't care whether you're on YouTube, a university portal, a Zoom call, or a streaming service. If audio plays in a tab, Overline can caption it.
The result is a semi-transparent caption bar that floats at the bottom of the video, showing the transcribed speech and — if you choose — a live translation into your language. It appears within milliseconds of the speaker's words, with no need to pause, reconfigure, or leave the page.
How It Works (Without the Jargon)
Three things happen in under a second every time you speak into a video:
- 1. Capture. Overline uses Chrome's tab audio capture API to stream the audio from your active tab. This is the same audio your speakers play — not your microphone.
- 2. Transcribe. The audio stream goes to Deepgram's real-time speech recognition engine. Deepgram is optimized for low-latency streaming — it processes speech as it happens, not after a sentence ends.
- 3. Translate. The transcribed text is sent to Google's Gemini model, which translates it into your chosen language in real time.
The translated text is pushed back to the extension and rendered on screen as the caption overlay. The entire round-trip takes under a second on a normal connection.
Where It Works: Platform by Platform
Here's a quick reference for the most common platforms:
Videos, Shorts, live streams
Meetings and recordings
Works in Chrome tab
All lecture players
Live streams and VODs
Shared recordings
DRM may block audio capture
Panopto, Kaltura, Echo360
Note on Netflix: Netflix uses DRM (Widevine) which can block Chrome extensions from capturing protected audio. This is a platform-level restriction, not an Overline limitation.
Captions vs. Translation — You Choose
Overline doesn't force you to translate. You can use it in two modes:
- Captions only — Transcribe speech into text in the source language. Useful for hard-of-hearing users, noisy environments, or content with poor audio.
- Captions + translation — Show the original transcription and a translation side by side. Switch target languages at any time with a single click.
The language switcher is a pill-style selector in the extension popup. Switching languages mid-video is instant — the translation updates from the next sentence onward without interrupting playback.
See How It Works on Specific Platforms
We've written dedicated guides for the most common use cases. Each guide covers platform-specific setup, tips, and FAQs:
Frequently Asked Questions
Does Overline work on Netflix?
Partially. Netflix uses DRM (Widevine) which may block browser extensions from capturing tab audio on protected content. This is a platform restriction. Overline works on most other streaming and video sites.
How accurate is the transcription?
Very accurate for clear speech in supported languages. Deepgram's streaming model performs well on conversational and lecture content. Accuracy can drop for heavy accents, overlapping speakers, or low-quality audio.
Does it work on all websites?
It works on any website where audio plays in a Chrome browser tab and is not protected by DRM. This covers the vast majority of video content on the web.
Is my audio sent to a server?
Yes — audio is streamed to Deepgram for transcription. It is processed in real time and not stored as raw audio. Only the resulting transcript text is saved (to your account), and only if you choose to keep it.
How is this different from browser built-in translate?
Browser translate (like Chrome's) translates the text content of a webpage — it doesn't understand spoken audio. Overline works on the actual speech in a video, in real time, and overlays the translation on the video itself rather than translating the page's UI.