Free · Chrome extension · Prime Video, YouTube, Netflix & Disney+

Two languages. One screen.
Turn your streaming nights into language class.

SubDuo shows two of a title's subtitle languages at the same time on Prime Video, YouTube, Netflix and Disney+ — the original on top, your language below. Read, compare, and keep watching without pausing. Runs 100% inside your browser.

Uses the subtitles each site already provides · No account · Nothing leaves your browser

‹The Long Way HomeSeason 1, Ep. 3
Llevo toda la vida esperando este momento.
I've been waiting for this moment my whole life.
42:18 / 1:05:30 CC
Top: subtitle 1 (original) Bottom: subtitle 2 (your language)

Works on the streaming services you already use

▶Prime Video ▶YouTube NNetflix DDisney+

Prime Video support covers primevideo.com and the video pages of these Amazon stores:

primevideo.comamazon.co.jpamazon.comamazon.co.ukamazon.deamazon.framazon.itamazon.esamazon.inamazon.com.auamazon.com.bramazon.com.mxamazon.nl

One language at a time. Pause, rewind, look it up, lose the plot.

Watching in a foreign language means choosing: subtitles you can learn from, or subtitles you can follow.
SubDuo ends the trade-off — both languages sit on screen together, so you read the original, glance at the translation, and keep watching.

Stop switching subtitle tracks

Streaming players show one subtitle language at a time. SubDuo adds a second one on top of it.

Without SubDuo
  • One subtitle language at a time
  • Pause and switch tracks to check a line
  • Rewind to catch what you missed
  • Subtitles stuck at one size and position
With SubDuo
  • Two languages on screen at once, in one clean box
  • Pick any two of the title's subtitle tracks
  • Drag, resize and align them right on the video
  • Color and transparency per line — each site remembers its own setup

Ready in three steps

No account, no setup screens. Install it and press play.

1

Install and press play

Add SubDuo to Chrome and play anything on Prime Video, YouTube, Netflix or Disney+.

2

Pick two languages

SubDuo detects the title's subtitle tracks as it plays. Choose one for the top and one for the bottom in the popup.

3

Watch and adjust

Both lines appear over the video. Drag to move, scroll to resize, right-click for colors — it remembers everything.

SubDuo in 40 seconds

Everything happens on the video

Four things SubDuo does, shown on a mock player. Switch with the tabs.

‹The Long Way HomeSeason 1, Ep. 3
Llevo toda la vida esperando este momento.
I've been waiting for this moment my whole life.
‹The Long Way HomeSeason 1, Ep. 3
No mires atrás. Ya casi llegamos.
Don't look back. We're almost there.
‹The Long Way HomeSeason 1, Ep. 3
LeftCenterRight
No puedes escapar de la marea.
You can't outrun the tide.
Drag: move / Arrows: nudge / Wheel: resize that line / Right-click: colors
Drag to move
Scroll to resize a line
Arrow keys to nudge · Esc to deselect
‹The Long Way HomeSeason 1, Ep. 3
Algunas puertas solo se abren una vez.
Some doors only open once.
SubDuo display settings✕
Top (subtitle 1)
Bottom (subtitle 2)
Reset colors & transparency

Small extension, thought through

Built for people who watch a lot and want the subtitles out of the way — until they need them.

📺

One extension, four services

Prime Video, YouTube, Netflix and Disney+ — the same two-line subtitles and the same controls, everywhere you watch.

🎬

Any two of the title's languages

Every subtitle track the site provides is detected the moment the video plays — on YouTube, auto-generated subtitles are offered too. Pick one per line, or hide one side.

🖱️

Adjust on the video

Drag to move, scroll to resize the line under the pointer, arrow keys to nudge, align left, center or right from the toolbar. It scales with fullscreen and steps aside when the control bar appears.

🎨

Style each line

Text color, text transparency and background transparency, set separately for the top and bottom lines. Both always share one clean box.

☁️

Each site remembers its own setup

Big subtitles on YouTube, subtle ones on Netflix — settings are saved per service and synced through your Chrome, so they follow you to any device.

🌏

12 interface languages

The popup and on-screen hints follow your Chrome language: English, 日本語, 简体中文, 繁體中文, 한국어, Español, Français, Deutsch, Italiano, Português, Русский, हिन्दी.

Nothing leaves your browser.

SubDuo has no server. It only reads the subtitle files each site already sends to your browser for the title you're watching.

🔒 100% local

Subtitle files are fetched from the streaming site itself, parsed in your browser, and drawn over the video. No text, no titles, no viewing history is sent anywhere.

🚫 No account, no tracking, no ads

There is nothing to sign up for. The extension contains no analytics, no advertising, and no third-party code.

🛡️ Minimal permissions

Only "storage" (your settings), "scripting" (reconnecting open tabs after an update) and access to the four supported sites. It runs nowhere else.

🧹 Uninstall removes everything

Your settings live in Chrome's storage. Removing the extension removes them; nothing is kept elsewhere.

Before you install

1No machine translation. SubDuo shows only subtitle languages the title actually offers (on YouTube this includes auto-generated subtitles). If a title has one language, only one line is possible.
2Turn off the site's own subtitles. Otherwise the same line shows twice. SubDuo draws its own.
3Tabs opened before you installed need one reload. After updates, SubDuo reconnects open tabs automatically — and the popup shows a reload button whenever a tab needs it.
4Netflix lists only some languages. Its player hands out a few subtitle tracks per title, depending on your account settings — SubDuo can only offer what it receives.
5It relies on each site's player. If a site changes how subtitles are delivered, detection may stop until SubDuo is updated. Live streams are unverified. Requires desktop Google Chrome 111 or later.

Frequently asked questions

Prime Video (primevideo.com and the video pages of the Amazon stores), YouTube, Netflix and Disney+. On any other page the popup simply tells you the site isn't supported.
No. It shows two of the subtitle tracks the site already provides — nothing is machine-translated. On YouTube you can pick auto-generated subtitles, but automatic translation is never used.
Any two the title offers. Press play and SubDuo lists every track it detects in the popup. Note that Netflix itself only hands out a few languages per title.
Yes. The subtitle block lives inside the player, so it stays in place and scales with the video in fullscreen.
No. SubDuo only reads the subtitle files the site delivers to your browser for the title you're watching. There's no account, no analytics, and nothing leaves your browser.
The site's built-in subtitles are still on. Turn them off in the player's subtitle menu — SubDuo draws its own two lines.
Yes, completely. No sign-up, no limits, no premium tier. A subscription to the streaming service itself is of course still needed where it requires one.

Watch in two languages tonight.

✓Two subtitle languages at once on Prime Video, YouTube, Netflix & Disney+
✓Drag, resize, and style right on the video
✓Completely free, no account
✓100% local — nothing leaves your browser
Add to Chrome — free

Installs from the Chrome Web Store in seconds