Free · Chrome extension · For Amazon Prime Video

Two languages. One screen.
Turn Prime Video into your language class.

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

Uses the subtitles Amazon 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 wherever you watch Prime Video

primevideo.com and the Prime 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

Prime Video lets you show one subtitle language. 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 — synced across your Chrome

Ready in three steps

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

1

Install and open a title

Add SubDuo to Chrome and play anything on Prime Video.

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.

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
I've been waiting for this moment my whole life.
この瞬間を、ずっと待っていたんだ。
The Long Way HomeSeason 1, Ep. 3
Don't look back. We're almost there.
振り返るな。もうすぐ着く。
The Long Way HomeSeason 1, Ep. 3
LeftCenterRight
You can't outrun the tide.
潮からは逃げられない。
Height 22% · Center 50% · Size top 100% / bottom 80%
Drag to move
Scroll to resize a line
Arrow keys to nudge · Esc to deselect
The Long Way HomeSeason 1, Ep. 3
Some doors only open once.
一度しか開かない扉もある。
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.

🎬

Any two of the title's languages

Every subtitle track Amazon provides for the title is detected the moment it plays. Pick one for the top line, one for the bottom — or hide one side.

🖱️

Adjust on the video

Drag to move, scroll to resize the line under the pointer, arrow keys to nudge by 1% (Shift: 5%), and align left, center or right from the toolbar.

🎨

Style each line

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

📐

Always fits, always readable

Font size follows the video height — fullscreen included. Long lines wrap naturally, the block shrinks to stay on screen, and it steps aside when the control bar appears.

☁️

Synced settings and presets

Languages, sizes, position and colors are saved to Chrome sync, so they follow you. Save up to 20 named presets and switch setups in one click.

🌏

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 Amazon already sends to your browser for the title you're watching.

🔒 100% local

Subtitle files are fetched from Amazon, 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) and "tabs" (to show the current tab's status in the popup). It runs solely on Prime Video and Amazon video pages.

🧹 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 can only show subtitle languages Amazon provides for that title. If a title has one language, only one line is possible.
2Turn off Prime Video's own subtitles. Otherwise the same line shows twice. SubDuo draws its own.
3Reload after installing or updating. Tabs that were already open need a refresh before SubDuo can see the subtitle tracks.
4It relies on Prime Video's player. If Amazon changes how subtitles are delivered, SubDuo may stop detecting tracks until it's updated.
5Live streams and ad-supported playback haven't been verified. Requires Google Chrome 111 or later on desktop.

Frequently asked questions

No. It shows two of the subtitle tracks Amazon already provides for the title — nothing is machine-translated. If a title offers only one language, only that one can be shown.
Any two the title offers. Press play and SubDuo lists every track it detects in the popup; before playback starts it offers the 12 most common languages as a preset list.
Yes. The subtitle block lives inside the player element, so it stays in place and scales with the video in fullscreen.
No. SubDuo only reads the subtitle files Amazon delivers to your browser for the title you're watching. There's no account, no analytics, and nothing leaves your browser.
Prime Video'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 Prime Video subscription is of course required to watch the videos themselves.

Watch in two languages tonight.

Two subtitle languages at once on Prime Video
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