SubDuo — Dual Subtitles for Streaming

Show two subtitle languages at once on Prime Video, YouTube, Netflix, Disney+ and TED. Made for language learners.

🎬 Turn what you love to watch into your best language lesson. SubDuo puts two subtitle languages on screen at the same time — the original on top, your language below — on Prime Video, YouTube, Netflix, Disney+ and TED. Read, compare and keep watching. No pausing, no rewinding, no switching tracks. Stuck on a word? Double-click it. An instant translation appears right on the video — done on your device — with the line from the scene as the example. Want more? Tap “Ask AI” for the meaning in context, the pronunciation and an example sentence. One tap saves it to your vocabulary list. ━━━━━━━━━━━━━━━━━━ ✨ WHAT SUBDUO DOES ━━━━━━━━━━━━━━━━━━ 🎯 Two subtitle languages at once, in one clean box 🌐 Pick any two of the subtitle tracks the title offers — detected the moment you press play 📖 Double-click a word (or Alt+drag a phrase) to look it up without leaving the video; playback pauses for you ⚡ Instant, free translation on your device with Chrome's built-in translator; tap “Ask AI” only when you want the meaning in context, the pronunciation and an example 📒 Built-in vocabulary list: save, search, filter by language, play the pronunciation 🔊 🖱️ Drag to move, scroll to resize a line, arrow keys to nudge, align left / center / right 🎨 Text color, text transparency and background transparency — set separately for each line ☁️ Each site remembers its own setup, synced through your Chrome account 🌏 Pick from 12 display languages — separate from Chrome's language, and used for translations and explanations too ━━━━━━━━━━━━━━━━━━ 📺 WORKS ON ━━━━━━━━━━━━━━━━━━ ▶ Prime Video — primevideo.com and the video pages of Amazon stores ▶ YouTube — auto-generated subtitles included ▶ Netflix ▶ Disney+ ▶ TED ━━━━━━━━━━━━━━━━━━ ⚡ READY IN 30 SECONDS ━━━━━━━━━━━━━━━━━━ 1️⃣ Add SubDuo to Chrome. 2️⃣ Play a video on any supported site. 3️⃣ Click the SubDuo icon and pick one language for the top line and one for the bottom. 4️⃣ Watch and tweak: drag the subtitles, scroll over a line to resize it, right-click for colors. Double-click a word to look it up, then press Save. Your vocabulary list opens from the popup. ━━━━━━━━━━━━━━━━━━ 🔒 PRIVACY ━━━━━━━━━━━━━━━━━━ 🚫 No account, no ads, no analytics. 💻 Subtitles are the files each site already streams to your browser. They are parsed and drawn locally — your settings and viewing history never leave your browser. 📖 Words you look up are translated on your device by Chrome's built-in translator — nothing is sent. Only when you tap “Ask AI” are that word, its subtitle line and the other line at the same moment sent to SubDuo's explanation server to generate the explanation. Nothing else is sent, and nothing that identifies you. 🛡️ Permissions: "storage" (your settings and vocabulary), "scripting" (reconnecting open tabs after an update) and access to the five supported sites. It runs nowhere else. ━━━━━━━━━━━━━━━━━━ 💡 GOOD TO KNOW ━━━━━━━━━━━━━━━━━━ • Subtitles are not machine-translated — only subtitle languages the title actually offers can be shown. • Turn off the site's own subtitles, or the same line appears twice. • Netflix lists only the subtitle languages its player hands out for your account. • On-device translation uses Chrome's built-in translator (Chrome 138 or later). The first time, Chrome downloads a language pack, and some languages aren't covered — then tap “Ask AI”. AI explanations can occasionally be wrong. If the service is unavailable, saving to the vocabulary list still works. • Detection depends on each site's player; if a site changes, it may stop until SubDuo is updated. Live streams are unverified. Requires desktop Google Chrome 111 or later. ━━━━━━━━━━━━━━━━━━ 💬 Questions or ideas? We read every message. 📄 Privacy policy: https://ramune441.github.io/subduo/privacy-policy.html ✉️ Contact: https://ramune441.github.io/subduo/contact.html