Dual Subtitles for YouTube™

Bilingual subtitles for YouTube — original and translation in one non-overlapping layer.

Dual Subtitles for YouTube™ shows the original caption and a translation at the same time, as one clean layer — great for language learning and for following along in a second language. Official site: https://gythiro.github.io/yt-dual-subs/ FEATURES • Two languages, one set of lines. Original and translation appear together, and YouTube's own caption layer is hidden so the two don't sit on top of each other. • Whole sentences, not word by word. Lines are rendered from the caption's own timings and turn over by sentence. • Three ways to translate. By default it uses YouTube's own whole-track translation, which is aligned to the original. When a track cannot be translated, fragmented auto-captions are first rebuilt into full sentences and then translated — no word salad. Either engine can also be pinned by hand. • Or bring your own API key. Twelve providers, including DeepSeek, Gemini, DeepL and Alibaba Cloud Model Studio; a provider with both a China and an international platform has a Site row, so the key goes to the platform that issued it. With an LLM key each sentence is understood as a whole and then split back across the subtitles; DeepL is given the sentence as context for the same effect. The key is stored on your own machine and is sent to nobody but the provider you picked. This is entirely optional — the extension works with no account and no key. • 50 translation languages, and you choose which ones appear in the popup menu. • Read the translation out loud. Each line is spoken as it appears, with the video's own audio ducking underneath; a line that runs long slows the picture a touch and borrows the gap after it, and a switch keeps slowing until every line finishes. The translation goes only to the speech provider you chose, nowhere else. Your browser's own voices need no key and no account; five cloud providers are there for better ones, including Chinese regional voices, and you can preview a voice in your own language before choosing it. Off by default. • Summarize the video you are watching. Pick Summary in the player menu and the whole caption track becomes a one-line overview plus timestamped chapters — click one to jump there. This needs a service of yours: your API key, or a model running on your own machine (Ollama, or an OpenAI-compatible server such as LM Studio); the panel says which provider it will use and how many parts it will send before anything is sent. • The extension's own interface comes in 44 languages, following your browser or set by hand. • Fully customizable. Per-line font (the fonts really installed on this computer, or a font file you import), size, text colour, background colour and opacity, outline, line spacing, and which line sits on top — with a live preview. • Draggable and positionable. Drop the subtitle box anywhere on the video; it remembers where. Works in fullscreen. Double-click to reset. • Select and copy the subtitle text. Off by default, since selecting would get in the way of click-to-pause; switch it on in the small menu behind the arrow on the player's subtitle button, or in the popup's Layout card. • One-click toggle. A caption button in the player's control bar turns the overlay on or off — handy for videos that already have burned-in subtitles. • Three keyboard shortcuts: subtitles on/off, read-aloud on/off, translation line on/off. They ship unbound — bind them from Settings → About → Set shortcuts (Chrome's own shortcuts page). • Works on YouTube Shorts — bilingual subtitles on the vertical player too. • Export to SRT. Save the current video's subtitles for offline study — original, translation, or bilingual. If you have set up your own key, the export can go through it instead: it tells you how many requests that will take before it sends anything, and it is off by default. • When something is wrong, one button explains it. Settings → About → Something not working has a three-step checklist and Copy diagnostic info; the popup shows the same button whenever something fails, so a bug report can start with facts. PRIVACY No accounts, no tracking, no analytics, no ads, and no developer server. Your settings stay in your browser. The only thing that leaves it is the caption text of the video you are watching, and it goes only to the service you chose: the translation service in use — YouTube's own, Google Translate, or the provider whose key you supplied; with read-aloud on, the current translated line goes to the speech provider you picked; when you ask for a summary, the caption track goes to the provider you set up for it. Each goes to that one service, for that one purpose. Nothing is sent to the developer. Full policy: https://github.com/Gythiro/yt-dual-subs/blob/main/PRIVACY.md Open source (MIT): https://github.com/Gythiro/yt-dual-subs Not affiliated with, endorsed by, or sponsored by YouTube or Google LLC. "YouTube" is a trademark of Google LLC, used only to describe compatibility.