Trancy

Trancy is a browser extension that adds bilingual subtitles to streaming video, showing the original language and the viewer's native language stacked together on screen. It works by pulling in a platform's existing captions and translating them in real time, and for videos that lack captions it can generate its own using Whisper speech-to-text under a feature called AI Subtitle 2.0. Processed videos are cached, so a video that has already been captioned loads instantly for the next viewer. It supports eight platforms on desktop, including YouTube, Netflix, Disney+, Udemy, Coursera, TED, edX, and HBO Max, with YouTube also supported on mobile. Beyond subtitles, the extension includes specialized viewing modes: a Theater mode for distraction-free watching, a Read mode, and a Practice mode aimed at active language learners. It is built for people learning a new language through real content rather than textbook exercises, and for anyone who wants dual captions on shows they already watch. Bilingual subtitles on content that already has captions are free to use. Generating captions from audio via AI Subtitle 2.0 requires a Premium subscription, which allows up to 40 AI-transcribed videos per day, or 60 per day on the higher Premium + Advanced AI tier. Trancy is available as a Chrome extension and a Firefox add-on, plus iOS and Android apps.