lasDoscas - YouTube™ Dual Subtitles

Sync bilingual subtitles on any subtitle-enabled YouTube video. Free, optional AI translation, fully customizable style.

Hi! I built lasDoscas to make watching YouTube in another language easier and more enjoyable. lasDoscas YouTube™ Dual Subtitles shows original and translated subtitles together, in sync — below the player in default/theater view, or at the bottom of the screen in full screen. Optional AI enhancement (your own free key from Gemini, Groq, or OpenRouter) gives more natural translations. Free, lightweight, and open-source. ✨ FEATURES - Dual Subtitles, Always in Sync — works with manual or auto-generated captions on any YouTube video with subtitles, staying synced through seeking, video changes, and track switches. - 55 Target Languages — auto-translated, with a smart default based on your browser language. Optional AI Enhancement — bring your own free API key (Gemini/Groq/OpenRouter) for more natural, context-aware translations. Off by default; falls back to standard translation if unavailable. - Works in Every View — default, theater, and full-screen mode. - In-Player Controls — toggle subtitles and AI enhancement, and open settings, without leaving the video. - Copy Captions — copy the current line with timestamp; Shift-click to also include video title, link, and date. Fully Customizable — font, size, weight, color, per-row visibility, and full-screen background style/opacity. - Instant Save — changes apply immediately, with a short undo window on reset. - Native-Style UI — matches YouTube's light/dark themes; popup available in English, Chinese, and Spanish. 📖 HOW TO USE 1/ Open a YouTube video with captions. 2/ Select an original or auto-generated caption track (not "Auto-translate"). 3/ Turn on lasDoscas from the player switch or popup. 4/ Pick your target language and adjust the look in settings. Optional: enable AI enhancement and add your API key. 🔑 GET A FREE API KEY AI enhancement needs your own free key from Google Gemini, Groq, or OpenRouter. Keys are kept only for your browser session by default — turn on "Remember key on this device" to save it. Keys are sent only to your chosen AI provider, never to YouTube. 🌐 COMPATIBILITY Chrome, Edge, Brave, Opera, Vivaldi, and other Chromium-based browsers. 🔒 PRIVACY No accounts, browsing history, or usage tracking. Settings, styles, keys, and translation cache stay local. To show subtitles, lasDoscas reads caption/video info from YouTube; with AI enhancement on, the current line and a few nearby lines are sent to your chosen provider. 🆓 Free, open-source, ad-free — no account needed. A personal project by one developer; feedback welcome. lasDoscas is an independent project, not affiliated with YouTube, Google, Groq, OpenRouter, or any AI provider. 💡 Only works on YouTube video pages with an available caption track. If subtitles don't appear, try refreshing. 📋 All 55 supported target languages: English, 中文（简体）, 中文（繁体）, español, français, français (Canada), Deutsch, 日本語, 한국어, português, Indonesia, Melayu, русский, العربية, हिन्दी, தமிழ், ไทย, Tiếng Việt, Türkçe, polski, Nederlands, svenska, dansk, norsk, suomi, italiano, română, magyar, čeština, hrvatski, Ελληνικά, עברית, Filipino, українська, euskara, català, galego, íslenska, Kiswahili, eesti, latviešu, lietuvių, slovenčina, slovenščina, български, српски, اردو, فارسی, मराठी, বাংলা, ગુજરાતી, తెలుగు, ಕನ್ನಡ, മലയാളം, አማርኛ