AI Caption Translator

Pretranslate supported video caption cues in batches and show cached translations in sync with playback.

AI Caption Translator is a personal study helper for supported video pages that already expose captions and transcript cues. Current support covers Udemy lecture pages and limited YouTube watch pages. When you press `[Start translation]`, the extension pauses the current video if it was playing, reads supported cue text from the current page, and sends only uncached cue batches to the translation provider you selected. Gemini API is the default provider, and OpenAI API is available as an alternative. After pretranslation is ready, the extension displays cached caption matches in sync with the visible video captions and resumes playback only when preparation succeeds. Request-saving behavior: - No individual-caption API request is sent during playback. - Cached cue translations are reused locally. - Transcript cue batches are paced with model-aware request intervals. - Gemini daily request limits are checked before provider calls. - Missing or unmatched cues show a status message instead of triggering an automatic fallback request. Data handling: - API keys and settings are stored in Chrome storage. - Translation cache entries stay in the user's browser profile. - Current-video caption cue batches can be sent to the selected Gemini or OpenAI endpoint only after the user starts translation. - The extension does not operate a developer backend and does not sell user data. Limitations: - Captions must be enabled in the supported video player. - The page must expose a transcript panel or transcript cue text for batch pretranslation. - Provider API limits, provider data handling, and billing are controlled by the user's selected API provider and account. This extension does not download video or audio files, crawl full courses, channels, playlists, or libraries, export transcripts, redistribute provider content, record the screen, or claim affiliation with Udemy, YouTube, Vimeo, or other video platforms.