Subtitle Translation
How it works
Section titled “How it works”Open a YouTube video and Flash Translate intercepts the auto-generated captions to build real-time bilingual subtitles synced to playback — you don’t need to turn on YouTube’s own captions first.
Sentence segmentation
Section titled “Sentence segmentation”Auto-generated captions arrive as a raw, largely unpunctuated stream of words. Instead of translating line by line, Flash Translate re-segments them into natural sentences using a punctuation-aware heuristic (tuned against real subtitle samples) before sending them for translation, which produces noticeably more natural results than word-by-word or fixed-line pairing.
Batching
Section titled “Batching”Subtitles are translated using a sliding window: once at least 5 new untranslated lines have accumulated, a batch of up to 50 lines is sent for translation, keeping translated subtitles a comfortable distance ahead of playback.
Display modes
Section titled “Display modes”Configurable in Settings → Subtitle Translation:
- Bilingual (default) — shows the original line and the translation together.
- Monolingual — shows only the translation.
- Auto-translate — off by default; when enabled, translation starts automatically as soon as you open a video page, instead of waiting for you to turn it on manually per video.
Settings
Section titled “Settings”Settings → Subtitle Translation lets you turn the feature on or off, toggle auto-translate and bilingual display, exclude specific domains, and choose which saved LLM configuration this feature uses.
Subtitle translation currently supports YouTube; more platforms may be added later.