Realtime caption translator
Create live microphone captions and an OBS-friendly chroma key subtitle screen.
Files are not uploaded to a server. Selected files and results are processed only inside your browser.
Chroma key caption screen
Use the green background as a chroma key in OBS Browser Source and show only the captions.
Recognized speech captions will appear here.
Translated captions will appear here.
翻訳字幕がここに表示されます。
ReadyPress Start microphone to begin speech recognition.
Speech and translation
Speech recognition uses the browser Web Speech API. Translation runs in the browser when Chrome's built-in Translator API is available.
Word replace and sentence handling
Enter 0 to disable auto-clear or silence-based sentence splitting. Defaults are clear 8000ms and split 900ms.
Caption style
Save settings and create launch files
How to use this tool safely
Realtime caption translator is designed to run directly in your browser. Prepare the required input, review the result, and keep original copies of important files before using browser-based tools.
Browser processingTools that handle files are designed, whenever possible, to process selected files on your device without uploading them to a FreeToolHub server.
LimitsVery large files or long-running tasks may be slower or fail depending on browser memory, device performance, and supported Web APIs.
FAQ
Common questions about browser-only file conversion.
Are files uploaded to a server?No. Selected files are processed in the browser, and converted results are not stored on a server.
What should I do if processing is slow?Lowering FPS, output size, color count, or processing duration reduces browser memory use and processing time.
Can I use it on mobile?Yes, but desktop browsers are more stable for large files.
Related tools
More tools built around the same local-processing approach.