Best for
- Creating live captions for streams, meetings, or practice recordings.
- Testing browser speech recognition and translation support before going live.
- Opening a separate overlay screen with saved caption settings.
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.
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
Why this tool is useful
Realtime caption translator is built for live caption workflows where microphone speech needs to become OBS-friendly chroma-key subtitles.
How to get good results
- Use HTTPS or localhost so microphone access is allowed by the browser.
- Test recognition language and translation targets before recording or streaming.
- Keep the overlay visible while adjusting font, placement, clear delay, and replacement rules.
Limits to know
- Speech recognition and translation availability depend on the browser and device.
- Network, microphone permission, and experimental Translator API support can affect results.
Privacy and local processingThe tool requests microphone access in the browser. Captions and settings stay local unless the browser's speech or translation service processes them according to that browser's behavior.
Practical Tool Guides
Short guides for common browser-based file, image, GIF, PDF, and privacy workflows.
What browser-only tools can and cannot keep private
A practical privacy guide for local file tools, browser permissions, and third-party browser services.
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.
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