Generate subtitles from a video
Make timed captions for a video in one go: Fizzdoc listens to the sound track and writes an SRT or VTT file for YouTube, VLC, Premiere, CapCut or any video player.
Free forever · Runs on your device · 0 bytes uploaded
Speed depends on your device; big files on phones take longer. Slow or not working? Report it on GitHub
How to subtitle Generator
- Choose a video or audio file (MP4, MOV, WebM, MP3, M4A or WAV).
- Pick the spoken language, or leave it on auto-detect, and choose SRT or VTT.
- Click “Create subtitles”, check the captions and download the file.
Also good for
- SRT subtitle generator
- auto captions for video
- generate subtitles from video free
- video to SRT
- subtitles for YouTube
Private by design — and you can check
Your files are never uploaded, because there is nowhere to upload them to.
- No upload step existsFiles are read and written inside this browser tab. There is no server that could receive them.
- The browser enforces itThis page’s Content Security Policy only allows connections back to this site, which serves nothing but the app itself.
- See for yourselfOpen developer tools, watch the Network tab and run a job: no request carries your document.
- Open sourceEvery line is on GitHub, built on qpdf, pdf.js & pdf-lib.
Frequently asked questions
Are my files uploaded anywhere?
No. Fizzdoc does the work inside your browser tab, using open-source engines compiled to WebAssembly and JavaScript. Your file is read from your device, processed locally, and the result is saved straight back to your device. You can check this yourself: open your browser’s developer tools, go to the Network tab, and run a job — no request carries your file.
How do I add the subtitles to my video?
Upload the .srt file next to your video on YouTube, Facebook or LinkedIn, or drag it into VLC, Premiere Pro, DaVinci Resolve or CapCut. VTT is the format web video players use.
How accurate is it?
Fizzdoc uses Whisper tiny, a small version of OpenAI’s open speech model that runs fully in your browser. Clear English speech comes out well; noisy recordings, strong accents and other languages are rougher, so read the text through before you rely on it.
Is Fizzdoc free?
Yes, and it stays free: no sign-up, no watermark, no daily limit and no premium tier. Fizzdoc is open source under the Apache-2.0 license, so anyone can run their own copy.
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