How AI Auto-Subtitles Works
Transcribe speech to word-timed subtitles (SRT / VTT / burned-in). Whisper-base, multi-language detect.
Try it free →Step-by-step process
- 1
Add your video
Drop or select the video you want to process — it stays on your device.
- 2
Run the model in-browser
AI Auto-Subtitles loads its model (~140 MB) once, caches it, then runs locally in a worker. No upload.
- 3
Download the srt
Preview the result and download the srt. Re-run with different settings anytime.
Frequently asked questions
Which languages?
Whisper detects and transcribes many languages automatically.
Is my audio uploaded?
No — Whisper runs in your browser; the audio never leaves your device.
Is it free to use?
Yes — AI Auto-Subtitles is completely free. No account, no watermark, no credits, and no usage limits.
Do my files or prompts ever leave my device?
No. Everything runs locally in your browser via WebAssembly/WebGPU — there is no server that receives your files, prompts, or results.
Which browser and hardware do I need?
A modern browser. Chrome and Edge get WebGPU acceleration for the fastest results; Firefox and Safari run via WebAssembly. The model (~140 MB) downloads once, then is cached for offline use.
Can I use the results commercially?
Yes. You own everything you create — NSS makes no claim to the images, videos, or text you process or export.
Does it work on mobile?
Lightweight tools run on phones; heavier models prefer a desktop with a GPU. The tool picks the best path for your device and falls back gracefully where needed.
Where can I see a step-by-step guide?
Yes — there is a full walkthrough at /how-it-works/ai-subtitles.