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100% Offline AI Subtitles

AI Subtitle Generator

Transcribe video to subtitles locally inside your browser. Generate timestamps, apply gorgeous social-media animations, and export SRT, VTT, or TXT completely free.

Local AI WhisperNo cloud API server lag
100% PrivateVideos never leave your disk
Zero CostUnlimited speech conversions
Multiple FormatsExport SRT, VTT & text
Transcription Language:

Drag & drop your video file here

Supports MP4, WEBM, AVI, MOV, and MKV. Extracted audio is transcribed 100% offline.

Processing Engine

Core Capabilities & local Suite

Perform professional-grade AI video transcribing and custom caption rendering entirely inside your browser.

  • Local AI Whisper Speech

    Transcribe spoken words offline natively inside browser Web Workers using OpenAI's highly optimized speech-to-text neural network.

  • Kinetics & Social Presets

    Select or customize animated subtitles like TikTok Bold and Karaoke Sweeps. Instantly preview fonts, colors, custom outlines, and backdrops.

  • SRT, WebVTT & Plain Text

    Download accurate timestamps compatible with YouTube, Premiere Pro, or CapCut as standard SubRip (.srt), WebVTT (.vtt), or plain text (.txt).

  • Instant Audio Demuxing

    Extract high-fidelity audio streams from large MP4/WebM uploads directly via local WebAssembly-based FFmpeg.WASM processing.

  • Zero-Knowledge Security

    All AI computations and frame-baking happen strictly inside your browser sandbox. Your files are never uploaded to any remote server.

  • Always Free & Unlimited

    No signups, no subscriptions, and no arbitrary video length caps. Process as many video clips and speech transcriptions as you need.

Frequently Asked Questions

Everything you need to know about the browser-local subtitle generator.

Is my video uploaded to an external server?
No. The entire process (FFmpeg audio extraction and Whisper AI transcription) runs entirely inside your local web browser sandbox. Your video files never leave your computer, ensuring absolute privacy.
Is this subtitle generator tool completely free and unlimited?
Yes, absolutely! Unlike other cloud-based subtitle generators that limit minutes, restrict file sizes, or charge monthly subscriptions, our local-first tool lets you transcribe unlimited videos of any length for free.
Are there any video length or size limits?
There are no arbitrary limits on file sizes or video lengths! Because the process runs inside your local browser tab, the speed and capacity depend on your device's physical memory (RAM) and CPU/GPU power.
Why does the first transcription take longer to load?
On the very first run, the tool downloads the local AI Whisper speech model (~75MB) and caches it inside your browser's Cache Storage. Subsequent transcripts are nearly instant since the model is loaded directly from your device's memory.
What subtitle file export formats are supported?
We support exporting subtitles in SubRip (.SRT) format, WebVTT (.VTT) format, and clean conversational plain text (.TXT) format directly from the options dashboard.
Do I need a continuous internet connection to generate subtitles?
Only for the initial visit to cache the Whisper model weights. Once stored locally, you can use the AI Subtitle Generator completely offline without any internet connection.
What AI speech-to-text engine powers the transcription?
The tool runs OpenAI's highly optimized Whisper model compiled to WebAssembly via @xenova/transformers, executing natively inside secure browser Web Workers.
Can I customize the caption styling before baking it into the video?
Yes! You can customize presets (Classic, TikTok, Cinematic, Glassmorphism, Neon Cyberpunk, Karaoke, and Kinetic Spotlight) and manually fine-tune text size, placement, backdrop opacity, text color, borders, and drop shadows.

Loved by Creators & Developers

Join thousands of users transcribing and designing captions with complete data privacy.

"This local Whisper subtitle generator is absolutely magic. Baking TikTok styled captions takes seconds and my private videos never leave my browser."

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Sarah J.Social Media Creator

"As an independent creator, I was wasting hours manually typing subtitles. Whisper AI's local translation accuracy is 99% correct, and the VTT export is seamless."

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Marcus ChenIndependent Filmmaker

"Extremely impressive engineering. Running OpenAI Whisper speech models directly in the browser via Web Workers is highly responsive and preserves 100% of my data privacy."

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Liam O'ConnorFrontend Engineer

"Adding beautiful captioned styles directly to my educational videos without an expensive subscription is a game-changer. Unlimited, fast, and gorgeous."

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Amara PatelEducator & Designer