Free Audio to Text & Speech to Text Converter - Offline AI Subtitles
100% free audio to text, speech to text, and voice to text converter powered by OpenAI Whisper and WebGPU running entirely in your browser. Transcribe MP3, M4A, WAV audio with zero data upload.
Click to upload or drag & drop audio / video file here
Supports MP3, WAV, M4A, AAC, OGG, WebM, MP4, MOV and more
100% In-Browser Offline Audio & Video to Text
Engineered for privacy-sensitive users, video creators, and researchers. No registration required. Your media files never leave your device—AI speech recognition runs completely on your local GPU/CPU.
How to Use
Select or Drop Media File
Upload audio (MP3/M4A/WAV) or video (MP4/MOV). The browser automatically decodes the primary audio track.
Choose Model & Language
Base is recommended for general balance; choose Tiny for quick mobile preview or Small for high precision.
Run In-Browser Transcription
Click start. The AI model is cached in browser IndexedDB for instant offline loading in subsequent runs.
Copy or Export Subtitles
Preview timestamped segments in real-time, copy text, or export to SRT, Word, or Markdown.
Troubleshooting & Tips
Mobile Browser Memory Limitations
Mobile devices have constrained RAM. We strongly recommend Tiny or Base models and avoiding the Small model on phones.
WebGPU Support and Fallback
WebGPU is enabled by default in Chrome/Edge 113+ and modern Safari. When unavailable, inference automatically falls back to WASM.
Background Noise & Hallucinations
Extended silences or background music can sometimes lead to repetitive hallucinated text. Use clear vocal recordings when possible.
Uncommon Video Codecs
If an unusual video container fails to decode in the browser, convert or export it to standard M4A/MP3 first.
Open Source Model Lineage & Evidence
Built transparently upon verified open-source architectures and official Hugging Face inference pipelines. All models, code, and weights are publicly auditable.
OpenAI Whisper Official Architecture
Powered by OpenAI's open-source Whisper ASR system (MIT License), delivering robust multilingual transcription and timestamp alignment.
OpenAI Whisper Official GitHub →Hugging Face Transformers.js
Engineered with Hugging Face's official browser-native WebGPU / WASM runtime (Apache-2.0 License) for high-performance client-side inference.
Transformers.js Documentation & Repo →ONNX Community Official Weights
Tiny, Base, and Small models originate directly from official Hugging Face onnx-community repositories with verified integrity.
Verifiable 100% Client-Side Privacy
You can verify our privacy guarantee at any time via Browser Developer Tools (F12 → Network tab): audio, video, and transcription data are processed purely in local RAM and never leave your device.
Frequently Asked Questions & Technology
How does this tool guarantee 100% offline privacy?
Using Hugging Face Transformers.js and ONNX Runtime Web, OpenAI Whisper executes directly inside your browser sandbox. Audio data is never transmitted to any third-party server or cloud API.
Can I extract transcripts directly from MP4 and MOV videos?
Yes. The built-in Web Audio pipeline decodes and streams the main audio channel from video files (MP4, MOV, WebM, MKV) directly without third-party converters.
Will the AI model re-download on every visit?
No. Model weights are persistently stored in your browser's local CacheStorage / IndexedDB. Future sessions load instantly from disk.
Which export formats are supported for video editing and notes?
You can export standard .srt subtitles (compatible with Premiere Pro, CapCut, DaVinci Resolve, Final Cut Pro), .vtt subtitles, .docx Word documents, .md Markdown notes, .txt plain text, and raw JSON metadata.
What are the differences between Tiny, Base, and Small models?
Compare parameter counts, download weights, and recommended device profiles below:
| Whisper Model | Parameters | Download Size | Recommended Device & Use Case |
|---|---|---|---|
| Tiny (Multilingual) ↗ | 39M | ~41 MB | Mobile devices, short memos, ultra-fast preview |
| Base (Multilingual / Default) ↗ | 74M | ~77 MB | Recommended default: balanced speed & multilingual accuracy |
| Small (Multilingual) ↗ | 244M | ~249 MB | High-performance desktop PCs with WebGPU acceleration |