RIYS Converter

A client-side media converter using FFmpeg compiled to WebAssembly. Files never leave the browser - no uploads, no servers.

Supports MP3, WAV, OGG, M4A, FLAC, and AAC output. Drag a file in, pick a format, download the result.

Try it | GitHub

Stack

• Vanilla JS + HTML/CSS
• FFmpeg.wasm (@ffmpeg/ffmpeg, @ffmpeg/core-mt) for transcoding
• Vite for bundling

How It Works

The app lazy-loads the FFmpeg WASM module on first use. Files are written to FFmpeg's in-memory virtual filesystem, transcoded via standard FFmpeg commands, and the output is triggered as a browser download.

Progress events from FFmpeg drive a progress bar in the UI. After download, the virtual filesystem is cleaned up.

Technical Details

FFmpeg.wasm requires SharedArrayBuffer for multi-threaded WASM workers. This means the page needs specific CORS headers:

// vite.config.js
headers: {
  "Cross-Origin-Opener-Policy": "same-origin",
  "Cross-Origin-Embedder-Policy": "require-corp"
}

FFmpeg dependencies are excluded from Vite's pre-bundling to avoid conflicts with WebAssembly module loading.

No framework, no state management. The problem is simple enough that ~140 lines of vanilla JS is the right call.