yt2mp3 - Portable YouTube to MP3 Converter

yt2mp3 is a single-executable desktop app that lets you batch-download YouTube videos and convert them to MP3 on any machine without pre-installed ffmpeg or Python. The entire toolchain—yt-dlp (v2025.09.26) and ffmpeg (v6.0)—is bundled and unpacked at runtime via Electron Builder's asar unpacking mechanism. The frontend is a React SPA using Tailwind CSS and React Router, communicating to the main process via IPC.

The architecture separates concerns cleanly: Vite builds the React renderer to `dist/`, Electron's main process spawns yt-dlp with injected ffmpeg PATH, and a preload bridge exposes safe IPC methods (download, folder selection, file operations). Download state is managed via React Context, with real-time log streaming and progress parsing from yt-dlp's stderr. The app guards against concurrent downloads, tracks active child processes for clean shutdown, and persists download history in the UI.

Building for portability meant solving the binary-distribution problem: `yt-dlp-exec` and `ffmpeg-static` packages download platform-specific binaries during `npm install`, and the electron-builder config unpacks them into `app.asar.unpacked/` so they remain executable after distribution. The test script verifies binary presence and functionality. Total built package size is around 95 MB—yt-dlp at 17.48 MB and ffmpeg at 77.36 MB—a tradeoff for true portability and zero external dependencies.