About Opus and OGG
Opus is the newest codec here and the most efficient — it outperforms MP3, Vorbis, and AAC at low bitrates, which is why WhatsApp, Discord, and WebRTC all use it. Support is universal in browsers, patchier in older hardware.
OGG Vorbis is a free, open lossy codec that beats MP3 at equivalent bitrates. It's common in game audio and open-source software, and every modern browser plays it.
Converting Opus to OGG is lossy. 192 kbps is transparent for most listeners on most material; pick 320 kbps if you want the ceiling, or drop lower when small files matter more than fidelity.
How the conversion works
This tool runs FFmpeg — the same engine behind most media software — compiled to WebAssembly, entirely in your browser. Your file is read locally, converted locally, and saved straight from memory; nothing is ever uploaded, which also means no queues and no server-side file size limits.
The converter itself is a one-time ~31 MB download on your first conversion, cached by the browser afterwards. Once it's loaded, everything works offline.