Convert an Opus file (e.g. a WhatsApp voice message) to the more universally compatible MP3 locally in your browser. No upload.
Running locally on your device ...
Running locally on your device ...
0%
Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
Opus is a modern, open codec (IETF RFC 6716, 2012), optimized for very low latency combined with high quality - which is why it is the standard behind WhatsApp and Telegram voice messages, Discord calls and WebRTC video conferencing. Outside these apps, not every player or older device opens it.
This tool natively decodes the Opus stream with ffmpeg and encodes it with libmp3lame to MP3 - the most universally supported format. For a saved voice message or an exported call recording, that makes the file playable on any device.
Opus voice messages usually sit at very low bitrates (often under 32 kbps) - for speech, a low MP3 bitrate in mono is therefore already entirely sufficient. The conversion runs entirely locally in the browser, with no upload.
| Input formats | OPUS |
|---|---|
| Output format | MP3 |
| Batch processing | No |
| Processing | Locally in your browser (WebAssembly) |
| File upload | None |
Limitations: Both formats are lossy. Since typical Opus voice messages were already recorded at very low bitrate, a very high MP3 bitrate brings no additional benefit. One file per run.
No, the conversion runs entirely locally in the browser.
Usually from WhatsApp or Telegram voice messages, Discord recordings or WebRTC captures.
128 kbps in mono is more than enough, since the Opus source itself is usually below 32 kbps.
Older devices and simple players often do not know the relatively young Opus codec - MP3, by contrast, is understood by practically every device.