What is a .opus file?
Opus Audio · Audio · Xiph.Org Foundation / IETF · 2012
Opus is a modern, open, royalty-free audio codec that beats MP3 and AAC at low bitrates, which is why voice chat, streaming and the web rely on it. Files usually end in .opus inside an Ogg container.
What is a .opus file used for?
Opus was standardised by the IETF (RFC 6716) to be one codec that does everything, from low-latency voice to high-quality music, all royalty-free.
It is what Discord, WhatsApp and WebRTC use for voice, and YouTube uses for much of its audio, because it sounds better than the alternatives at the low bitrates those uses demand.
An .opus file is Opus audio wrapped in an Ogg container. VLC and most browsers play it directly.
Older hardware and some Apple software may not support Opus natively, in which case converting to MP3 or AAC is the fix.
What opens a .opus file?
The .opus format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- VLC
- foobar2000
macOS
- VLC
- Music (recent macOS)
Linux
- VLC
- mpv
- Rhythmbox
Web
- Most modern browsers
Open a .opus file step by step
- Confirm the file really is a .opus. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with VLC or foobar2000.
- On Mac, use VLC or Music (recent macOS).
- On Linux, try VLC or mpv.
- Still stuck? Convert the .opus to MP3, which opens more widely.
Why can't I open my .opus file?
Almost always because no installed app understands Opus. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .opus at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
How to convert a .opus file
You can convert a .opus file to MP3, AAC, WAV, OGG using a conversion tool or the export menu of an app that opens it.
What is the .opus file signature (magic bytes)?
A .opus file starts with the hex bytes 4F 67 67 53, which read as OggS in ASCII. Programs identify Opus by those bytes, not by the filename, so a renamed file still gives itself away.
These are the documented signatures for Opus. For a full breakdown, see the OGG file signature page.
| Hex signature | Offset | ASCII | Note |
|---|---|---|---|
| 4F 67 67 53 | 0 | OggS | 'OggS'; Opus audio is carried inside an Ogg container |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .opus file?
Opus is a modern, open, royalty-free audio codec that beats MP3 and AAC at low bitrates, which is why voice chat, streaming and the web rely on it. Files usually end in .opus inside an Ogg container.
How do I open an .opus file?
Play it in VLC or drag it into most modern browsers. On a device that does not support Opus, convert it to MP3 or AAC first.
Is Opus better than MP3?
At the same bitrate, yes, especially at low bitrates, where Opus sounds noticeably clearer. MP3 still wins on universal device support, so convert to MP3 if compatibility matters more than size.
Related formats
Sources
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