OPUS file format: what it is and how to use it

Opus is the best lossy audio codec ever standardized: IETF RFC 6716, transparent at low bitrates, built for everything from voice calls to music streaming. Learn when to use it and what to choose instead.

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What is a OPUS file?

An .opus file is audio compressed with Opus, the IETF's RFC 6716 codec merging Xiph's SILK (speech) and CELT (music) into one algorithm that beats every predecessor at its own game: transparent music around 128–160 kbps, near-perfect speech at 32 kbps, latency low enough for real-time calls. It is the audio of WebRTC, Discord, WhatsApp and YouTube's Opus tracks, usually inside an Ogg container.

When should you use OPUS?

  • Voice and calls: the standard codec of WebRTC, Discord and modern VoIP.
  • Low-bitrate music: quality nothing else matches below ~96 kbps.
  • Modern pipelines: open, royalty-free and better than AAC on paper.

When is another format a better fit?

For maximum playback compatibility on old hardware and cars, MP3 and AAC still open on more devices. For editing and masters use FLAC or WAV, since Opus is lossy. And for video sound inside MP4, AAC remains the convention.

The short version: OPUS is the best lossy codec available. Reach for it everywhere the playback side is modern.

How to open a OPUS file

On Windows

Double-click the file, or open it with Foobar2000.

On macOS

VLC opens OPUS files on macOS.

In your browser

Open OPUS files right in a browser tab or with the dexrr viewer. No install, no upload.

Also opens in

  • VLC
  • Foobar2000
  • mpv
  • Any modern browser

View or convert OPUS files

A quick preview or a new format. No install, no upload.

View OPUS files Preview and inspect OPUS files Convert to OPUS Turn files into OPUS OPUS to VORBIS Vorbis audio codec OPUS to AAC Advanced Audio Coding OPUS to MP3 MPEG-1/2 Audio Layer III

OPUS technical details

Full name
Opus audio
Extensions
.opus
MIME type
audio/opus, audio/ogg
Magic bytes
4F 67 67 53 (OggS) + OpusHead
Compression
Lossy
Developer
IETF / Xiph.Org (RFC 6716)
Specification
datatracker.ietf.org

OPUS questions, answered

How do I open an .opus file?

VLC, foobar2000, browsers and most modern players decode it; old hardware often does not. dexrr plays and converts opus files directly in your browser.

Can I convert OPUS files online?

Yes, dexrr converts opus locally in your browser: OPUS to MP3 for compatibility, OPUS to WAV for editing or OPUS to OGG for open pipelines.

Is Opus better than MP3 and AAC?

Technically yes, it outperforms both at equal bitrates, especially below 128 kbps, and adds real-time latency. Its only deficit is device support.

Why won't my car/phone play .opus?

Opus is newer than the hardware in many devices. Convert to MP3 or AAC for guaranteed playback.

Is the OPUS format outdated?

No, it is the current state of the art in lossy audio and the standard codec of real-time communication.