Definition
Opus — Opus is a free, open-source lossy audio codec standardized by the IETF in 2012. It handles both speech and music, scales from 6 to 510 kbps, and has very low delay. Opus powers browser voice and video calls through WebRTC and is a common audio track in WebM videos online.
Why Opus was created
Before Opus, voice apps and music services used different codecs: one tuned for low-delay speech, another for high-fidelity music. Opus merges both approaches. It was developed with contributions from Xiph.Org, Skype and others, and was published as an open standard (RFC 6716). Anyone can use it without paying royalties.
Where you meet Opus
- Video calls in the browser: WebRTC, the technology behind many web-based meeting tools, requires Opus support.
- Web video: WebM files commonly pair VP9 or AV1 video with Opus audio, and large video sites offer Opus audio streams.
- Chat and gaming apps: several popular voice apps use Opus for its quality at small bitrates.
How good is Opus?
In listening tests Opus is among the most efficient general-purpose codecs. Around 96–128 kbps it is usually very close to transparent for music, and it keeps speech clear at bitrates where MP3 would sound watery. Compared with AAC, it tends to do especially well at low and medium bitrates.
| Opus | AAC | MP3 | |
|---|---|---|---|
| Royalty-free | Yes | Licensed | Patents expired |
| Low-bitrate quality | Excellent | Good (HE-AAC) | Weak |
| Old device support | Limited | Good | Universal |
Why Opus matters when downloading audio
If a video's best audio stream is Opus, you will rarely want to keep it as-is, because many car stereos, older phones and editing apps do not accept .opus files. Converting to MP3 or M4A involves transcoding, so pick a generous bitrate to keep the result close to the source. For music, 320 kbps MP3 is a safe choice in the video to MP3 converter; for editing, extract a WAV instead.
If you want to keep the original Opus stream for a computer music library, players such as VLC, mpv and foobar2000 handle it well. Please keep audio downloads to recordings you own or are licensed to use.
FAQ
Frequently asked questions
Is Opus better than MP3?
At the same bitrate Opus usually sounds clearly better than MP3, especially at low bitrates, but MP3 plays on more devices.
Can my phone play Opus files?
Android supports Opus natively, and recent Apple systems handle it in some apps, but support varies, so MP3 or M4A is safer for sharing.