What is MIME type "audio/opus"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

audio/opus is the official MIME type for audio streams that use the Opus codec.
It compresses sound with low latency and high quality. This makes it ideal for both voice and music in dynamic network conditions.

Key Facts and Use Cases:

Real-Time Communication: Optimized for VoIP, video conferencing, and live streaming.
Music Streaming: Provides crisp audio at low bitrates while maintaining clarity.
Multimedia Integration: Often found embedded in containers such as OGG and OPUS.

It dynamically adjusts compression based on the audio content and available bandwidth. This adaptability results in efficient data use and improved user experiences.
Further technical details are available at Opus Codec.

Associated file extensions

.ogg, .opus

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: audio/opus

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="audio/opus">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'audio/opus');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.ogg, .opus

FAQs

Which file extension should I use for audio/opus?

The standard file extension is .opus, which clearly indicates the specific codec used. However, because Opus data is typically encapsulated within an Ogg container, you may also encounter files using the generic .ogg extension.

How do I configure Apache or Nginx to serve audio/opus?

For Apache, add the line AddType audio/opus .opus to your .htaccess or configuration file. For Nginx, ensure your mime.types file contains the entry audio/opus opus; or add it manually inside the types block.

Is audio/opus supported in all modern web browsers?

Most modern browsers, including Chrome, Firefox, and Edge, support audio/opus natively. Safari added support in recent versions (iOS 11+ and macOS High Sierra+), though compatibility can depend on the container format (e.g., CAF vs. Ogg).

What is the difference between audio/opus and audio/ogg?

audio/opus specifically identifies the Opus codec, while audio/ogg is a broader type that usually defaults to the older Vorbis codec. Using the specific audio/opus MIME type helps browsers and players select the correct decoder immediately.

How do I implement audio/opus in an HTML5 audio player?

Use the <audio> tag with a <source> element specifying the MIME type. For example: <source src="music.opus" type="audio/opus">. Always provide a fallback format like audio/mpeg to ensure playback on older devices.

Why is Opus often preferred over MP3 for streaming?

Opus delivers significantly higher audio quality at lower bitrates compared to MP3, saving bandwidth without sacrificing clarity. Additionally, its low latency makes it the superior choice for real-time applications like VoIP and live internet radio.

What should I do if my Opus file plays as a download instead of streaming?

This usually happens if the server sends the wrong MIME type (often application/octet-stream) or a Content-Disposition: attachment header. Ensure your server is configured to send the Content-Type: audio/opus header for .opus files.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.