What is MIME type "audio/atrac-x"?

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

The MIME type audio/atrac-x is used for files encoded with the Adaptive Transform Acoustic Coding algorithm. These files use advanced compression to keep file sizes small while retaining good audio quality.

It is a proprietary format developed for systems where efficient storage and playback are critical. The technology is often found in specialized audio environments and certain portable devices. Current file types that implement this format include AT3 and AA3.

Efficient Compression: Reduces file size with minimal quality loss.
Optimized Performance: Supports smooth playback on resource-limited devices.
Proprietary Use: Common in systems that rely on Sony’s audio technology.

Learn more about this technology on ATRAC on Wikipedia.

Associated file extensions

.at3, .aa3

Usage Examples

HTTP Header

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


    Content-Type: audio/atrac-x

HTML

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


    <a href="file.dat" type="audio/atrac-x">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/atrac-x');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.at3, .aa3

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.