What is MIME type "audio/mp4a"?

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

audio/mp4a signals that a file uses the Advanced Audio Coding (AAC) format.

It tells systems, browsers, and media players how to decode the audio. The encoding holds quality while keeping file sizes low.

Main use case: To correctly identify and play AAC audio streams.
Additional use cases: It helps in streaming media and ensures compatibility with various software and hardware platforms.

This MIME type labels files found in multimedia containers or as standalone audio. Examples include files in formats like MP4, M4A, and 3GP. It also applies to files such as AAC, M4B, and M4P.

For more details on MIME types, see MDN's resource on MIME types.

Associated file extensions

.mp4, .m4a, .3gp, .aac, .m4b, .m4p

Usage Examples

HTTP Header

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


    Content-Type: audio/mp4a

HTML

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


    <a href="file.dat" type="audio/mp4a">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/mp4a');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.mp4, .m4a, .3gp, .aac, .m4b, .m4p

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.