What is MIME type "audio/amr"?

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

audio/amr is a MIME type for audio files that use the Adaptive Multi-Rate codec. It is built to compress speech efficiently for mobile communications.
Files like 3GP, AMR, and 3GA commonly use this MIME type.
For more details, see the resources at IANA Media Types and Wikipedia.

Associated file extensions

.3gp, .amr, .3ga

Usage Examples

HTTP Header

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


    Content-Type: audio/amr

HTML

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


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

Associated file extensions

.3gp, .amr, .3ga

FAQs

Can I use audio/amr in the HTML5 <audio> tag?

No, most modern desktop browsers (including Chrome, Firefox, and Safari) do not natively support the audio/amr format in HTML5. While AMR is standard for mobile voice recordings, you should convert these files to MP3 or AAC (audio/mp4) to ensure they play correctly on websites.

How do I configure Apache or Nginx to serve AMR files?

For Apache, add the line AddType audio/amr .amr to your .htaccess or configuration file. For Nginx, ensure your mime.types file includes audio/amr amr;. This ensures the server sends the correct MIME header so browsers and download managers handle the file appropriately.

Is audio/amr suitable for music streaming?

No, the AMR codec is specifically optimized for human speech compression. It achieves very small file sizes by discarding frequencies not needed for voice, which makes music sound distorted and low-quality. For music, use audio/mpeg or audio/ogg instead.

Why do some .3gp files use the audio/amr MIME type?

While 3GP files are often video containers (video/3gpp), they can also contain audio-only tracks encoded with the AMR codec. In these cases, serving them as audio/amr specifically identifies the content as voice audio, though audio/3gpp is also commonly used.

How do I open a file with the audio/amr MIME type on Windows or Mac?

Default system players (like Windows Media Player or QuickTime) often cannot decode AMR files. You should use a third-party player like VLC Media Player, or convert the file to a standard format like WAV or MP3 using an audio converter.

What is the difference between audio/amr and audio/amr-wb?

The standard audio/amr usually refers to Narrowband (AMR-NB), which provides standard GSM voice quality. audio/amr-wb refers to Wideband (AMR-WB), which captures a wider frequency range for "HD Voice" quality used in modern VoLTE mobile calls.

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.