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

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

audio/x-dff is a MIME type for audio files that use Direct Stream Digital (DSD) encoding.
It stores bitstream audio data in a format optimized for high-resolution playback. This format is common in systems that demand top fidelity and is often linked to audio from Super Audio CDs (SACDs).
Files using this MIME type include formats such as DSF and DFF, which carry uncompressed digital audio data.

Used for high-resolution audio playback and professional production.
Favored for archiving and preserving audio with minimal loss.
Supports ultra-high sampling rates found in DSD formats.

Learn more about Direct Stream Digital on Wikipedia.

Associated file extensions

.dsf, .dff

Usage Examples

HTTP Header

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


    Content-Type: audio/x-dff

HTML

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


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

Associated file extensions

.dsf, .dff

FAQs

Can web browsers natively play audio/x-dff files?

No, standard web browsers like Chrome, Firefox, and Safari do not support Direct Stream Digital (DSD) playback natively. To listen to files served as audio/x-dff, users must typically download the file and open it in specialized audiophile software like Foobar2000, Audirvana, or JRiver Media Center.

How do I configure Apache to serve .dff and .dsf files correctly?

You need to manually register the MIME type in your configuration or .htaccess file. Add the line AddType audio/x-dff .dff .dsf to ensure the server sends the correct Content-Type header instead of defaulting to a generic binary stream.

What is the difference between .dsf and .dff files?

While both file extensions are associated with DSD audio, .dsf files support ID3v2 metadata tags, allowing for artist and track information storage. The .dff format (Philips DSDIFF) generally does not support metadata tagging, making .dsf the preferred choice for digital music libraries.

Why does this MIME type start with 'x-'?

The x- prefix in audio/x-dff indicates that it is a non-standard or experimental subtype not officially registered with the IANA. Since DSD is a proprietary format developed by Sony and Philips, it uses this vendor-specific designation rather than a standard type like audio/mpeg.

How do I fix Nginx serving .dff files as text/plain?

If Nginx serves these files as text, it lacks the correct MIME mapping. Open your mime.types file or server block and add the directive audio/x-dff dff dsf;. This ensures browsers and download managers recognize the file as high-resolution audio.

When should I use audio/x-dff over FLAC or WAV?

Use audio/x-dff when distributing DSD (Direct Stream Digital) content intended for high-end audio hardware or archival purposes. For general web compatibility and streaming, FLAC or WAV (PCM audio) are better choices, as they have broader support across devices and browsers.

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.