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

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

The MIME type audio/x-sid identifies files that hold music data created for the Commodore 64 SID chip.
This chip produced the iconic sounds of early computer and video game music.

Instead of raw audio, a SID file contains instructions for synthesizing music.
This lets compatible players recreate the sounds by emulating the original hardware.

Technical players like VICE or SIDPlay use these instructions to mimic the authentic audio characteristics of the SID chip.
This format remains popular among retro computing enthusiasts.

For more details on the SID chip, visit the Wikipedia page on the Sound Interface Device.

Associated file extensions

.sid

Usage Examples

HTTP Header

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


    Content-Type: audio/x-sid

HTML

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


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

Associated file extensions

.sid

FAQs

How do I play audio/x-sid files in a web browser?

Most modern browsers like Chrome or Firefox do not natively support the audio/x-sid format. To play these files directly on a webpage, you typically need to embed a JavaScript-based emulator (like WebAudio SID) or install a specialized browser extension designed for retro formats.

How do I configure Apache to serve .sid files correctly?

To ensure your server sends the correct headers, add the MIME type definition to your .htaccess or httpd.conf file. Insert the line AddType audio/x-sid .sid so that browsers and download managers identify the SID files as Commodore 64 audio data.

Why does the MIME type start with "x-"?

The x- prefix indicates that audio/x-sid is a non-standard or proprietary type not officially registered with the IANA. It is a convention used by the developer community to identify Commodore 64 music files before a standard potentially replaces it.

What software is required to open audio/x-sid files on a desktop?

Standard media players like Windows Media Player cannot play these files because they require hardware emulation. You need specialized software like SIDPlay, VICE, or a plugin for advanced players like foobar2000 or Winamp to synthesize the audio instructions.

Can I convert audio/x-sid files to MP3?

Yes, but because SID files contain code rather than sound waves, they must be "rendered" through an emulator first. Tools like SIDPlay allow you to record the playback output and save it as a standard WAV or MP3 file for use on modern devices.

How do I add audio/x-sid support to Nginx?

You need to update your Nginx configuration to recognize the extension. Open the mime.types file (often found in /etc/nginx/) and add the line audio/x-sid sid;, then reload the server to apply the changes.

Is audio/x-sid the same as MIDI?

No, although both store musical instructions rather than recorded audio. audio/x-sid is specific to the Commodore 64 SID chip architecture, manipulating specific oscillators and filters, whereas MIDI is a universal standard for controlling digital instruments.

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.