What is MIME type "video/x-matroska"?

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

video/x-matroska is the MIME type for the Matroska multimedia container.
It encloses video, audio, subtitles, and metadata in one file. The format is flexible and open source, supporting high-quality and interactive media.

Playback: Many media players handle this format well.
Archiving: It stores long videos with multiple tracks efficiently.
Multiple tracks: It supports several audio and subtitle streams.
Interactive features: It can include chapters and menus.

Files that use this MIME type include the video container MKV, and the containers for subtitles (MKS), audio (MKA), and 3D video (MK3D).

For technical details and updates, check the Matroska official site.

Associated file extensions

.mkv, .mks, .mka, .mk3d

Usage Examples

HTTP Header

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


    Content-Type: video/x-matroska

HTML

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


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

Associated file extensions

.mkv, .mks, .mka, .mk3d

FAQs

Can I use video/x-matroska in the HTML5 <video> tag?

No, most modern web browsers do not natively support the Matroska container for direct playback in HTML5. To ensure your video plays across all browsers and devices, you should convert the file to video/mp4 or video/webm.

How do I configure Apache to serve MKV files correctly?

You can enable support by adding AddType video/x-matroska .mkv .mk3d to your site's .htaccess file or httpd.conf. This ensures the server sends the correct MIME type header instead of a generic binary stream.

What is the correct Nginx configuration for Matroska files?

Add the file extension mapping to your mime.types file or directly inside the types block in nginx.conf. Use the line: video/x-matroska mkv mk3d; to ensure Nginx serves these files with the correct headers.

Why does IIS return a 404 error for .mkv files?

Microsoft IIS does not have a wildcard MIME mapping by default and will block unknown file extensions for security. To fix this, open MIME Types in IIS Manager and add an entry for extension .mkv with the type video/x-matroska.

Is video/x-matroska different from video/webm?

Yes, although they are related. WebM is a restricted subset of the Matroska container designed specifically for the web using open codecs like VP8 or VP9. While video/webm plays natively in browsers, video/x-matroska is a more flexible container that can hold virtually any video codec, making it less suitable for direct web streaming.

Should I use video/x-matroska or video/matroska?

The prefix x- generally denotes a non-standard or experimental type, but it became the de facto standard for Matroska files before official registration. While video/matroska is the official IANA registration, video/x-matroska remains widely used in legacy server configurations and older media player software.

What other file extensions use the Matroska MIME type?

Beyond standard video (.mkv), the Matroska format includes specific extensions for audio-only files (.mka), subtitle files (.mks), and stereoscopic 3D video (.mk3d).

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.