What is MIME type "video/x-ms-asx"?

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

video/x-ms-asx is a MIME type for Windows Media Metafile playlists. It holds instructions that direct media players to stream audio or video from various sources.

Files using this MIME type include ASX, WAX, and WXV.

Main use: Enable media players to build streaming playlists.
Key fact: They do not contain media content but pointers to it.
Other uses: Help manage media redirection and organize streaming sessions.

For further details, visit IANA Media Types.

Associated file extensions

.asx, .wax, .wxv

Usage Examples

HTTP Header

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


    Content-Type: video/x-ms-asx

HTML

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


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

Associated file extensions

.asx, .wax, .wxv

FAQs

What is the primary purpose of the video/x-ms-asx MIME type?

The video/x-ms-asx MIME type is used for Windows Media Metafiles. These are not actual video files, but small XML text files that act as playlists or shortcuts, instructing a media player to stream content from specific URLs.

Why won't files with this MIME type play in modern web browsers?

Modern browsers (Chrome, Firefox, Edge) do not natively support video/x-ms-asx via the HTML5 <video> tag. This is a legacy format designed for standalone applications like Windows Media Player or VLC, which must be launched externally to handle the stream.

How do I configure my web server to serve ASX files correctly?

For Apache, add the line AddType video/x-ms-asx .asx .wax .wxv to your .htaccess file. For Nginx, ensure your mime.types file includes the entry video/x-ms-asx asx wax wxv; so the browser recognizes the file type correctly.

Are ASX files larger than standard video files?

No, they are significantly smaller. Because video/x-ms-asx files only contain text-based metadata and pointers (URLs) to the actual media, they are typically only a few kilobytes in size, regardless of the length of the video they reference.

What is the difference between .asx, .wax, and .wxv extensions?

While all three use the video/x-ms-asx MIME type, the extensions indicate specific intent: .asx is a generic Windows Media playlist, .wax is strictly for audio redirects (Windows Media Audio), and .wxv is for video redirects.

Can I edit a video/x-ms-asx file with a video editor?

No, you should use a text editor like Notepad or VS Code. Since the format is XML-based text, video editing software cannot process it. You edit the file to change the streaming URLs or playlist order.

Why does my browser download the ASX file instead of playing it?

If the browser downloads the file, it likely lacks a plugin to handle it or the operating system hasn't associated the video/x-ms-asx MIME type with a media player. Users usually need to open the downloaded file manually in a player like VLC.

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.