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

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

video/x-flv is the MIME type for files that use the Flash video format.
It serves as a container for video, audio, and metadata. Files with this MIME type are often saved as FLV.

The main use is to stream video content on the web.
It was widely deployed with Adobe Flash Player.
It efficiently compresses data for low-bandwidth transmission.
It supports playback in media players like VLC and similar software.

Although modern formats have largely replaced it, legacy websites and applications still rely on video/x-flv for delivering multimedia content.
For more details, visit Flash Video on Wikipedia.

Associated file extensions

.flv

Usage Examples

HTTP Header

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


    Content-Type: video/x-flv

HTML

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


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

Associated file extensions

.flv

FAQs

Do modern web browsers support video/x-flv?

No, modern browsers (Chrome, Firefox, Edge, Safari) no longer support Flash Video natively. Since Adobe Flash Player reached its End of Life (EOL) in 2020, you must convert files with the .flv extension to modern formats like MP4 or WebM for web playback.

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

To ensure correct delivery, you must define the MIME type in your server configuration. For Apache, add AddType video/x-flv .flv to your .htaccess file. For Nginx, add video/x-flv flv; to your mime.types file or server block.

What is the best alternative to video/x-flv for web streaming?

The standard replacement is video/mp4 using the H.264 codec, which is supported by virtually all devices and browsers. Alternatively, video/webm is a popular open-source option for HTML5 video elements.

How can I open a video/x-flv file on my computer?

Because default media players often lack the necessary codecs, you should use a versatile third-party player like VLC Media Player. Alternatively, you can use video conversion software (like HandBrake) to convert the file to a more common format.

Why does IIS return a 404 error when accessing an .flv file?

Microsoft IIS often does not have the video/x-flv MIME type configured by default, causing it to block the file for security reasons. You must open the MIME Types feature in the IIS Manager and manually add the extension .flv with the MIME type video/x-flv.

What does the 'x-' prefix mean in this MIME type?

The x- prefix indicates that video/x-flv was originally a non-standard or experimental subtype not officially registered with the IANA at the time. While it became the de facto standard for Flash Video, it retains this prefix in legacy systems.

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.