What is MIME type "image/avif-sequence"?

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

image/avif-sequence is a MIME type for files that store multiple frames using the AVIF technology. It means the file holds a sequence of images, much like an animation.
This format uses the advanced AV1 codec. It offers better compression and quality compared to older animated formats.
Key details:

Main use case: Animated images in web pages and applications.
Other uses: Displaying storyboards or multi-frame previews in multimedia projects.
Benefits: Efficient file size, high image quality, and support for advanced features such as transparency and wide color gamut.

Files tagged with this MIME type are typically in the AVIF or AVIFS format. These animated sequences are useful in modern browsers and software that support the latest imaging standards.
For more technical details and background, please see resources like AOMedia.

Associated file extensions

.avif, .avifs

Usage Examples

HTTP Header

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


    Content-Type: image/avif-sequence

HTML

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


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

Associated file extensions

.avif, .avifs

FAQs

What is the difference between image/avif and image/avif-sequence?

While image/avif is the general MIME type used for both still images and animations (similar to how WebP works), image/avif-sequence is explicitly defined for files containing multiple frames. Files served with image/avif-sequence typically use the .avifs extension to distinguish them from static .avif files.

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

To ensure your Apache server sends the correct headers for AVIF sequences, add the MIME type definition to your .htaccess file or httpd.conf. Use the directive: AddType image/avif-sequence .avifs.

How do I add image/avif-sequence support to Nginx?

You need to update your mime.types file or the types block within your Nginx configuration. Add the line image/avif-sequence avifs; and reload the server to ensure browsers recognize the file format correctly.

Why use AVIF sequences over GIF for web animations?

AVIF sequences utilize the AV1 codec, which offers vastly superior compression compared to the outdated GIF format. This results in much smaller file sizes, support for HDR colors, and high-quality transparency, making it a better choice for modern web performance.

Is image/avif-sequence supported in all browsers?

Most modern browsers that support AVIF (such as Chrome and Firefox) can render animated AVIF content. However, developers often serve these files with the generic image/avif MIME type to ensure maximum compatibility, as some implementations might not strictly look for the image/avif-sequence subtype.

What should I do if my .avifs file downloads instead of displaying?

This usually indicates that the web server is sending the wrong Content-Type header, often defaulting to application/octet-stream. Verify your server configuration to ensure it maps the .avifs extension to image/avif-sequence or image/avif.

Can I rename an .avif file to .avifs?

Yes, if the file actually contains an animation sequence. However, simply renaming the file does not change its internal structure or the MIME type sent by the server; you must also ensure the server is configured to handle the .avifs extension, as detailed on mime-type.com.

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.