AVIFS File

What are AVIFS files and how to open them

Are you having problems opening an AVIFS file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your AVIFS files.

What is an AVIFS file?

An .AVIFS file is an AV1 Image File Format Sequence Bitmap file.

AV1 Image Sequence Bitmap files store an animated image sequence made of multiple frames compressed with the AV1 codec and held in a container format derived from ISOBMFF (the same base as MP4 and HEIF). These are motion-capable images rather than simple stills, allowing smooth animations or micro-movements using the efficiency of AV1 compression.

They are produced by encoding tools that support AV1 image sequences - writers such as encoders in the AVIF specification that generate multiple frames. Native use is for creating animations, short video-like loops, live photos, or otherwise dynamic image content. After creation, reader applications or libraries decode and display the frames in sequence.

These files are part of the AV1 Image File Format defined by the Alliance for Open Media. The specification supports image frames (image items), image sequences (animation tracks), auxiliary image sequences (like alpha or other extra channels), and multiple profiles and brands to control compatibility and features like bit depth, resolution, and color handling. It follows HEIF file constraints (which itself is built on ISOBMFF) and includes defined brands such as "avis" for image sequences.

Internally they begin with a FileTypeBox (ftyp) identifying brands like "avis" or "avif", followed by boxes such as moov, trak, mdia, mdhd, stbl, stsd, stsz, stts for organizing timing and sample tables, and mdat for the media data. The AV1 codec identifiers "av01" or "AV1C" appear, along with "AV01" in bitstreams.

How to open AVIFS files

Important: Different programs may use files with the AVIFS file extension for different purposes, so unless you are sure which format your AVIFS file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested two different AVIFS openers which you will find listed below.

Last updated: August 22, 2026

Various apps that use files with this extension

These apps are known to open certain types of AVIFS files. Remember, different programs may use AVIFS files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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File.org helps thousands of users every day, and we would love to hear from you if you have additional information about AVIFS file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.