What Is AVIF? The Next-Generation Image Format Based on AV1

AVIF (AV1 Image File Format) brings the still-image compression of the AV1 video codec to image files. It can store photos in smaller files than JPEG, and in many cases WebP, and it supports transparency, animation, 10 and 12-bit color depth and HDR. This article explains where AVIF comes from, what is inside the file, how much it really saves and where it causes trouble.

Who is behind AVIF?

AVIF was developed by the Alliance for Open Media (AOMedia), an industry consortium founded in 2015 to build open, royalty-free media technology. Its first major project was the AV1 video codec, which AOMedia says was published in 2018. According to the Library of Congress format description, version 1.0.0 of the AVIF specification is dated 19 February 2019 and version 1.1.0 is dated 15 April 2022. The current version of the specification is 1.2.0, dated 16 October 2025.

Being royalty free is a key difference: MDN also describes AVIF as a high-performance, royalty-free format. HEIC, which uses the same HEIF container, relies on the HEVC codec and has nowhere near the same browser support.

Inside an AVIF file

The HEIF container

AVIF stores AV1-compressed images in the HEIF container (High Efficiency Image File Format, ISO/IEC 23008-12). HEIF itself is based on the ISO base media file format (ISOBMFF), the same foundation as MP4 files. According to the specification, an AVIF file is designed to be a conformant HEIF file for both single images and image sequences, and it must also comply with MIAF. The file type is identified by brands in the ftyp box at the start: avif for still images and avis for animated sequences.

Profiles

The specification defines two profiles: Baseline (brand MA1B), which uses the AV1 Main profile at level 5.1 or lower, and Advanced (brand MA1A), which allows the AV1 High profile for still images. These profiles make it predictable which files a decoder can open.

Transparency and animation

The alpha channel is stored as a separate auxiliary AV1 image linked to the main image. That alpha image must be monochrome and use the same bit depth as the main image. An animated AVIF is essentially an AV1 video track, which is why it compresses far more efficiently than an animated GIF of the same content.

Compression, color depth and HDR

AVIF uses AV1's intra-frame coding tools: the image is split into blocks of variable size, each block is predicted using the best of many directional prediction modes, and the remaining difference is transformed and quantized. Compared with JPEG's fixed 8x8 blocks, this flexibility reduces blocking, especially at small file sizes, and leaves flat areas cleaner.

According to MDN, AVIF supports 8, 10 and 12-bit color depth and YUV 4:4:4, 4:2:2 and 4:2:0 chroma sampling. The AVIF specification states that the format supports High Dynamic Range (HDR) and Wide Color Gamut (WCG) images, and MDN lists the PQ and HLG transfer functions and the Rec. 2020 color space. Given the 8-bit limit of JPEG and WebP, AVIF is one of the most mature options for serving HDR photos on the web.

How much smaller is AVIF?

The authors of the AVIF guide on web.dev (Jai Krishnan, Wan-Teh Chang and Jeremy Wagner) report seeing more than 50% savings compared with JPEG in their own work and that of others, and MDN says lossy AVIF images are around 50% smaller than JPEG images. These figures vary with the content, encoder settings and target quality.

Real-world web data paints a more careful picture. According to the HTTP Archive Web Almanac 2024, the median AVIF image on mobile uses 1.4 bits per pixel, against 1.3 for WebP and 2.0 for JPEG. The report also notes that the AVIF median rose from about 1.0 bits per pixel in 2022, an increase of about 47%. In other words, the format's theoretical advantage does not always turn into smaller files in practice, depending on the quality settings sites choose.

Browser support and adoption

According to Can I use, browsers that support AVIF account for 96.35% of global usage (October 2026). Support arrived with Chrome 85, Firefox 93, Edge 121 and Safari 16.4, with partial support in Safari 16.1 to 16.3. MDN notes that Firefox added support for animated AVIF in version 113.

Adoption is still low but growing fast. W3Techs data from October 2026 shows AVIF on 1.7% of the websites it monitors. The Web Almanac 2024 reports that 1.0% of images on mobile pages are AVIF, a share that grew by 386% in relative terms over two years.

How to serve AVIF on a website

Because AVIF support is more recent than WebP's, MDN also recommends providing fallbacks in more widely supported formats. The most common approach is to list sources in the HTML <picture> element from most efficient to most compatible. The browser loads the first source it understands, and if it knows none of them it uses the JPG in the <img> tag:

<picture>
  <source srcset="photo.avif" type="image/avif">
  <source srcset="photo.webp" type="image/webp">
  <img src="photo.jpg" alt="Descriptive alt text" width="1200" height="800">
</picture>

This setup means preparing three files, but every visitor downloads the smallest file their browser supports.

Weaknesses of AVIF

• Slow encoding: producing AVIF takes noticeably more CPU time than JPEG or WebP. The web.dev guide notes that faster speed settings reduce compression efficiency and quality.
• No progressive display: according to MDN, AVIF does not support progressive rendering, so the file must be fully downloaded before it can be displayed.
• Software support lags behind browsers: even though browsers display AVIF, older viewers, office programs and upload forms often do not accept it.
• Gains shrink at very high quality: near-lossless files grow quickly; for archival copies, PNG or the original file is a better fit.

Common problems

An AVIF file will not open

Usually the program simply does not know AVIF. To share the file or use it in older software, converting photos to JPG and transparent images to PNG is the quickest fix.

Colors look washed out after conversion

When an HDR or wide-gamut AVIF is converted to an 8-bit sRGB format, the extra brightness and color information does not fit, and the image can look duller than intended. This is a limit of the target format.

The animation disappeared

JPG and PNG do not carry animation, so an animated AVIF converted to either format keeps only one frame.

Tips for converting AVIF

• To open AVIF anywhere: convert AVIF to JPG, or AVIF to PNG to keep transparency. For animated AVIF files only the first frame is used.
• To create AVIF: our JPG to AVIF and PNG to AVIF converters use quality 60 by default. AVIF's quality scale does not mean the same as JPEG's, and 60 gives good results for most photos. At quality 95 and above, color is encoded at full resolution (4:4:4); below that, 4:2:0 is used.
• Be patient: AVIF encoding runs in your browser with WebAssembly and is slower than other formats; the interface shows progress. Your files never leave your device.
• Color and metadata: our tools adapt colors to sRGB, so HDR information is not carried into the output. EXIF and location data are not written to the output either.
• For batch jobs, choose AVIF as the target in the image converter and convert several files at once.

Frequently Asked Questions

Are AVIF and HEIC the same?

No, but they are related. Both use the HEIF container; HEIC compresses the image with HEVC (H.265), while AVIF uses AV1. AV1 is a royalty-free codec, and today AVIF opens in every major browser, while HEIC has stayed largely tied to Apple devices.

Is AVIF better than WebP?

AVIF usually produces smaller files for photos and supports HDR; WebP encodes much faster and its support goes back further. Offering both on your site through the <picture> element lets every browser get the most efficient format it supports.

Can AVIF be lossless?

Yes, AV1 supports lossless coding too. Lossless AVIF files are usually large, though, so if you need lossless storage, PNG or lossless WebP is often more practical.

Does AVIF open on iPhone?

Safari on current iOS versions displays AVIF; according to Can I use, full support arrived with Safari 16.4. Support in individual apps varies from app to app.

Why is saving AVIF so slow?

AV1 tries many block sizes and prediction directions to find the best compression. That search makes files smaller but costs CPU time. An encoder's speed setting shifts the balance: faster settings produce larger files.

Sources

• AOMedia: AV1 Image File Format (AVIF) specification
• AOMedia: Our story
• Library of Congress: AVIF format description
• MDN: Image file type and format guide
• web.dev: Using AVIF to compress images on your site
• Can I use: AVIF image format
• W3Techs: Usage statistics of image file formats for websites
• HTTP Archive Web Almanac 2024: Media