What Is an AVIF File?
The AV1 Image Format Explained

What Is AVIF (AV1 Image File Format)

AVIF stands for AV1 Image File Format. It is a next-generation image format that combines the AV1 video codec with the HEIF (High Efficiency Image File Format) container. The result is an image format that delivers dramatically better compression than JPEG, WebP, or PNG while remaining completely open-source and royalty-free.

AVIF was developed by the Alliance for Open Media (AOM), a consortium founded in 2015 by Google, Mozilla, Cisco, Microsoft, Netflix, Amazon, and Intel. Apple joined later. The alliance's primary goal was to create a next-generation video codec (AV1) free from the patent licensing issues that plagued its predecessors H.264 and H.265/HEVC. AVIF is the still-image application of that same codec technology.

The format specification was finalized in February 2019, and browser adoption began almost immediately. Chrome added support in version 85 (August 2020), Firefox in version 93 (October 2021), and Safari in version 16 (September 2022). Edge followed in version 121 (January 2024), so every current major browser now displays AVIF.

AVIF vs HEIC: The Licensing Difference

AVIF and HEIC are often confused because they share the same HEIF container format. The critical difference is the codec inside:

• HEIC uses the H.265/HEVC codec, which is encumbered by patents held by multiple patent pools (MPEG-LA, HEVC Advance, Access Advance). Any company implementing HEVC must negotiate licensing fees. Chrome and Firefox do not display HEIC, and HEVC licensing is widely cited as the reason.
• AVIF uses the AV1 codec, which was specifically designed to be royalty-free. All AOM members irrevocably licensed their relevant patents for AV1. Anyone can implement AVIF encoding or decoding without paying licensing fees.

This licensing distinction is the primary reason AVIF has achieved broad browser adoption while HEIC is used mainly on Apple devices. Both formats offer similar compression efficiency, but AVIF's open nature makes it the practical choice for the web.

How AVIF Compression Works

AVIF leverages the AV1 intra-frame compression pipeline — the same technology AV1 uses to compress individual video frames without reference to other frames. This is fundamentally more advanced than the DCT-based approach JPEG uses.

The AV1 Compression Pipeline

When an image is encoded as AVIF, the following process occurs:

1. Superblock partitioning — the image is divided into superblocks (up to 128×128 pixels, compared to JPEG's fixed 8×8 blocks). These superblocks are then recursively split into smaller blocks using a flexible quad-tree/binary-tree partitioning scheme that adapts to image content. Smooth areas use large blocks; detailed areas use small blocks.
2. Intra prediction — each block is predicted from already-encoded neighboring pixels using 56 directional angles plus smooth, Paeth and chroma-from-luma modes (JPEG has no prediction of this kind). The encoder stores only the difference between the prediction and the actual pixel values, which is typically much smaller than the raw pixel data.
3. Transform coding — the prediction residuals are transformed using a combination of DCT and ADST (Asymmetric Discrete Sine Transform) with block sizes ranging from 4×4 to 64×64. This multi-scale approach captures image features at various frequencies more efficiently than JPEG's fixed 8×8 DCT.
4. Quantization — transformed coefficients are quantized (rounded), discarding less perceptually important information. AV1's quantization is more sophisticated than JPEG's, with per-block quantization parameters and support for lossless mode (quantization step = 1).
5. Entropy coding — the final data is compressed using a multi-symbol arithmetic coder, which is more efficient than JPEG's Huffman coding. Context-dependent probability models adapt to the image content for optimal compression.

Lossy and Lossless Modes

AVIF supports both lossy and lossless compression:

• Lossy mode is what most people use. It produces the dramatic file size reductions (50% smaller than JPEG) by selectively discarding imperceptible visual information. Quality is controlled via a quantization parameter (QP) that maps to a 0–63 scale.
• Lossless mode preserves every pixel exactly. AVIF’s lossless mode is much less efficient than its lossy mode; in many tests, lossless WebP and sometimes PNG produce smaller files.

Key Features of AVIF

AVIF is not just about smaller file sizes. The format includes several advanced features that JPEG, and in some cases WebP, simply cannot match.

HDR and Wide Color Gamut

AVIF natively supports High Dynamic Range (HDR) imaging with up to 12-bit color depth per channel, providing 4,096 brightness levels compared to JPEG's 256 (8-bit). This enables:

• PQ (Perceptual Quantizer) and HLG (Hybrid Log-Gamma) transfer functions for HDR content
• Wide color gamuts including BT.2020 and Display P3, covering colors beyond what sRGB can represent
• Smoother gradients with 4,096 levels per channel versus 256, eliminating banding in subtle tonal transitions

WebP is limited to 8 bits per channel with no HDR transfer functions. Classic JPEG is also 8-bit; it can carry HDR only through gain-map extensions such as Ultra HDR. JPEG XL, a separate format, supports HDR natively. Among widely supported web formats, AVIF is the main one with native HDR.

Transparency (Alpha Channel)

AVIF supports a full alpha channel for transparency, with the alpha plane compressed using the same efficient AV1 codec. This makes AVIF a viable replacement for PNG in cases where you need both photographic-quality compression and transparency — something JPEG has never supported.

An AVIF image with transparency can be many times smaller than the equivalent PNG-32 while maintaining comparable visual quality in the transparent-to-opaque transitions.

Animation Support

AVIF supports animated image sequences, functioning as a modern alternative to GIF and animated WebP. Because AV1's compression is vastly superior to GIF's LZW algorithm, animated AVIF files can be 50–90% smaller than equivalent GIFs with better color fidelity (no 256-color palette limitation) and smoother playback.

Compression Efficiency

The headline feature of AVIF is its compression ratio. Across independent benchmarks and real-world testing:

• ~50% smaller than JPEG at equivalent perceptual quality (measured by SSIM, VMAF, and Butteraugli metrics)
• ~20–25% smaller than WebP lossy at equivalent quality
• Lossless mode is less impressive: often larger than lossless WebP

These savings translate directly to faster page loads, lower bandwidth costs, and improved Core Web Vitals scores for websites.

Browser Support in 2026

AVIF has achieved broad browser adoption remarkably quickly for an image format. Here is the current support landscape:

In 2026, every current major browser supports AVIF. Users without it are mainly on Safari 15 or older, Edge before version 121, and old Android browsers. For web delivery, using AVIF with a JPEG fallback via the <picture> element covers virtually 100% of users.

Where AVIF Is Used Today

AVIF has moved well beyond experimental adoption. Major platforms and services use it at scale:

• Netflix — one of the earliest AVIF adopters, Netflix uses AVIF for title card images, thumbnails, and promotional stills across all platforms
• Cloudflare — Cloudflare's image optimization service automatically converts and serves AVIF to supported browsers via its CDN
• WordPress — since WordPress 6.5, the core media library supports AVIF uploads and serving natively

Limitations of AVIF

Despite its advantages, AVIF has genuine limitations that make JPEG still necessary in many scenarios.

Slow Encoding Speed

AVIF encoding is much slower than JPEG encoding, often many times slower at default settings. The AV1 codec was designed to maximize compression efficiency at the expense of encoding speed. For batch processing thousands of images, this overhead is significant.

Hardware acceleration is improving the situation. Intel Arc, NVIDIA RTX 40-series and AMD RDNA 3 GPUs include hardware AV1 encoders, although most AVIF tools still encode in software. As hardware encoding becomes widespread, the speed gap will narrow considerably. Decoding speed (which affects the user viewing the image) is already fast and comparable to JPEG.

Maximum Dimension Limits

The AVIF Baseline and Advanced profiles limit each coded image to 8,192 × 4,352 pixels. Larger images are stored as a grid of separately coded tiles. While most AVIF decoders support tiling, some older implementations may not handle tiled AVIF correctly. For panoramic photography or ultra-high-resolution imaging, this can be a practical limitation.

JPEG has no practical dimension limit (the specification supports up to 65,535 × 65,535 pixels), and PNG supports up to 2,147,483,647 × 2,147,483,647 pixels in theory.

Less Efficient for Simple Graphics

AVIF's compression advantage is most pronounced for photographs and complex natural images. For simple graphics with large areas of flat color, sharp geometric edges, and limited color palettes, AVIF's advantage shrinks considerably. PNG-8 (indexed 256-color mode) can sometimes produce smaller files than AVIF for very simple icons and logos, because AVIF's sophisticated prediction engine has little to gain on content that is already trivially compressible.

Incomplete Software Ecosystem

While browser support is excellent, the broader software ecosystem is still catching up:

• Adobe Photoshop opens AVIF only in recent versions; older versions need a plug-in or a conversion
• Email clients — most email clients (Gmail, Outlook, Apple Mail) do not reliably render inline AVIF images. JPEG remains required for email
• Social media — many social platforms do not accept AVIF uploads; they expect JPEG, PNG or WebP
• Print services — the print industry has zero AVIF support. JPEG and TIFF remain the standard
• Windows Explorer — Windows 11 supports AVIF thumbnails natively; Windows 10 requires the AV1 Video Extension from the Microsoft Store

Quick Comparison: AVIF vs JPEG vs WebP vs PNG

* Approximate file size for a typical 12-megapixel photograph at equivalent perceptual quality. JPEG at quality 85, WebP at quality 80, AVIF at quality 50 (CRF-based).

When to Convert AVIF to JPG

Despite AVIF's technical superiority, there are many real-world situations where you need a JPEG version of an AVIF image:

• Sharing via email — most email clients render JPEG reliably but may not display AVIF. Converting ensures every recipient can see your images.
• Social media uploads — platforms like Instagram, Facebook, LinkedIn, and X/Twitter accept JPEG but not AVIF. Uploading JPEG gives you control over the compression quality before the platform re-encodes.
• Printing — print shops, photo labs, and document services accept JPEG and TIFF. AVIF has zero presence in the print workflow.
• Older software compatibility — legacy applications, some CMS platforms, and image galleries may not recognize AVIF files. JPEG works everywhere.
• File size is not a concern — when you are transferring files locally (USB, AirDrop, local network), JPEG's larger size is irrelevant and its universal compatibility is more valuable.
• Editing in older software — while Photoshop supports AVIF, many free editors and older software versions do not. Converting to JPEG enables editing in any image application.

How to Open an AVIF File

• Browsers: drag the file into Chrome, Firefox, Safari 16+ or Edge 121+.
• Windows 11: Photos opens AVIF; install the free AV1 Video Extension from the Microsoft Store if it does not.
• Mac: Preview opens AVIF on macOS Ventura (13) or later.
• iPhone and Android: iOS 16+ and Android 12+ display AVIF.
• Editors: GIMP 2.10.22 or later and recent Photoshop versions.
• Anything else: convert the AVIF to JPG or PNG.