What Is AVIF and How Is It Derived from AV1?

The AV1 Image File Format (AVIF) is an open-source, royalty-free image format engineered to provide significantly better compression efficiency than legacy formats like JPEG, PNG, and WebP while preserving high visual quality. Derived directly from the Alliance for Open Media's (AOMedia) AV1 video codec, AVIF encapsulates AV1-compressed still image frames inside the standardized ISO Base Media File Format (ISOBMFF) container. This article explains what AVIF is, its core capabilities, and the exact architectural process that links it to the AV1 video compression standard.

What Is the AV1 Image File Format (AVIF)?

AVIF is a modern image format developed by the Alliance for Open Media—a consortium that includes tech industry leaders such as Google, Apple, Mozilla, Microsoft, and Netflix. Its primary goal is to minimize web bandwidth usage and improve digital storage efficiency by drastically reducing file sizes without sacrificing fidelity.

Key features of AVIF include:

• High Compression Efficiency: Generates file sizes up to 50% smaller than JPEG and noticeably smaller than WebP at comparable visual quality.
• Modern Color Support: Native support for High Dynamic Range (HDR), Wide Color Gamut (WCG), and standard color spaces such as sRGB, BT.2020, and DCI-P3.
• Higher Bit Depths: Supports 8-bit, 10-bit, and 12-bit color depths, virtually eliminating color banding in gradients.
• Advanced Visual Features: Native support for transparency via an alpha channel, lossless and lossy compression, and image sequences (animations) comparable to animated GIFs or WebPs.

How AVIF Is Derived from AV1

AVIF is not an entirely new compression algorithm built from scratch; rather, it is a specialized application of the AV1 video codec tailored for still imagery.

1. Utilizing AV1 Intra-Frames (I-Frames)

In digital video encoding, video streams consist of several frame types:

• Inter-frames (P-frames and B-frames): Rely on differences between previous or future frames to save data.
• Intra-frames (I-frames or Keyframes): Self-contained images encoded entirely on their own, independent of any surrounding frames.

AVIF extracts this intra-frame compression mechanism from AV1. A standard static AVIF file is essentially a single, standalone AV1 intra-frame. Because video compression engineers spent years optimizing AV1's intra-coding tools—such as directional spatial prediction, flexible transform block sizes (from 4x4 up to 64x64), and sophisticated deblocking and restoration filters—these same high-efficiency tools are directly applied to static images.

2. Packaging in the ISOBMFF Container

While AV1 handles the actual pixel compression, it does not define how image metadata, color profiles, or file structures should be saved. To solve this, AVIF packages the AV1-compressed bitstream within the ISO Base Media File Format (ISOBMFF, specified in ISO/IEC 14496-12).

This structure is conceptually identical to how the High Efficiency Image File Format (HEIF) works:

• HEIF/HEIC: Uses the ISOBMFF container with H.265/HEVC video compression.
• AVIF: Uses the ISOBMFF container with AV1 video compression.

By utilizing the ISOBMFF standard, an AVIF file can carry auxiliary image items (such as alpha masks and depth maps), Exif data, XMP metadata, and color profile items (ICC profiles) alongside the compressed AV1 payload.

3. Image Sequences and Animation

Because AV1 is inherently a video format, AVIF naturally extends into multi-frame formats. An animated AVIF image, often referred to as an AVIFS (AVIF Sequence), utilizes short sequences of AV1 video frames stored within the ISOBMFF container. This allows animated graphics to leverage both intra-frame and inter-frame temporal compression, producing animated graphics that are a fraction of the size of equivalent animated GIFs.