Patent Landscape of AV1 Intra-Coding in AVIF

This article provides an analysis of the patent landscape governing the AV1 intra-coding technologies that underpin the AV1 Image File Format (AVIF). While AVIF was designed by the Alliance for Open Media (AOMedia) as an open, royalty-free standard, third-party patent pools—most notably Sisvel—and external intellectual property holders assert claims over fundamental intra-prediction, transform, and filtering algorithms inherited from the AV1 video standard. Below is an examination of the foundational licensing mechanisms, third-party patent claims, contested coding tools, and the commercial risks facing AVIF implementers.

The Foundation: AOMedia Patent License 1.0

AVIF utilizes the intra-frame (still image) coding toolset of the AV1 video compression standard. The Alliance for Open Media developed AV1 to be fundamentally royalty-free under the AOMedia Patent License 1.0.

Under this framework:

Grant of Rights: Founding members (including Google, Microsoft, Apple, Amazon, Netflix, Meta, and Intel) grant non-exclusive, worldwide, royalty-free patent licenses for their essential patent claims reading directly onto the AV1 specification.
Defensive Termination: If a licensee files an intellectual property infringement lawsuit against any entity alleging that an AV1 implementation infringes its own patents, the royalty-free license granted to the litigating party is revoked.
Scope for AVIF: Because AVIF uses AV1 intra-coded frames encapsulated inside an ISOBMFF (ISO Base Media File Format) container, the core image compression steps rely entirely on the AOMedia AV1 patent grant.

Contested Intra-Coding Tools

Intra-coding represents roughly a third of the overall AV1 specification. The tools used by AVIF to compress still images without temporal referencing include:

Directional and Non-Directional Intra-Prediction: Extending nominal prediction angles from 8 nominal directions up to 56 fine-grained angles, alongside Smooth, DC, and Paeth predictors.
Chroma from Luma (CfL): Predicting chrominance planes based on reconstructed luminance pixels.
Palette Mode and Intrablock Copy (IBC): Treating pixel blocks as indexed color maps or reusing previously decoded blocks in the same image.
Super-Resolution and Multi-Transform Selection: Using variable Discrete Cosine Transforms (DCT) and Asymmetric Discrete Sine Transforms (ADST) with rectangular and square partitionings.
In-Loop Filtering: Applying Deblocking, Constrained Directional Enhancement Filter (CDEF), and Loop Restoration (Wiener and Self-Guided Filters).

Because many of these mechanisms are iterative evolutions of techniques originally developed for H.264/AVC, H.265/HEVC, and VP9, external patent holders claim that baseline intra-coding concepts are impossible to practice without infringing earlier, overlapping patents.

Third-Party Patent Pools: The Sisvel Threat

The primary commercial disruption to AV1 and AVIF's royalty-free status is the patent pool administered by Sisvel International. Launched in early 2019, Sisvel's AV1 licensing program pools patents from organizations that did not sign the AOMedia royalty-free agreement, including:

Koninklijke Philips
Dolby Laboratories
SK Telecom
ETRI (Electronics and Telecommunications Research Institute)
Mitsubishi Electric
NTT Docomo

Sisvel claims to hold over 1,500 patents and applications globally that it alleges are essential to AV1. A significant portion of these patents target intra-prediction mechanics, spatial partitioning, and transform operations that directly affect AVIF file generation and rendering. Sisvel publishes explicit royalty schedules demanding per-unit fees for hardware and software implementations, directly challenging AOMedia's royalty-free mandate.

Prior Art and Antitrust Investigations

To defend the ecosystem, AOMedia relies on several structural protections:

Unconstrained Prior Art Analysis: AV1 was developed using an explicit patent-clearing process, where proposed algorithms were scrubbed against known third-party claims to ensure novel non-infringing implementations or reliance on expired prior art.
Regulatory Scrutiny: Antitrust regulators in the European Union (European Commission) scrutinized AOMedia’s licensing terms in 2022 to verify whether the mandatory defensive termination clauses constituted anticompetitive behavior. The EU closed its preliminary investigation in 2023 without action, bolstering AOMedia’s legal standing in Europe.
Patent Defense Programs: AOMedia maintains an internal Patent Defense Program designed to indemnify and defend participating members against third-party patent assertions.

Current Commercial Assessment for AVIF Implementers

The total patent landscape for AV1 intra-coding in AVIF remains dualistic. Within the AOMedia member ecosystem, AVIF operates as a fully licensed, royalty-free standard backed by some of the world's largest patent holders. Outside that perimeter, entities such as Sisvel continue to assert that practicing AV1 intra-prediction and filtering unavoidably infringes valid third-party patents. While major web browsers, operating systems, and platforms continue to ship AVIF support natively without paying pool royalties, smaller independent software developers and hardware manufacturers remain caught between AOMedia's royalty-free guarantee and ongoing exposure to third-party pool assertions.