AV1 Source Code Open Source License Explained
The reference source code for the AV1 video codec is governed by a royalty-free licensing model created by the Alliance for Open Media (AOMedia). This article outlines the specific open-source terms applied to the official AV1 reference implementation, explaining the combination of its permissive software license and its associated patent grant.
The official reference implementation for AV1, known as
libaom, is distributed under the BSD 2-Clause
License, paired with an additional Alliance for Open
Media Patent License 1.0. Together, these two documents form
the complete AOMedia licensing framework found within the codebase
repository via the LICENSE and PATENTS
files.
The Software License: BSD 2-Clause
The copyright on the reference source code itself is governed by the standard BSD 2-Clause "Simplified" License. This is a permissive open-source license that allows developers to:
- Use, copy, modify, and distribute the source code in both source and binary forms.
- Integrate the reference code into both proprietary and open-source projects.
- Distribute their products without being obligated to open-source their own proprietary modifications.
The only primary requirements under this component are retaining the original copyright notice, the list of conditions, and the standard disclaimer of liability.
The Patent Grant: AOMedia Patent License 1.0
Because modern video codecs are heavily impacted by patent portfolios, the BSD 2-Clause license alone is insufficient to protect users from patent litigation. To resolve this, AOMedia includes a dedicated patent license that grants a royalty-free, perpetual, worldwide patent license to anyone implementing the AV1 specification.
This patent grant includes a defensive termination clause: if an entity initiates patent infringement litigation against any licensee claiming that an AV1 implementation violates their patents, that entity immediately loses all patent rights granted to them under the AOMedia license. This mechanism ensures that AV1 remains a commercially viable, royalty-free alternative to legacy codecs like H.264 and HEVC (H.265).