What License Is libdav1d Distributed Under?

This article provides a quick and clear overview of the open-source licensing terms for libdav1d, the popular AV1 video decoder developed by VideoLAN. Readers will learn about the specific license governing the project, its core permissions, and why this licensing model was chosen to encourage widespread adoption of the AV1 video format.

The BSD 2-Clause License

The libdav1d decoder (frequently referred to simply as dav1d) is distributed under the BSD 2-Clause “Simplified” License (sometimes called the “FreeBSD License”).

This is a highly permissive open-source license that allows developers to freely use, modify, and distribute the software in both source and binary forms.

Key Conditions of the License

To comply with the BSD 2-Clause License, developers integrating libdav1d into their projects must adhere to two simple conditions:

1. Source Code Redistribution: If you redistribute the libdav1d source code, you must retain the original copyright notice, the list of conditions, and the disclaimer.
2. Binary Redistribution: If you distribute libdav1d in binary form (compiled), you must reproduce the copyright notice, the list of conditions, and the disclaimer in the documentation or other materials provided with the distribution.

Why This License Was Chosen

VideoLAN, alongside the Alliance for Open Media (AOMedia), selected the BSD 2-Clause License to maximize the adoption of the AV1 video codec.

Unlike copyleft licenses (such as the GNU General Public License, or GPL), the permissive BSD license allows libdav1d to be integrated into both open-source projects and proprietary, commercial software applications. This flexibility ensures that web browsers, operating systems, and media players can adopt the fast decoder without legal friction regarding their own proprietary codebases.