libjpeg-turbo Licenses

libjpeg-turbo is covered by two compatible BSD-style open source licenses:

  • The IJG (Independent JPEG Group) License, which is listed in README.ijg

    This license applies to the libjpeg API library and associated programs, including any code inherited from libjpeg and any modifications to that code.

  • The Modified (3-clause) BSD License, which is listed below

    This license applies to the TurboJPEG API library and associated programs, libspng (which is used by cjpeg and djpeg), and the build/test system.

    • The TurboJPEG API library wraps the libjpeg API library, so in the context of the overall TurboJPEG API library, both the terms of the IJG License and the terms of the Modified (3-clause) BSD License apply.
    • cjpeg and djpeg use libspng, so in the context of those programs, both the terms of the IJG License and the terms of the Modified (3-clause) BSD License apply.

Component Licenses

Some of libjpeg-turbo's modules and internal dependencies are covered by less restrictive licenses, but in the context of libjpeg-turbo as a whole, the terms of the less restrictive licenses are subsumed by either the IJG License or the Modified BSD License. (In other words, the terms of the less restrictive licenses are satisfied if the terms of the IJG and Modified BSD Licenses are satisfied.)

  • The libjpeg-turbo SIMD source code and zlib are covered by the zlib License, which is subsumed by the IJG License in the context of the cjpeg and djpeg programs and the libjpeg API library.

  • Some of the libspng source code is covered by the PNG Reference Library License v2, which is subsumed by the IJG License in the context of the cjpeg and djpeg programs and the TurboJPEG API library.

  • Most of the libspng source code is covered by the Simplified (2-clause) BSD License, which is subsumed by the Modified BSD License in the context of the cjpeg and djpeg programs and the TurboJPEG API library.

Complying with the libjpeg-turbo Licenses

This section provides a roll-up of the libjpeg-turbo licensing terms, to the best of our understanding. This is not a license in and of itself. It is intended solely for clarification.

  1. If you are distributing a modified version of the libjpeg-turbo source, then:

    1. You cannot alter or remove any existing copyright or license notices from the source.

      Origin

      • Clause 1 of the IJG License
      • Clause 1 of the Modified BSD License

    2. You must add your own copyright notice to the header of each source file you modified, so others can tell that you modified that file. (If there is not an existing copyright header in that file, then you can simply add a notice stating that you modified the file.)

      Origin

      • Clause 1 of the IJG License

    3. You must include the IJG README file, and you must not alter any of the copyright or license text in that file.

      Origin

      • Clause 1 of the IJG License

  2. If you are distributing only libjpeg-turbo binaries without the source, or if you are distributing an application that statically links with libjpeg-turbo, then:

    1. Your product documentation must include a message stating:

      This software is based in part on the work of the Independent JPEG Group.

      Origin

      • Clause 2 of the IJG license

    2. If your binary distribution includes or uses the TurboJPEG API or associated programs, cjpeg, or djpeg, then your product documentation must include the text of the Modified BSD License (see below.)

      Origin

      • Clause 2 of the Modified BSD License

  3. You cannot use the name of the IJG or The libjpeg-turbo Project or the contributors thereof in advertising, publicity, etc.

    Origin

    • IJG License
    • Clause 3 of the Modified BSD License

  4. The authors and distributors do not warrant libjpeg-turbo to be free of defects, nor do we accept any liability for undesirable consequences resulting from your use of the software.

    Origin

    • IJG License
    • Modified BSD License

The Modified (3-clause) BSD License

Copyright (C) 2009-2026 D. R. Commander
Copyright (C) 2018-2023 Randy randy408@protonmail.com

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of the libjpeg-turbo Project nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”, AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.