Opus BSD 3-clause license

The Praat source code contains a copy of the Opus software (see Acknowledgments). Here is the Opus license text:

    Copyright (c) 2001-2011 Xiph.Org, Skype Limited, Octasic,
                            Jean-Marc Valin, Timothy B. Terriberry,
                            CSIRO, Gregory Maxwell, Mark Borgerding,
                            Erik de Castro Lopo
   
    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 Internet Society, IETF or IETF Trust, nor the
    names of specific 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 FOUNDATION 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.
   
    Opus is subject to the royalty-free patent licenses which are
    specified at:
   
    Xiph.Org Foundation:
    https://datatracker.ietf.org/ipr/1524/
   
    Microsoft Corporation:
    https://datatracker.ietf.org/ipr/1914/
   
    Broadcom Corporation:
    https://datatracker.ietf.org/ipr/1526/

© Paul Boersma 2021