The following license applies to most of the sm-ssc additions:

sm-ssc is copyright  AJ Kelly, Midiman, shakesoda (referred to as
"the spinal shark collective" hereafter), and other contributors.
All rights reserved.

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, and/or sell copies of the Software, and to permit persons to
whom the Software is furnished to do so, provided that the above
copyright notice(s) and this permission notice appear in all copies of
the Software and that both the above copyright notice(s) and this
permission notice appear in supporting documentation.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

The rest of the codebase is then licensed as follows:
******************************************************************************

StepMania is (c) Chris Danford, the StepMania development team, et al.
All rights reserved.

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, and/or sell copies of the Software, and to permit persons to
whom the Software is furnished to do so, provided that the above
copyright notice(s) and this permission notice appear in all copies of
the Software and that both the above copyright notice(s) and this
permission notice appear in supporting documentation.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

******************************************************************************

RageSurface_Load_GIF contains code from Xpaint under the following license:

 Copyright 1990, 1991, 1993 David Koblas.
 Copyright 1996 Torsten Martinsen.
   Permission to use, copy, modify, and distribute this software
   and its documentation for any purpose and without fee is hereby
   granted, provided that the above copyright notice appear in all
   copies and that both that copyright notice and this permission
   notice appear in supporting documentation.  This software is
   provided "as is" without express or implied warranty.

******************************************************************************

Code in RageSurfaceUtils_Palettize.cpp is under the following permissive
license:

Copyright (C) 1989, 1991 by Jef Poskanzer.
Copyright (C) 1997, 2000, 2002 by Greg Roelofs; based on an idea by
                               Stefan Schneider.

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, provided
that the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.  This software is provided "as is" without express or
implied warranty.

******************************************************************************

Simply Love is licensed under the GPLv3, or (at your option) any later version.
See Themes/Simply Love/LICENSE for the full license text.

******************************************************************************

External dependencies

No guarantee this list is accurate, please check the licenses of the individual
projects.

* ffmpeg: LGPL with some parts GPLv2
* glew: Modified BSD + Mesa 3-D + Khronos License (all of them seem MITish to me)
* IXWebSocket: BSD
* jsoncpp: public domain or MIT depending on the jurisdiction
* libjpeg: some permissive license
* libmad: GPL
* libpng: something permissive
* libtomcrypt: public domain or do-what-the-fuck-you-want-public-license depending on jurisdiction
* libtommath: public domain or something permissive
* lua: MIT
* mbedtls: Apache-2.0 or GPLv2
* miniz: MIT
* ogg: BSD
* pcre: BSD
* vorbis: BSD
* zlib: under the zlib license

When building a full release with all the libraries above, the resulting
binares are probably some frankensteinish Apache-2.0/GPLv2/GPLv3/zlib
monstrosity. Please don't sue us! :)
