mpv is a fork of mplayer2, which is a fork of MPlayer. mpv as a whole is licensed as GPL version 2 or later (see LICENSE). Most source files are GPLv2+, but some files are available under a more liberal license, such as LGPLv2.1+, BSD, MIT, ISC, and possibly others. Look at the copyright header of each source file, and grep the sources for "Copyright" if you need to know details. C source files without Copyright notice are licensed as LGPLv2.1+. Also see the list of files with specific licenses below (not all files can have a standard license header). All new contributions must be LGPLv2.1+ licensed, or if the changes are done on GPL code, must come with the implicit agreement that the project can relicense the code to LGPLv2.1+ at a later point without asking the contributor. (This is a safeguard for making potential relicensing of the project to LGPLv2.1+ easier.) Using a more liberal license compatible to LGPLv2.1+ is also ok. For information about authors and contributors, consult the git log, which contains the complete SVN and CVS history as well. Note that mplayer2 as a whole is licensed under GPLv3+. This is because it uses a copy of talloc (part of Samba), which is LGPLv3+, and the next compatible license for this mix is GPLv3+. MPlayer as a whole is licensed under GPLv2 (incompatible to GPLv3!), because some files are licensed to GPLv2 (and _not_ any later version of the license). In particular, this affects the file libmpdemux/demux_ty_osd.c. It is disabled under mplayer2, and has been removed from mpv. "v2.1+" in this context means "version 2.1 or later". Source files with specific licenses: - everything under etc/ is unknown - everything under DOCS/man/ is GPLv2+ - sub/osd_font.otf is GPLv2+ - some tests under waftools/fragments/ might be GPLv2+ - version.sh is GPLv2+