mpv is a fork of mplayer2, which is a fork of MPlayer. mpv as a whole is licensed under the GNU General Public License GPL version 2 or later (called GPLv2+ in this document, see LICENSE.GPL for full license text) by default, or the GNU Lesser General Public License LGPL version 2 or later (LGPLv2.1+ in this document, see LICENSE.LGPL for full license text) if built with the --enable-lgpl configure switch. Most source files are LGPLv2.1+ or GPLv2+, but some files are available under more liberal licenses, such as 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 usually 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. Using a more liberal license compatible to LGPLv2.1+ is also ok. Changes done to GPL code must come with the implicit/explicit agreement that the project can relicense the changes to LGPLv2.1+ at a later point without asking the contributor. This is a safeguard for making potential relicensing of remaining GPL code to LGPLv2.1+ easier. See DOCS/contribute.md for binding rules wrt. licensing for contributions. For information about authors and contributors, consult the git log, which contains the complete SVN and CVS history as well. "v2.1+" in this context means "version 2.1 or later". Some libraries are GPLv2+ or GPLv3+ only. Building mpv with Samba support makes it GPLv3+. mpv can be built as LGPLv2.1+ with the --enable-lgpl configure option. To add a LGPL mode to mpv, MPlayer code had to be relicensed from GPLv2+ to LGPLv2.1+ by asking the MPlayer authors for permission. Since permission could not be obtained from everyone, LGPL mode disables the following features, some of them quite central: - Linux X11 video output - BSD audio output via OSS - NVIDIA/Linux hardware decoding (vdpau, although nvdec usually works) - Linux TV input - minor features: jack, DVD, CDDA, SMB, CACA, legacy direct3d VO Some of these will be fixed in the future. The intended use for LGPL mode is with libmpv, and currently it's not recommended to build mpv CLI in LGPL mode at all. The following files are still GPL only (--enable-lgpl disables them): audio/out/ao_jack.c will stay GPL audio/out/ao_oss.c will stay GPL stream/dvb* must stay GPL stream/stream_cdda.c unknown stream/stream_dvb.* must stay GPL stream/stream_dvdnav.c unknown video/out/vo_caca.c unknown video/out/vo_direct3d.c unknown video/out/vo_vaapi.c probably impossible (some company's code) video/out/vo_vdpau.c probably impossible (nVidia's code) video/out/vo_x11.c probably impossible video/out/vo_xv.c probably impossible video/out/x11_common.* probably impossible video/vdpau.c hard (GPL-only parts must be ifdefed) video/vdpau.h unknown video/vdpau_mixer.* actual code must be rewritten DOCS/man/ GPLv2+ bootstrap.py unknown license, probably GPLv2+ or LGPLv2+ etc/mplayer-input.conf unknown license, probably GPLv2+ mpv.desktop unknown license, probably GPLv2+ etc/restore-old-bindings.conf unknown license, probably GPLv2+ None of the cases listed above affect the final binary if it's built as LGPL. Linked libraries still can affect the final license (for example if FFmpeg was built as GPL).