1# License 2 3Most files in FFmpeg are under the GNU Lesser General Public License version 2.1 4or later (LGPL v2.1+). Read the file `COPYING.LGPLv2.1` for details. Some other 5files have MIT/X11/BSD-style licenses. In combination the LGPL v2.1+ applies to 6FFmpeg. 7 8Some optional parts of FFmpeg are licensed under the GNU General Public License 9version 2 or later (GPL v2+). See the file `COPYING.GPLv2` for details. None of 10these parts are used by default, you have to explicitly pass `--enable-gpl` to 11configure to activate them. In this case, FFmpeg's license changes to GPL v2+. 12 13Specifically, the GPL parts of FFmpeg are: 14 15- libpostproc 16- optional x86 optimization in the files 17 - `libavcodec/x86/flac_dsp_gpl.asm` 18 - `libavcodec/x86/idct_mmx.c` 19 - `libavfilter/x86/vf_removegrain.asm` 20- the following building and testing tools 21 - `compat/solaris/make_sunver.pl` 22 - `doc/t2h.pm` 23 - `doc/texi2pod.pl` 24 - `libswresample/tests/swresample.c` 25 - `tests/checkasm/*` 26 - `tests/tiny_ssim.c` 27- the following filters in libavfilter: 28 - `signature_lookup.c` 29 - `vf_blackframe.c` 30 - `vf_boxblur.c` 31 - `vf_colormatrix.c` 32 - `vf_cover_rect.c` 33 - `vf_cropdetect.c` 34 - `vf_delogo.c` 35 - `vf_eq.c` 36 - `vf_find_rect.c` 37 - `vf_fspp.c` 38 - `vf_histeq.c` 39 - `vf_hqdn3d.c` 40 - `vf_kerndeint.c` 41 - `vf_lensfun.c` (GPL version 3 or later) 42 - `vf_mcdeint.c` 43 - `vf_mpdecimate.c` 44 - `vf_nnedi.c` 45 - `vf_owdenoise.c` 46 - `vf_perspective.c` 47 - `vf_phase.c` 48 - `vf_pp.c` 49 - `vf_pp7.c` 50 - `vf_pullup.c` 51 - `vf_repeatfields.c` 52 - `vf_sab.c` 53 - `vf_signature.c` 54 - `vf_smartblur.c` 55 - `vf_spp.c` 56 - `vf_stereo3d.c` 57 - `vf_super2xsai.c` 58 - `vf_tinterlace.c` 59 - `vf_uspp.c` 60 - `vf_vaguedenoiser.c` 61 - `vsrc_mptestsrc.c` 62 63Should you, for whatever reason, prefer to use version 3 of the (L)GPL, then 64the configure parameter `--enable-version3` will activate this licensing option 65for you. Read the file `COPYING.LGPLv3` or, if you have enabled GPL parts, 66`COPYING.GPLv3` to learn the exact legal terms that apply in this case. 67 68There are a handful of files under other licensing terms, namely: 69 70* The files `libavcodec/jfdctfst.c`, `libavcodec/jfdctint_template.c` and 71 `libavcodec/jrevdct.c` are taken from libjpeg, see the top of the files for 72 licensing details. Specifically note that you must credit the IJG in the 73 documentation accompanying your program if you only distribute executables. 74 You must also indicate any changes including additions and deletions to 75 those three files in the documentation. 76* `tests/reference.pnm` is under the expat license. 77 78 79## External libraries 80 81FFmpeg can be combined with a number of external libraries, which sometimes 82affect the licensing of binaries resulting from the combination. 83 84### Compatible libraries 85 86The following libraries are under GPL version 2: 87- avisynth 88- frei0r 89- libcdio 90- libdavs2 91- librubberband 92- libvidstab 93- libx264 94- libx265 95- libxavs 96- libxavs2 97- libxvid 98 99When combining them with FFmpeg, FFmpeg needs to be licensed as GPL as well by 100passing `--enable-gpl` to configure. 101 102The following libraries are under LGPL version 3: 103- gmp 104- libaribb24 105- liblensfun 106 107When combining them with FFmpeg, use the configure option `--enable-version3` to 108upgrade FFmpeg to the LGPL v3. 109 110The VMAF, mbedTLS, RK MPI, OpenCORE and VisualOn libraries are under the Apache License 1112.0. That license is incompatible with the LGPL v2.1 and the GPL v2, but not with 112version 3 of those licenses. So to combine these libraries with FFmpeg, the 113license version needs to be upgraded by passing `--enable-version3` to configure. 114 115The smbclient library is under the GPL v3, to combine it with FFmpeg, 116the options `--enable-gpl` and `--enable-version3` have to be passed to 117configure to upgrade FFmpeg to the GPL v3. 118 119### Incompatible libraries 120 121There are certain libraries you can combine with FFmpeg whose licenses are not 122compatible with the GPL and/or the LGPL. If you wish to enable these 123libraries, even in circumstances that their license may be incompatible, pass 124`--enable-nonfree` to configure. This will cause the resulting binary to be 125unredistributable. 126 127The Fraunhofer FDK AAC and OpenSSL libraries are under licenses which are 128incompatible with the GPLv2 and v3. To the best of our knowledge, they are 129compatible with the LGPL. 130