blob: ba65b059c5ba0525ed91594c17fbb73839b6868e
| 1 | # License |
| 2 | |
| 3 | Most files in FFmpeg are under the GNU Lesser General Public License version 2.1 |
| 4 | or later (LGPL v2.1+). Read the file `COPYING.LGPLv2.1` for details. Some other |
| 5 | files have MIT/X11/BSD-style licenses. In combination the LGPL v2.1+ applies to |
| 6 | FFmpeg. |
| 7 | |
| 8 | Some optional parts of FFmpeg are licensed under the GNU General Public License |
| 9 | version 2 or later (GPL v2+). See the file `COPYING.GPLv2` for details. None of |
| 10 | these parts are used by default, you have to explicitly pass `--enable-gpl` to |
| 11 | configure to activate them. In this case, FFmpeg's license changes to GPL v2+. |
| 12 | |
| 13 | Specifically, 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/swresample-test.c` |
| 25 | - `tests/checkasm/*` |
| 26 | - `tests/tiny_ssim.c` |
| 27 | - the following filters in libavfilter: |
| 28 | - `vf_blackframe.c` |
| 29 | - `vf_boxblur.c` |
| 30 | - `vf_colormatrix.c` |
| 31 | - `vf_cover_rect.c` |
| 32 | - `vf_cropdetect.c` |
| 33 | - `vf_delogo.c` |
| 34 | - `vf_eq.c` |
| 35 | - `vf_find_rect.c` |
| 36 | - `vf_fspp.c` |
| 37 | - `vf_geq.c` |
| 38 | - `vf_histeq.c` |
| 39 | - `vf_hqdn3d.c` |
| 40 | - `vf_interlace.c` |
| 41 | - `vf_kerndeint.c` |
| 42 | - `vf_mcdeint.c` |
| 43 | - `vf_mpdecimate.c` |
| 44 | - `vf_owdenoise.c` |
| 45 | - `vf_perspective.c` |
| 46 | - `vf_phase.c` |
| 47 | - `vf_pp.c` |
| 48 | - `vf_pp7.c` |
| 49 | - `vf_pullup.c` |
| 50 | - `vf_repeatfields.c` |
| 51 | - `vf_sab.c` |
| 52 | - `vf_smartblur.c` |
| 53 | - `vf_spp.c` |
| 54 | - `vf_stereo3d.c` |
| 55 | - `vf_super2xsai.c` |
| 56 | - `vf_tinterlace.c` |
| 57 | - `vf_uspp.c` |
| 58 | - `vsrc_mptestsrc.c` |
| 59 | |
| 60 | Should you, for whatever reason, prefer to use version 3 of the (L)GPL, then |
| 61 | the configure parameter `--enable-version3` will activate this licensing option |
| 62 | for you. Read the file `COPYING.LGPLv3` or, if you have enabled GPL parts, |
| 63 | `COPYING.GPLv3` to learn the exact legal terms that apply in this case. |
| 64 | |
| 65 | There are a handful of files under other licensing terms, namely: |
| 66 | |
| 67 | * The files `libavcodec/jfdctfst.c`, `libavcodec/jfdctint_template.c` and |
| 68 | `libavcodec/jrevdct.c` are taken from libjpeg, see the top of the files for |
| 69 | licensing details. Specifically note that you must credit the IJG in the |
| 70 | documentation accompanying your program if you only distribute executables. |
| 71 | You must also indicate any changes including additions and deletions to |
| 72 | those three files in the documentation. |
| 73 | * `tests/reference.pnm` is under the expat license. |
| 74 | |
| 75 | |
| 76 | ## External libraries |
| 77 | |
| 78 | FFmpeg can be combined with a number of external libraries, which sometimes |
| 79 | affect the licensing of binaries resulting from the combination. |
| 80 | |
| 81 | ### Compatible libraries |
| 82 | |
| 83 | The following libraries are under GPL: |
| 84 | - frei0r |
| 85 | - libcdio |
| 86 | - librubberband |
| 87 | - libvidstab |
| 88 | - libx264 |
| 89 | - libx265 |
| 90 | - libxavs |
| 91 | - libxvid |
| 92 | |
| 93 | When combining them with FFmpeg, FFmpeg needs to be licensed as GPL as well by |
| 94 | passing `--enable-gpl` to configure. |
| 95 | |
| 96 | The OpenCORE and VisualOn libraries are under the Apache License 2.0. That |
| 97 | license is incompatible with the LGPL v2.1 and the GPL v2, but not with |
| 98 | version 3 of those licenses. So to combine these libraries with FFmpeg, the |
| 99 | license version needs to be upgraded by passing `--enable-version3` to configure. |
| 100 | |
| 101 | ### Incompatible libraries |
| 102 | |
| 103 | There are certain libraries you can combine with FFmpeg whose licenses are not |
| 104 | compatible with the GPL and/or the LGPL. If you wish to enable these |
| 105 | libraries, even in circumstances that their license may be incompatible, pass |
| 106 | `--enable-nonfree` to configure. But note that if you enable any of these |
| 107 | libraries the resulting binary will be under a complex license mix that is |
| 108 | more restrictive than the LGPL and that may result in additional obligations. |
| 109 | It is possible that these restrictions cause the resulting binary to be |
| 110 | unredistributable. |
| 111 | |
| 112 | The Fraunhofer FDK AAC and OpenSSL libraries are under licenses which are |
| 113 | incompatible with the GPLv2 and v3. To the best of our knowledge, they are |
| 114 | compatible with the LGPL. |
| 115 | |
| 116 | The NVENC library, while its header file is licensed under the compatible MIT |
| 117 | license, requires a proprietary binary blob at run time, and is deemed to be |
| 118 | incompatible with the GPL. We are not certain if it is compatible with the |
| 119 | LGPL, but we require `--enable-nonfree` even with LGPL configurations in case |
| 120 | it is not. |
| 121 |