ffmpeg/LICENSE.md

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#FFmpeg:
Most files in FFmpeg are under the GNU Lesser General Public License version 2.1
or later (LGPL v2.1+). Read the file `COPYING.LGPLv2.1` for details. Some other
files have MIT/X11/BSD-style licenses. In combination the LGPL v2.1+ applies to
FFmpeg.
Some optional parts of FFmpeg are licensed under the GNU General Public License
version 2 or later (GPL v2+). See the file `COPYING.GPLv2` for details. None of
these parts are used by default, you have to explicitly pass `--enable-gpl` to
configure to activate them. In this case, FFmpeg's license changes to GPL v2+.
Specifically, the GPL parts of FFmpeg are:
- libpostproc
- optional x86 optimizations in the files
- `libavcodec/x86/flac_dsp_gpl.asm`
- `libavcodec/x86/idct_mmx.c`
- `libavfilter/x86/vf_removegrain.asm`
- libutvideo encoding/decoding wrappers in
`libavcodec/libutvideo*.cpp`
- the X11 grabber in `libavdevice/x11grab.c`
- the swresample test app in
`libswresample/swresample-test.c`
- the `texi2pod.pl` tool
- the following filters in libavfilter:
- `f_ebur128.c`
- `vf_blackframe.c`
- `vf_boxblur.c`
- `vf_colormatrix.c`
- `vf_cover_rect.c`
- `vf_cropdetect.c`
- `vf_delogo.c`
- `vf_eq.c`
- `vf_find_rect.c`
- `vf_fspp.c`
- `vf_geq.c`
- `vf_histeq.c`
- `vf_hqdn3d.c`
- `vf_interlace.c`
- `vf_kerndeint.c`
- `vf_mcdeint.c`
- `vf_mpdecimate.c`
- `vf_owdenoise.c`
- `vf_perspective.c`
- `vf_phase.c`
- `vf_pp.c`
- `vf_pp7.c`
- `vf_pullup.c`
- `vf_sab.c`
- `vf_smartblur.c`
- `vf_repeatfields.c`
- `vf_spp.c`
- `vf_stereo3d.c`
- `vf_super2xsai.c`
- `vf_tinterlace.c`
- `vf_uspp.c`
- `vsrc_mptestsrc.c`
Should you, for whatever reason, prefer to use version 3 of the (L)GPL, then
the configure parameter `--enable-version3` will activate this licensing option
for you. Read the file `COPYING.LGPLv3` or, if you have enabled GPL parts,
`COPYING.GPLv3` to learn the exact legal terms that apply in this case.
There are a handful of files under other licensing terms, namely:
* The files `libavcodec/jfdctfst.c`, `libavcodec/jfdctint_template.c` and
`libavcodec/jrevdct.c` are taken from libjpeg, see the top of the files for
licensing details. Specifically note that you must credit the IJG in the
documentation accompanying your program if you only distribute executables.
You must also indicate any changes including additions and deletions to
those three files in the documentation.
* `tests/reference.pnm` is under the expat license.
external libraries
==================
FFmpeg can be combined with a number of external libraries, which sometimes
affect the licensing of binaries resulting from the combination.
compatible libraries
--------------------
The following libraries are under GPL:
- frei0r
- libcdio
- librubberband
- libutvideo
- libvidstab
- libx264
- libx265
- libxavs
- libxvid
When combining them with FFmpeg, FFmpeg needs to be licensed as GPL as well by
passing `--enable-gpl` to configure.
The OpenCORE and VisualOn libraries are under the Apache License 2.0. That
license is incompatible with the LGPL v2.1 and the GPL v2, but not with
version 3 of those licenses. So to combine these libraries with FFmpeg, the
license version needs to be upgraded by passing `--enable-version3` to configure.
incompatible libraries
----------------------
avcodec: Remove libaacplus TODO: bump minor It's inferior in quality to fdk-aac and has an arguably more problematic license. As early as 2012, a HydrogenAudio user reported: > It has however one huge advantage: much better quality at low bitrates than > faac and libaacplus. (https://hydrogenaud.io/index.php?PHPSESSID=ckiq394pdglka0kj2fin6ij8t7&topic=95989.msg804633#msg804633) I myself have made a few spectrograms for a comparison of the two encoders as well. The FDK output is consistently better than the libaacplus one, in all bitrates I tested. libaacplus license is 3GPP + LGPLv2. 3GPP copyright notice is completely proprietory, as follows: > No part may be reproduced except as authorized by written permission. > > The copyright and the foregoing restriction extend to reproduction in > all media. > > © 2008, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC). > > All rights reserved. (The latest 26410-d00 zip from 3GPP has the same notice, but the copyright year is changed to 2015) The copyright part of the FDK AAC license (section 2) is a copyleft license that permits redistribution under certain conditions (and therefore the LGPL + libfdk-aac combination is not prohibited by configure): > Redistribution and use in source and binary forms, with or without > modification, are permitted without payment of copyright license fees > provided that you satisfy the following conditions: > > You must retain the complete text of this software license in > redistributions of the FDK AAC Codec or your modifications thereto in > source code form. > > You must retain the complete text of this software license in the > documentation and/or other materials provided with redistributions of > the FDK AAC Codec or your modifications thereto in binary form. > > You must make available free of charge copies of the complete source > code of the FDK AAC Codec and your modifications thereto to recipients > of copies in binary form. > > The name of Fraunhofer may not be used to endorse or promote products > derived from this library without prior written permission. > > You may not charge copyright license fees for anyone to use, copy or > distribute the FDK AAC Codec software or your modifications thereto. > > Your modified versions of the FDK AAC Codec must carry prominent > notices stating that you changed the software and the date of any > change. For modified versions of the FDK AAC Codec, the term > "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the > term "Third-Party Modified Version of the Fraunhofer FDK AAC Codec > Library for Android."
2016-01-24 18:49:12 +01:00
The Fraunhofer AAC library and FAAC are under licenses which
are incompatible with the GPLv2 and v3. We do not know for certain if their
licenses are compatible with the LGPL.
If you wish to enable these libraries, pass `--enable-nonfree` to configure.
But note that if you enable any of these libraries the resulting binary will
be under a complex license mix that is more restrictive than the LGPL and that
may result in additional obligations. It is possible that these
restrictions cause the resulting binary to be unredistributeable.