Add configure option to upgrade (L)GPL to version 3.
[libav.git] / LICENSE
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1FFmpeg:
2-------
3
aae9c405 4Most files in FFmpeg are under the GNU Lesser General Public License version 2.1
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5or later (LGPL v2.1+). Read the file COPYING.LGPLv2.1 for details. Some other
6files have MIT/X11/BSD-style licenses. In combination the LGPL v2.1+ applies to
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7FFmpeg.
8
9Some optional parts of FFmpeg are licensed under the GNU General Public License
ecc1330a 10version 2 or later (GPL v2+). See the file COPYING.GPLv2 for details. None of
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11these parts are used by default, you have to explicitly pass --enable-gpl to
12configure to activate them. In this case, FFmpeg's license changes to GPL v2+.
13
14Specifically, the GPL parts of FFmpeg are
15
16- libpostproc
b2184b9c 17- some x86 optimizations in libswscale
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18- optional x86 optimizations in the files
19 libavcodec/x86/h264_deblock_sse2.asm
20 libavcodec/x86/h264_idct_sse2.asm
21 libavcodec/x86/idct_mmx.c
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22- the X11 grabber in libavdevice/x11grab.c
23
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24There are a handful of files under other licensing terms, namely:
25
26* The files libavcodec/jfdctfst.c, libavcodec/jfdctint.c, libavcodec/jrevdct.c
27 are taken from libjpeg, see the top of the files for licensing details.
28
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29Should you, for whatever reason, prefer to use version 3 of the (L)GPL, then
30the configure parameter --enable-version3 will activate this licensing option
31for you. Read the file COPYING.LGPLv3 or, if you have enabled GPL parts,
32COPYING.GPLv3 to learn the exact legal terms that apply in this case.
33
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34
35external libraries:
36-------------------
37
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38Some external libraries, e.g. libx264, are under GPL and can be used in
39conjunction with FFmpeg. They require --enable-gpl to be passed to configure
40as well.
41
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42The nonfree external libraries libamrnb, libamrwb and libfaac can be hooked up
43in FFmpeg. You need to pass --enable-nonfree to configure to enable them. Employ
44this option with care as FFmpeg then becomes nonfree and unredistributable.
45Note that libfaac claims to be LGPL, but is not.