-Most files in FFmpeg are under the GNU Lesser General Public License version 2.1
+Libav:
+------
+
+Most files in Libav 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.
+Libav.
-Some optional parts of FFmpeg are licensed under the GNU General Public License
+Some optional parts of Libav 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+.
+configure to activate them. In this case, Libav's license changes to GPL v2+.
-Specifically, the GPL parts of FFmpeg are
+Specifically, the GPL parts of Libav are
- libpostproc
-- some x86 optimizations in libswscale
- optional x86 optimizations in the files
- libavcodec/x86/h264_deblock_sse2.asm
- libavcodec/x86/h264_idct_sse2.asm
libavcodec/x86/idct_mmx.c
- the X11 grabber in libavdevice/x11grab.c
-Some external libraries, e.g. libx264, are under GPL and can be used in
-conjunction with FFmpeg. They require --enable-gpl to be passed to configure
-as well.
-
-The nonfree external libraries libamrnb, libamrwb and libfaac can be hooked up
-in FFmpeg. You need to pass --enable-nonfree to configure to enable them. Employ
-this option with care as FFmpeg then becomes nonfree and unredistributable.
-Note that libfaac claims to be LGPL, but is not.
-
There are a handful of files under other licensing terms, namely:
* The files libavcodec/jfdctfst.c, libavcodec/jfdctint.c, libavcodec/jrevdct.c
are taken from libjpeg, see the top of the files for licensing details.
+
+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.
+
+
+external libraries:
+-------------------
+
+Some external libraries, e.g. libx264, are under GPL and can be used in
+conjunction with Libav. They require --enable-gpl to be passed to configure
+as well.
+
+The OpenCORE external 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 the OpenCORE libraries with Libav, the license
+version needs to be upgraded by passing --enable-version3 to configure.
+
+The nonfree external library libfaac can be hooked up in Libav. You need to
+pass --enable-nonfree to configure to enable it. Employ this option with care
+as Libav then becomes nonfree and unredistributable.
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