LICENCE: add markdown syntax

Reviewed-by: llogan
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 103 insertions, 0 deletions

diff --git a/LICENSE.md b/LICENSE.md
new file mode 100644
index 0000000000..04decbf46a
--- /dev/null
+++ b/LICENSE.md
@@ -0,0 +1,103 @@
+#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
+- libmpcodecs
+- optional x86 optimizations in the files
+  libavcodec/x86/idct_mmx.c
+- 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_cropdetect.c
+    - vf_decimate.c
+    - vf_delogo.c
+    - vf_geq.c
+    - vf_histeq.c
+    - vf_hqdn3d.c
+    - vf_kerndeint.c
+    - vf_mcdeint.c
+    - vf_mp.c
+    - vf_owdenoise.c
+    - vf_perspective.c
+    - vf_phase.c
+    - vf_pp.c
+    - vf_pullup.c
+    - vf_sab.c
+    - vf_smartblur.c
+    - vf_spp.c
+    - vf_stereo3d.c
+    - vf_super2xsai.c
+    - vf_tinterlace.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.
+
+
+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
+    - 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
+----------------------
+
+The Fraunhofer AAC library, FAAC and aacplus 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.