Update README.md

Author: Raveler

README.md

@@ -66,3 +66,9 @@ I developed this project to be able to to integrate FFmpeg into our program with
 - Audio filtering
 - Adding proper unit tests
 - Testing with more codecs, containers
+
+# License
+
+This library is licensed under LGPL (https://en.wikipedia.org/wiki/GNU_Lesser_General_Public_License).
+
+Please note though that FFmpeg, which you will need to build this library, is not. Depending on how you build it, it is either LGPL or GPL. So once you use the LGPL-version of FFmpeg in your project, this library will be GPL too.