Air Video is distributed with a custom build of FFmpeg software. FFmpeg is licensed under LGPL and GPL licenses.
FFmpeg is linked with libX264 (GPL)
You can download the complete source code used to build FFmpeg here.
FFmpeg source code used in Air Video Server 2.2.0 can be downloaded here.
FFmpeg source code used in Air Video Server 2.2.5 and newer can be downloaded here.