Patents - tanersener/ffmpeg-kit GitHub Wiki

It is not clearly explained in their documentation but it is believed that FFmpeg, kvazaar, x264 and x265 include algorithms which are subject to software patents. If you live in a country where software algorithms are patentable then you'll probably need to pay royalty fees to patent holders. We are not lawyers though, so we recommend that you seek legal advice first. See FFmpeg Patent Mini-FAQ.

openh264 clearly states that it uses patented algorithms. Therefore, if you build ffmpeg-kit with openh264 and distribute that library, then you are subject to pay MPEG LA licensing fees. Refer to OpenH264 FAQ page for the details.